Co-reporter:Sheng Yang ; Kun Nie ; Yong Zhang ; Mingqiang Xue ; Yingming Yao
Inorganic Chemistry 2014 Volume 53(Issue 1) pp:105-115
Publication Date(Web):December 6, 2013
DOI:10.1021/ic401747n
Two divalent ytterbium (YbII) complexes, 1 and 2, supported by new [ONOO]-type amine bis(phenolate) ligands La,b were synthesized in good yield by an amine elimination reaction of YbII(N(SiMe3)2)2(TMEDA) (TMEDA = tetramethylethylenediamine) with one equivalent of the ligand precursor. X-ray structural determination showed complexes 1 and 2 both have a monomeric structure. Each adopts distorted octahedral coordination geometry around the six-coordinate YbII ion. Two new trivalent ytterbium (YbIII) aryloxide complexes, 4 and 5, bearing [ONOO]-type amine bis(phenolate) ligands Lc and Ld were prepared by double-protonation reaction of Yb(C5H5)3THF with one equivalent of the ligand precursor, then one equivalent of phenol. Complex 4 has a symmetric dimeric structure with a Yb2O2 core bridging through the oxygen atoms of the OC6H4-4-CH3 groups. Complex 5 is a THF-solvated monomer. Each six-coordinated YbIII ion in both complexes adopts a distorted octahedron. All the complexes synthesized together with the known YbII complex 3 were evaluated in the ring-opening polymerization (ROP) of rac-lactide (rac-LA). Complexes 1 and 4 were found to be extremely active for controlled ROP of rac-LA, as judged by narrow molar mass distributions (Mw/Mn: 1.07–1.16 for complex 1 and 1.07–1.10 for complex 4) and experimental molar mass Mn,exp values in good agreement with theoretic Mn,calcd values calculated on a single PLA chain produced per metal center of initiator. Complex 5 is less controlled. Complexes 1, 4, and 5 exhibited the same high stereoselectivity to give heterotactic polylactide with a Pr (probability of racemic enchainment of monomer units) ranging from 0.97 to 0.99. Dramatic decreases in activity and stereoselectivity were found for complexes 2 (Pr = 0.82) and 3 (Pr = 0.67), indicating the framework of L in the unit of [YbL] is crucial for determining activity and stereoselectivity of either YbII or YbIII complexes.
Co-reporter:Peng Liu, Hongxia Chen, Yong Zhang, Mingqiang Xue, Yingming Yao and Qi Shen
Dalton Transactions 2014 vol. 43(Issue 14) pp:5586-5594
Publication Date(Web):13 Jan 2014
DOI:10.1039/C3DT52706A
The readily accessible dianionic β-diketiminato lanthanide amido complexes LnLN(SiMe3)2(THF) (L = {(2,6-iPr2C6H3)NC(CH2)CHC(CH3)N(2,6-iPr2C6H3)}2−) show an unprecedented reactivity toward carbodiimides. The reaction with N,N′-dicyclohexylcarbodiimide (DCC) led via [4 + 2] cycloaddition to γ-amidine-functionalized dianionic β-diketiminato lanthanide amido complexes, LnL1N(SiMe3)2 (L1 = {[(NHC6H11)(NC6H11)C]HC[C(CH2)N(2,6-iPr2C6H3)]2}2−, Ln = Sm(1), Yb(2), Y(3), Gd(4)). Conversion of a mixture of SmLN(SiMe3)2(THF) and NaN(SiMe3)2 with carbodiimide furnished the heterobimetallic complexes of Sm/Na with a novel amidinate-functionalized trianionic β-diketiminate ligand, [Na(DME)2](μ-L2)[SmN(SiMe3)2] (L2 = {[C(NiPr)2]HC[C(CH2)N(2,6-iPr2C6H3)]2}3−, DME = dimethoxyethane) (5) for N,N′-diisopropylcarbodiimide (DIC) and [Na(DME)3]+[SmL3N(SiMe3)2]− (L3 = {[C(NCy)2]HC[C(CH2)N(2,6-iPr2C6H3)]2}3−) (6) for DCC. Molecular structures of complexes 1–6 were determined by an X-ray single crystal structure analysis. Complexes 1–4 were found to be highly active initiators of the ring-opening polymerization (ROP) of L-lactide (L-LA). The activity depended on the central metal with the increasing sequence of Yb < Y < Gd < Sm. Notably, the binary 1/BnOH (benzyl alcohol) system exhibited an “immortal” nature and proved able to convert 2000 equivalents of L-LA with up to 100 equivalents of BnOH per initiator. All the polylactides (PLAs) obtained showed monomodal, narrow molar mass distributions (Mw/Mn = 1.08–1.13) with the Mn (average number molar mass) decreasing with increasing amount of BnOH proportionally.
Co-reporter:Yu Zheng;Rui Jiao;Xiao-dong Shen;Ming-qiang Xue;Ying-ming Yao;Yong Zhang
Applied Organometallic Chemistry 2014 Volume 28( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/aoc.3150
Treatment of the chlorides (L2,6-iPr2Ph)2LnCl (L2,6-iPr2Ph = [(2,6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−) with 1 equiv. of NaNH(2,6-iPr2C6H3) afforded the monoamides (L2,6-iPr2Ph)2LnNH(2,6-iPr2C6H3) (Ln = Y (1), Yb (2)) in good yields. Anhydrous LnCl3 reacted with 2 equiv. of NaL2,6-iPr2Ph in THF, followed by treatment with 1 equiv. of NaNH(2,6-iPr2C6H3), giving the analogues (L2,6-iPr2Ph)2LnNH(2,6-iPr2C6H3) (Ln = Sm (3), Nd (4)). Two monoamido complexes stabilized by two L2-Me ligands, (L2-Me)2LnNH(2,6-iPr2C6H3) (L2-Me = [N(2-MeC6H4)C(Me)]2CH)−; Ln = Y (5), Yb (6)), were also synthesized by the latter route. Complexes 1, 2, 3, 4, 5, 6 were fully characterized, including X-ray crystal structure analyses. Complexes 1, 2, 3, 4, 5, 6 are isostructural. The central metal in each complex is ligated by two β-diketiminato ligands and one amido group in a distorted trigonal bipyramid. All the complexes were found to be highly active in the ring-opening polymerization of L-lactide (L-LA) and ε-caprolactone (ε-CL) to give polymers with relatively narrow molar mass distributions. The activity depends on both the central metal and the ligand (Yb < Y < Sm ≈ Nd and L2-Me < L2,6-iPr2Ph). Remarkably, the binary 3/benzyl alcohol (BnOH) system exhibited a striking ‘immortal’ nature and proved able to quantitatively convert 5000 equiv. of L-LA with up to 100 equiv. of BnOH per metal initiator. All the resulting PLAs showed monomodal, narrow distributions (Mw/Mn = 1.06 − 1.08), with molar mass (Mn) decreasing proportionally with an increasing amount of BnOH. The binary 4/BnOH system also exhibited an ‘immortal’ nature in the polymerization of ε-CL in toluene. Copyright © 2014 John Wiley & Sons, Ltd.
Co-reporter:Jing Tu, Wenbo Li, Mingqiang Xue, Yong Zhang and Qi Shen
Dalton Transactions 2013 vol. 42(Issue 16) pp:5890-5901
Publication Date(Web):04 Feb 2013
DOI:10.1039/C3DT33069A
Various lanthanide aryloxide complexes supported by bridged bis(amidinate) ligand L, LLnOAr(DME) (L = Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3, DME = dimethoxyethane, Ln = Y, Ar = 2,6-(Me)2C6H3 (1), 2,6-(iPr)2C6H3 (2), 2,6-(tBu)2-4-(Me)C6H2 (3); Ar = 2,6-(tBu)2-4-(Me)C6H2, Ln = Nd (4), Sm (5), Yb (6)) were synthesized, and complexes 1, 2 and 4–6 were characterized by single crystal X-ray diffraction. All the complexes are efficient precatalysts for catalytic addition of amines to carbodiimides. The catalytic activity is influenced by lanthanide metals and the aryloxide groups (Nd (4) ∼ Sm (5) < Y (3) ∼ Yb (6) and -2,6-(Me)2C6H3 < -2,6-(iPr)2C6H3 < -2,6-(tBu)2-4-(Me)C6H2). The catalytic addition reaction with 3 showed a good scope of substrates. The mechanism investigation revealed the real active intermediate being the monoguanidinate complexes supported by an aryloxide and an amidine-functionalized amidinate group, L′Ln[O2,6-(tBu)2-4-(Me)C6H2][RNCNHRN(Ar′)] (L′ = Me3SiNHC(Ph)N(CH2)3NC(Ph)NSiMe3, R = iPr, Ar′ = phenyl, Ln = Yb (8), Y (11); R = Cy, Ar′ = phenyl, Ln = Yb (10), Y (12); R = iPr, Ar′ = 4-ClC6H4, Ln = Yb (9)), which were isolated from the reactions of 6 (or 3) with amine and carbodiimide in a molar ratio of 1:1:1 and structurally characterized. The Ln-active group in the present precatalyst is a Ln–amidinate species, not the Ln–OAr group.
Co-reporter:Chuanyong Wang, Xingmin Zhang, Mingqiang Xue, Yong Zhang and Qi Shen
Dalton Transactions 2013 vol. 42(Issue 19) pp:7009-7018
Publication Date(Web):22 Feb 2013
DOI:10.1039/C3DT32882A
Reaction of LnCl3 with a lithium salt of bridged bis(guanidinate) bearing a rigid naphthalene linker [Li2{LH2}2Li2] (LH2 = 1,8-C10H6{NC(NiPr)(NHiPr)}2) (1), which was synthesized by the reaction of 1,8-diaminonaphthalene with 2 equiv. of nBuLi, followed by treatment with 2 equiv. of N,N′-diisopropylcarbodiimide, yielded the chlorides [LnCl{LH2}] (Ln = Yb (2), Y (3)) in good yields. Metathesis reaction of 2 and 3 with NaN(SiMe3)2 did not afford the corresponding amide complexes, but the deprotonation products of [Ln{LH}]2 (LH = 1,8-C10H6{NC(NiPr)(NHiPr)}{NC(NiPr)2}; Ln = Yb (4), Y (5)) were isolated instead. The LH in 4 and 5 both act as a bridging ligand binding to two metals in a μ–η1:η2:η2 fashion, and the re-arrangement of LH occurred during the reaction. The size of the amido group was found to have a great influence on the outcome of the metathesis reaction. Reaction of 2 with bulky NaNH(C6H3iPr2-2,6) afforded 4 as the only product, whereas the same reaction with less bulky LiNH(C6H4Cl-4) and LiNH(C6H4CH3-4) led to the corresponding amides, [Yb{LH2}(NHC6H4Cl-4)]2 (6) and [Yb{LH2}(NHC6H4CH3-4)]2 (7), respectively. The re-arrangement of ligands was also observed in both cases. A possible pathway for the deprotonation of LH2 was discussed. Molecular structures of 1–7 were determined by X-ray single crystal analysis.
Co-reporter:Jinyong Zhuang, Wanfei Li, Wenming Su, Yuan Liu, Qi Shen, Liangsheng Liao, Ming Zhou
Organic Electronics 2013 Volume 14(Issue 10) pp:2596-2601
Publication Date(Web):October 2013
DOI:10.1016/j.orgel.2013.06.029
•Homoleptic tris(phenyl-imidazole) iridium(III) complex Ir(dbi)3 as a sky-blue dopant.•A maximum current efficiency and external quantum efficiency (EQE) of 61.5 cd A−1 and 23.1% obtained.•High efficiencies of 53.5 cd A−1 and 20.1% EQE achieved at the luminance of 1000 cd m−2.Homoleptic triscyclometalated iridium(III) complex Ir(dbi)3 was used as a dopant for sky blue phosphorescent organic light-emitting diodes (PHOLEDs). Its photophysical, thermal, electrochemical properties as well as the device performances were investigated. Ir(dbi)3 exhibited high quantum yield of 0.52 in solution at room temperature. A maximum current efficiency and external quantum efficiency (EQE) of 61.5 cd A−1 and 23.1% were obtained, which are the highest ever reported for blue homoleptic iridium complexes. High efficiencies of 53.5 cd A−1 and 20.1% EQE were achieved even at the luminance of 1000 cd m−2.Graphical abstract
Co-reporter:Ling-xia Cai;Ying-ming Yao;Ming-qiang Xue;Yong Zhang
Applied Organometallic Chemistry 2013 Volume 27( Issue 6) pp:366-372
Publication Date(Web):
DOI:10.1002/aoc.2996
The steric effect of an aryloxido group on the synthesis and molecular structures of ytterbium aryloxides supported by β-diketiminato ligand L (L = [N(2,6-Me2C6H3)C(Me)]2CH−) is reported. Reactions of β-diketiminatoytterbium dichloride, LYbCl2(THF)2, with NaOAr1 in THF (Ar1 = [2,6-tBu2-4-MeC6H2], THF = tetrahydrofuran) at 60°C gave the corresponding ytterbium complexes LYb(OAr1)Cl(THF) (1) and LYb(OAr1)2 (1), depending on the molar ratio of dichloride to sodium aryloxide, respectively, while the same reactions with NaOAr2 and NaOAr3 (Ar2 = [2,6-iPr2C6H3], Ar3 = [2,6-Me2C6H3]) in 1:1 or 1:2 molar ratio in THF afforded only bisaryloxide complexes LYb(OAr2)2(THF) (1) and LYb(OAr3)2(THF) (4) in good yields, respectively. Complexes 1, 2, 3, 4 were fully characterized, including X-ray crystal structure analyses. All the complexes are efficient pre-catalysts for the catalytic addition of amines to carbodiimides giving guanidines. Copyright © 2013 John Wiley & Sons, Ltd.
Co-reporter:Aijiao Zhang;Lijian Cai;Zhigang Yao;Fan Xu
Heteroatom Chemistry 2013 Volume 24( Issue 5) pp:345-354
Publication Date(Web):
DOI:10.1002/hc.21099
ABSTRACT
Lanthanide-catalyzed addition of diethyl phosphite with chalcones was achieved under mild conditions. The reaction exhibited good product selectivity using different catalysts. γ-Oxophosphonates were obtained in high yields in the reactions catalyzed by Yb(OAr)3(THF)2, while those catalyzed by [(Me3Si)2N]3La(μ-Cl)Li(THF)3 afforded 1,2-oxaphospholane-5-phosphonates as the main products in moderate to good yields. This methodology provides facile and practical approaches to the corresponding organophosphorus compounds with biological interest.
Co-reporter:Chuanyong Wang, Xingmin Zhang, Mingqiang Xue, Yong Zhang, and Qi Shen
Organometallics 2013 Volume 32(Issue 13) pp:3618-3624
Publication Date(Web):June 21, 2013
DOI:10.1021/om400200f
A novel binuclear ytterbium(II) complex supported by a naphthalene-bridged bis(guanidinate) ligand, [Yb(μ-L)(THF)]2 (1; L = 1,8-C10H6{NC(NiPr)(NHiPr)}2), was synthesized by the reduction reaction of [Yb(L)Cl(THF)2] with Na/K alloy in THF and structurally characterized. The reactions of 1 with CH3CN and p-ClC6H4CH2CN resulted in the formation of the corresponding binuclear (crotononitrileamido)ytterbium(III) complexes [Yb(L)(μ(N,N′)-N(H)C(Me)═C(H)C≡N)(THF)]2 (2) and [Yb(L)(μ(N,N′)-N(H)C(CH2C6H4-p-Cl)═C(C6H4-p-Cl)C≡N)(THF)]2 (3) via metalation of the nitrile, followed by insertion of a second nitrile molecule. Treatment of 1 with the bulkier Ph2CHCN afforded the mononuclear (keteniminato)ytterbium(III) complex [Yb(L)(N═C═CPh2)(THF)2] (4) by deprotonation of Ph2CHCN. The molecular structures of 2–4 have been determined.
Co-reporter:Peng Liu, Yong Zhang, and Qi Shen
Organometallics 2013 Volume 32(Issue 5) pp:1295-1299
Publication Date(Web):January 7, 2013
DOI:10.1021/om301023u
Dianionic β-diketiminato samarium amide LSmN(SiMe3)2(THF) (1) (L = {(2,6-iPr2C6H3)NC(CH2)CHC(CH3)N(2,6-iPr2C6H3)}2–) shows striking reactivity toward aromatic nitrile and ketenimine. Reaction of 1 with C6H5CN and p-MeOC6H4CN leads via nucleophilic addition followed by 1,5-H shift to entirely modified dianionic β-diketiminato samarium amides with two asymmetric alkylideneamido bridges, [L1SmN(SiMe3)2(C6H5CN)]2 (L1 = {μ-N═C(C6H5)CHC(CHC(CH3)NH(2,6-iPr2C6H3))N(2,6-iPr2C6H3)}2–) (2) and [L2SmN(SiMe3)2(p-MeOC6H4CN)]2 (L2 = {μ-N═C(p-CH3OC6H4)CHC(CHC(CH3)NH(2,6-iPr2C6H3))N(2,6-iPr2C6H3)}2–) (3), while conversion of Ph2C═C═NtBu affords the cycloadduct [L3SmN(SiMe3)2(THF)] (L3 = {(2,6-iPr2C6H3)NC(CHC(CH3)N(2,6-iPr2C6H3))CHC(CH(C6H5)2)N(C(CH3)3)}2–) (4) via nucleophilic addition and 1,3-H shift.
Co-reporter:Jie Huang;Yong Yu;Lu Hua;ZhiGang Yao;Fan Xu
Science Bulletin 2013 Volume 58( Issue 7) pp:717-723
Publication Date(Web):2013 March
DOI:10.1007/s11434-012-5631-z
A clean, efficient method to synthesize 2-amino-4H-3,1-benzothiazines by ytterbium chloride-catalyzed tandem addition-cyclization reaction of o-aminocinnamate and isothiocyanates under solvent-free conditions is developed.
Co-reporter:Sheng Yang, Zhu Du, Yong Zhang and Qi Shen
Chemical Communications 2012 vol. 48(Issue 78) pp:9780-9782
Publication Date(Web):13 Aug 2012
DOI:10.1039/C2CC34451C
Polymerization of racemic lactide initiated by divalent ytterbium complexes supported by either dimethylamino-amino bis(phenolate) or methoxy-amino bis(phenolate) ligands proceeds rapidly at room temperature in a living fashion to give heterotactic polylactide with the racemic enchainment of monomer units Pr ranging from 0.97–0.99.
