Co-reporter:Mei-Jiao Liu;Juan Yuan;Yi-Quan Zhang;Hao-Ling Sun;Cai-Ming Liu
Dalton Transactions 2017 vol. 46(Issue 38) pp:13035-13042
Publication Date(Web):2017/10/03
DOI:10.1039/C7DT02409F
Two new chiral six-coordinate lanthanide complexes (1 for Dy and 2 for Tb) have been synthesized using the achiral flexible ligand H2L (2,2′-[1,2-ethanediylbis[(methylimino)methylene]]bis[4,5-dimethylphenol]). Both complexes crystallize in the chiral P1 group space, and the enantiomers [Zn(L)Cl]3Dy·MeOH·0.5H2O (Λ-1), [Zn(L)Cl]3Dy·1.5H2O (Δ-1), [Zn(L)Cl]3Tb·1.5H2O (Λ-2) and [Zn(L)Cl]3Tb·H2O (Δ-2) are isolated in the reaction. Three [Zn(L)Cl]− anions coordinate to the central lanthanide ion using two phenoxo oxygen atoms of L2−, and the lanthanide ion has the coordination geometry of D3. Complex 1 exhibits a field-induced slow magnetization relaxation, which is typical of a single-ion magnet (SIM). Ab initio calculations on complex 1 and studies on magneto-structural correlationship of six-coordinate Dy(III) SIMs indicate that the small energy barrier of complex 1 might be related to the absence of a unique anisotropic axis for the regular octahedral coordination configuration of Dy(III) and the high quantum tunneling gap between the ground states (mJ = ±15/2). Complex 2 displays green photofluorescence and triboluminescence.
Co-reporter:Juan Yuan;Mei-Jiao Liu;Cai-Ming Liu
Dalton Transactions 2017 vol. 46(Issue 47) pp:16562-16569
Publication Date(Web):2017/12/06
DOI:10.1039/C7DT03233A
Four new mononuclear Fe(III) complexes 1–4 of 2-methyl-6-(pyrimidin-2-yl-hydrazonomethyl)-phenol (H2L) have been synthesized and characterized by magnetic susceptibility measurements and single-crystal X-ray diffraction analysis. Complexes 1–3 are ionic compounds with the formula [Fe(HL)2]X·nsolvent (X = ClO4− (1), BF4− (2) and Cl− (3)), while complex 4 ([Fe(HL)(L)]) is neutral. The central Fe(III) ion in complexes 1–4 is coordinated by four nitrogen and two oxygen atoms of two Schiff base ligands HL− or L2−, and the coordination geometries of FeIII are all distorted octahedral. Magnetic measurements indicate that complex 1 shows an abrupt spin transition with a thermal hysteresis of 32 K (T1/2↓ = 158 K and T1/2↑ = 190 K), and complex 4 exhibits a gradual incomplete spin transition. Complexes 2 and 3 are high spin with a room-temperature χmT value of 4.32 cm3 K mol−1 and 4.39 cm3 K mol−1, respectively.
Co-reporter:Mei-Jiao Liu;Kong-Qiu Hu;Cai-Ming Liu;Ai-Li Cui
Dalton Transactions 2017 vol. 46(Issue 20) pp:6544-6552
Publication Date(Web):2017/05/23
DOI:10.1039/C7DT00948H
We herein report the synthesis, crystal structure and magnetic properties of nine new heterotrimetallic complexes. [Ni(Me2valpn)] (H2Me2valpn = N,N′-bis(3-methoxysalicylidene)-2,2-dimethyl-1,3-diaminopropane) was used as the precursor to construct phenoxo-bridged [Ni2Ln]3+ (Ln3+ = Dy, Tb, Gd and Y) species that were respectively connected by two [M(CN)6]3− (M = Cr, Fe or Co) anions to form octanuclear cyclic complexes, i.e. {[Ni(Me2valpn)]2Ln(H2O)M(CN)6}2 in which Ln = Y, Gd, Tb and Dy and M = Cr, Fe or Co (1–9). Each of the complexes contains many lattice-bound molecules of solvation. The Ni(II) ions are penta-coordinate, while the Ln(III) ions are nine coordinated with a muffin geometry. The fitting to the χmT vs. T curves of complexes 6–9 gave the parameters of JNiCr = 11.82 cm−1, JNiGd = 0.94 cm−1 and g = 2.04 for complex 6, JNiFe = 10.58 cm−1, JNiGd = 1.24 cm−1 and g = 2.03 for complex 7, JNiCr = 9.4(1) cm−1, zJ′ = −0.050(2) cm−1 and g = 2.06(1) for complex 8 and JNiFe = 4.9(7) cm−1, zJ′ = −0.35(2) cm−1 and g = 2.24(1) for complex 9, respectively. The dynamic magnetic investigations demonstrate that complexes 1–5 display single-molecule magnet properties with an effective energy barrier (Ueff) of 38.9 K (1, M1 = Dy, M2 = Cr), 37.2 K (2, M1 = Dy, M2 = Cr), 24.4 K (3, M1 = Dy, M2 = Co), 21.9 K (4, M1 = Tb, M2 = Cr) and 29.6 K (5, M1 = Tb, M2 = Fe), respectively. Complex 1 shows the highest energy barrier among the octanuclear [Ni4LnM2] (Ln = Dy or Tb, M = Fe, Cr, Co or W) system. Although the [Ni4Dy2Cr2] complexes have Ueff higher than that of [Ni4Dy2Fe2], complex [Ni4TbCr2] shows lower Ueff than that of [Ni4TbFe2]. The results indicate that besides the M–CN–Ni magnetic coupling the lanthanide ions can significantly affect the magnetic performances of heterotrimetallic SMMs as well. Moreover, the SMMs are achieved when diamagnetic Co(III) was substituted by paramagnetic Cr(III) or Fe(III) in the [Ni4Tb2 M2] system, suggesting that the trimetallic strategy is effective in the construction of new 3d–4f SMMs.
Co-reporter:Xiang Jiang and Hui-Zhong Kou
Chemical Communications 2016 vol. 52(Issue 14) pp:2952-2955
Publication Date(Web):08 Jan 2016
DOI:10.1039/C5CC09808D
Herein, we present an exceptional structural transformation from a porous supramolecular network to a porous coordination polymer. The transformation involves a change of interpenetrating dimensionality from 6-fold to 5-fold. Simultaneously, the spin state of nickel(II) is altered from S = 0 to S = 1, which is concomitant with the formation of the Ni–Ocarboxylate coordination bonds.