Co-reporter:Lijuan Yan ; Haidong Liu ; Junfeng Wang ; Yong Zhang
Inorganic Chemistry 2012 Volume 51(Issue 7) pp:4151-4160
Publication Date(Web):March 12, 2012
DOI:10.1021/ic202505d
Metathesis reactions of YbI2 with Li2L (L = Me3SiN(Ph)CN(CH2)3NC(Ph)NSiMe3) in THF at a molar ratio of 1:1 and 1:2 both afforded the Yb(II) iodide complex [{YbI(DME)2}2(μ2-L)] (1), which was structurally characterized to be a dinuclear Yb(II) complex with a bridged L ligand. Treatment of EuI2 with Li2L did not afford the analogous [{EuI(DME)2}2(μ2-L)], or another isolable Eu(II) complex, but the hexanuclear heterobimetallic cluster [{Li(DME)3}+]2[{(EuI)2(μ2-I)2(μ3-L)2(Li)4}(μ6-O)]2– (2) was isolated as a byproduct in a trace yield. The rational synthesis of cluster 2 could be realized by the reaction of EuI2 with Li2L and H2O in a molar ratio of 1:1.5:0.5. The reduction reaction of LLnCl(THF)2 (Ln = Yb and Eu) with Na/K alloy in THF gave the corresponding Ln(II) complexes [Yb3(μ2-L)3] (3) and [Eu(μ2-L)(THF)]2 (4) in good yields. An X-ray crystal structure analysis revealed that each L in complex 3 might adopt a chelating ligand bonding to one Yb atom and each Yb atom coordinates to an additional amidinate group of the other L and acts as a bridging link to assemble a macrocyclic structure. Complex 4 is a dimer in which the two monomers [Eu(μ2-L)(THF)] are connected by two μ2-amidinate groups from the two L ligands. Complex 3 reacted with CyN═C═NCy and diazabutadienes [2,6-iPr2C6H3N═CRCR═NC6H3iPr2-2,6] (R═H, CH3) (DAD) as a one-electron reducing agent to afford the corresponding Yb(III) derivatives: the complex with an oxalamidinate ligand [LYb{(NCy)2CC(NCy)2}YbL] (5) and the complexes containing a diazabutadiene radical anion [LYb(iPr2C6H3NCRCRNC6H3iPr2)] (R = H (6), R = CH3 (7)). Complexes 5–7 were confirmed by an X-ray structure determination.
Co-reporter:Xiaodong Shen, Yong Zhang, Mingqiang Xue and Qi Shen
Dalton Transactions 2012 vol. 41(Issue 13) pp:3668-3674
Publication Date(Web):14 Feb 2012
DOI:10.1039/C2DT12176J
The metathesis reaction of anhydrous EuCl3 with sodium salt of bulky β-diketiminato NaL (L = [N(2, 4, 6- Me3C6H2)C(Me)]2CH−, L2, 4, 6-Me3; [N(2,6-iPr2C6H3)C(Me)]2CH−, L2, 6-ipr2 and [(2, 6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−, L2, 6-ipr2Ph) in THF at 60 °C afforded the corresponding EuII complexes: EuII(L2, 4, 6-Me3)2(THF) (1), EuII(L2, 6-ipr2)2 (2) and EuII(L2, 6-ipr2Ph)2 (5) with the formations of dimers (L2, 4, 6-Me3)2 (3) and (L2, 6-ipr2)2 (4) for the former two reactions and proligand L2, 6-ipr2PhH (6) for the latter one. Compounds 1–6 were confirmed by an X-ray crystal structure analysis. The central metal EuII in 1 is coordinated by two monoanionic L2, 4, 6-Me3 ligands and one THF molecule in a trigonal bipyramid. The EuII in each of 2 and 5 is ligated by two monoanionic ligands to form a tetrahedral geometry. The BVS (Bond Valence Sum) calculation indicates the oxidation state of Eu in all the three complexes is 2+ (2.12 for 1, 1.86 for 2 and 1.99 for 5). The isolation of dimers of (L2, 4, 6-Me3)2 and L2, 6-ipr2)2 and proligand L2, 6-ipr2PhH demonstrates that the reducing agent in the present reduction of a EuIII ion to a EuII ion might be the (L2, 4, 6-Me3)−, (L2, 6-ipr2)− and (L2, 6-ipr2Ph)−, respectively. The possible mechanism for the reduction pathway is presented.
Co-reporter:Wenbo Li, Mingqiang Xue, Jing Tu, Yong Zhang and Qi Shen
Dalton Transactions 2012 vol. 41(Issue 24) pp:7258-7265
Publication Date(Web):11 Apr 2012
DOI:10.1039/C2DT30096F
Metathesis reaction of LLnCl(THF)2 [L = (Me3SiNC(C6H5)N)2(CH2)3] with NaBH4 in a 1:1.5 molar ratio in THF (THF = tetrahydrofuran) at 60 °C afforded the monoborohydride LLn(BH4)(DME) [Ln = Y (1), Nd (2), Sm(3) and Yb(4)] crystallized from DME solution (DME = dimethoxyethane). Crystal structure analyses revealed 1–4 are monomers, in which each metal is ligated by one L ligand, one η3-BH4 group and one DME molecule in a trigonal bipyramid geometry. Complexes 1–4 were found to be very active single-site initiators for the controlled ring opening polymerization of ε-caprolactone (ε-CL) and L-lactide (L-LA) as judged by relatively narrow molecular weight distributions (Mw/Mn: 1.34–1.50) and experimental values Mn(exp) were in good agreement with theoretic values Mn(theo). The highest activity and the best control over the molecular weight for both monomers were found for the system with 2. These monoborohydride complexes can also initiate the ring opening polymerization of rac-LA to gave heterotactically enriched polyLA with Pr (heterotactic enrichment) values in a range of 0.69–0.85 depending on the lanthanide metals and the most effective heterotactic enrichment (Pr) was found for 1 (Pr = 0.85). Moreover, complex 1 initiated the polymerization of rac-LA in a living fashion.
Co-reporter:Wenbo Li, Mingqiang Xue, Fan Xu, Jing Tu, Yong Zhang and Qi Shen
Dalton Transactions 2012 vol. 41(Issue 27) pp:8252-8260
Publication Date(Web):16 Mar 2012
DOI:10.1039/C2DT30400G
A series of lanthanide amide complexes supported by bridged bis(amidinate) ligand L, LLnNHAr1(DME) (L = [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3], Ar1 = 2,6-iPr2C6H3, DME = dimethoxyethane, Ln = Y (1), Pr (2), Nd (3), Gd (4), Yb (5)), [Yb(μ2-NHPh)]2(μ2-L)2 (6) and [LYb]2(μ2-NHAr2)2 (7) (Ar2 = (o-OMe)C6H4), were synthesized by reaction of LLnCl(THF)2 with the corresponding lithium amide in good yields and structurally characterized by X-ray crystal structure analyses. All complexes were found to be precatalysts for the catalytic addition of aromatic amines to aromatic nitriles to give monosubstituted N-arylamidines. The catalytic activity was influenced by lanthanide metals and the amido groups with the active sequence of Y (1) < Gd (4) < Nd (3) < Pr (2) ∼ Yb (5) for the lanthanide metals and –NHAr2 < –NHPh < –NHAr1 for the amido groups. The catalytic addition reaction with complex 5 showed a good scope of aromatic amines. Some key reaction intermediates were isolated and structurally characterized, including the amidinate complexes LLn[NPhCNAr1](PhCN) (Ln = Y (8), Ln = Yb (9)), LYb[NAr2CNAr1](Ar2CN) (10), and amide complex 5 prepared by protonation of 9 by Ar1NH2. Reactivity studies of these complexes suggest that the present catalytic formation of monosubstituted N-arylamidines proceeds through nucleophilic addition of an amido species to a nitrile, followed by amine protonolysis of the resultant amidinate species.
Co-reporter:Jinyong Zhuang, Wenming Su, Wanfei Li, Yuyang Zhou, Qi Shen, Ming Zhou
Organic Electronics 2012 Volume 13(Issue 10) pp:2210-2219
Publication Date(Web):October 2012
DOI:10.1016/j.orgel.2012.06.025
A series of structurally isomeric carbazole/triazole (TAZ)-based bipolar host materials 1–4 were designed and synthesized. These new materials were found to exhibit wide energy gaps (Eg: 3.29–3.52 eV), high triplet energies (ET: 2.56–2.76 eV), high thermal stability (Td: 426–454 °C), high glass-transition temperatures (Tg: 116–156 °C) and excellent film-forming property. Green and blue emitting devices with fac-tris(2-phenylpyridine)iridium (Ir(ppy)3) and iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) as phosphorescent dopants have been fabricated. The measurements of turn-on voltages, efficiencies and luminance suggested that the practice of combining carbazole’s high triplet energy and excellent hole-transporting ability with TAZ’s electron-transporting ability at the molecular level was effectively translated into better performance at the device level. The molecular structure of compound 4 is well-correlated with its efficiencies, which (32.7 and 21.1 cd/A for green and blue devices, respectively) were the best among the four materials.Graphical abstractHighlights► The novel carbazole/triazole-based bipolar hosts materials synthesized. ► The carbazole and triazole coupling modes are associated with the materials and device performance. ► The green and blue emitting devices showed reasonable good performance.
Co-reporter:Xingmin Zhang;Cunwei Qian;Chuanyong Wang;Yong Zhang;Yaorong Wang;Yingming Yao
European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 5) pp:847-858
Publication Date(Web):
DOI:10.1002/ejic.201100901
Abstract
Anhydrous LnCl3 was treated with [LiiPrNC(HNiPr)N(C6H4p-Cl)] and nBuLi at a molar ratio of 1:2:2 in THF to afford heterometallic Ln–Li chlorides stabilized by two dianionic guanidinate ligands [{(iPrN)2C[NLi(THF)3(C6H4p-Cl)]}2Ln(μ-Cl2)Li(THF)2]·nTHF [Ln = La (1), Nd (2) n = 2; Sm (3), Yb (4), Y (5) n = 3] in good yields. Treatment of thechlorides with NaOiPr and KOtBu yielded the corresponding isopropoxides [{[(iPrN)2CN(C6H4p-Cl)Li]2(DME)(LiCl)Ln(OiPr)2}2]2–[{Li(DME)3}+]2·3C6H14 [Ln = Nd (6), Sm (7), Yb (8), Y (9); DME = 1,2-dimethoxyethane] and tert-butoxides [{(iPrN)2C(NC6H4p-Cl)Li(DME)(LiCl)}2Ln(OtBu)2]–[Li(DME)3]+·0.5C6H14 [Ln = Nd (10), Yb (11)]. Attempts to synthesize the corresponding amide and guanidinate complexes by treating 2 with LiNHC6H5 and [LiiPrNC(HNiPr)N(C6H5)] led to the isolation of guanidinate lithium,[LiiPrNC(HNiPr)N(C6H4p-Cl)(THF)]2 (12). Addition of diisopropylcarbodiimide (iPrN=C=NiPr) into the reaction system of trisguanidinate lanthanide complex [{iPrNHC(NiPr)(NC6H4p-Cl)}3Yb(THF)] and nBuLi led to the preparation of the first heterometallic Yb–Li complex with a novel biguanidinate ligand [{iPrNHC(NiPr)N(C6H4p-Cl)}2Yb{(iPrNC(NiPr)2)N(C6H4p-Cl)C(iPrN)}Li(THF)]·THF (13). The molecular structures of 1–3 and 6–13 were determined by X-ray crystal structural analysis.
Co-reporter:Lu Wang;Zhigang Yao;Fan Xu
Heteroatom Chemistry 2012 Volume 23( Issue 5) pp:449-456
Publication Date(Web):
DOI:10.1002/hc.21036
Abstract
The tetracoordinated lanthanide amides [(Me3Si)2N]3Ln(µ-Cl)Li(THF)3 were found to serve as highly active catalysts for the phospho-Aldol-Brook rearrangement reaction of various dialkyl phosphites and isatins. The reactions produced dialkyl 2-oxoindolin-3-yl phosphates in good to excellent yields in the presence of 1 mol% [(Me3Si)2N]3La(µ-Cl)Li(THF)3 at room temperature within 5 min. A mechanism for this highly efficient process was proposed. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:449–456, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21036
Co-reporter:Xiaodong Shen, Mingqiang Xue, Rui Jiao, Yong Ma, Yong Zhang, and Qi Shen
Organometallics 2012 Volume 31(Issue 17) pp:6222-6230
Publication Date(Web):August 15, 2012
DOI:10.1021/om3005299
Reaction of LnCl3 (Ln = Y, Yb) with 2 equiv of NaL2,6-ipr2Ph (L2,6-ipr2Ph = [(2,6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−) afforded the chlorides (L2,6-ipr2Ph)2YCl (1) and (L2,6-ipr2Ph)2YbCl (2). Crystal structure analysis revealed 2 to be the unsolvated monomer. Treatment of the chlorides 1 and 2 with NaBH4 in a 1/1 molar ratio in THF led to the preparation of the monoborohydrides (L2,6-ipr2Ph)2LnBH4 (Ln = Y (3), Yb (4)) in good yields. Reaction of LnCl3 (Ln = Y, Yb) with 2 equiv of NaL2-Me (L2-Me = [N(2-MeC6H4)C(Me)]2CH–) in THF, followed by treatment with 1 equiv of NaBH4, afforded the monoborohydrides (L2-Me)2LnBH4 (Ln = Y (5), Yb (6)). Complexes 3–6 were fully characterized, including X-ray crystal structure analyses. Complexes 3–6 are isostructural. The central metal in each complex is ligated by two β-diketiminate ligands and one η3-BH4– group in a distorted trigonal bipyramid. Complexes 3–6 were found to be highly active in the ring-opening polymerization of l-lactide (l-LA) and ε-caprolactone (ε-CL) to give polymers with relatively narrow molar mass distributions. The activity depends on both the central metal and the ligand (Y > Yb and L2,6-ipr2Ph > L2-Me). The best control over the molar mass was found for complex 6. The Mn(obsd) values (Mn = the number-average molar mass) of the resulting PCL are in good agreement with Mn(calcd), with a ratio of monomer to 6 of up to 1000. The polymerization kinetics of l-LA in THF at 20 °C by complex 6 displays a first-order dependence on the monomer concentration. Notably, the binary 6/iPrOH system exhibited an “immortal” nature and proved able to quantitatively convert 10 000 equiv of l-LA with up to 200 equiv of iPrOH per metal initiator. All the obtained PLAs showed monomodal, narrow distributions (Mw/Mn = 1.06–1.11), with the Mn values decreasing proportionally with an increasing amount of iPrOH. Complex 4 can also initiate the polymerization of methyl methacrylate (MMA) at −40 °C with high activity, affording the PMMA with 83.3% syndiotacticity.
Co-reporter:Xingmin Zhang, Chuanyong Wang, Mingqiang Xue, Yong Zhang, Yingming Yao, Qi Shen
Journal of Organometallic Chemistry 2012 713() pp: 182-188
Publication Date(Web):
DOI:10.1016/j.jorganchem.2012.05.011
Co-reporter:Zhi Li, Mingqiang Xue, Haisheng Yao, Hongmei Sun, Yong Zhang, Qi Shen
Journal of Organometallic Chemistry 2012 713() pp: 27-34
Publication Date(Web):
DOI:10.1016/j.jorganchem.2012.04.006
Co-reporter:Jiang-Hua Chen, Sai-Hu Liao, Xiu-Li Sun, Qi Shen, Yong Tang
Tetrahedron 2012 68(25) pp: 5042-5045
Publication Date(Web):
DOI:10.1016/j.tet.2012.04.049
Co-reporter:Xingmin Zhang, Chuanyong Wang, Mingqiang Xue, Yong Zhang, Yingming Yao, Qi Shen
Journal of Organometallic Chemistry 2012 716() pp: 86-94
Publication Date(Web):
DOI:10.1016/j.jorganchem.2012.06.004
Co-reporter:ChunHui Yan;LinLin Wang;HuanHuan Gao;HongMei Sun
Science Bulletin 2012 Volume 57( Issue 16) pp:1953-1958
Publication Date(Web):2012 June
DOI:10.1007/s11434-011-4660-3
1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride, [DIPrim]Cl, was used to produce a novel iron(III)-containing imidazolium salt [DIPrim][FeCl4], which included a N,N-diarylimidazolium cation (R = 2,6-diisopropylphenyl), [DIPrim]+, and tetrachloroferrate(III) anion, [FeCl4]−. This compound was an effective and easy-to-use catalyst for the cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing β-hydrogens. After simply decanting the cross-coupling product in the ether layer, [DIPrim][FeCl4] could be reused in at least four successive runs without significant loss of catalytic activity.
Co-reporter:QianNan Wang;ZhiGang Yao;Fan Xu
Science Bulletin 2012 Volume 57( Issue 14) pp:1612-1615
Publication Date(Web):2012 May
DOI:10.1007/s11434-011-4744-0
An efficient method was developed for the synthesis of arylidene heterobicyclic 3-cyano-2-pyridones via ytterbium chloride catalyzed tandem condensation of aromatic aldehydes, cyclic ketones, and cyanoacetamide. The conditions and scope of the reaction were investigated and a reaction mechanism was proposed.
Co-reporter:XueHua Zhu;Fan Xu
Science Bulletin 2012 Volume 57( Issue 26) pp:3419-3422
Publication Date(Web):2012 September
DOI:10.1007/s11434-012-5332-7
A catalytic addition of amine N-H bonds to carbodiimides using aluminum chloride as a Lewis acid catalyst is developed. The reaction proceeds under mild conditions without solvent to afford a series of substituted guanidines in good to excellent yields using a wide range of amines as substrates. Evidence of the proposed mechanism is provided by in situ infrared spectroscopy.
Co-reporter:Zhu Du, Hui Zhou, Haisheng Yao, Yong Zhang, Yingming Yao and Qi Shen
Chemical Communications 2011 vol. 47(Issue 12) pp:3595-3597
Publication Date(Web):07 Feb 2011
DOI:10.1039/C0CC04504G
The reaction of YbL(THF)2 (L = [–OC6H2(2,4-tBu2)(6-CH2)]2NCH2CH2NMe2) with iPrN=C=NiPr led to the bridged carbene ytterbium complex (YbL)2(μ-NiPrCNiPr)via a two-electron reduction process of carbodiimide, which reacted with PhNCO to afford a dinuclear ytterbium complex and a spiro derivative.
Co-reporter:Fubin Han ; Qiaoqiao Teng ; Yong Zhang ; Yaorong Wang
Inorganic Chemistry 2011 Volume 50(Issue 6) pp:2634-2643
Publication Date(Web):February 14, 2011
DOI:10.1021/ic102529d
The monoamido lanthanide complexes stabilized by Schiff base ligand L2LnN(TMS)2 (L = 3,5-But2-2-(O)-C6H2CH═N-8-C9H6N, Ln = Yb (1), Y (2), Eu (3), Nd (4), and La (5)) were synthesized in good yields by the reactions of Ln[N(TMS)2]3 with 1.8 equiv of HL in hexane at room temperature. It was found that the stability of 1−5 depends greatly on the size of the lanthanide metals with the increasing trend of Yb ≈ Y < Nd < La. The amine elimination of Ln[N(TMS)2]3 with the bulky bidentate Schiff base HL′ (L′ = 3,5-But2-2-(O)-C6H2CH═N-2,6-Pri2-C6H3) afforded the monoamido lanthanide complexes L′2LnN(TMS)2 (Ln = Yb (9), Y (10), Nd (11), and La (12)). While the amine elimination with the less bulky Schiff base HL′′ (L′′ = 3,5-But2-2-(O)-C6H2CH═N-2,6-Me2-C6H3) yielded the desired monoamido complexes with the small metals of Y and Yb, L′′2LnN(TMS)2 (Ln = Yb (13) and Y (14)), and the more stable tris-Schiff base complexes with the large metals of La and Nd, yielded L′′3Ln as the only product. Complexes 1−14 were fully characterized including X-ray crystal structural analysis. Complexes 1−5, 10, and 14 can serve as the efficient catalysts for addition of amines to carbodiimides, and the catalytic activity is greatly affected by the lanthanide metals with the active sequence of Yb < Y < Eu ≈ Nd ≈ La.
Co-reporter:Yang Cao ; Zhu Du ; Wenbo Li ; Junmei Li ; Yong Zhang ; Fan Xu
Inorganic Chemistry 2011 Volume 50(Issue 8) pp:3729-3737
Publication Date(Web):March 22, 2011
DOI:10.1021/ic200091s
Reaction of Ln(OAr1)3(THF)2 (Ar1= [2,6-(tBu)2-4-MeC6H2] with carbodiimides (RNCNR) in toluene afforded the RNCNR coordinated complexes (Ar1O)3Ln(NCNR) (R = iPr (isopropyl), Ln = Y (1) and Yb (2); R = Cy (cyclohexyl), Ln = Y (3)) in high yields. Treatment of 1 and 2 with 4-chloroaniline, respectively, at a molar ratio of 1:1 yielded the corresponding monoguanidinate complex (Ar1O)2Y[(4-Cl-C6H4N)C(NHiPr)NiPr](THF) (4) and (Ar1O)2Yb[(4-Cl-C6H4N)C(NHiPr)NiPr](THF) (5). Complexes 4 and 5 can be prepared by the reaction of Ln(OAr1)3(THF)2 with RNCNR and amine in toluene at a 1:1:1 molar ratio in high yield directly. A remarkable influence of the aryloxide ligand on this transformation was observed. The similar transformation using the less bulky yttrium complexes Y(OAr2)3(THF)2 (Ar2 = [2,6-(iPr)2C6H3]) or Y(OAr3)3(THF)2 (Ar3 = [2,6-Me2C6H3]) did not occur. Complexes Ln(OAr1)3(THF)2 were found to be the novel precatalysts for addition of RNCNR with amines, which represents the first example of catalytic guanylation by the lanthanide complexes with the Ln-O active group. The catalytic activity of Y(OAr1)3(THF)2 was found to be the same as that of monoguanidinate complex 4, indicating 4 is one of the active intermediates in the present process. The other intermediate, amide complex (Ar1O)2Ln[(2-OCH3-C6H4NH)(2-OCH3-C6H4NH2)] (6), was isolated by protonolysis of 4 with 2-OCH3-C6H4NH2. All the complexes were structurally characterized by X-ray single crystal determination.
Co-reporter:Zhu Du, Yong Zhang, Yingming Yao and Qi Shen
Dalton Transactions 2011 vol. 40(Issue 29) pp:7639-7644
Publication Date(Web):24 Jun 2011
DOI:10.1039/C1DT10081E
The reaction of Sm[N(TMS)2]2(THF)2 with H2L (L = 1,4-bis(2-hydroxy-3-tert-butyl-5-methyl-benzyl)-piperazidine) afforded [SmL(HMPA)2]4·8THF 2 upon treatment with 2 equivalents of HMPA (hexamethyl phosphoric triamide). X-ray crystallographic analysis of 2 reveals a tetrametallic macrocyclic structure, which represents the first example of a crystal structure of a Sm(II) complex stabilized by heteroatom bridged bis(phenolate) ligands. Reduction of carbodiimides RNCNR (R = iPr and Cy) by [SmL]2(THF) 1, which was formed in situ by the reaction of Sm[N(TMS)2]2(THF)2 with H2L in THF, yielded the Sm(III) complex with an oxalamidinate ligand [LSm{(NiPr)2CC(NiPr)2}SmL]·THF 3 for iPrNCNiPr and the Sm(III) complex with a diamidocarbene ligand [LSm(μ-CyNCNCy)SmL]·5.5THF 4 for CyNCNCy.
Co-reporter:Rui Jiao;Mingqiang Xue;Xiaodong Shen;Yong Zhang;Yingming Yao
European Journal of Inorganic Chemistry 2011 Volume 2011( Issue 9) pp:1448-1453
Publication Date(Web):
DOI:10.1002/ejic.201000759
Abstract
Attempted synthesis of tris(β-diketiminato)lanthanide complexes [Ln(L)3] (L = [{N(C6H3Me2-2,6)C(Me)}2CH]) resulted in ligand deprotonation, and different outcomes depending on the central metal used were observed. Reaction of YbCl3 with NaL (3 equiv.) afforded the five-membered cyclometalated ytterbium β-diketiminate complex [Yb(L)(L)dep] (1). The same reaction with LnCl3 (Ln = Nd, Sm, and Er) gave the new complexes composed of one normal L and one deprotonated neighboring benzazacyclopentane ligand derived from deprotonation of the 2-methyl group followed by an attack of thecarbon atom on the β-diketiminate backbone, [Ln(L)(L)dep′(thf)] [Ln = Nd (2), Sm (3), and Er (4)]. The bonding mode in the {Ln(L)dep′} moiety was also found to depend on the central metal ions.
Co-reporter:Lijian Cai;Xiaofeng Ji;Zhigang Yao;Fan Xu
Chinese Journal of Chemistry 2011 Volume 29( Issue 9) pp:1880-1886
Publication Date(Web):
DOI:10.1002/cjoc.201180328
Abstract
An efficient method is developed for the synthesis of functionalized benzimidazoles and perimidines by the condensation of aryl diamines with β-carbonyl compounds catalyzed by ytterbium chloride. The reactions give good yields under mild conditions. A mechanism involving a lanthanide activated CC bond cleavage is proposed.
Co-reporter:Xingmin Zhang, Chuanyong Wang, Cunwei Qian, Fubin Han, Fan Xu, Qi Shen
Tetrahedron 2011 67(45) pp: 8790-8799
Publication Date(Web):
DOI:10.1016/j.tet.2011.08.072
Co-reporter:HaiDong Liu;Lan Li;HongTing Sheng;XueHua Zhu;Fan Xu
Science Bulletin 2011 Volume 56( Issue 13) pp:1357-1360
Publication Date(Web):2011 May
DOI:10.1007/s11434-011-4451-x
Catalytic acylation of nitriles with esters in the presence of 10 mol% NdNa8(OtBu)10(OH) is developed. The procedure is suitable for both enolizable and nonenolizable esters and affords β-ketonitriles in moderate to high yields. The heterometallic alkoxide cluster NdNa8(OtBu)10(OH) is structurally characterized by X-ray diffraction, and a mechanism for the production of β-ketonitriles using the cluster is proposed and verified.
Co-reporter:Yang Cao;JunMei Li;YaoRong Wang;YingMing Yao
Science Bulletin 2011 Volume 56( Issue 26) pp:
Publication Date(Web):2011 September
DOI:10.1007/s11434-011-4652-3
Polymerization of acrylonitrile was carried out using, for the first time, the lanthanide-sodium alkoxide clusters Ln2(OCH2CH2NMe2)12(OH)2Na8 [Ln=Yb (1), Nd (2) and Sm (3)] as single component catalysts. These heterobimetallic complexes exhibit high activity and give atactic polyacrylonitriles with high molecular weight. The polymerization temperature can be varied over the range −78 to 50°C. The solvent has a substantial effect on the polymerization activity. The order of activity for solvents is DMF>DME≈toluene≈THF>hexane.
Co-reporter:Rui Jiao, Xiaodong Shen, Mingqiang Xue, Yong Zhang, Yingming Yao and Qi Shen
Chemical Communications 2010 vol. 46(Issue 23) pp:4118-4120
Publication Date(Web):11 May 2010
DOI:10.1039/B927582G
Attempted synthesis of sterically demanding tris-β-diketiminate complexes of europium led to oxidation–coupling of β-diketiminates and the formation of the THF-solvated divalent europium complex Eu(L2,6-Me2)2(THF) (L2,6-Me2 = [{N(2,6-Me2C6H3)C(Me)}2CH]−), while the normal tris-β-diketiminate complex Eu(L2-Me)3 for the less bulky ligand L2-Me ([{N(2-MeC6H4)C(Me)}2CH]−) was isolated by the same procedure.
Co-reporter:Hongxia Chen, Peng Liu, Haisheng Yao, Yong Zhang, Yingming Yao and Qi Shen
Dalton Transactions 2010 vol. 39(Issue 29) pp:6877-6885
Publication Date(Web):22 Jun 2010
DOI:10.1039/C002385J
The reaction of monomeric [(DIPPh)2nacnac]YbCl2(THF)2 ((DIPPh)2nacnac = N,N-diisopropylphenyl-2,4-pentanediimineanion) with NaOAr (OAr = 2,6-diisopropylphenoxide) in THF afforded the mononuclear complexes [(DIPPh)2nacnac]Yb(OAr)Cl(THF) 1 and [(DIPPh)2nacnac]Yb(OAr)22 depending on the molar ratio of dichloride to sodium salt, while the same reaction with NaOAr′ (OAr′ = 2,6-dimethylphenoxide) in toluene yielded the binuclear complex [{(DIPPh)2nacnac}Yb(OAr′)]2(μ-Cl)23. Treatment of [(DIPPh)2nacnac]Yb(THF)(μ-Cl)3Yb(Cl)[(DIPPh)2nacnac] with NaOAr and NaOAr′, respectively, in toluene yielded selectively the corresponding binuclear complexes {[(DIPPh)2nacnac]Yb(OAr)(μ-Cl)3Yb[(DIPPh)2nacnac](THF)} 4 and {[(DIPPh)2nacnac]Yb(OAr′)(μ-Cl)3Yb[(DIPPh)2nacnac](THF)} 5 in high yields. All complexes were structurally characterized. Complex 2 was found to be a highly active initiator for both polymerizations of ε-caprolactone (ε-CL) and L-lactide. All monoaryloxide complexes can initiate the polymerization of ε-CL in a controlled manner giving polymers with narrow molecular weight distributions (Mw/Mn around 1.06) with relatively low activity relative to complex 2.
Co-reporter:Rui Jiao;Mingqiang Xue;Xiaodong Shen;Yong Zhang;Yingming Yao
European Journal of Inorganic Chemistry 2010 Volume 2010( Issue 17) pp:2523-2529
Publication Date(Web):
DOI:10.1002/ejic.201000156
Abstract
A series of tris-β-diketiminate ytterbium complexes with the general formula [YbL3] {L = [N(C6H5)C(Me)]2CH–, LH (1); [N(4-MeC6H4)C(Me)]2CH–, L4-Me (2), and [N(2-MeC6H4)C(Me)]2CH–, L2-Me (3)} were synthesized and structurally characterized. All complexes have longer Yb–N bond lengths than other YbL-containing derivatives, and complex 3 has the longest average Yb–N bond length. A comparative study on the reactivity of complexes 1–3 revealed that complex 3 was a highly active catalyst for the polymerization of ϵ-caprolactone and L-lactide, as well as for the addition of amines to carbodiimides, whereas both complexes 1 and 2 were almost inactive under the same conditions. The active sequence is consistent with the distance of the Yb–N bond, which is reflected in the sterically induced activation of the bulky tris-β-diketiminate ytterbium complexes.
Co-reporter:Hongting Sheng;Yan Feng;Yong Zhang
European Journal of Inorganic Chemistry 2010 Volume 2010( Issue 35) pp:5579-5586
Publication Date(Web):
DOI:10.1002/ejic.201000831
Abstract
The effect of the alkali metal on the synthesis, crystal structure, and catalytic reactivity of lanthanide–alkali metal alkoxide clusters is reported. Anhydrous LnCl3 reacts with 6.5 equiv. of KOCH2CH2N(CH3)2 and 1.5 equiv. of KOH in tetrahydrofuran (THF) to give the corresponding lanthanide–potassium biheterometal alkoxide clusters [Ln4K20(OCH2CH2NMe2)26(OH)6] [Ln = Nd (1), Pr (2), Yb (3)] in high yield. Anhydrous YbCl3 reacts with KOCH2CH2N(CH3)2 and NaOH with different molar ratios of 1:9:3 and 1:9:4 to afford the lanthanide–potassium–sodium triheterometal alkoxide clusters [Yb2K10Na6(OCH2CH2NMe2)18(OH)4] (4) and [Yb2K8Na8(OCH2CH2NMe2)18(OH)4] (5), respectively. These clusters were fully characterized by elemental analysis, IR, 1H NMR, and single-crystal structural analysis. The heterometal alkoxide clusters 1–5 exhibited good catalytic activity for the ring-opening polymerization of ϵ-caprolactone (ϵ-CL). It is interesting to note that the catalytic activity of these heterometal alkoxide clusters increases with the increase of the molar ratio of alkali metal to lanthanide metal. For the same molar ratio of alkali metal to lanthanide metal, however, the catalytic activity of the heterometal clusters is highly dependent on the type and molar ratio of the alkali metal centers. The higher the molar ratio of potassium to sodium, the higher the catalytic activity.
Co-reporter:Yong Yu;Jun Zhou;Zhigang Yao;Fan Xu
Heteroatom Chemistry 2010 Volume 21( Issue 5) pp:351-354
Publication Date(Web):
DOI:10.1002/hc.20612
Abstract
A simple and efficient method for the cis-selective synthesis of pyrano- and furano[3,2-c]quinolines via gadolinium chloride catalyzed one-pot aza–Diels–Alder reaction is described. Solvent conditions played a major role in affecting the diastereoselectivity of the products. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:351–354, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20612
Co-reporter:Qingmao Wu, Jun Zhou, Zhigang Yao, Fan Xu, and Qi Shen
The Journal of Organic Chemistry 2010 Volume 75(Issue 21) pp:7498-7501
Publication Date(Web):October 6, 2010
DOI:10.1021/jo101743e
A highly efficient method for the synthesis of α-hydroxy phosphonates via lanthanide amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 catalyzed hydrophosphonylation of aromatic aldehydes was developed. The reactions produced the products in excellent yields in the presence of 0.1 mol % [(Me3Si)2N]3La(μ-Cl)Li(THF)3 at room temperature within 5 min. The existence of LiCl in the catalyst was a key factor affecting the catalytic activity. The mechanism for the process of high efficiency was proposed.
Co-reporter:Cunwei Qian, Xingmin Zhang, Yong Zhang, Qi Shen
Journal of Organometallic Chemistry 2010 695(5) pp: 747-752
Publication Date(Web):
DOI:10.1016/j.jorganchem.2009.12.010
Co-reporter:Haisheng Yao, Jinguo Zhang, Yong Zhang, Hongmei Sun, and Qi Shen
Organometallics 2010 Volume 29(Issue 22) pp:5841-5846
Publication Date(Web):October 8, 2010
DOI:10.1021/om100562q
The lithium salt of the novel amido-phenoxo-functionalized NHC L (L = [3,5-tBu2-2-(O)C6H2CH(nBu)NH(CH2)2(C{N(CH)2NiPr})]), (LiL)2 (1), was synthesized by the direct reaction of the salicylaldimino-functionalized imidazolium salt H2L′Br (L′ = [3,5-tBu2-2-(O)C6H2CH═N(CH2)2(C{N(CH)2NiPr})]) with 2 equiv of LinBu and structurally characterized. Treatment of LnCl3 with in situ formed 1 in a molar ratio of 1:1 at room temperature yielded the first cationic complexes [LnL2]+[Br]− (Ln = Y (2), Lu (3), Er (4)) in good yields. Treatment of Li(THF)Ln(NiPr2)4 with 2 equiv of H2L′Br at −78 °C afforded the cationic complexes [L′2Ln(THF)]+[Br]− (Ln = Y (5) and Yb (6)) in desired yields. Each central metal in cations [LnL2]+ for 2−4 is coordinated by two L ligands, while the central metal in [L′2Ln(THF)]+ for 5 and 6 is ligated by two ligands and one THF molecule. The structures of NHC lanthanide bromides have been found to depend on both the size of the metal and the ligand.
Co-reporter:ChengYi Cai;Lan Li;Fan Xu
Science Bulletin 2010 Volume 55( Issue 32) pp:3641-3643
Publication Date(Web):2010 November
DOI:10.1007/s11434-010-4139-7
Heterobimetallic clusters of Na8Ln(OtBu)10(OH) (Ln = ytterbium, europium, samarium and neodymium) are found to be useful catalysts for amidation of aldehydes with amines under mild conditions. The catalytic activity depends on the central metal ion in the cluster, and the order activity is ytterbium < europium < samarium ≈ neodymium. The catalysts show a wide range of scope in their activity towards amines including aliphatic amines and secondary cyclic amines such as pyrrolidine and piperidine.
Co-reporter:LianBin Yao;Fan Xu
Science Bulletin 2010 Volume 55( Issue 36) pp:4108-4111
Publication Date(Web):2010 December
DOI:10.1007/s11434-010-4230-0
An efficient method for the synthesis of tetrahydroquinoline derivatives via lanthanide halides catalyzed domino reactions of arylamines with dihydropyran is described. Either the cis or the trans isomer can be obtained as the major product in good yield by changing the catalyst and reaction conditions.
Co-reporter:Junfeng Wang;Junmei Li;Fan Xu
Advanced Synthesis & Catalysis 2009 Volume 351( Issue 9) pp:1363-1370
Publication Date(Web):
DOI:10.1002/adsc.200800697
Co-reporter:Junfeng Wang, Yingming Yao, Yong Zhang and Qi Shen
Inorganic Chemistry 2009 Volume 48(Issue 2) pp:744-751
Publication Date(Web):December 18, 2008
DOI:10.1021/ic801189j
Bridged bis(amidinate) ytterbium alkoxide and phenoxide with diverse molecular structures were synthesized in high yields and confirmed by X-ray crystal structural analysis. The reaction of LYbCl(THF)2 (L = Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3) with 1 equiv of NaOAr (ArO = 2,6-diisopropylphenoxo) afforded the mononuclear complex LYb(OAr)DME 1 with a seven-coordinated ytterbium atom surrrounded by one chelating bis(amidinate) ligand, one phenoxo group, and one DME (dimethoxyethane) molecule. The same reaction with 1 equiv of NaOiPr yielded the binuclear complex Yb(μ2-L)2(μ2-OiPr)2Yb, 2, with two equivalent six-coordinate metal centers connected by two linked bis(amidinate)s and two OiPr bridges formed via a ligand redistribution reaction that occurred during the metathesis reaction. Both 1 and 2 initiated the ring-opening polymerization of l-lactide, as well as ε-caprolactone (ε-CL), in a controlled manner with high reactivity, as indicated by a linear relationship between Mn and conversion and by narrow molecular weight distributions (PDI = 1.15−1.25) up to 100% conversion. The differences in catalytic performance between complexes 1 and 2 are discussed.