Co-reporter:Xiang Jiang, Cai-Ming Liu, and Hui-Zhong Kou
Inorganic Chemistry 2016 Volume 55(Issue 12) pp:5880-5885
Publication Date(Web):June 3, 2016
DOI:10.1021/acs.inorgchem.6b00179
In this paper, three isostructural porous coordination polymers, namely, [Mn6(μ3-O)2(sao)6(DMF)4(L1)2/3]·4DMF·2H2O·2CH3OH (1), [Mn6(μ3-O)2(sao)6(DMF)4(L2)2/3]·4DMF·2H2O·2CH3OH (2), and [Mn6(μ3-O)2(sao)6(DMF)4(L3)2/3]·4DMF·4H2O·2CH3OH (3) (DMF = dimethylformamide, H2sao = salicylaldoxime, H3L1 = benzene-1,3,5-trisbenzoic acid, H3L2 = 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid, and H3L3 = 2,4,6-tris(4-carboxyphenoxy)-1,3,5-s-triazine), based on the oximato-bridged {Mn6} single-molecule magnet (SMM) and tricarboxylic acid ligands, were designed and synthesized. X-ray structural analysis shows that they possess a two-dimensional layered structure, where the {Mn6} moieties are linked by the corresponding (Lx)3– carboxylate ligands (x = 1, 2, 3) forming a huge honeycomb layer. These compounds not only show the SMM behavior as confirmed by alternative current susceptibility measurements but also show selectivity for CO2 over N2 at 273 K. On the basis of the magnetic fitting to the magnetic susceptibilities and the field dependence of magnetization for complexes 1–3, the spin ground states are S = 4. Compared with isolated {Mn6} SMMs with S = 4, the out-of-phase susceptibilities of 1–3 show obvious peaks only under the external direct-current field of 2 kOe. However, no peaks in χm″ are observed in the partially desolvated sample of compound 1.
Co-reporter:Xiang Jiang, Kong-Qiu Hu and Hui-Zhong Kou
CrystEngComm 2016 vol. 18(Issue 22) pp:4084-4093
Publication Date(Web):16 Nov 2015
DOI:10.1039/C5CE01577D
By using the semi-rigid ligand tetrakis[4-(carboxyphenyl)oxamethyl]methane acid (H4TCM) and various macrocyclic metallic tectons, eight new Ni(II) coordination polymers, namely, [(NiL1)2(TCM)]·17H2O (1), [(NiL2)2(TCM)]·17H2O (2), [(NiL3)2(TCM)]·18H2O (3), [(NiL4)2(TCM)]·4DMF·10H2O (4), [(NiL5)2(TCM)]·4DMF·9H2O (5), [(NiL6)2(TCM)]·20H2O (6), [(NiL7)2(TCM)]·18H2O (7), [(NiL8)2(TCM)]·4H2O (8) (L1 = 1,8-dimethyl-1,3,6,8,10,13-hexaaza-cyclotetradecane, L2 = 1,3,6,9,11,14-hexaaza-tricyclooctadecane, L3 = 1,3,6,10,12,15-hexaaza-tricycloeicosane, L4 = 1,3,6,8,11,14-hexaaza-tricyclooctadecane, L5 = 4-methyl-1,3,6,8,11,14-hexaaza-tricyclooctadecane, L6 = 1,3,6,8,12,15-hexaaza-tricycloeicosane, L7 = 11-methyl-1,4,8,10,13,15-hexaaza-tricycloicosane and L8 = 3,10-diisobutyl-1,3,5,8,10,12-hexaaza-cyclotetradecane), were synthesized and structurally characterized. Single crystal X-ray analyses reveal that compounds 1–8 exhibit a similar diamondoid (dia) topology network. Regulated by macrocyclic metallic tectons, compounds 1–3 feature a three-dimensional (3D) framework with 7-fold interpenetration, giving rise to a 1D porous channel with size of ca. 1 nm. Compounds 4–7 possess a 3D network with 2D porous channels (porous size ca. 0.5 nm) and 4-fold interpenetration. Compound 8 shows a 3D dense packing arrangement with 2-fold interpenetration. The porosity of compounds 1–7 was confirmed by N2 gas adsorption measurements at 77 K. Furthermore, due to functional groups exposed on the porous surface, activated compound 3 exhibits selective adsorption of CO2 over N2. The results show the crystal structure, stability and gas adsorption can be tuned by the modification of macrocyclic metallic tectons.
Co-reporter:Kong-Qiu Hu, Xiang Jiang, Shu-Qi Wu, Cai-Ming Liu, Ai-Li Cui, and Hui-Zhong Kou
Inorganic Chemistry 2015 Volume 54(Issue 4) pp:1206-1208
Publication Date(Web):January 20, 2015
DOI:10.1021/ic502874n
Two cyano- and phenoxo-bridged hexanuclear NiII2DyIII2FeIII2 (1) and octanuclear NiII4DyIII2FeIII2 (2) trimetallic cyclic complexes have been obtained. They are the first trimetallic metallocycles. Magnetic studies reveal that 1 and 2 exhibit single-molecule-magnet behavior with an energy barrier of 17.9 K for complex 1 in a 2000 Oe static field and 25.0 K for complex 2 in a zero static field.
Co-reporter:Kong-Qiu Hu, Xiang Jiang, Shu-Qi Wu, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2015 vol. 44(Issue 35) pp:15413-15416
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5DT02175H
Two cyano- and phenoxo-bridged octanuclear complexes ZnII4DyIII2CoIII2 (complex 1) and ZnII4DyIII2CrIII2 (complex 2) with diamagnetic Zn(II) and Co(III) are reported. Dy(III) is surrounded by nine oxygen atoms of two [Zn(Me2valpn)] (Me2valpn2− = dianion of N,N′-2,2-dimethylpropylenebis(3-methoxysalicylideneimine)) and one water molecule. Magnetic studies reveal that both exhibit single-ion magnet (SIM) behavior with the energy barrier of 85.9 K for complex 1 and 100.9 K for complex 2.
Co-reporter:Xiang Jiang and Hui-Zhong Kou
RSC Advances 2015 vol. 5(Issue 108) pp:89052-89055
Publication Date(Web):15 Oct 2015
DOI:10.1039/C5RA18848B
Two isostructural porous coordination polymers based on a tetrahedral ligand and azamacrocyclic Ni(II) complexes were synthesized and structurally characterized. This work demonstrates that a robust porous coordination polymer can be stabilized by intermolecular C–H⋯π contacts between the sub-networks. Furthermore, these compounds exhibit two kinds of gas separation mechanism related to the different pore sizes they possess.
Co-reporter:Xiang Jiang;Guang-Yu An;Cai-Ming Liu
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 32) pp:5314-5317
Publication Date(Web):
DOI:10.1002/ejic.201500930
Abstract
A new mixed-valent {Mn14} cluster based on pyridine-2-amidoxime (H2pyaox), [MnIV2MnIII10MnII2(μ3-O)8(Hpyaox)14(pyaox)2(N3)2](ClO4)4(OH)2·2MeOH·23H2O (1), has been synthesized and characterized. Magnetic susceptibility studies show that complex 1 displays an S = 6 spin ground state and slow magnetic relaxation.
Co-reporter:Xi Chen, Shu-Qi Wu, Ai-Li Cui and Hui-Zhong Kou
Chemical Communications 2014 vol. 50(Issue 17) pp:2120-2122
Publication Date(Web):10 Dec 2013
DOI:10.1039/C3CC48117D
The chains in complex [Mn(TPP)][Mn(TPP)(CN)2] (H2TPP = meso-tetra(4-phenyl)-porphyrin) demonstrate perfect linearity, and are well isolated with the nearest interchain Mn–Mn separation of 12.95 Å. Ferromagnetic coupling is present among adjacent Mn(III) ions, and single-chain magnet (SCM) behaviour is verified.
Co-reporter:Shu-Qi Wu, Yi-Tong Wang, Ai-Li Cui, and Hui-Zhong Kou
Inorganic Chemistry 2014 Volume 53(Issue 5) pp:2613-2618
Publication Date(Web):February 20, 2014
DOI:10.1021/ic402971a
Supramolecular strategy was employed to achieve the highest nuclearity Co(II) cluster exhibiting spin-crossover (SCO) behavior. Magnetic susceptibility characterization of the Co4II complex shows that two different spin-transition processes occur. The SCO behavior is directed by the partially deprotonated polydentate ligand, which favors the structural distortion required by the spin transition.
Co-reporter:Wen-Bo Shi, Ai-Li Cui and Hui-Zhong Kou
CrystEngComm 2014 vol. 16(Issue 34) pp:8027-8034
Publication Date(Web):24 Jun 2014
DOI:10.1039/C4CE01082E
Four Cu(II) complexes, the one-dimensional [Cu(HL1)2(CuCl4)]n (1), {[Cu2(L1)2(N(CN)2)(CH3OH)](ClO4)}n (2), dinuclear [Cu2(L2)2Cl2] (3), and two-dimensional layered [Cu2(L2)2(N(CN)2)2]n (4) were synthesized by Cu(II) salts (CuCl2·2H2O or Cu(ClO4)2·6H2O), alkanol bidentate ligands trans-2-(1-pyrazolyl)cyclohexanol (HL1) or 3,5-dimethyl-N-hydroxyethyl-pyrazolyl (HL2) together with sodium dicyanamide. For complex 1, the bridging chlorine atoms of the tetrahedral [CuCl4]2− moieties are located at the Jahn–Teller axis of the elongated octahedral Cu(II), forming an alternate elongated-octahedral-tetrahedral Cu(II) chain complex. For complexes 2, 3 and 4, the alkyl oxygen atoms of the deprotonated ligands HL1 and HL2 bridge two Cu(II) ions, yielding a dinuclear Cu(II) unit [Cu2(Lx)2]2+ (x = 1, 2), and one- or two-dimensional complexes via bridging dicyanamide ligands. Complex 1 shows weak ferromagnetic coupling, whilst complexes 2–4 display strong antiferromagnetic coupling or are even nearly diamagnetic due to the large Cu–O–Cu bond angles.
Co-reporter:Guang-Yu An, Hong-Bo Wang, Ai-Li Cui and Hui-Zhong Kou
New Journal of Chemistry 2014 vol. 38(Issue 10) pp:5037-5042
Publication Date(Web):06 Aug 2014
DOI:10.1039/C4NJ01055H
Four Ni(II) complexes [Ni2(Br-pao)3(Me3tacn)]ClO4 (1), [Ni2(Br-pao)3(Me3tacn)]BF4 (2), [Ni2(Hpyaox)3(Me3tacn)]BPh4·3MeOH (3) and [Ni5(Hpyaox)4(pyaox)2L2](ClO4)2·4CH3CN·2H2O (4) have been synthesized and characterized (Br-Hpao = 6-Br-2-pyridinealdoxime, Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane, H2pyaox = pyridine-2-amidoxime, L = 2-(2-aminoethylamino)ethanol). Complexes 1–3 have a similar triply oximato-bridged dinuclear structure, and complex 4 has a novel pentanuclear structure with three octahedral and two square planar Ni(II) ions. The variable temperature magnetic susceptibility measurement data show the antiferromagnetic (AFM) coupling for 1–3 and uncommon ferromagnetic (FM) coupling for 4. Furthermore, the oxime N–O bond lengths are a crucial factor affecting the magnetic coupling between two adjacent ions.
Co-reporter:Wei-Wei Ni, Xi Chen, Ai-Li Cui, Cai-Ming Liu, Hui-Zhong Kou
Polyhedron 2014 81() pp: 450-456
Publication Date(Web):
DOI:10.1016/j.poly.2014.06.058
Co-reporter:Wen-Bo Shi;Dr. Ai-Li Cui ; Hui-Zhong Kou
ChemPlusChem 2014 Volume 79( Issue 2) pp:310-317
Publication Date(Web):
DOI:10.1002/cplu.201300304
Abstract
Five CuII complexes of trinuclear [Cu3(L1)2(N3)6] (1), one-dimensional chain [Cu5(L2)2(N3)10]n (2), trinuclear [Cu3(L3)2(N3)6] (3) and dinuclear [Cu2(L4)2(N3)2Cl2] (4) and [Cu2(L5)2(N3)2Cl2] (5) (L1–5=RCH2OR′, R=substituted pyrazole or imidazole, R′=Me, Et or nPr) were synthesized by the reaction of CuCl2⋅2 H2O, sodium azide with RCH2Cl in CH3OH, C2H5OH or n-C3H7OH. The ether ligands L1 and L2 can be alternatively prepared by the alcoholysis of RCH2Cl in the presence of sodium azide, whereas the ligands L3–5 form in corresponding alcohols without azide. For complexes 1–5, the oxygen atom of the ether ligands is located at the Jahn–Teller axis of CuII with the long CuO separations of 2.377(3)–2.830(3) Å. The nitrogen atoms of bridging azides are located in the equatorial or basal planes of CuII ions, favoring strong magnetic coupling. The Cu-Nazido-Cu bridging angles in complexes 1–3 are 98.8(2)°–101.6(1)°, leading to ferromagnetic coupling, whereas the Cu-Nazido-Cu angles in complexes 4 and 5 are close to 103°, leading to antiferromagnetic coupling.