Co-reporter:Duwei Qin, Fubin Han, Yingming Yao, Yong Zhang and Qi Shen
Dalton Transactions 2009 (Issue 28) pp:5535-5541
Publication Date(Web):04 Jun 2009
DOI:10.1039/B904580E
The protonolysis of anionic lanthanide amide complexes (THF)LiLn(NPri2)4 with two equiv. of tridentate Schiff base HL (L = 3,5-But2-2-O-C6H2CHN-C5H4N) afforded the unanticipated products LiL′2Ln(THF) (L′ = 3,5-But2-2-O-C6H2CH(NPri2)-N-C5H4N; Ln = Y 1, Sm 2 and Yb 3) formed by intramolecular nucleophilic attack of the amide groups at the imine carbon atoms of the original ligand, L. The protonolysis is greatly affected by the amide group. When amine elimination was carried out with a mixture of Ln[N(TMS)2]3(μ-Cl)Li(THF)3 (TMS = SiMe3) and LiN(TMS)2, the expected lanthanide amide complexes with two Schiff base ligands, L2Ln[N(TMS)2] (Ln = Sm 4 and Nd 5), were isolated and no migration of the N(TMS)2 group was observed because of steric hindrance. Complexes 1–5 were well characterized including X-ray structural analyses.
Co-reporter:Haisheng Yao;Yong Zhang;Hongmei Sun
European Journal of Inorganic Chemistry 2009 Volume 2009( Issue 13) pp:1920-1925
Publication Date(Web):
DOI:10.1002/ejic.200801109
Abstract
A series of anionic lanthanide complexes supported by bis(phenoxy)-functionalized N-heterocyclic carbene (NHC) ligand L, where L = 1,3-bis[O-4,6-di-tBu-C6H2-2-CH2][C{N(CHCH)N}], were synthesized by the amine-elimination reaction. The in situ reaction of LH3Cl with Li(thf)Ln(NiPr2)4 and nBuLi in a 2:1:2 molar ratio in thf afforded the discrete ion-pair complexes [L2Ln][Li(dme)3] (Ln = Sm 1, Er 2, Yb 3) upon crystallization from dme/toluene (10 mL:15 mL). The reaction of LH3Cl with Li(thf)Sm(NiPr2)4 and nBuLi in a 2:1:2 molar ratio proceeded in thf, followed by crystallization from thf/toluene (2 mL:15 mL), to yield an “ate” complex [(thf)Li(μ-L)SmL] (4). The analogous “ate” complex with sodium metal [(Et2O)Na(μ-L)SmL] (5) was also prepared by the in situ treatment of LH3Cl with Sm[N(SiMe3)2]3 and NaN(SiMe3)2 in a 2:1:3 molar ratio. Single-crystal X-ray structural analyses of 1–5 revealed that complexes 1–3 have ion-pair structure consisting of an anion [L2Ln]– and a cation [Li(dme)3]+, in which the coordination geometries about each lanthanide metal ion can be best described as a distorted octahedron, while the samarium ion and the alkali metal ion in complexes 4 and 5 are connected together by two phenoxide oxygen bridges, and each alkali metal ion is bound to anadditional oxygen atom of one thf (for 4) and one Et2O (for 5).(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Co-reporter:Mingqiang Xue;Rui Jiao;Yong Zhang;Yingming Yao
European Journal of Inorganic Chemistry 2009 Volume 2009( Issue 27) pp:
Publication Date(Web):
DOI:10.1002/ejic.200900313
Abstract
Metathesis of {[(4–XC6H4)NC(Me)]2CH}Li with anhydrous lanthanide trichlorides (LnCl3) in a 3:1 molar ratio yielded a series of tris-β-diketiminate complexes with the general formula [LnLX3] [X = Cl, LCl: Ln = Pr (1), Nd (2), Sm (3); X = H, L: Ln = Nd (4); X = Me, LMe: Ln = Nd (5)]. Reaction of sodium salt of β-diketiminate with anhydrous LnCl3 in a 1:1 molar ratio in thf afforded the corresponding β-diketiminate lanthanide dichlorides [LClPrCl2(thf)2] (6), [LMeNdCl2(thf)2] (7), and [LNdCl2(thf)2] {L = [(2,6-iPr2C6H3)NC(Me)]2CH–} (8), respectively. Each of these complexes was characterized, and the molecular structures of complexes 1–5 and 8 were determined by X-ray single-crystal structure analysis. Complexes 1–5 were found to be very active single-component initiators for the ring-opening polymerization of ϵ-caprolactone (ϵ-CL) and L-lactide (L-LA) under mild conditions, giving polymers with high molecular weight and moderate polydispersities, whereas complexes 6–8 displayed no activity under the same polymerization conditions. The high catalytic activity shown by tris-β-diketiminate lanthanide complexes may be attributed to the activated Ln–β-diketiminate bond caused by the crowded coordination sphere around the central metal.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Co-reporter:Lan LI;Hongting SHENG;Fan XU
Chinese Journal of Chemistry 2009 Volume 27( Issue 6) pp:1127-1131
Publication Date(Web):
DOI:10.1002/cjoc.200990188
Abstract
The heterometal alkoxide clusters of Group 3 metal and lanthanides with sodium Ln2Na8(OCH2CH2NMe2)12(OH)2 (Ln=Y, lanthanide) were found to serve as highly active catalysts for the Tishchenko reaction of various aldehydes to form the corresponding esters. The reaction scope and the influence of lanthanide and sodium metal on the catalytic activity were investigated, and the proposed mechanism of the reaction was discussed.
Co-reporter:Xuehua ZHU;Fan XU
Chinese Journal of Chemistry 2009 Volume 27( Issue 1) pp:19-22
Publication Date(Web):
DOI:10.1002/cjoc.200990017
Abstract
An efficient guanylation of aromatic amine with carbodiimide in the presence of a catalytic amount of samarium diiodide, a Lewis-acid type precatalyst readily accessible, was developed. The reaction was carried out under mild conditions giving a variety of guanidines in good to excellent yields.
Co-reporter:Liying Zhou;Yingming Yao
Journal of Applied Polymer Science 2009 Volume 114( Issue 4) pp:2403-2409
Publication Date(Web):
DOI:10.1002/app.30656
Abstract
Lanthanide(II) complexes supported by amido ligands, [(C6H5)(Me3Si)N]2Ln(DME)2 [Ln = Sm (1) or Yb (2); DME = 1,2-dimethoxyethane] and [(C6H3iPr2-2,6)(Me3Si)N]2Ln(THF)2 [Ln = Sm (3) or Yb (4); THF = tetrahydrofuran], were found to initiate the polymerization of methyl methacrylate (MMA) as efficient single-component initiators (in toluene for 3 and 4 and in toluene with a small amount of THF for 1 and 2) to produce syndiotactic polymers. The catalytic behavior was highly dependent on both the amido ligand and the polymerization temperature. Initiators 3 and 4 initiated MMA polymerization over a wide range of temperatures (20°C to −40°C), whereas the polymerization with 1 and 2 proceeded smoothly only at low temperatures (≤0°C). The kinetic behavior and some features of the polymerizations of MMA initiated by 3 and 4 were studied at −40°C. The polymerization rate was first-order with the monomer concentration. The molar masses of the polymers increased linearly with the increase in the polymer yields, whereas the molar mass distributions remained narrow and unchanged throughout the polymerization; this indicated that these systems had living character. A polymerization mechanism initiated by bimetallic bisenolate formed in situ was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Hongting Sheng;Junmei Li;Yong Zhang Yingming Yao
Journal of Applied Polymer Science 2009 Volume 112( Issue 1) pp:454-460
Publication Date(Web):
DOI:10.1002/app.29428
Abstract
Heterometal alkoxide clusters of lanthanide and sodium, LnNa8[OC(CH3)3]10(OH) [where Ln = Nd (1) or Yb (2)], which were synthesized by the metathesis reaction of LnCl3 with NaOC(CH3)3 and NaOH in a 1 : 10 : 1 molar ratio in high yields and fully characterized including X-ray analysis for 2, were found to be highly active catalysts in the ring-opening polymerization of ε-caprolactone and trimethylene carbonate and their copolymerization. All of the polymers obtained showed a unimodal molecular weight distribution, indicating that 1 and 2 could really be used as single-component catalysts. The dependence of catalytic activity on the lanthanide metals was observed: Yb < Nd. A coordination–insertion mechanism for the ring-opening polymerization is proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Tao Cai, Xiaoniu Chen, Fan Xu, Yong Zhang, Yingming Yao, Qi Shen
Journal of Organometallic Chemistry 2009 694(19) pp: 3167-3171
Publication Date(Web):
DOI:10.1016/j.jorganchem.2009.05.011
Co-reporter:Huihui Zhang, Zhuqing Zhou, Zhigang Yao, Fan Xu, Qi Shen
Tetrahedron Letters 2009 50(14) pp: 1622-1624
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.01.103
Co-reporter:Cunwei Qian, Xingmin Zhang, Junmei Li, Fan Xu, Yong Zhang and Qi Shen
Organometallics 2009 Volume 28(Issue 13) pp:3856-3862
Publication Date(Web):May 20, 2009
DOI:10.1021/om900120v
A series of new trisguanidinate lanthanide complexes including the first THF-solvated trisguanidinate lanthanum complexes were synthesized and fully characterized. The complexes were found to be efficient catalysts for amidation of aldehydes with amines under mild conditions with a wide scope of substrates including pyrrolidine, piperidine, and morpholine, and one of the intermediates for this process, lanthanum amido complex {[(iPrN)CNHiPr(NC6H4p-Cl)]2La(NHC6H5)}2·C7H8, was isolated.
Co-reporter:XiaoNiu Chen;Zhu Du;Yong Zhang;Fan Xu
Science Bulletin 2009 Volume 54( Issue 18) pp:3225-3230
Publication Date(Web):2009 September
DOI:10.1007/s11434-009-0519-2
Divalent ytterbium complex YbL(ONNO)(THF)2 (L(ONNO)= Me2NCH2CH2N(CH2-2-O-3,5-C6H2(tBu)2)2) (I) has first been found to serve as a catalyst for addition of amines to nitriles to give monosubstituted N-arylamidine in moderate to good yields. The aromatic amines and nitriles showed better activity. The outcome of the addition reaction was greatly affected by the structure of divalent ytterbium complexes. The reaction mechanism was proposed and the benzonitrile-coordinated divalent ytterbium phenoxide Yb(OAr)2(C6H5CN)(THF)2 (Ar = 2,6-ditBu-4-MeC6H3) was isolated as one of the intermediates.
Co-reporter:Bangyu Li, Yaorong Wang, Yingming Yao, Yong Zhang, Qi Shen
Journal of Organometallic Chemistry 2009 694(15) pp: 2409-2414
Publication Date(Web):
DOI:10.1016/j.jorganchem.2009.03.024
Co-reporter:Bang-Yu Li, Ying-Ming Yao, Yao-Rong Wang, Yong Zhang, Qi Shen
Inorganic Chemistry Communications 2008 Volume 11(Issue 3) pp:349-352
Publication Date(Web):March 2008
DOI:10.1016/j.inoche.2007.12.035
SmCl3 reacted with sodium salt of the Schiff base ligand L (L=3,5-Bu2t-2-O–C6H2CH–N-8-C9H6N) in a 1:2 molar ratio in THF to afford samarium Schiff base chloride L2SmCl(THF) (1). Treatment of complex 1 with excessive metallic sodium produced an unprecedented samarium complex [Na(DME)3][SmL3′Na(DME)] (2), in which three Schiff base ligands were trimerized to form the new ligand L3′ by the reductive coupling reactions of imine groups involving a rare coupling reaction of CN bond of quinoline ring with imine group of Schiff base ligand.Reduction of samarium Schiff base chloride L2SmCl(THF) (1) (L=3,5-Bu2t-2-O–C6H2CH–N–8-C9H6N) with excessive metallic sodium produced an unprecedented samarium complex [Na(DME)3][SmL3′Na(DME)] (2), in which three Schiff base ligands were trimerized to form the new ligand L3′ by the reductive coupling reactions of imine groups involving a rare coupling reaction of CN bond of quinoline ring with imine group of Schiff base ligand.
Co-reporter:Bangyu LI, Yingming YAO, Yaorong WANG, Yong ZHANG, Qi SHEN
Journal of Rare Earths 2008 Volume 26(Issue 4) pp:469-472
Publication Date(Web):August 2008
DOI:10.1016/S1002-0721(08)60120-9
The lanthanide complexes containing a bulky tridentate [N,N,O] Schiff base ligand 3,5-But2-2-(OH)C6H2CH=N-8-C9H6N (HL) were synthesized and characterized. The reaction of anhydrous LnCl3 with NaL formed in situ in a 1:1 molar ratio in THF at room temperature afforded the lanthanide Schiff base dichloride complexes LnLCl2(DME) (Ln=Eu (1); Sm (2)). Complexes 1 and 2 can be used as precursors for the synthesis of the lanthanide cyclopentadienyl Schiff base derivatives. The reactions of complexes 1 and 2 with one equiv of NaCH3C5H4 in THF provided the desired products LnL(CH3C5H4)Cl(THF)·THF (Ln=Eu (3); Sm (4)) in good isolated yields. These complexes were characterized by elemental analysis, IR spectra, and X-ray structural determination, in the case of complexes 3 and 4. The crystal data of complex 3 are monoclinic, P21/c space group, a=1.3370(2) nm, b=1.5190(2) nm, c=1.8910(3) nm, β=109.846(4)°, V=3.6125(8) nm3, Z=4, Dc=1.416 mg/m3, μ=1.847 mm−1, F(000)=1584, R=0.0707, wR=0.1350. The crystal data of complex 4 are monoclinic, P21/c space group, a=1.3383(1) nm, b=1.5210(2) nm, c=1.8960(2) nm, β =109.878(3)°, V=3.6293(7) nm3, Z=4, Dc=1.407 mg/m3, μ=1.728 mm−1, F(000)=1580, R=0.0670, wR=0.1385.
Co-reporter:Jinguo Zhang, Haisheng Yao, Yong Zhang, Hongmei Sun and Qi Shen
Organometallics 2008 Volume 27(Issue 11) pp:2672-2675
Publication Date(Web):May 6, 2008
DOI:10.1021/om8001922
The three salicylaldiminato-functionalized N-heterocyclic carbene lanthanide bromides L2LnBr (Ln = Nd (2), Sm (3), Er (4); L = [3,5-tBu2-2-(O)C6H2CH═NCH2CH2(C{NCHCHNiPr})]) with early to late lanthanide metals were conveniently synthesized in moderate yields by a protonolysis strategy via the direct reaction of LiLn(NiPr2)4 with [H2L]Br (1). All complexes were characterized by X-ray crystal determinations.
Co-reporter:Junfeng Wang, Tao Cai, Yingming Yao, Yong Zhang and Qi Shen
Dalton Transactions 2007 (Issue 45) pp:5275-5281
Publication Date(Web):10 Sep 2007
DOI:10.1039/B709310A
The steric effect of an amide group on the synthesis, molecular structures and reactivity of ytterbium amides supported by linked bis(amidinate) L (L = [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3]) is reported. Reaction of LYbCl(THF)2 with equimolar NaNHAr′ and NaNHAr (Ar′ = 2,6-Me2C6H3; Ar = 2,6-iPr2C6H3), respectively, gave the corresponding monometallic amide complexes LYb(NHAr′)(DME) 1 and LYb(NHAr)(DME) 2, in which the linked bis(amidinate) is coordinated to the metal center as a chelating ligand. The similar reaction with NaN(SiMe3)2 afforded a bimetallic amide complex (TMS)2NYb(L)2YbN(TMS)23 formed through the rearrangement reaction of L induced by the bulky N(SiMe3)2 group. In complex 3 the two linked bis(amidinate)s act as bridging ancillary ligands to link two YbN(TMS)2 species in one molecule. The definite molecular structures of 1–3 were provided by single-crystal X-ray analysis. Complexes 1–3 are efficient initiators for the polymerization of L-lactide, and their catalytic performance is highly dependent on the amido groups and molecular structures. The polymerizations initiated by complexes 1 and 2 proceeded in a living fashion as evidenced by the narrow polydispersities of the resulting polymers, together with the linear natures of the number average molecular weight versus conversion plots, while the polymerization system with complex 3 provided polymers with rather broad molecular weight distributions.
Co-reporter:Zhuqing Zhou;Fan Xu;Xiaoyan Han;Jun Zhou
European Journal of Organic Chemistry 2007 Volume 2007(Issue 31) pp:5265-5269
Publication Date(Web):30 AUG 2007
DOI:10.1002/ejoc.200700288
Three-component aza-Diels–Alder reactions involving aromatic aldehydes, aromatic amines, and dihydropyran or dihydrofuran are effectively catalyzed by samarium diiodide to afford pyrano[3,2-c]- or furano[3,2-c]quinolines in good yields and with high stereoselectivities. Either the cis or the trans isomers can be obtained as the major products by conveniently controlling reaction conditions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:C. R. Lu;B. Zhao;Q. Shen
Journal of Applied Polymer Science 2007 Volume 106(Issue 2) pp:1383-1389
Publication Date(Web):12 JUL 2007
DOI:10.1002/app.26761
Lanthanide metal (II) 2,6-di-tert-butylphenoxide complexes (ArO)2Ln(THF)3 (Ln = Sm 1, Yb 2) alone have been developed to catalyze the ring-opening polymerization of trimethylenecarbonate (TMC) and random copolymerization of TMC and ε-caprolactone (ε-CL) for the first time. The influence of reaction conditions, such as initiator, initiator concentration, polymerization temperature, and polymerization time, on monomer conversion, molecular weight, and molecular weight distribution of the resulting PTMC was investigated. It was found that the divalent complex 1 showed higher activity for the polymerization of TMC than complex 2. The random structure and thermal behavior of the copolymers P(TMC-co-CL) have been characterized by 1H NMR, 13C NMR, GPC, and DSC analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Co-reporter:Cheng-Rong LU;Hong-Hai LI;Bei ZHAO;Ying-Ming YAO;Yong ZHANG
Chinese Journal of Chemistry 2007 Volume 25(Issue 10) pp:1588-1592
Publication Date(Web):16 OCT 2007
DOI:10.1002/cjoc.200790294
The reactions of dilithium salt of trans-1,2-bis(trimethylsilylamino)cyclohexane with anhydrous lanthanide trichlorides LnCl3 (Ln=Yb, Nd) in THF afforded the dianionic binuclear tricycles of lanthanide chlorides {Li(THF)3[LnCl(µ2-trans-1,2-(NSiMe3)2C6H10)((2-Cl)]}2·2THF (Ln=Yb 1, Nd 2) in moderate yields. Both of the bridged complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that the two complexes are the analogues which have a tricyclic framework built by two bridged lanthanide metals, four nitrogens and four carbons from two diamide ligands. Each lanthanide metal coordinates to three nitrogen atoms and two chlorines to form a distorted trigonal bipyramid and connects with a lithium by a bridging chlorine.
Co-reporter:Cheng-Rong Lu;Bei Zhao;Li-Ying Zhou;Ying-Ming Yao;Yong Zhang
Chinese Journal of Chemistry 2007 Volume 25(Issue 5) pp:
Publication Date(Web):11 MAY 2007
DOI:10.1002/cjoc.200790125
The reaction of anhydrous YbCl3 with 1 equiv. of Li2Me2Si(NPh)2 in THF, after workup, yielded a ytterbium(III) chloride [{Me2Si(NPh)2Yb}(μ2-Cl)(TMEDA)]2·3PhMe (1) (TMEDA=tetramethylethanediamine). The same reaction followed by treatment with Na-K alloy afforded a new ytterbium(II) complex supported by a bridged diamide with four coordinated LiCl molecules, [{Me2Si(NPh)2Yb(THF)2}(μ3-Cl)(μ4-Cl){Li(THF)}2]2·2THF (2) in high yield. Both complexes were structurally characterized by X-ray analysis to be dimers. Complex 1 was a chlorine-bridged dimer with ytterbium in a distorted octahedral geometry. In complex 2 two [Me2Si(NPh)2Yb(THF)2]-(μ3-Cl)[Li(THF)]2 moieties were connected with each other by two μ4-Cl bridges to form a "chair-form" framework.
Co-reporter:Yun-Jie Luo;Yong Zhang
Chinese Journal of Chemistry 2007 Volume 25(Issue 4) pp:
Publication Date(Web):5 APR 2007
DOI:10.1002/cjoc.200790105
Reactions of 1,3-diisopropylcarbodiimide with alkali metal amides, MN(SiMe3)2 (M=Li or Na) in hexane or THF produced the alkali metal guanidinates {(i-PrN)2C[N(SiMe3)2]Li}2 (1) and {(i-PrN)2C[N(SiMe3)2]Na(THF)}2 (2) in nearly quantitative yields. Both complexes 1 and 2 were well characterized by elemental analysis, IR spectra, 1H and 13C NMR spectra, and X-ray diffraction. It was found that the guanidinates adopt different coordination modes in these complexes.
Co-reporter:XiaoPing Xu;YingMing Yao;Yong Zhang
Science Bulletin 2007 Volume 52( Issue 12) pp:1623-1628
Publication Date(Web):2007 June
DOI:10.1007/s11434-007-0251-8
Lanthanide methoxides supported by carbon-bridged bis(phenolate) ligands 2,2′-methylene-bis(6-tert-butyl-4-methylphenoxo) (MBMP2−) [(MBMP)Ln(µ-OMe)(THF)2]2 (Ln = Nd (1), Yb (2)) were synthesized in high yields by the protolysis reaction using (C5H5)3Ln(THF) as starting materials, and complex 1 was structurally characterized. The coordination geometry around the center metal can be best described as a distorted octahedron. Complexes 1 and 2 were shown to be efficient initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and L-lactide. The mechanism of DTC polymerization was explored by the end group analysis of the oligomer.
Co-reporter:YongSheng Wang;HongMei Sun;XuePing Tao;Yong Zhang
Science Bulletin 2007 Volume 52( Issue 23) pp:3193-3199
Publication Date(Web):2007 December
DOI:10.1007/s11434-007-0477-5
The reaction of anhydrous FeBr2 with two equivalents of anionic N-heterocyclic carbene (NaL1 and NaL2), which are generated in situ by the reaction of the corresponding salt [4-R-C6H4COCH2{CH-(NCHCHNiPr)}Br] (R = OCH3, H2L1Br, 1; R = F, H2L2Br, 2) with two equivalents of NaN(SiMe3)2, affords bis-ligand Fe(II) complexes of L12Fe (3) and L22Fe (4) in high yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr2 is unsuccessful, and the same complexes of 3 and 4 were obtained. Both 3 and 4 have been depicted by elemental analysis and X-ray structure determination. Preliminary studies show that both 3 and 4 can be used as single-component catalyst for the ring-opening polymerization of ɛ-caprolactone, and the catalytic activity of 3 is higher than that of 4.
Co-reporter:Hongting Sheng;Liying Zhou;Yong Zhang;Yingming Yao
Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 7) pp:1210-1218
Publication Date(Web):15 FEB 2007
DOI:10.1002/pola.21888
The anionic lanthanide-sodium-2,6-di-tert-butyl-phenoxide complexes [Ln(OAr)4][Na(DME)3]·DME (Ln = Nd 1 (neodymium), Sm 2 (samarium), or Gd 3 (gadolium); DME = dimethoxyethane) were synthesized by the reaction of anhydrous LnCl3 with 4 equiv of sodium-2,6-di-tert-butyl-phenoxide NaOAr in high yields and structurally characterized. These complexes showed high catalytic activity in the ring-opening polymerizations of ϵ-caprolactone (ϵ-CL) and trimethylene carbonate (TMC). The catalytic activity profoundly depended on the lanthanide metals. The active order of Gd < Sm < Nd for the polymerization of ϵ-CL and TMC was observed. The polymers obtained with these initiators all showed a unimodal molecular weight distribution, indicating that the [Ln(OAr)4][Na(DME)3]·DME anionic complexes could be used as single-component initiators. The anionic complex was more efficient than the corresponding neutral complex, Ln(OAr)3(THF)2. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1210–1218, 2007
Co-reporter:Yaorong Wang;Liying Zhou;Cheng Li;Hongmei Sun
Journal of Applied Polymer Science 2006 Volume 102(Issue 1) pp:22-28
Publication Date(Web):28 JUN 2006
DOI:10.1002/app.24109
The ring-opening polymerization of trimethylene carbonate (TMC) using homoleptic lanthanide amidinate complexes [CyNC(R)NCy]3Ln as single component initiators has been fully investigated for the first time. The substituents on amidinate ligands and center metals show great effect on the catalytic activities of these complexes, that is, Me > Ph, and La > Nd > Sm > Yb. Among them, [CyNC(Me)NCy]3La shows the highest catalytic activity. Some features of the TMC polymerization initiated by [CyNC(Me)NCy]3La were studied in detail. A mechanism that the polymerization occurs via acyl-oxygen bond cleavage rather than alkyl-oxygen bond cleavage was proposed. The copolymerization of TMC with ϵ-caprolactone initiated by [CyNC(Me)NCy]3La was also tested. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 22–28, 2006
Co-reporter:Hongmei Sun;Shuang Chen;Yingming Yao;Kaibei Yu
Applied Organometallic Chemistry 2006 Volume 20(Issue 5) pp:
Publication Date(Web):20 APR 2006
DOI:10.1002/aoc.1047
Homoleptic lanthanide metallocenes Cp′3Ln [Cp′ = methylcyclopentadienyl, Ln = Y (1), Er (2), Sm (3); Cp′ = cyclopentadienyl, Ln = Er (4) and Sm (5)] have been found to be a novel type of initiators for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). Among them, complex 1 shows the highest catalytic activity for ROP of ε-CL. In addition, a novel neutral trifluoroethoxo yttrium complex [(MeC5H4)2Y(µ-OCH2CF3)]2 (6) has been synthesized by the reaction of 1 with trifluoroethanol in 1:1 molar ratio in toluene and characterized by single-crystal X-ray structural analysis. Preliminary study shows that the catalytic activity of tris(methylcyclopentadienyl)yttrium complex 1 is higher than that of bis(methylcyclopentadienyl)yttrium complex 6. The mechanism of the present polymerization was studied by NMR spectra. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Hong-Mei Sun;Wan-Fei Li;Dong-Mei Hu;Qing Shao
Chinese Journal of Chemistry 2006 Volume 24(Issue 3) pp:
Publication Date(Web):13 MAR 2006
DOI:10.1002/cjoc.200690078
The catalytic activity of a series of indenylnickel(II) halides: (1-R-Ind)Ni(PPh3)X (R=ethyl, cyclopentyl and benzyl, while X=Cl, Br and I), towards styrene polymerization was studied in the presence of NaBPh4 and PPh3. The catalytic property of these halides was related to the substituent group on the indenyl ligand and the halogen atom bonded to the metal atom. Among them, the (1-Et-Ind)Ni(PPh3)Cl/NaBPh4/PPh3 system showed the highest activity for the polymerization of styrene, and the polystyrene obtained was a syndio-rich (rr triad) atactic polymer with Mn values in the range of 103–104. The mechanism of the styrene polymerization initiated by the (1-Et-Ind)Ni(PPh3)Cl/NaBPh4/PPh3 system was studied.
Co-reporter:Bao Liu, Yingming Yao, Mingyu Deng, Yong Zhang, Qi Shen
Journal of Rare Earths 2006 Volume 24(Issue 3) pp:264-267
Publication Date(Web):June 2006
DOI:10.1016/S1002-0721(06)60106-3
Co-reporter:Hongmei Peng, Yingming Yao, Mingyu Deng, Yong Zhang, Qi Shen
Journal of Rare Earths 2006 Volume 24(Issue 4) pp:509-512
Publication Date(Web):August 2006
DOI:10.1016/S1002-0721(06)60153-1
A polynuclear yttrium trifluoroethoxide was synthesized and its activity for the oligomerization of phenyl isocyanate was tested. Reaction of anhydrous YCl3 with CF3CH2ONa in a 1:3 molar ratio in THF at room temperature, after workup, gave complex 1 as colorless crystals. The composition of complex 1 is [Y (OCH2CF3)3]6ONa2(THF)12, which was identified by elemental analysis and 1H NMR. Further X-ray structure determination reveals that complex 1 is a poly-nuclear ion pair compound, [Y6(μ6-O) (OCH2CF3)18]2− [Na(THF)6]2+ (1). The crystal data of complex 1 are trigonal, P-3 space group, a = 1.78440(14) nm, b = 1.78440(14) nm, c = 1.27395 (12) nm, γ = 120°, V = 3.5129(5) nm3, Z = 1, Dc = 1.607 mg·m−3, μ = 2.591 mm−1(Mo Kα), F(000) = 1710, R = 0.067, wR = 0.182. Preliminary results demonstrated that complex 1 is a highly effective catalyst for the oligomerization of phenyl isocyanate.
Co-reporter:Yiqin Luo;Fan Xu;Jianting Wu;Hou Chen
Heteroatom Chemistry 2006 Volume 17(Issue 5) pp:389-392
Publication Date(Web):7 JUL 2006
DOI:10.1002/hc.20219
An efficient preparation of α-amino phosphonates by the one-pot condensation of aldehydes, amines, and dialkyl phosphites using catalytic amounts of lanthanide chloride under mild conditions is successfully developed. Moreover, the catalyst is water-tolerant and could be recovered and reused. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:389–392, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20219
Co-reporter:Xingan Pang;Hongmei Sun;Yong Zhang;Hongjie Zhang
European Journal of Inorganic Chemistry 2005 Volume 2005(Issue 8) pp:
Publication Date(Web):21 APR 2005
DOI:10.1002/ejic.200400750
Two guanidinate-based terbium complexes [iPrNC(NiPr2)NiPr]mTbCl3–m [m = 3 (1), 2 (2)] were synthesized, and the crystal structure of 1 was determined by single-crystal X-ray diffraction. Complexes 1 and 2 were further characterized by elemental analysis, IR, and 1H NMR spectroscopy. In complex 1 the guanidinate ligand coordinates to the terbium atom through the nitrogen atoms in a bidentate chelating coordination mode. As a result of an efficient energy transfer from the guanidinate ligand to the central Tb3+, both 1 and 2 have been found to exhibit strong green emission corresponding to Tb3+5D4-7FJ (J = 6, 5, 4, 3) transitions. Among them, the emission 5D4-7F5 (550 nm) is the most prominent. The lifetimes of the 5D4 Tb3+ excited levels of the two complexes were determined to be around 0.90 ms. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Co-reporter:Xing-An Pang;Ying-Ming Yao;Jun-Feng Wang;Hong-Ting Sheng;Yong Zhang
Chinese Journal of Chemistry 2005 Volume 23(Issue 9) pp:
Publication Date(Web):12 OCT 2005
DOI:10.1002/cjoc.200591193
Addition of one equivalent of LiN(i-Pr)2 or LiN(CH2)5 to carbodiimides, RNCNR [R=cyclohexyl (Cy), isopropyl (i-Pr)], generated the corresponding lithium of tetrasubstituted guanidinates {Li[RNC(N R2′)NR](THF)}2 [R=i-Pr, N R2′=N(i-Pr)2 (1), N(CH2)5 (2); R=Cy, N R2′=N(i-Pr) 2 (3), N(CH2)5 (4)]. Treatment of ZrCl4 with freshly prepared solutions of their lithium guanidinates provided a series of bis(guanidinate) complexes of Zr with the general formula Zr[RNC(N R2′)NR]2Cl2 [R=i-Pr, NR2′=N(i-Pr) 2 (5), N(CH2)5 (6); R=Cy, N R2′=N(i-Pr)2 (7), N(CH2)5 (8)]. Complexes 1, 2, 5–8 were characterized by elemental analysis, IR and 1H NMR spectra. The molecular structures of complexes 1, 7 and 8 were further determined by X-ray diffraction studies.
Co-reporter:Hong-Mei Sun;Huan-Rong Li;Chang-Sheng Yao;Ying-Ming Yao;Hong-Ting Sheng
Chinese Journal of Chemistry 2005 Volume 23(Issue 11) pp:
Publication Date(Web):30 NOV 2005
DOI:10.1002/cjoc.200591541
The ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) using lanthanide thiolate complexes [(CH3C5H4)2Sm(μ-SPh)(THF)] 2 (1) and Sm(SPh)3(HMPA)3 (2) as initiators has been investigated for the first time. Both of 1 and 2 were found to be highly efficient initiators for the ROP of ε-CL. The poly(ε-caprolactone) (PCL) with molecular weight Mn up to 1.97×105 and relatively narrow molecular weight distributions (1.20< Mw/Mn<2.00) have been obtained in high yield in the temperature range of 35–65 °C. According to the polymer yield, 2 showed much higher activity than 1. However, the number-average molecular weight of PCL obtained with 2 was much lower than with 1. The possible polymerization mechanism of the ε-CL polymerization has been proposed based on the results of the end group analysis of the ε-CL oligomer.
Co-reporter:Junfeng Wang, Yingming Yao, Jinlei Cheng, Xing'an Pang, Yong Zhang, Qi Shen
Journal of Molecular Structure 2005 Volume 743(1–3) pp:229-235
Publication Date(Web):31 May 2005
DOI:10.1016/j.molstruc.2005.02.027
Reaction of the dilithium salt of a linked bis(amidinate) dianionic ligand LLi2 [L=Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3] with anhydrous YbCl3 in THF in 1:1 molar ratio, after crystallized from hexane, afforded the linked bis(amidinate) ytterbium chloride LYb(μ-Cl)2YbL(THF) (1). The chloro bridges in complex 1 can be easily broken by donor solvent. Recrystallization of complex 1 from hexane in the presence of THF formed the monomeric ytterbium chloride LYbCl(THF)2 (2). Reaction of complex 2 with 1 equiv. of CpNa, after workup, gave the desired ytterbium complex LYbCp(DME) (3) in high yield. All the complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction.
Co-reporter:Mingqiang Xue, Yingming Yao, Qi Shen, Yong Zhang
Journal of Organometallic Chemistry 2005 Volume 690(21–22) pp:4685-4691
Publication Date(Web):1 November 2005
DOI:10.1016/j.jorganchem.2005.07.050
The synthesis and structure of the salt-free diamido complexes of lanthanide supported by β-diketiminate ligand (2,6-Me2C6H3)NC(Me)CHC(Me)N(2,6-Me2C6H3) are described. The β-diketiminate lanthanide dichloride LLnCl2(THF)2 (L = N,N′-bis(2,6-dimethylphenyl)-2,4-pentanediiminate) [Ln = Yb (1), Nd (2)] was prepared by the metathesis reaction of LLi with anhydrous LnCl3 in a 1:1 molar ratio in THF at room temperature. Reactions of 1 and 2 with 2 equiv. of LiNPh2 in THF gave the salt-free complex LLn(NPh2)2(THF) [Ln = Yb (3), Nd (4)] in good yield as crystalline solids. Both compounds were characterized crystallographically. The coordinated geometry around the central metal can be described as a distorted trigonal bipyramid. Complexes 3 and 4 showed good catalytic activity for the polymerization of acrylonitrile and high activity for the ring-opening polymerization of ε-caprolactone at room temperature.Treatment of β-diketiminate lanthanide dichloride LLnCl2(THF)2 (L = N,N′-bis(2,6-dimethylphenyl)-2,4-pentanediiminate) [Ln = Yb (1), Nd (2)] with freshly prepared solutions of LiNPh2 in THF gave LLn(NPh2)2(THF) [Ln = Yb (3), Nd (4)] in good yield as crystalline solids. Both of these lanthanide amides supported by β-diketiminate ligand were found to exhibit high activity for the polymerization of acrylonitrile and ring-opening polymerization of ε-caprolactone at room temperature.
Co-reporter:Liying Zhou;Yingming Yao;Yong Zhang;Hongting Sheng;Mingqiang Xue
Applied Organometallic Chemistry 2005 Volume 19(Issue 3) pp:
Publication Date(Web):14 FEB 2005
DOI:10.1002/aoc.855
The title complex, [Ph2NC(NCy)2]3Yb·2PhCH3 is a monomer with a six-coordinate ytterbium center ligated by six nitrogen atoms of three chelating bidentate guanidinate ligands. The coordination geometry around the lanthanide ion is best described as a distorted trigonal prism. Copyright © 2005 John Wiley & Sons, Ltd.
Co-reporter:Huanrong Li;Changsheng Yao;Yingming Yao;Hongting Sheng
Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 6) pp:1312-1316
Publication Date(Web):8 FEB 2005
DOI:10.1002/pola.20620
The tri- and divalent samarium thiolate derivatives were first found to be highly active initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and the copolymerization of DTC and ε-caprolactone (ε-CL).
Co-reporter:Bei Zhao;Yaorong Wang;Chengrong Lu;Mingyu Deng
Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 17) pp:3966-3972
Publication Date(Web):21 JUL 2005
DOI:10.1002/pola.20885
N-Phenyl maleimide (N-PMI) was successfully polymerized by divalent rare-earth complexes (ArO)2Sm(THF)4 (ArO = 2,6-di-tert-butyl-4-methyl phenoxo-; THF = tetrahydrofuran) and (Ar′O)2Ln(THF)3 (Ar′O = 2,6-di-tert-butyl phenoxo-; Ln = Sm, Yb, or Eu). The central metals greatly affected the reactivity, and the reactivity order was Sm(II) > Yb(II) > Eu(II). The activity of (Ar′O)2Sm(THF)3 was higher than that of (ArO)2Sm(THF)4. The polymerization yields were higher in THF than in other solvents, and the maximum yields were obtained around 25 °C. A proposed mechanism is discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3966–3972, 2005
Co-reporter:Mingyu Deng, Yingmin Yao, Yong Zhang and Qi Shen
Chemical Communications 2004 (Issue 23) pp:2742-2743
Publication Date(Web):15 Oct 2004
DOI:10.1039/B410599K
Treatment of the THF solution of (MeC5H4)2Sm(THF) with an equivalent of carbodiimine [RNCNR]
(R = Pri or Cy; Cy = cyclohexyl) in the presence of an equivalent of hexamethylphosphoric triamide (HMPA) at room temperature gives, via a reduction-coupling reaction of carbodiimine, the corresponding bimetallic oxalamidino complex of samarium [η4-C2(NR)4][(MeC5H4)2Sm(HMPA)]2·2THF.