Co-reporter:Shu-Tao Li;Chong-Chao Zhao;Ai-Li Cui
Transition Metal Chemistry 2014 Volume 39( Issue 4) pp:387-392
Publication Date(Web):2014 May
DOI:10.1007/s11243-014-9812-2
The reactions of [MIII(CN)6]3− (M = Cr or Co) with CuII complexes of a tridentate schiff base [Cu(aemp)Cl] or [Cu(aemp)Ac]2 (Haemp = 2-[(2-amino-ethylimino)-methyl]-phenol) give rise to 1D cyanide-bridged bimetallic coordination polymers [Cu4(aemp)4(H2O)2][Cr(CN)6]Cl (1) and [Cu3(aemp)3(H2O)][Co(CN)6]·2H2O·MeOH (2). In complex 1, the six cyanide ligands of the [Cr(CN)6]3− moiety are involved in bridging, while in complex 2 only five cyanide ligands act as bridges to give a neutral chain. Magnetic studies reveal that complex 1 exhibits intermetallic ferromagnetic coupling, with J = 8.2 cm−1.
Co-reporter:Zhaoming Zhang;Lifang Zhang;Zhonghai Ni;Huizhong Kou
Transition Metal Chemistry 2014 Volume 39( Issue 5) pp:527-534
Publication Date(Web):2014 August
DOI:10.1007/s11243-014-9828-7
Four azido-bridged dinuclear Mn(II) complexes, [Mn2(phen)4μ-1,1-N3)2][FeIII(bpmb)(CN)2]2·H2O (1), [Mn2(phen)4(μ-1,1-N3)2][FeIII(bpClb)(CN)2]2·H2O (2), and [Mn2(phen)4(μ-1,1-N3)2][MIII(bpdmb)(CN)2]2·3H2O [M = Fe (3) or Cr (4); phen = 1,10-phenanthroline, bpmb2– = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpClb2– = 1,2-bis(pyridine-2-carboxamido) 4-chloro-benzenate, bpdmb2– = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate], have been synthesized using the synthetic strategy of large anion inducement. Single-crystal X-ray diffraction analysis reveals that all four complexes are doubly end-on (EO) azido-bridged binuclear Mn(II) complexes with two large [M(L)(CN)2]– (L = bpmb2−, bpClb2−, or bpdmb2−) building blocks acting as charge-compensating anions. The magnetic properties of the complexes have been investigated, and the results indicate that the magnetic coupling between two Mn(II) centers through the EO azide bridges is ferromagnetic, with J = 0.64(1) cm−1 for 1, 0.43(1) cm−1 for 2, 0.50(1) cm−1 for 3, and 0.66(2) cm−1 for 4. The magneto-structural relationships of EO azido-bridged Mn(II) systems are discussed.
Co-reporter:Kong-Qiu Hu;Shu-Qi Wu;Ai-Li Cui
Transition Metal Chemistry 2014 Volume 39( Issue 6) pp:713-718
Publication Date(Web):2014 September
DOI:10.1007/s11243-014-9854-5
Two novel heterotrimetallic tetranuclear complexes [Cu(H2L)(CH3OH)]2Gd(DMF)Fe(CN)6·2H2O·DMF (1) and [Cu(H2L)(CH3OH)]2Tb(H2O)0.57(DMF)0.43Fe(CN)6·5.5H2O (2) are reported (H4L = N,N′-ethylenebis(3-hydroxysalicylidene)). The central Ln(III) ion is surrounded by two neutral [Cu(H2L)(CH3OH)] moieties, forming a Cu2Ln trinuclear unit. The [Fe(CN)6]3− anion is weakly coordinated to one Cu(II) ion of [Cu(H2L)(CH3OH)] through a cyanide nitrogen atom with the N–Cu distance of ca. 3.2 Å. Magnetic susceptibility measurements indicate the presence of overall ferromagnetic interactions in complexes 1 and 2. The magnetic coupling constant in complex 1 is JCu1Gd1 = 4.54 cm−1 and JCu2Gd1 = 7.97 cm−1 based on \( \hat{H} = - 2J_{\text{Cu1Gd1}} \hat{S}_{\text{Cu1Gd1}} - 2J_{\text{Cu2Gd1}} \hat{S}_{\text{Cu2Gd1}} \). Dynamic AC magnetic susceptibility studies reveal that complex 2 shows frequency-dependent out-of-phase signals, typical of single molecule magnet behavior. The energy barrier for complex 2 under a 2 kOe applied DC magnetic field is 13 K.
Co-reporter:Yi-Tong Wang ; Shu-Tao Li ; Shu-Qi Wu ; Ai-Li Cui ; De-Zhong Shen
Journal of the American Chemical Society 2013 Volume 135(Issue 16) pp:5942-5945
Publication Date(Web):April 2, 2013
DOI:10.1021/ja312622c
Two bis(tridentate) Schiff base ligands H2Lx were used to construct three 2×2 grid-type tetranuclear Fe(II) complexes 1–3 to obtain polynuclear spin-crossover materials. Magnetic susceptibility measurements show that the spin states of the complexes are related to the substituents of H2Lx, and that spin transition occurs only in complexes 1 and 2, which are derived from a bulky ligand, whereas complex 3 is diamagnetic. The transition temperatures of complexes 1 and 2 are close to room temperature and are dependent on counteranions. The spin transition of complex 1 can be reversibly tuned by the dehydration and hydration process.
Co-reporter:Shu-Qi Wu, Qi-Wei Xie, Guang-Yu An, Xi Chen, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 vol. 42(Issue 13) pp:4369-4372
Publication Date(Web):14 Feb 2013
DOI:10.1039/C3DT50265A
A supramolecular strategy has been applied to construct two tetranuclear lanthanide complexes for investigating the magnetic properties of individual lanthanide ions. The LnIII complexes (Ln = Dy, Tb) display field-induced slow magnetization relaxation, typical of single-molecule magnet behavior. The four lanthanide ions in the molecules are well separated by distances of ca. 9 Å, and thus the slow magnetization relaxation should be assigned to single-ion magnet (SIM) behavior. Therefore, the present complexes are novel supramolecular aggregates of four isolated SIMs.
Co-reporter:Qi-Wei Xie, Shu-Qi Wu, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 vol. 42(Issue 31) pp:11227-11233
Publication Date(Web):31 May 2013
DOI:10.1039/C3DT50818H
The synthesis and characterization of three isomorphous complexes [NiII(L)LnIII(DBM)3] (Ln = Gd (1·2.5CH3CN·0.5H2O), Tb (2·2CH3CN·0.5MeOH), and Dy (3·2CH3CN·0.5MeOH·0.5H2O)) are reported (H2L = N,N′-dimethyl-N,N′-(2-hydroxy-3-methoxy-5-methylbenzyl)ethylenediamine, DBM− = anion of 1,3-diphenylpropane-1,3-dione). The flexible ligand L2− contains an N2O2-inner and an O4-outer coordination site. There are diphenoxo bridges between NiII and LnIII ions in these complexes. The remaining coordination sites are occupied by DBM− anions. Direct current (dc) magnetic susceptibility measurements indicate the presence of intramolecular ferromagnetic interactions in desolvated complexes 1–3. The magnetic coupling constant JNiGd in complex 1 is estimated to be 1.11 cm−1 (H = −2JNiGdSNiSGd). Alternating current (ac) magnetic susceptibility studies reveal that complexes 2 and 3 show frequency-dependent out-of-phase signals, which indicate that they exhibit SMM behavior. The energy barriers for complexes 2 and 3 under a 2 kOe applied direct current (dc) magnetic field are estimated from Arrhenius plots to be 14.4 and 11.3 K, respectively.
Co-reporter:Kong-Qiu Hu, Shu-Qi Wu, Guang-Yu An, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 vol. 42(Issue 4) pp:1102-1108
Publication Date(Web):09 Oct 2012
DOI:10.1039/C2DT31708G
The compartmental Schiff base ligands N,N′-ethylenebis(3-hydroxysalicylidene) (H4L) and N,N′-propylenebis(3-hydroxysalicylidene) (H4L′) have been employed in the synthesis of a cyclic tetranuclear Cu(II) complex [Cu4(L′)2(MeOH)3(H2O)]·[Cu4(L′)2(MeOH)3] (1), a novel octanuclear Cu(II) complex [Cu8(L–L)2(H2O)4(μ2-H2O)]·3DMF·3H2O (2) and a hetero-octanuclear Cu(II)–Fe(III) complex [Cu4Fe4(L)4(H2O)3(μ3-O)2]·3DMF·3H2O (3). During the formation of the Cu8 complex (2), a new bis-Schiff base ligand (L–L)8− forms via the ortho–para C–C coupling of two H4L ligands. The bicyclic complex (2) is comprised of two cyclic Cu4 units that are similar to that of complex 1. In the Cu4 unit, the alternate Cu(II) ions are singly bridged by phenoxo groups. The three complexes display overall antiferromagnetic coupling, and the Cu(II)–Cu(II) magnetic coupling constant falls in the range −117.2 to −473.6 cm−1 for complexes 1 and 2 corresponding to the bridging Cu–Ophenoxide–Cu bond angles of 124.3–131.0°.
Co-reporter:Xi Chen;Ai-Li Cui;Cai-Ming Liu
Transition Metal Chemistry 2013 Volume 38( Issue 6) pp:683-688
Publication Date(Web):2013 September
DOI:10.1007/s11243-013-9737-1
Four linear trinuclear transition metal complexes have been prepared and characterized. The complexes [MII(MeOH)4][FeIII(L)2]2·2MeOH (M = Fe (1) or Ni (2)), [CoII(EtOH)2(H2O)2][FeIII(L)2]2·2EtOH (3), and [MnII(phen)2][MnIII(L)2]2·4MeOH (4) (H2L = ((2-carboxyphenyl)azo)-benzaldoxime, phen = 1,10-phenanthroline) possesses a similar syn–anti carboxylate-bridged structure. The terminal Fe(III) or Mn(III) ions are low spin, and the central M(II) ions are high spin. Magnetic measurements show that antiferromagnetic interactions were present between the adjacent metal ions via the syn–anti carboxylate bridges. The antiferromagnetic coupling between low-spin Fe(III) and Ni(II) is unusual, which has been tentatively assigned to the structural distortion of Fe(III).
Co-reporter:Wen-Bo Shi, Ai-Li Cui, and Hui-Zhong Kou
Crystal Growth & Design 2012 Volume 12(Issue 7) pp:3436-3443
Publication Date(Web):May 24, 2012
DOI:10.1021/cg201605w
Three Cu(II) complexes of tetranuclear [Cu4(cmpy)4(N3)5Cl3] (1), 1D chain [Cu2(cea)2(N3)4]n (2), and two-dimensional layer [Cu5(cmpy)2(N3)10]n (3) were synthesized by controlling the molar ratio of Cu(ClO4)2·6H2O, pyCH2Cl·HCl (cmpy·HCl), or H2NCH2CH2Cl·HCl (cea·HCl) and sodium azide. For complexes 1–3, the atom Cl of the ligands (cmpy and cea) is located at the Jahn–Teller axis of Cu(II) with the weak Cu–Cl separations of 2.920(1) - 3.177(1) Å that are shorter than the sum of van der Waals radii of Cu and Cl atoms, 3.3 Å. The azide ligands coordinate to Cu(II) in the equatorial or basal plane of the coordination pyramid, favoring strong magnetic coupling. The bridging angles of Cu–Nazido–Cu in complexes 1–3 are nearly 101°, corresponding to the presence of global ferromagnetic coupling. The end-to-end azide bridges appear exclusively in complex 3, linking the end-on azide-bridged 1D chains into a 2D layer.