Co-reporter:Liying Zhou;Yingming Yao;Yong Zhang;Mingqiang Xue;Jinglei Chen
European Journal of Inorganic Chemistry 2004 Volume 2004(Issue 10) pp:
Publication Date(Web):1 APR 2004
DOI:10.1002/ejic.200300856
Two methods to synthesize homoleptic guanidinate lanthanide complex are described. The samarium guanidinate complex [Sm{Ph2NC(NCy)2}3]·2C7H8 (1) can be synthesized by the metathesis reaction of lithium guanidinate with anhydrous samarium trichloride in a 3:1 molar ratio. The analogous complexes [Ln{Ph2NC(NCy)2}3]·2C7H8 [Ln = Yb (2), Nd (3)] can also be synthesized by the insertion reaction of N,N′-dicyclohexylcarbodiimide into the Ln−N bond of [(THF)4Li][Ln(NPh2)4] in a 3:1 molar ratio in good yield. Complexes 1−3 were characterized by elemental analysis, IR and 1H NMR spectroscopy. The molecular structures of complexes 1 and 3 were further determined by X-ray diffraction techniques. These complexes showed high activity for the ring-opening polymerization of trimethylene carbonate (TMC), giving polymers with Mw/Mn ranging from 1.41−1.73. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Co-reporter:Qing Shao;Hongmei Sun;Yong Zhang
Applied Organometallic Chemistry 2004 Volume 18(Issue 6) pp:
Publication Date(Web):21 MAY 2004
DOI:10.1002/aoc.624
The first α-diimine nickel(I) complex having a chloro bridge is reported. The centrosymmetric dinuclear structure of {[ArNC(Me)C(Me)NAr]NiCl}2[Ar2,6−C6H3(i-Pr)2] features two chelating α-diimine ligands and two bridged chlorine atoms, so that a distorted tetrahedral N2Cl2 coordination geometry for nickel results. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Xiaoping Xu;Yingming Yao;Yong Zhang
Applied Organometallic Chemistry 2004 Volume 18(Issue 8) pp:
Publication Date(Web):10 AUG 2004
DOI:10.1002/aoc.667
A low-coordinate aryloxo erbium complex, [(ArO)3Er(THF)](MePh), has been synthesized by the reaction of anhydrous ErCl3 with three equivalents of NaOAr in tetrahydrofuran. The central erbium atom is coordinated by three oxygen atoms of the aryloxo ligands and one oxygen atom of the tetrahydrofuran molecule, resulting in a distorted tetrahedron. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Chen Jing-Lei, Yao Ying-Ming, Luo Yun-Jie, Zhou Li-Ying, Zhang Yong, Shen Qi
Journal of Organometallic Chemistry 2004 Volume 689(Issue 6) pp:1019-1024
Publication Date(Web):15 March 2004
DOI:10.1016/j.jorganchem.2003.12.041
A series of homoleptic lanthanide guanidinate (guan)3Ln · ((C2H5)2O)n (Ln=Yb, n=1 guan=(CyN)2CNiPr2, (1); Ln=Nd, n=0, guan=(CyN)2CNiPr2, (2); (iPrN)2CNiPr2, (3); (iPrN)2CN(CH2)5, (4)); (iPr=isopropyl, Cy=Cyclohexyl) were synthesized by the reaction of THF solution of lithium guanidinate with anhydrous lanthanide trichlorides in THF in 3:1 molar ratio. The molecular structures of 2 and 3 were determined to be monomeric in solid state with a six coordinate lanthanide metal ligated by six nitrogens of three guanidinate groups. All the complexes exhibited extremely high activity for the ring-opening polymerization of ε-caprolactone and the polymerization gave the polymers with high molecular weights. The different substituents at guanidino ligands have great effect on the catalytic activity. The mechanism of the polymerization was presented.A series of homoleptic lanthanide guanidinate (guan)3Ln · ((C2H5)2O)n (Ln=Yb, n=1 guan=(CyN)2CNiPr2, (1); Ln=Nd, n=0, guan=(CyN)2CNiPr2, (2); (iPrN)2CNiPr2, (3); (iPrN)2CN(CH2)5, (4)); (iPr=isopropyl, Cy=Cyclohexyl) were synthesized by the reaction of THF solution of lithium guanidinate with anhydrous lanthanide trichlorides in THF in 3:1 molar ratio.
Co-reporter:Fan Xu;Yiqin Luo;Mingyu Deng
European Journal of Organic Chemistry 2003 Volume 2003(Issue 24) pp:
Publication Date(Web):4 DEC 2003
DOI:10.1002/ejoc.200300545
A simple and efficient preparation of α-amino phosphonates under relatively mild conditions by the one-pot reaction of aldehydes with amines and dialkyl phosphites using catalytic amounts of SmI2 is described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Co-reporter:Yunjie Luo;Yingming Yao;Kaibei Yu;Linhong Weng
European Journal of Inorganic Chemistry 2003 Volume 2003(Issue 2) pp:
Publication Date(Web):8 JAN 2003
DOI:10.1002/ejic.200390043
The synthesis and structure of new lanthanide complexes with the guanidinate ligand [(Me3Si)2NC(NiPr)2−] are described. Reaction of a THF slurry of LnCl3 with a hexane solution of [(SiMe3)2NC(NiPr)2]Li (1) in a 1:2 molar ratio afforded the new soluble organolanthanide complexes [(SiMe3)2NC(NiPr)2]Ln(μ-Cl)2Li(THF)2 [Ln = Yb (2), Nd (3)]. Alkylation of 2 and 3 with 2 equiv. of MeLi in hexane gave [(SiMe3)2NC(NiPr)2]Ln(μ-Me)2Li(TMEDA) [Ln = Yb (4), Nd (5)] in good yield as crystalline solids. The molecular structures of 2 and 5 were determined by single-crystal X-ray analysis. The lanthanide ions in these complexes display a distorted pseudo-octahedral coordination geometry. Complexes 4 and 5 exhibited extremely high activity for the ring-opening polymerization of ϵ-caprolactone to give high molecular weight polymers. Complex 5 also showed good catalytic activity for the syndiotactic polymerization of methyl methacrylate. (© Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2002)
Co-reporter:Deng Ming-Yu;Yao Ying-Ming;Zhou Yu-Fang;Zhang Li-Fen;Shen Qi
Chinese Journal of Chemistry 2003 Volume 21(Issue 5) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20030210519
A series of lanthanide complexes including (Ind)3Sm(THF) (1), [(MeCp)2Sm(μ-SPh)(THF)]2(2), [(MeCp)2Y(μ-O-i-Pr)]2 (3), (MeCp)3Sm·θF (4), Sm(SPh)3(hmpa)3(5), [(MeCp)2Y-(μ-OCH2CF3)]2(6) and (OF3CH2O)3 Y(THF)3 (7) were synthesized and they have good activity for the oligomerization of phenyl isocyanate. Among them 5 shows the highest activity. The conversion is as high as 96.2%, with 1/2500 of the molar ratio of cat./ PhNCO. The main components in oligomer were characterized to be a cyclodimer and a cyclotrimer. The ratio of cyclodimer to cyclotrimer depends on the lanthanide complexes used. 7 gave 85.2% cyclotrimer with 1/300 of the molar ratio of cat./PhNCO at 40 °C for 0.5 h, while 5 gave 77.6% cyclodimer with 1/300 of the molar ratio of cat./PhNCO at 40 °C for 4 h.
Co-reporter:Yao Ying-Ming;Yu Long-Bao;Shen Qi;Zhang Jing;Wu Li-Xin;Ye Ling
Chinese Journal of Chemistry 2003 Volume 21(Issue 4) pp:442-445
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20030210418
Anhydrous LnCl3 reads with 2 equiv. of the sodium salt of the bidentate Schiff base N-(2, 6-diisopropylphenyl) salicylaldimine in THF to form the monomeric lanthanide chlorides [2-OC6H4CH = N(2,6-i-Pr2C6H3)]2LnCl(THF) [Ln=Yb (1), Er (2)]. Complex 1 crystallizes in P1 space group with a = 0.9215(2) nm, b = 1.36612(4) nm, c = 1.6899(2) nm, a = 74.83(3)°, β = 77.43(2)°, γ = 81.04(1)°, Z = 2, V = 1.9929(4) nm3, Dc = 1.402 g/cm3. The two complexes exhibited fairly good catalytic activity in the ring-opening polymerization of ϵ-caprolactone.
Co-reporter:Hongmei Sun, Wanfei Li, Xiaoyan Han, Qi Shen, Yong Zhang
Journal of Organometallic Chemistry 2003 Volume 688(1–2) pp:132-137
Publication Date(Web):15 December 2003
DOI:10.1016/j.jorganchem.2003.09.002
Neutral indenyl nickel complexes with the general formula (η-1-R–Ind)Ni(PPh3)Cl (R=cyclopentyl (1), benzyl (2)) have been prepared and characterized by 1H-NMR spectroscopy and single-crystal X-ray analysis. The results of X-ray crystal structural determination reveal that the hapticity of indenyl ligand in complex 1 or 2 is significantly distorted away from an idealized η5 mode to an unsymmetrical η3 mode. Furthermore, the structures of (R–Ind)Ni(PPh3)Cl exhibit a progressively more distorted coordination of the indenyl ring from cyclopentyl to benzyl. Both of them are inert toward the insertion of styrene, however, they are able to catalyze the polymerization of styrene effectively in the presence of NaBPh4 and PPh3 to give syndio-rich atactic poly(styrene) with Mw values in the range of 104. The NaBPh4·1·PPh3 system shows the higher catalytic activity than the NaBPh4·2·PPh3 system.Neutral indenyl nickel complexes (η-1-R–Ind)Ni(PPh3)Cl (R=cyclopentyl (1), benzyl (2)) have been synthesized and characterized by single-crystal X-ray analysis. When combined with NaBPh4 and PPh3, both of them are able to catalyze the polymerization of styrene effectively to give syndio-rich (rr) atactic poly(styrene) with Mw values in the range of 104.
Co-reporter:Mingyu Deng, Yingming Yao, Qi Shen, Yong Zhang, Jianping Lang, Yufang Zhou
Journal of Organometallic Chemistry 2003 Volume 681(1–2) pp:174-179
Publication Date(Web):12 September 2003
DOI:10.1016/S0022-328X(03)00598-9
Synthesis and characterization of a new class of ion-pairs complexes [Ln2(PhMe2CC5H4)4(μ-X)2][Li(DME)3]2 (Ln=Sm, X=I; Ln=Yb, X=Cl) are described. The reaction of SmI2(THF)2 (THF=tetrahydrofuran) with two equivalents of PhMe2CC5H4Li(DME) in THF affords the Sm(II) complex [Sm2(PhMe2CC5H4)4(μ-I)2][Li(DME)3]2 (1), while the Na–K alloy reduction of (PhMe2CC5H4)2YbCl, which was formed in situ by the reaction of YbCl3 and PhMe2CC5H4Li in 1:2 molar ratio, gives Yb(II) complex [Yb2(PhMe2CC5H4)4(μ-Cl)2][Li(DME)3]2 (2). The single-crystal structural analyses of 1 and 2 reveal that they both comprise two Li+(DME)3 cations and a new class of dianion, {[C5H4(CMe2Ph)]4Ln2(μ-X)2}2−, in which two [C5H4(CMe2Ph)]2Ln were bridged together by two iodine atoms for Sm and two chlorine atoms for Yb. The coordination geometry of the central metal is best described as a distorted tetrahedral.A new class of ion-pairs complexes of lanthanide(II) supported by substituted cyclopentadienyl ligand {[C5H4(Me2Ph)]4Ln2(μ-X)2}[Li(DME)3]2 (Ln=Sm, X=I (1); Ln=Yb, X=Cl (2)) were synthesized and well characterized. The single-crystal structural analyses of 1 and 2 revealed that these two lanthanocenes(II) comprise two Li+(DME)3 cations and a {[C5H4(Me2Ph)]4Ln2(μ-X)2}2− dianion, in which two [C5H4(Me2Ph)]2Ln were bridged together by two iodines for Sm and two chlorines for Yb. The coordination geometry of the central metal is best described as a distorted tetrahedral.
Co-reporter:Yunjie Luo, Yingming Yao, Wenjing Li, Jinglei Chen, Zhenqin Zhang, Yong Zhang, Qi Shen
Journal of Organometallic Chemistry 2003 Volume 679(Issue 1) pp:125-129
Publication Date(Web):1 August 2003
DOI:10.1016/S0022-328X(03)00545-X
Reactions of [N(C6H3i-Pr2-2,6)(SiMe3)]2LnCl(THF) (Ln=Nd, Yb) with two equivalents of MeLi in a mixture solution of toluene and Et2O gave [N(C6H3i-Pr2-2,6)(SiMe3)]2LnCH3(μ-CH3)Li(THF)3·PhCH3 (Ln=Nd (1), Yb (2)) in good isolated yields as crystalline solids. The single-crystal structural analysis of 2 revealed that the coordination geometry of ytterbium ion is best described as a distorted pseudo-tetrahedron. Both 1 and 2 are active for the polymerization of methyl methacrylate to give syndiotactic-rich and high molecular weight polymers (Mn>104) with relatively narrow molecular weight distributions (Mw/Mn<2).Reactions of [N(C6H3i-Pr2-2,6)(SiMe3)]2LnCl(THF) (Ln=Nd, Yb) with two equivalents of MeLi in a mixture solution of toluene and Et2O gave [N(C6H3i-Pr2-2,6)(SiMe3)]2LnCH3(μ-CH3)Li(THF)3·PhCH3 (Ln=Nd (1), Yb (2)) in good isolated yields as crystalline solids. The single-crystal structural analysis of 2 revealed that the coordination geometry of ytterbium ion is best described as a distorted pseudo-tetrahedron. Both 1 and 2 are active for the polymerization of methyl methacrylate to give syndiotactic-rich and high molecular weight polymers (Mn>104) with relatively narrow molecular weight distributions (Mw/Mn<2).
Co-reporter:Yingming Yao, Yunjie Luo, Jinglei Chen, Zhenqin Zhang, Yong Zhang, Qi Shen
Journal of Organometallic Chemistry 2003 Volume 679(Issue 2) pp:229-237
Publication Date(Web):15 August 2003
DOI:10.1016/S0022-328X(03)00600-4
Treatment of LnCl3 with [(SiMe3)2NC(NiPr)2]Li in 1:2 molar ratio afforded the soluble bis(guanidinate)lanthanide chlorides {[(SiMe3)2NC(NiPr)2]2Ln(μ-Cl)}2 (Ln=Y (1), Nd (2)). Amination of 1 and 2 with two equivalents of LiN(iPr)2 in a mixture solution of toluene and hexane gave [(SiMe3)2NC(NiPr)2]2LnN(iPr)2 (Ln=Y (3), Nd (4)) in good isolated yields. The single-crystal structural analyses of 2 and 3 revealed that the coordination geometries of lanthanide metals are best described as a distorted pseudo-octahedron and a pseudo-pyramid, respectively. Complexes 3 and 4 exhibited extremely high activity for the polymerizations of ε-caprolactone and methyl methacrylate (MMA).A series of bis(guanidinate)organolanthanide complexes, {[(SiMe3)2NC(NiPr)2]2Ln(μ-Cl)}2 (Ln=Y (1), Nd (2)) and [(SiMe3)2NC(NiPr)2]2LnN(iPr)2 (Ln=Y (3), Nd (4)), were synthesized and well characterized. The single-crystal structural analyses of 2 and 3 revealed that the coordination geometries of lanthanide metals are best described as a distorted pseudo-octahedron and a pseudo-pyramid, respectively. Complexes 3 and 4 exhibited extremely high activity for the polymerizations of ε-caprolactone and MMA.
Co-reporter:Yingming Yao, Mingqiang Xue, Yunjie Luo, Zhenqin Zhang, Rui Jiao, Yong Zhang, Qi Shen, Wingtak Wong, Kaibei Yu, Jie Sun
Journal of Organometallic Chemistry 2003 Volume 678(1–2) pp:108-116
Publication Date(Web):15 July 2003
DOI:10.1016/S0022-328X(03)00453-4
The reactions of ytterbium dichlorides with different β-diketiminate ligand ((Ar)NC(Me)CHC(Me)N(Ar′), Ar=Ar′=C6H5 (L1); Ar=Ar′=2,6-Me2C6H3 (L2); Ar=C6H5, ) with 1 equiv of Cp′Na were studied. It was found that the bulkiness of β-diketiminate ligand and cyclopentadienyl group both have significant effect on the above reaction. For less bulky ligands L1 and L2, the reaction affords not the expected mixed-ligand ytterbium chloride, (C5H5)YbLCl or (CH3C5H4)YbCl, but the ligand-redistributed product (C5H5)2YbL or (CH3C5H4)2YbL. For bulkier ligand L3, the desired anionic ytterbium chloride (C5H5)YbL3(μ-Cl)2Li(THF)2 is obtained. For the smallest ligand L1, the expected ytterbium monochloride can also be obtained using bulky C5Me5Na as reactant. Each of these complexes was well characterized, while several have been characterized by X-ray diffraction structure determination.The reactions of β-diketiminate ytterbium dichlorides with 1 equiv of Cp′Na were studied. These results reveal that choice suitable bulkiness of β-diketiminate and cyclopentadienyl are both important for the synthesis of mixed-ligand lanthanide chloride supported by β-diketiminate and cyclopentadienyl.
Co-reporter:Fan Xu;Xue-Hua Zhu;Jun Lu;Jiu-Qin Li
Chinese Journal of Chemistry 2002 Volume 20(Issue 11) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20020201130
Samarium(II) complexes or Samarium(II) complexes/n-hexylamine systems were found to be efficient catalysts for cyclotrimerization of arylnitriles. A variety of nitrites can be converted into the corresponding substituted-s-triazines under mild conditions in good to high yields by using samarium (II) complexes/n-hexylamine as catalysts. The same reaction catalyzed by samarium(II) complexes alone gives s-triazines in moderate yields.