Co-reporter:Qi-Wei Xie, Ai-Li Cui, Jun Tao and Hui-Zhong Kou
Dalton Transactions 2012 vol. 41(Issue 35) pp:10589-10595
Publication Date(Web):22 Jun 2012
DOI:10.1039/C2DT30785E
The synthesis and characterizations of a family of isomorphous [MnIII2MIII4L2(μ4-O)2(N3)2(CH3O)2(CH3OH)4(NO3)2]·2H2O (M = Y(1), Gd(2), Tb(3), Dy(4)) are reported, where H4L = N,N′-dihydroxyethyl-N,N′-(2-hydroxy-4,5-dimethylbenzyl)ethylenediamine. They were obtained from the reactions of H4L with M(NO3)3·6H2O, Mn(ClO4)2·6H2O, NaN3 and NEt3 in a 1:1:1:2:2 molar ratio. The core structure consists of a Mn2M4 unit. The four MIII ions that are held together by two μ4-bridging oxygen atoms form a butterfly M4 moiety. The M4 core is further connected to the two five-coordinate trigonal-bipyramidal MnIII ions via one μ4-O2−, two alkyloxo and one methoxo triple bridges. Magnetic susceptibility measurements indicate the presence of intramolecular antiferromagnetic interactions in complex 2, and overall intramolecular ferromagnetic interactions in complexes 3 and 4. The alternating current (AC) magnetic susceptibility studies revealed that complexes 3 and 4 showed frequency-dependent out-of-phase signals, which indicates that they exhibit slow relaxation of the magnetization.
Co-reporter:Guang-Yu An, Bin Yuan, Jun Tao, Ai-Li Cui, Hui-Zhong Kou
Inorganica Chimica Acta 2012 Volume 387() pp:401-406
Publication Date(Web):30 May 2012
DOI:10.1016/j.ica.2012.02.036
Four oximato-bridged trinuclear complexes [NiII2(Hpyaox)6MnIV]Cl·ClO4·6H2O (1), [NiII2(Hpyaox)6MnIV](ClO4)2·2DMF·4H2O (2), [NiII2(Hpyaox)6CrIII]ClO4·6H2O (3) and [NiII2(Hpyaox)6FeIII]ClO4·6H2O (4) based on pyridine-2-amidoxime (H2pyaox) were prepared in water–DMF solution. X-ray diffraction analysis reveals that they are isomorphous, and consist of linear triply oximato-bridged NiII2MnIV (1 and 2), NiII2CrIII (3) and NiII2FeIII (4) cations with MnIV, CrIII and FeIII ions at the centre. The Ni(II) ion is coordinated by three mono-deprotonated Hpyaox− anions, giving a [Ni(Hpyaox)3]− anion. Two [Ni(Hpyaox)3]− anions coordinate to the central M(III/IV) ion with six oximato oxygen atoms, yielding the trinuclear unit. The magnetic susceptibility measurements show that complexes 1–4 exhibit antiferromagnetic interaction between adjacent metal ions through the triple oximato bridges. By comparison, the unusual antiferromagnetic property of complexes 1–3 has been found to be related to the distortion of the NiN6 coordination configuration from octahedral to trigonal. The magnetic data were fitted by considering the magnetic coupling between adjacent ions, two terminal ions and nearest molecules, respectively.Graphical abstractTriply oximato-bridged hetero-trinuclear complexes display antiferromagnetic coupling, which has been attributed to the distortion of the Ni(II) coordination environment from octahedral to trigonal.Highlights► Four Ni2M (M = Mn(IV), Cr(III) and Fe(III)) complexes based on pyridine-2-amidoxime were synthesized. ► Two complexes contains rare high valence Mn(IV) ions. ► The distortion of the Ni(II) coordination environment greatly affects the magnetic interaction.
Co-reporter:Guo-Ling Li;Wei-Qin Cheng;Li-Fang Zhang;Zhong-Hai Ni
Transition Metal Chemistry 2012 Volume 37( Issue 5) pp:469-474
Publication Date(Web):2012 August
DOI:10.1007/s11243-012-9611-6
Three cyanide-bridged FeIII–MnII binuclear complexes [Mn(phen)2Cl][Fe(bpmb)(CN)2]·H2O (1), [Mn(phen)2Cl][Fe(bpdmb)(CN)2]·H2O (2) and [Mn(phen)2Cl][Fe(bpClb)(CN)2]·3H2O·EtOH (3) [phen = 1,10-phenanthroline, bpmb2− = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpdmb2− = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate, bpClb2− = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate)] have been synthesized by the reaction of Mn(phen)2Cl2 with K[Fe(L)(CN)2]. The syntheses, crystal structures and magnetic properties of the complexes have been investigated. Single-crystal X-ray diffraction analysis reveals that all three complexes are binuclear complexes and contain FeIII–C≡N–MnII linkages. Magnetic investigations indicate antiferromagnetic coupling between low-spin Fe(III) and high-spin Mn(II) centers through cyanide bridging, with JMnFe = −1.39(5) cm−1 for 1, JMnFe = −3.33(2) cm−1 for 2 and JMnFe = −1.96(5) cm−1 for 3. The magneto-structural relationships for cyanide-bridged FeIII–MnII systems are discussed based on binuclear FeIII–MnII and trinuclear FeIII–MnII–FeIII magnetic models.
Co-reporter:Qi-Wei Xie, Xi Chen, Kong-Qiu Hu, Yi-Tong Wang, Ai-Li Cui, Hui-Zhong Kou
Polyhedron 2012 Volume 38(Issue 1) pp:213-217
Publication Date(Web):11 May 2012
DOI:10.1016/j.poly.2012.03.005
Four linear trinuclear manganese complexes containing ligands with an N2O2 donor set have been prepared and characterized structurally and magnetically. The complexes have the general formula [Mn3(Ln)2(OAc)2(OCH3)2] (n = 1, 2, 3, 4. H2L1 = N,N′-dimethyl-N,N′-(2-hydroxy-4,5-dimethylbenzyl)ethylenediamine, H2L2 = N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N-(2-pyridylmethyl)amine, H2L3 = N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N,N′-dimethylethylenediamine, H2L4 = N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-2-aminoethanol). X-ray single-crystal structure analyzes of the complexes show that the linear MnIII–MnII–MnIII cores are triply bridged by phenolate, acetate (syn–syn), and MeO− groups with the MnIII and MnII distances in the range 3.123(3)–3.167(4) Å. Magnetic studies show that the spin exchange coupling constants (J) between MnIII and MnII ions range from −1.58(1) to 1.15(3) cm−1 (Hˆ=-2J(Sˆ1·Sˆ2+Sˆ1·Sˆ3)). The antiferromagnetic and ferromagnetic interactions were analyzed based on the structural features, and the MnIII–O–MnII bond angles have been found to be the dominant factor affecting the intermetallic magnetic coupling.Graphical abstractFour mixed-valence trinuclear Mn(II/III) complexes that have similar structural motif display intramolecular intermetallic antiferromagnetic or ferromagnetic coupling. The results verify that bridging MnII–Oalkoxide–MnIII bond angles are crucial to the magnetic coupling of the linear manganese complexes: the interaction becomes less antiferromagnetic with larger Mn–Oalkoxide–Mn bond angles.Highlights► Four mixed-valence trinuclear Mn(II/III) complexes are derived from tetradentate tripodal ligands. ► The analogous complexes display intramolecular antiferromagnetic or ferromagnetic coupling. ► The results verify that the MnII–Oalkoxide–MnIII bond angles are crucial to the magnetic coupling.