Co-reporter:Min-Hua Qi;Xin-Qiang Gong;Zhi-Quan Shen;Lin-Hong Weng
Chinese Journal of Chemistry 2002 Volume 20(Issue 6) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20020200609
The reaction between K(1-C5H9C9H6) and anhydrous LnCl3 (Ln=Sm, Yb) in the molar ratio of 2:1 in THF with subsequent treatment by Na-K alloy afforded (1-C5H9C9H6)2Ln-(THF)n(Ln=Sm, n=1; Ln=Yb, n=2), while the reaction of Sml2 with K(1-C5H9C9H6) in the molar ratio of 1:2 in THF gave the anionic complex K(1-C5H9C9H6)3Sm(THF)3. The X-ray structure of (1-C5H9C9H6)2Yb(THF)2 showed that central metal Yb is coordinated by two cyclopentadienyl rings of 1-cyclopentylindenyls and two oxygen atoms from two tetrahydrofuran molecules to form pseudo-tetrahedral coordinate geometry. All these complexes are active for the polymerization of acrylonitrile.
Co-reporter:Qi Shen;Yaorong Wang;Keda Zhang;Yingming Yao
Journal of Polymer Science Part A: Polymer Chemistry 2002 Volume 40(Issue 4) pp:612-616
Publication Date(Web):4 JAN 2002
DOI:10.1002/pola.10141
Polymerization of (dimethylamino)ethyl methacrylate (DMAEMA) by lanthanocene amide complexes was investigated. The results show that (MeC5H4)2LnN(i-Pr)2[tetrahydrofuran (THF)] (Ln = Y, Er, Yb), (MeC5H4)2YbNC5H10(HNC5H10) (HNC5H10 = piperidine), (MeC5H4)2YbNPh2(THF), and (t-BuC5H4)2YbNPh2(THF) are effective initiators for the polymerization of DMAEMA, and the molecular weights of the polymers obtained exceed 100 × 103. The polymerization reactions can be varied over quite a broad range of temperatures from −78 to 40 °C. The central metals and amido groups had a significant effect on the polymerization activity. The increasing activity of central metals and amido groups was Yb < Er < Y and NPh2 < N(i-Pr)2 < NC5H10, respectively. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 612–616, 2002; DOI 10.1002/pola.10141
Co-reporter:Ying-Ming Yao;Yue Zhang;Qian-Cai Liu;Qing-Jin Meng;Yong-Hua Lin
Chinese Journal of Chemistry 2001 Volume 19(Issue 6) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20010190609
Reaction of Ndcl3 with AlCl3 and mesitylene in benzene gives complex [Nd(η6-1, 3, 5-C6H3Me3)-(AlCl4)3](C6H6) (1) which was characterized by elemental analysis, IR spectra, MS and X-ray diffractions. The X-ray determination indicates that 1 has a distorted pentagonal bipyramidal geometry and crystallizes in the monoclinic, space group P21/n with a = 0.9586(2), b = 1.1717(5), c = 2.8966(7) nm, β = 90.85 (2)°, V = 3.2529 (6) nm3,Dc= 1.573 g/cm3, Z = 4. A comparison of bond parameters for all the reported Ln (η6-Ar) (AlCl4)3 complexes indicates that the bond distance of LaC is shortened with the increasing of methyl group on benzene and with the decreasing of radius of lanthanide ions.
Co-reporter:Yaorong Wang, Qi Shen, Liping Wu, Yue Zhang, Jie Sun
Journal of Organometallic Chemistry 2001 Volume 626(1–2) pp:176-180
Publication Date(Web):30 April 2001
DOI:10.1016/S0022-328X(01)00687-8
Reaction of (MeC5H4)2LnCl (Ln=Yb, Y, Er) with LiNH2 in toluene at 0°C yielded the complexes {(MeC5H4)2Ln[OC̄H2]}2 [Ln=Yb (1), Y (2), Er (3)] in fairly good yields. The crystal structure of 1 [monoclinic, space group P21/n (#14); a=12.247(1), b=11.137(2), c=12.708(3) Å; β=107.36(1)°, V=1654.2(5) Å3, Z=2, Dcalc=1.780 g cm−3] was identified by X-ray diffraction analysis. The two trivalent (MeC5H4)2Yb units are bridged by two deprotonated ε-caprolactam ligands via Yb–N (2.374(4) Å) and Yb–O* (2.277(3) Å) bonds. All the complexes exhibit good catalytic activity for the ring-opening polymerization of ε-caprolactone.
Co-reporter:Xuehua Zhu, Guoyao Li, Fan Xu, Yong Zhang, Mingqiang Xue, Qi Shen
Tetrahedron (16 March 2017) Volume 73(Issue 11) pp:
Publication Date(Web):16 March 2017
DOI:10.1016/j.tet.2017.01.051
Cationic lanthanide complexes of the type [Ln(CH3CN)9]3+[(AlCl4)3]3–·CH3CN (Ln = Pr, Nd, Sm, Gd, Er, Yb, Y) served as effective catalysts for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols to yield the cyclic ethers with Markovnikov regioselectivity under mild conditions. Novel cationic complexes, [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN and [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN, were synthesized and evaluated for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols for comparison. The active sequence of [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN < [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN < [Nd(CH3CN)9]3+[(AlCl4)3]3–·CH3CN observed indicated that both the cation and anion have great influence on the activity. Comparative study on the activity of AlCl3 and its cationic complex [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN revealed the formation of the cationic Al center enhanced the activity greatly. The 1H NMR studies indicated the activation of hydroxyl and olefin by the cationic Ln3+ center were involved in the reaction pathways.
Co-reporter:Duwei Qin, Fubin Han, Yingming Yao, Yong Zhang and Qi Shen
Dalton Transactions 2009(Issue 28) pp:NaN5541-5541
Publication Date(Web):2009/06/04
DOI:10.1039/B904580E
The protonolysis of anionic lanthanide amide complexes (THF)LiLn(NPri2)4 with two equiv. of tridentate Schiff base HL (L = 3,5-But2-2-O-C6H2CHN-C5H4N) afforded the unanticipated products LiL′2Ln(THF) (L′ = 3,5-But2-2-O-C6H2CH(NPri2)-N-C5H4N; Ln = Y 1, Sm 2 and Yb 3) formed by intramolecular nucleophilic attack of the amide groups at the imine carbon atoms of the original ligand, L. The protonolysis is greatly affected by the amide group. When amine elimination was carried out with a mixture of Ln[N(TMS)2]3(μ-Cl)Li(THF)3 (TMS = SiMe3) and LiN(TMS)2, the expected lanthanide amide complexes with two Schiff base ligands, L2Ln[N(TMS)2] (Ln = Sm 4 and Nd 5), were isolated and no migration of the N(TMS)2 group was observed because of steric hindrance. Complexes 1–5 were well characterized including X-ray structural analyses.
Co-reporter:Xiaodong Shen, Yong Zhang, Mingqiang Xue and Qi Shen
Dalton Transactions 2012 - vol. 41(Issue 13) pp:NaN3674-3674
Publication Date(Web):2012/02/14
DOI:10.1039/C2DT12176J
The metathesis reaction of anhydrous EuCl3 with sodium salt of bulky β-diketiminato NaL (L = [N(2, 4, 6- Me3C6H2)C(Me)]2CH−, L2, 4, 6-Me3; [N(2,6-iPr2C6H3)C(Me)]2CH−, L2, 6-ipr2 and [(2, 6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−, L2, 6-ipr2Ph) in THF at 60 °C afforded the corresponding EuII complexes: EuII(L2, 4, 6-Me3)2(THF) (1), EuII(L2, 6-ipr2)2 (2) and EuII(L2, 6-ipr2Ph)2 (5) with the formations of dimers (L2, 4, 6-Me3)2 (3) and (L2, 6-ipr2)2 (4) for the former two reactions and proligand L2, 6-ipr2PhH (6) for the latter one. Compounds 1–6 were confirmed by an X-ray crystal structure analysis. The central metal EuII in 1 is coordinated by two monoanionic L2, 4, 6-Me3 ligands and one THF molecule in a trigonal bipyramid. The EuII in each of 2 and 5 is ligated by two monoanionic ligands to form a tetrahedral geometry. The BVS (Bond Valence Sum) calculation indicates the oxidation state of Eu in all the three complexes is 2+ (2.12 for 1, 1.86 for 2 and 1.99 for 5). The isolation of dimers of (L2, 4, 6-Me3)2 and L2, 6-ipr2)2 and proligand L2, 6-ipr2PhH demonstrates that the reducing agent in the present reduction of a EuIII ion to a EuII ion might be the (L2, 4, 6-Me3)−, (L2, 6-ipr2)− and (L2, 6-ipr2Ph)−, respectively. The possible mechanism for the reduction pathway is presented.
Co-reporter:Junfeng Wang, Tao Cai, Yingming Yao, Yong Zhang and Qi Shen
Dalton Transactions 2007(Issue 45) pp:NaN5281-5281
Publication Date(Web):2007/09/10
DOI:10.1039/B709310A
The steric effect of an amide group on the synthesis, molecular structures and reactivity of ytterbium amides supported by linked bis(amidinate) L (L = [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3]) is reported. Reaction of LYbCl(THF)2 with equimolar NaNHAr′ and NaNHAr (Ar′ = 2,6-Me2C6H3; Ar = 2,6-iPr2C6H3), respectively, gave the corresponding monometallic amide complexes LYb(NHAr′)(DME) 1 and LYb(NHAr)(DME) 2, in which the linked bis(amidinate) is coordinated to the metal center as a chelating ligand. The similar reaction with NaN(SiMe3)2 afforded a bimetallic amide complex (TMS)2NYb(L)2YbN(TMS)23 formed through the rearrangement reaction of L induced by the bulky N(SiMe3)2 group. In complex 3 the two linked bis(amidinate)s act as bridging ancillary ligands to link two YbN(TMS)2 species in one molecule. The definite molecular structures of 1–3 were provided by single-crystal X-ray analysis. Complexes 1–3 are efficient initiators for the polymerization of L-lactide, and their catalytic performance is highly dependent on the amido groups and molecular structures. The polymerizations initiated by complexes 1 and 2 proceeded in a living fashion as evidenced by the narrow polydispersities of the resulting polymers, together with the linear natures of the number average molecular weight versus conversion plots, while the polymerization system with complex 3 provided polymers with rather broad molecular weight distributions.
Co-reporter:Chuanyong Wang, Xingmin Zhang, Mingqiang Xue, Yong Zhang and Qi Shen
Dalton Transactions 2013 - vol. 42(Issue 19) pp:NaN7018-7018
Publication Date(Web):2013/02/22
DOI:10.1039/C3DT32882A
Reaction of LnCl3 with a lithium salt of bridged bis(guanidinate) bearing a rigid naphthalene linker [Li2{LH2}2Li2] (LH2 = 1,8-C10H6{NC(NiPr)(NHiPr)}2) (1), which was synthesized by the reaction of 1,8-diaminonaphthalene with 2 equiv. of nBuLi, followed by treatment with 2 equiv. of N,N′-diisopropylcarbodiimide, yielded the chlorides [LnCl{LH2}] (Ln = Yb (2), Y (3)) in good yields. Metathesis reaction of 2 and 3 with NaN(SiMe3)2 did not afford the corresponding amide complexes, but the deprotonation products of [Ln{LH}]2 (LH = 1,8-C10H6{NC(NiPr)(NHiPr)}{NC(NiPr)2}; Ln = Yb (4), Y (5)) were isolated instead. The LH in 4 and 5 both act as a bridging ligand binding to two metals in a μ–η1:η2:η2 fashion, and the re-arrangement of LH occurred during the reaction. The size of the amido group was found to have a great influence on the outcome of the metathesis reaction. Reaction of 2 with bulky NaNH(C6H3iPr2-2,6) afforded 4 as the only product, whereas the same reaction with less bulky LiNH(C6H4Cl-4) and LiNH(C6H4CH3-4) led to the corresponding amides, [Yb{LH2}(NHC6H4Cl-4)]2 (6) and [Yb{LH2}(NHC6H4CH3-4)]2 (7), respectively. The re-arrangement of ligands was also observed in both cases. A possible pathway for the deprotonation of LH2 was discussed. Molecular structures of 1–7 were determined by X-ray single crystal analysis.
Co-reporter:Peng Liu, Hongxia Chen, Yong Zhang, Mingqiang Xue, Yingming Yao and Qi Shen
Dalton Transactions 2014 - vol. 43(Issue 14) pp:NaN5594-5594
Publication Date(Web):2014/01/13
DOI:10.1039/C3DT52706A
The readily accessible dianionic β-diketiminato lanthanide amido complexes LnLN(SiMe3)2(THF) (L = {(2,6-iPr2C6H3)NC(CH2)CHC(CH3)N(2,6-iPr2C6H3)}2−) show an unprecedented reactivity toward carbodiimides. The reaction with N,N′-dicyclohexylcarbodiimide (DCC) led via [4 + 2] cycloaddition to γ-amidine-functionalized dianionic β-diketiminato lanthanide amido complexes, LnL1N(SiMe3)2 (L1 = {[(NHC6H11)(NC6H11)C]HC[C(CH2)N(2,6-iPr2C6H3)]2}2−, Ln = Sm(1), Yb(2), Y(3), Gd(4)). Conversion of a mixture of SmLN(SiMe3)2(THF) and NaN(SiMe3)2 with carbodiimide furnished the heterobimetallic complexes of Sm/Na with a novel amidinate-functionalized trianionic β-diketiminate ligand, [Na(DME)2](μ-L2)[SmN(SiMe3)2] (L2 = {[C(NiPr)2]HC[C(CH2)N(2,6-iPr2C6H3)]2}3−, DME = dimethoxyethane) (5) for N,N′-diisopropylcarbodiimide (DIC) and [Na(DME)3]+[SmL3N(SiMe3)2]− (L3 = {[C(NCy)2]HC[C(CH2)N(2,6-iPr2C6H3)]2}3−) (6) for DCC. Molecular structures of complexes 1–6 were determined by an X-ray single crystal structure analysis. Complexes 1–4 were found to be highly active initiators of the ring-opening polymerization (ROP) of L-lactide (L-LA). The activity depended on the central metal with the increasing sequence of Yb < Y < Gd < Sm. Notably, the binary 1/BnOH (benzyl alcohol) system exhibited an “immortal” nature and proved able to convert 2000 equivalents of L-LA with up to 100 equivalents of BnOH per initiator. All the polylactides (PLAs) obtained showed monomodal, narrow molar mass distributions (Mw/Mn = 1.08–1.13) with the Mn (average number molar mass) decreasing with increasing amount of BnOH proportionally.
Co-reporter:Hongxia Chen, Peng Liu, Haisheng Yao, Yong Zhang, Yingming Yao and Qi Shen
Dalton Transactions 2010 - vol. 39(Issue 29) pp:NaN6885-6885
Publication Date(Web):2010/06/22
DOI:10.1039/C002385J
The reaction of monomeric [(DIPPh)2nacnac]YbCl2(THF)2 ((DIPPh)2nacnac = N,N-diisopropylphenyl-2,4-pentanediimineanion) with NaOAr (OAr = 2,6-diisopropylphenoxide) in THF afforded the mononuclear complexes [(DIPPh)2nacnac]Yb(OAr)Cl(THF) 1 and [(DIPPh)2nacnac]Yb(OAr)22 depending on the molar ratio of dichloride to sodium salt, while the same reaction with NaOAr′ (OAr′ = 2,6-dimethylphenoxide) in toluene yielded the binuclear complex [{(DIPPh)2nacnac}Yb(OAr′)]2(μ-Cl)23. Treatment of [(DIPPh)2nacnac]Yb(THF)(μ-Cl)3Yb(Cl)[(DIPPh)2nacnac] with NaOAr and NaOAr′, respectively, in toluene yielded selectively the corresponding binuclear complexes {[(DIPPh)2nacnac]Yb(OAr)(μ-Cl)3Yb[(DIPPh)2nacnac](THF)} 4 and {[(DIPPh)2nacnac]Yb(OAr′)(μ-Cl)3Yb[(DIPPh)2nacnac](THF)} 5 in high yields. All complexes were structurally characterized. Complex 2 was found to be a highly active initiator for both polymerizations of ε-caprolactone (ε-CL) and L-lactide. All monoaryloxide complexes can initiate the polymerization of ε-CL in a controlled manner giving polymers with narrow molecular weight distributions (Mw/Mn around 1.06) with relatively low activity relative to complex 2.
Co-reporter:Wenbo Li, Mingqiang Xue, Jing Tu, Yong Zhang and Qi Shen
Dalton Transactions 2012 - vol. 41(Issue 24) pp:NaN7265-7265
Publication Date(Web):2012/04/11
DOI:10.1039/C2DT30096F
Metathesis reaction of LLnCl(THF)2 [L = (Me3SiNC(C6H5)N)2(CH2)3] with NaBH4 in a 1:1.5 molar ratio in THF (THF = tetrahydrofuran) at 60 °C afforded the monoborohydride LLn(BH4)(DME) [Ln = Y (1), Nd (2), Sm(3) and Yb(4)] crystallized from DME solution (DME = dimethoxyethane). Crystal structure analyses revealed 1–4 are monomers, in which each metal is ligated by one L ligand, one η3-BH4 group and one DME molecule in a trigonal bipyramid geometry. Complexes 1–4 were found to be very active single-site initiators for the controlled ring opening polymerization of ε-caprolactone (ε-CL) and L-lactide (L-LA) as judged by relatively narrow molecular weight distributions (Mw/Mn: 1.34–1.50) and experimental values Mn(exp) were in good agreement with theoretic values Mn(theo). The highest activity and the best control over the molecular weight for both monomers were found for the system with 2. These monoborohydride complexes can also initiate the ring opening polymerization of rac-LA to gave heterotactically enriched polyLA with Pr (heterotactic enrichment) values in a range of 0.69–0.85 depending on the lanthanide metals and the most effective heterotactic enrichment (Pr) was found for 1 (Pr = 0.85). Moreover, complex 1 initiated the polymerization of rac-LA in a living fashion.
Co-reporter:Zhu Du, Hui Zhou, Haisheng Yao, Yong Zhang, Yingming Yao and Qi Shen
Chemical Communications 2011 - vol. 47(Issue 12) pp:NaN3597-3597
Publication Date(Web):2011/02/07
DOI:10.1039/C0CC04504G
The reaction of YbL(THF)2 (L = [–OC6H2(2,4-tBu2)(6-CH2)]2NCH2CH2NMe2) with iPrN=C=NiPr led to the bridged carbene ytterbium complex (YbL)2(μ-NiPrCNiPr)via a two-electron reduction process of carbodiimide, which reacted with PhNCO to afford a dinuclear ytterbium complex and a spiro derivative.
Co-reporter:Rui Jiao, Xiaodong Shen, Mingqiang Xue, Yong Zhang, Yingming Yao and Qi Shen
Chemical Communications 2010 - vol. 46(Issue 23) pp:NaN4120-4120
Publication Date(Web):2010/05/11
DOI:10.1039/B927582G
Attempted synthesis of sterically demanding tris-β-diketiminate complexes of europium led to oxidation–coupling of β-diketiminates and the formation of the THF-solvated divalent europium complex Eu(L2,6-Me2)2(THF) (L2,6-Me2 = [{N(2,6-Me2C6H3)C(Me)}2CH]−), while the normal tris-β-diketiminate complex Eu(L2-Me)3 for the less bulky ligand L2-Me ([{N(2-MeC6H4)C(Me)}2CH]−) was isolated by the same procedure.
Co-reporter:Sheng Yang, Zhu Du, Yong Zhang and Qi Shen
Chemical Communications 2012 - vol. 48(Issue 78) pp:NaN9782-9782
Publication Date(Web):2012/08/13
DOI:10.1039/C2CC34451C
Polymerization of racemic lactide initiated by divalent ytterbium complexes supported by either dimethylamino-amino bis(phenolate) or methoxy-amino bis(phenolate) ligands proceeds rapidly at room temperature in a living fashion to give heterotactic polylactide with the racemic enchainment of monomer units Pr ranging from 0.97–0.99.
Co-reporter:Jing Tu, Wenbo Li, Mingqiang Xue, Yong Zhang and Qi Shen
Dalton Transactions 2013 - vol. 42(Issue 16) pp:NaN5901-5901
Publication Date(Web):2013/02/04
DOI:10.1039/C3DT33069A
Various lanthanide aryloxide complexes supported by bridged bis(amidinate) ligand L, LLnOAr(DME) (L = Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3, DME = dimethoxyethane, Ln = Y, Ar = 2,6-(Me)2C6H3 (1), 2,6-(iPr)2C6H3 (2), 2,6-(tBu)2-4-(Me)C6H2 (3); Ar = 2,6-(tBu)2-4-(Me)C6H2, Ln = Nd (4), Sm (5), Yb (6)) were synthesized, and complexes 1, 2 and 4–6 were characterized by single crystal X-ray diffraction. All the complexes are efficient precatalysts for catalytic addition of amines to carbodiimides. The catalytic activity is influenced by lanthanide metals and the aryloxide groups (Nd (4) ∼ Sm (5) < Y (3) ∼ Yb (6) and -2,6-(Me)2C6H3 < -2,6-(iPr)2C6H3 < -2,6-(tBu)2-4-(Me)C6H2). The catalytic addition reaction with 3 showed a good scope of substrates. The mechanism investigation revealed the real active intermediate being the monoguanidinate complexes supported by an aryloxide and an amidine-functionalized amidinate group, L′Ln[O2,6-(tBu)2-4-(Me)C6H2][RNCNHRN(Ar′)] (L′ = Me3SiNHC(Ph)N(CH2)3NC(Ph)NSiMe3, R = iPr, Ar′ = phenyl, Ln = Yb (8), Y (11); R = Cy, Ar′ = phenyl, Ln = Yb (10), Y (12); R = iPr, Ar′ = 4-ClC6H4, Ln = Yb (9)), which were isolated from the reactions of 6 (or 3) with amine and carbodiimide in a molar ratio of 1:1:1 and structurally characterized. The Ln-active group in the present precatalyst is a Ln–amidinate species, not the Ln–OAr group.
Co-reporter:Zhu Du, Yong Zhang, Yingming Yao and Qi Shen
Dalton Transactions 2011 - vol. 40(Issue 29) pp:NaN7644-7644
Publication Date(Web):2011/06/24
DOI:10.1039/C1DT10081E
The reaction of Sm[N(TMS)2]2(THF)2 with H2L (L = 1,4-bis(2-hydroxy-3-tert-butyl-5-methyl-benzyl)-piperazidine) afforded [SmL(HMPA)2]4·8THF 2 upon treatment with 2 equivalents of HMPA (hexamethyl phosphoric triamide). X-ray crystallographic analysis of 2 reveals a tetrametallic macrocyclic structure, which represents the first example of a crystal structure of a Sm(II) complex stabilized by heteroatom bridged bis(phenolate) ligands. Reduction of carbodiimides RNCNR (R = iPr and Cy) by [SmL]2(THF) 1, which was formed in situ by the reaction of Sm[N(TMS)2]2(THF)2 with H2L in THF, yielded the Sm(III) complex with an oxalamidinate ligand [LSm{(NiPr)2CC(NiPr)2}SmL]·THF 3 for iPrNCNiPr and the Sm(III) complex with a diamidocarbene ligand [LSm(μ-CyNCNCy)SmL]·5.5THF 4 for CyNCNCy.
Co-reporter:Wenbo Li, Mingqiang Xue, Fan Xu, Jing Tu, Yong Zhang and Qi Shen
Dalton Transactions 2012 - vol. 41(Issue 27) pp:NaN8260-8260
Publication Date(Web):2012/03/16
DOI:10.1039/C2DT30400G
A series of lanthanide amide complexes supported by bridged bis(amidinate) ligand L, LLnNHAr1(DME) (L = [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3], Ar1 = 2,6-iPr2C6H3, DME = dimethoxyethane, Ln = Y (1), Pr (2), Nd (3), Gd (4), Yb (5)), [Yb(μ2-NHPh)]2(μ2-L)2 (6) and [LYb]2(μ2-NHAr2)2 (7) (Ar2 = (o-OMe)C6H4), were synthesized by reaction of LLnCl(THF)2 with the corresponding lithium amide in good yields and structurally characterized by X-ray crystal structure analyses. All complexes were found to be precatalysts for the catalytic addition of aromatic amines to aromatic nitriles to give monosubstituted N-arylamidines. The catalytic activity was influenced by lanthanide metals and the amido groups with the active sequence of Y (1) < Gd (4) < Nd (3) < Pr (2) ∼ Yb (5) for the lanthanide metals and –NHAr2 < –NHPh < –NHAr1 for the amido groups. The catalytic addition reaction with complex 5 showed a good scope of aromatic amines. Some key reaction intermediates were isolated and structurally characterized, including the amidinate complexes LLn[NPhCNAr1](PhCN) (Ln = Y (8), Ln = Yb (9)), LYb[NAr2CNAr1](Ar2CN) (10), and amide complex 5 prepared by protonation of 9 by Ar1NH2. Reactivity studies of these complexes suggest that the present catalytic formation of monosubstituted N-arylamidines proceeds through nucleophilic addition of an amido species to a nitrile, followed by amine protonolysis of the resultant amidinate species.
![1,3-bis[2,6-bis(1-methylethyl)phenyl]-4,5-dihydro-1H-imidazolium bromide](http://img.cochemist.com/ccimg/1034200/1034137-22-8.png)
![1,3-bis[2,6-bis(1-methylethyl)phenyl]-4,5-dihydro-1H-imidazolium bromide](http://img.cochemist.com/ccimg/1034200/1034137-22-8_b.png)
![METHANONE, [(2S,3R)-3-(2-FLUOROPHENYL)OXIRANYL]PHENYL-](http://img.cochemist.com/ccimg/851100/851011-04-6.png)
![METHANONE, [(2S,3R)-3-(2-FLUOROPHENYL)OXIRANYL]PHENYL-](http://img.cochemist.com/ccimg/851100/851011-04-6_b.png)
![PYRROLIDINE, 2-METHYL-1-[(4-NITROPHENYL)METHYL]-4,4-DIPHENYL-](http://img.cochemist.com/ccimg/846600/846577-00-2.png)
![PYRROLIDINE, 2-METHYL-1-[(4-NITROPHENYL)METHYL]-4,4-DIPHENYL-](http://img.cochemist.com/ccimg/846600/846577-00-2_b.png)
![METHANONE, (4-CHLOROPHENYL)[(2S,3R)-3-PHENYLOXIRANYL]-](http://img.cochemist.com/ccimg/637100/637042-66-1.png)
![METHANONE, (4-CHLOROPHENYL)[(2S,3R)-3-PHENYLOXIRANYL]-](http://img.cochemist.com/ccimg/637100/637042-66-1_b.png)
![2-Azaspiro[4.5]decane, 3-methyl-](http://img.cochemist.com/ccimg/592500/592478-37-0.png)
![2-Azaspiro[4.5]decane, 3-methyl-](http://img.cochemist.com/ccimg/592500/592478-37-0_b.png)
![Benzene, 1-[(4-methoxyphenyl)methyl]-4-(trifluoromethyl)-](http://img.cochemist.com/ccimg/398200/398126-85-7.png)
![Benzene, 1-[(4-methoxyphenyl)methyl]-4-(trifluoromethyl)-](http://img.cochemist.com/ccimg/398200/398126-85-7_b.png)
![Pyridine, 2-[(1Z)-2-(diphenylphosphino)ethenyl]-](/data/chemimg/102900/350798-41-3.png)
![Pyridine, 2-[(1Z)-2-(diphenylphosphino)ethenyl]-](/data/chemimg/102900/350798-41-3_b.png)
![Methanone, (4-methoxyphenyl)[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/288000/287930-22-7.png)
![Methanone, (4-methoxyphenyl)[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/288000/287930-22-7_b.png)
![Methanone, [(2S,3R)-3-(4-methoxyphenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/204500/204450-47-5.png)
![Methanone, [(2S,3R)-3-(4-methoxyphenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/204500/204450-47-5_b.png)
![Methanone, (4-methylphenyl)[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/189100/189017-49-0.png)
![Methanone, (4-methylphenyl)[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/189100/189017-49-0_b.png)
![Acetamide, N-[(methylphenylamino)methyl]-](http://img.cochemist.com/ccimg/186300/186298-92-0.png)
![Acetamide, N-[(methylphenylamino)methyl]-](http://img.cochemist.com/ccimg/186300/186298-92-0_b.png)
![Phosphine, [2-(4-methoxyphenyl)ethyl]diphenyl-](http://img.cochemist.com/ccimg/152100/152076-32-9.png)
![Phosphine, [2-(4-methoxyphenyl)ethyl]diphenyl-](http://img.cochemist.com/ccimg/152100/152076-32-9_b.png)
![PHOSPHINE, [2-(4-CHLOROPHENYL)ETHYL]DIPHENYL-](http://img.cochemist.com/ccimg/152100/152076-31-8.png)
![PHOSPHINE, [2-(4-CHLOROPHENYL)ETHYL]DIPHENYL-](http://img.cochemist.com/ccimg/152100/152076-31-8_b.png)
![2-Propen-1-one, 1-phenyl-3-[4-(trifluoromethyl)phenyl]-, (2E)-](http://img.cochemist.com/ccimg/144100/144017-74-3.png)
![2-Propen-1-one, 1-phenyl-3-[4-(trifluoromethyl)phenyl]-, (2E)-](http://img.cochemist.com/ccimg/144100/144017-74-3_b.png)
![Methanone, [(2S,3R)-3-(4-methylphenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/128200/128134-36-1.png)
![Methanone, [(2S,3R)-3-(4-methylphenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/128200/128134-36-1_b.png)
![1,3-Dioxolane, 2-(4'-methoxy[1,1'-biphenyl]-4-yl)-2-methyl-](http://img.cochemist.com/ccimg/117600/117530-17-3.png)
![1,3-Dioxolane, 2-(4'-methoxy[1,1'-biphenyl]-4-yl)-2-methyl-](http://img.cochemist.com/ccimg/117600/117530-17-3_b.png)
![[1,1'-Biphenyl]-4-carboxylic acid, 4'-methyl-, ethyl ester](http://img.cochemist.com/ccimg/106600/106508-97-8.png)
![[1,1'-Biphenyl]-4-carboxylic acid, 4'-methyl-, ethyl ester](http://img.cochemist.com/ccimg/106600/106508-97-8_b.png)
![Methanone, [(2S,3R)-3-(4-chlorophenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/67400/67381-80-0.png)
![Methanone, [(2S,3R)-3-(4-chlorophenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/67400/67381-80-0_b.png)
![Pyridine, 4-[2-(diphenylphosphino)ethyl]-](http://img.cochemist.com/ccimg/67000/66934-97-2.png)
![Pyridine, 4-[2-(diphenylphosphino)ethyl]-](http://img.cochemist.com/ccimg/67000/66934-97-2_b.png)
![Methanone, phenyl[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/61900/61840-93-5.png)
![Methanone, phenyl[(2S,3R)-3-phenyloxiranyl]-](http://img.cochemist.com/ccimg/61900/61840-93-5_b.png)
![Methanone, phenyl[4-(phenylmethyl)phenyl]-](http://img.cochemist.com/ccimg/58300/58280-04-9.png)
![Methanone, phenyl[4-(phenylmethyl)phenyl]-](http://img.cochemist.com/ccimg/58300/58280-04-9_b.png)
![Thiophene, 2-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/53100/53039-61-5.png)
![Thiophene, 2-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/53100/53039-61-5_b.png)
![Benzene, 1-[(4-methoxyphenyl)methyl]-2-methyl-](http://img.cochemist.com/ccimg/53100/53039-52-4.png)
![Benzene, 1-[(4-methoxyphenyl)methyl]-2-methyl-](http://img.cochemist.com/ccimg/53100/53039-52-4_b.png)
![PHOSPHONIC ACID, [HYDROXY(3-METHOXYPHENYL)METHYL]-, DIETHYL ESTER](http://img.cochemist.com/ccimg/49700/49640-97-3.png)
![PHOSPHONIC ACID, [HYDROXY(3-METHOXYPHENYL)METHYL]-, DIETHYL ESTER](http://img.cochemist.com/ccimg/49700/49640-97-3_b.png)
![Phosphoric acid, [1,1'-biphenyl]-2-yl diethyl ester](http://img.cochemist.com/ccimg/39900/39835-01-3.png)
![Phosphoric acid, [1,1'-biphenyl]-2-yl diethyl ester](http://img.cochemist.com/ccimg/39900/39835-01-3_b.png)
![Benzene, 1-fluoro-4-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/38700/38695-26-0.png)
![Benzene, 1-fluoro-4-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/38700/38695-26-0_b.png)
![Pyridine, 2-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/35900/35854-45-6.png)
![Pyridine, 2-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/35900/35854-45-6_b.png)
![Poly[oxy(1-oxo-1,2-ethanediyl)oxy-1,2-ethanediyl]](http://img.cochemist.com/ccimg/31700/31621-87-1.png)
![Poly[oxy(1-oxo-1,2-ethanediyl)oxy-1,2-ethanediyl]](http://img.cochemist.com/ccimg/31700/31621-87-1_b.png)
![Benzene, 1-methoxy-4-[(4-methylphenyl)methyl]-](http://img.cochemist.com/ccimg/22900/22865-60-7.png)
![Benzene, 1-methoxy-4-[(4-methylphenyl)methyl]-](http://img.cochemist.com/ccimg/22900/22865-60-7_b.png)
![Phosphine, diphenyl[(1E)-2-phenylethenyl]-](http://img.cochemist.com/ccimg/14100/14090-06-3.png)
![Phosphine, diphenyl[(1E)-2-phenylethenyl]-](http://img.cochemist.com/ccimg/14100/14090-06-3_b.png)
![1,3-DIOXOLANE, 2-[1,1'-BIPHENYL]-4-YL-2-METHYL-](http://img.cochemist.com/ccimg/6200/6135-51-9.png)
![1,3-DIOXOLANE, 2-[1,1'-BIPHENYL]-4-YL-2-METHYL-](http://img.cochemist.com/ccimg/6200/6135-51-9_b.png)
![1H-Naphtho[2,1-b]pyran, 2,3-dihydro-](http://img.cochemist.com/ccimg/3800/3722-88-1.png)
![1H-Naphtho[2,1-b]pyran, 2,3-dihydro-](http://img.cochemist.com/ccimg/3800/3722-88-1_b.png)
![Phosphonic acid, [hydroxy(2-methylphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/203700/203637-01-8.png)
![Phosphonic acid, [hydroxy(2-methylphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/203700/203637-01-8_b.png)
![Phosphonic acid, [hydroxy(2-methoxyphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/67700/67691-77-4.png)
![Phosphonic acid, [hydroxy(2-methoxyphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/67700/67691-77-4_b.png)
![Phosphonic acid, [(3-chlorophenyl)hydroxymethyl]-, diethyl ester](http://img.cochemist.com/ccimg/50700/50652-90-9.png)
![Phosphonic acid, [(3-chlorophenyl)hydroxymethyl]-, diethyl ester](http://img.cochemist.com/ccimg/50700/50652-90-9_b.png)
![Phosphonic acid, [hydroxy(4-methoxyphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/49700/49640-96-2.png)
![Phosphonic acid, [hydroxy(4-methoxyphenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/49700/49640-96-2_b.png)
![Tris[N,N-bis(trimethylsilyl)amide]yttrium (III)](http://img.cochemist.com/ccimg/41900/41836-28-6.png)
![Tris[N,N-bis(trimethylsilyl)amide]yttrium (III)](http://img.cochemist.com/ccimg/41900/41836-28-6_b.png)
![Poly[oxy(1-methyl-3-oxo-1,3-propanediyl)]](http://img.cochemist.com/ccimg/26800/26744-04-7.png)
![Poly[oxy(1-methyl-3-oxo-1,3-propanediyl)]](http://img.cochemist.com/ccimg/26800/26744-04-7_b.png)
![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2.png)
![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2_b.png)
![diethyl [(4-chlorophenyl)(hydroxy)methyl]phosphonate](http://img.cochemist.com/ccimg/20700/20641-28-5.png)
![diethyl [(4-chlorophenyl)(hydroxy)methyl]phosphonate](http://img.cochemist.com/ccimg/20700/20641-28-5_b.png)
![Phosphonic acid, [(4-bromophenyl)hydroxymethyl]-, diethyl ester](http://img.cochemist.com/ccimg/20700/20641-24-1.png)
![Phosphonic acid, [(4-bromophenyl)hydroxymethyl]-, diethyl ester](http://img.cochemist.com/ccimg/20700/20641-24-1_b.png)
![Phosphonic acid, [hydroxy(4-nitrophenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/1800/1776-87-0.png)
![Phosphonic acid, [hydroxy(4-nitrophenyl)methyl]-, diethyl ester](http://img.cochemist.com/ccimg/1800/1776-87-0_b.png)
![Phenol, 2,2'-[[(2-methoxyethyl)imino]bis(methylene)]bis[4,6-bis(1,1-dimethylethyl)-](/data/chemimg/1817900/388083-30-5.png)
![Phenol, 2,2'-[[(2-methoxyethyl)imino]bis(methylene)]bis[4,6-bis(1,1-dimethylethyl)-](/data/chemimg/1817900/388083-30-5_b.png)
![Poly[oxy(1-oxo-1,6-hexanediyl)]](http://img.cochemist.com/ccimg/25300/25248-42-4.png)
![Poly[oxy(1-oxo-1,6-hexanediyl)]](http://img.cochemist.com/ccimg/25300/25248-42-4_b.png)
![Phenol, 2,2'-[[[2-(dimethylamino)ethyl]imino]bis(methylene)]bis[4,6-bis(1,1-dimethylethyl)-](/data/chemimg/135600/188713-27-1.png)
![Phenol, 2,2'-[[[2-(dimethylamino)ethyl]imino]bis(methylene)]bis[4,6-bis(1,1-dimethylethyl)-](/data/chemimg/135600/188713-27-1_b.png)