Co-reporter:Guang-Yu An ; Cong-Min Ji ; Ai-Li Cui
Inorganic Chemistry 2011 Volume 50(Issue 3) pp:1079-1083
Publication Date(Web):December 22, 2010
DOI:10.1021/ic1022714
Tetranuclear [Ni4(Hpzaox)2(pzaox)2(py)4](ClO4)2·2py (1), [Ni4(Hpzaox)2(pzaox)2(py)4](NO3)2·4py (2), and two-dimensional (2D) [Ni4(Hpzaox)2(pzaox)2(H2O)2](NO3)2·2H2O (3) are prepared via the reaction of NiX2·6H2O and pyrazine-2-amidoxime (H2pzaox). All compounds contain [Ni4(Hpzaox)2(pzaox)2]2+ fragments, which assemble to form a tetranuclear or polymeric network. Magnetic studies show that the tetranuclear compounds display usual ferromagnetic coupling via the oxime N−O bridges, and the 2D compound displays unusual antiferromagnetic behavior.
Co-reporter:Guang-Yu An, Ai-Li Cui, Hui-Zhong Kou
Inorganic Chemistry Communications 2011 Volume 14(Issue 9) pp:1475-1478
Publication Date(Web):September 2011
DOI:10.1016/j.inoche.2011.05.050
Hexanuclear [MnIII6O2(Hsalaox)6(MeOH)4(MeCO2)2]·4MeOH·2H2O (1) and polymeric [MnIII6O2(Hsalaox)6(MeOH)6(tp)]·12H2O (2) are prepared by the reaction of Mn2+, salicylamidoxime (H3salaox) and corresponding carboxylates (tp2− = terephthalate). Magnetic studies show that both complexes display slow magnetization relaxation.Hexanuclear [Mn6O2(Hsalaox)6]2+ fragments can form discrete clusters and a terephthalate-bridged 1D chain, which display slow magnetization relaxation.Research highlights► Salicylamidoxime as the ligand for polynuclear Mn6 complexes. ► Terephthalic acid as the bridging ligand for polymeric coordination compound. ► Novel 1D complex that contains hexanuclear Mn(III) as nodes. ► Slow relaxation of magnetization for two compounds has been observed. ► No obvious improvements in magnetism by changing Mn6 to 1D.
Co-reporter:Li-Fang Zhang, Ming-Ming Yu, Zhong-Hai Ni, Ai-Li Cui, Hui-Zhong Kou
Journal of Molecular Structure 2011 Volume 1006(1–3) pp:629-634
Publication Date(Web):14 December 2011
DOI:10.1016/j.molstruc.2011.10.017
A one-dimensional (1D) copper(II) complex [Cu3(μ1,1-N3)6(dmp)2]n (1) has been synthesized and structurally characterized. The molecular structure of 1 is constructed by trimeric [Cu3(μ1,1-N3)6(dmp)2] units formed through two double symmetric (basal-to-basal) end-on (EO) azide bridges and the trimeric units are connected further by double asymmetric (basal-to-apical) EO azide bridges, giving 1D chain-like structure. The chains of 1 are linked together by N–H⋯Nazide hydrogen bonds and very weak Cu⋯Nazide coordination interactions from μ-1,1,3,3-N3 fashion to form two-dimensional (2D) supramolecular architecture. The magnetic structure can be considered as uniform 1D chain formed by linear trimeric CuII–CuII–CuII units and the dominating magnetic coupling occurs within the trimeric Cu3II unit. The magnetic study shows that the compound exhibits ferromagnetic interactions with Jt = + 8.36(2) cm−1 and Jc = + 0.35(4) cm−1 for intratrimeric and intertrimeric Cu3II unit based on 1D magnetic model, respectively.Highlight► A new copper(II) complex [Cu3(μ1,1-N3)6(dmp)2]n (1) has been synthesized and characterized. ► The molecular structure of 1 is 1D chain bridged by different double end-on azide bridges. ► The magnetic study shows that the compound exhibits overall ferromagnetic interactions. ► The magnetic susceptibilities of 1 have been fitted based on two magnetic models.
Co-reporter:Ai-Li Cui, Xi Chen, Long Sun, Jing-Zhi Wei, Jin Yang, and Hui-Zhong Kou
Journal of Chemical Education 2011 Volume 88(Issue 3) pp:311-312
Publication Date(Web):December 17, 2010
DOI:10.1021/ed100103a
The synthesis and characterization of two copper(II) complexes, [Cu(deen)2](BF4)2 and [Cu(deen)2](NO3)2 (deen = N,N-diethylethylenediamine), that show interesting thermochromic properties, are described. The subtle alternation of coordination geometry around Cu(II) is responsible for the color change from red to violet. This experiment is suitable for first-year chemistry students and could demonstrate one of the colorful properties of chelate compounds.Keywords (Audience): First-Year Undergraduate/General; Keywords (Domain): Inorganic Chemistry; Laboratory Instruction; Physical Chemistry; Keywords (Pedagogy): Hands-On Learning/Manipulatives; Keywords (Topic): Calorimetry/Thermochemistry; Coordination Compounds; Molecular Properties/Structure; Physical Properties; Synthesis;
Co-reporter:Dr. Guang Li;Mingyang Liu;Dr. Hui-Zhong Kou
Chemistry - A European Journal 2011 Volume 17( Issue 15) pp:4323-4329
Publication Date(Web):
DOI:10.1002/chem.201003068
Abstract
A solvothermal route is adopted to produce mesoporous α-Fe2O3 nanospheres by using polyethylene glycol as soft template and n-butanol/H2O as mixed solvent. The mesoporous α-Fe2O3 nanospheres are subjected to calcination at different temperatures, and the specific surface area, pore size, and magnetic properties of the as-prepared nanospheres are investigated. The studies reveal that the pore sizes of the mesoporous α-Fe2O3 nanospheres increase with higher calcination temperature, and high-temperature calcination brings about tightness of the pore wall. Magnetic studies show that aggregation of the small particles raises the Morin transition temperature.
Co-reporter:Hui-Zhong Kou, Guang-Yu An, Cong-Min Ji, Bing-Wu Wang and Ai-Li Cui
Dalton Transactions 2010 vol. 39(Issue 40) pp:9604-9610
Publication Date(Web):27 Aug 2010
DOI:10.1039/C0DT00528B
Single-, double- and triple-decker oximato-bridged Ni(II) clusters based on pyridine-2-amidoxime (H2pyaox) have been synthesized and characterized. The decks have the same tetranuclear cationic units [Ni4(Hpyaox)2(pyaox)2]2+ that are stably present in the reaction solution. Magnetic studies show that uncommon ferromagnetic exchange between the adjacent Ni(II) ions through the oxime bridges is operative in the compounds with the magnetic coupling constant (J) in the range 0.6–6.3 cm−1 (H = −2JSNi1SNi2). Density function theoretical (DFT) calculations and the experimental data confirm that the N–O bond distances of the bridging oxime group have a decisive effect in magnetic coupling. For the present Ni(II) species, the elongation of N–O bond distances are responsible for the switching from antiferromagnetic to ferromagnetic exchange with the critical bond distance of 1.394 Å.
Co-reporter:Zhong-Hai Ni, Jun Tao, Wolfgang Wernsdorfer, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2009 (Issue 15) pp:2788-2794
Publication Date(Web):23 Feb 2009
DOI:10.1039/B814860K
The reaction of trans-[Fe(R-bpb)(CN)2]− (R-bpb2− = R-substituted-1,2-bis(pyridine-2-carboxamido)benzenate) with trans-Mn(III) Schiff base complexes [Mn(5-X-saltn)]ClO4 (5-X-saltn2− = N,N′-propanolbis(5-X-substituted-salcylideneiminato) dianion) gave rise to cyanide-bridged neutral binuclear [MnFe] compounds [Mn(saltn)(MeOH)][Fe(bpb)(CN)2]·3H2O (1), [Mn(saltn)(H2O)Fe(bpmb)(CN)2]·H2O (2), [Mn(saltn)(MeOH)Fe(bpClb)(CN)2]·2H2O (3), and ionic [Mn2Fe]+-[Fe]− complexes [Mn2(5-Br-saltn)2(H2O)(EtOH)Fe(bpb)(CN)2][Fe(bpb)(CN)2]·6H2O (4) and [Mn2(5-Cl-saltn)2(CH3OH)(EtOH)Fe(bpb)(CN)2][Fe(bpb)(CN)2]·5H2O·MeCN (5). Four binuclear units of complexes 1–3 assemble in a head-to-tail way viahydrogen bonding giving rise to a metallo-supramolecular [MnFe]4 square, while two [Mn2Fe]+-[Fe]− units of complexes 4–5 form a metallo-supramolecular macrocyclic structure. Magnetic studies reveal that complexes 1–3 and 5 exhibit intermetallic ferromagnetic coupling, while complex 4 displays antiferromagnetic interaction between low-spin Fe(III) and high-spin Mn(III) through the cyanide bridges. Complexes 1, 4 and 5 display frequency dependent of current-alternating (ac) magnetic susceptibility, typical of the presence of slow magnetization relaxation. Because of the existence of intermolecular magnetic interaction, complex 4 shows an exchange-biased single-molecule magnet (SMM) behavior below 0.5 K.
Co-reporter:Hui-Zhong Kou, Zhong-Hai Ni, Cai-Ming Liu, De-Qing Zhang and Ai-Li Cui
New Journal of Chemistry 2009 vol. 33(Issue 11) pp:2296-2299
Publication Date(Web):22 Sep 2009
DOI:10.1039/B9NJ00316A
Cyanide-bridged Mn(III)–Fe(III) complexes have been synthesized in order to find new molecular materials with interesting magnetic properties. 1D complexes of trans-dicyanoferrite(III), [Mn(5-Cl-salen)Fe(bpClb)(CN)2]·0.67MeCN·0.5H2O (1), [Mn(5-Cl-salen)Fe(bpb)(CN)2]·0.5H2O·MeOH (2), [Mn(5-Br-salen)Fe(bpb)(CN)2]·0.5H2O·MeOH (3), and [Mn(5-Me-salen)Fe(bpb)(CN)2]·0.5H2O·MeOH (4) have been prepared and characterized by X-ray single-crystal structure analysis and magnetic measurements. All complexes possesses 1D chains of alternate [Mn(5-R-salen)]+ and [Fe(bpRb)(CN)2]− units that are linked by two trans-cyanide ligands of [Fe(bpRb)(CN)2]−. Magnetic studies reveal that they exhibit overall intermetallic ferromagnetic coupling, while complex 4 shows a frequency-dependent AC magnetic susceptibility typical of a single-chain magnet.
Co-reporter:Chun-Hua Ge, Ai-Li Cui, Hui-Zhong Kou
Inorganic Chemistry Communications 2009 Volume 12(Issue 9) pp:926-928
Publication Date(Web):September 2009
DOI:10.1016/j.inoche.2009.07.015
Co-reporter:Chun-Hua Ge, Zhong-Hai Ni, Cai-Ming Liu, Ai-Li Cui, De-Qing Zhang, Hui-Zhong Kou
Inorganic Chemistry Communications 2008 Volume 11(Issue 6) pp:675-677
Publication Date(Web):June 2008
DOI:10.1016/j.inoche.2008.03.005
Reaction of Mn(ClO4)2 · 6H2O with 2,6-bis(hydroxymethyl)-4-methylphenol (H3hmmp) in the presence of sodium azide gives rise to a high-nuclearity cluster [Mn7IIMn12III(μ4-O)8(μ1,1,1-N3)8(Hhmmp)12(OH)2(H2O)4]·24H2O that displays a spin ground state as high as 73/2.High-nuclearity cluster [Mn7IIMn12III(μ4-O)8(μ1,1,1-N3)8(Hhmmp)12(H2O)6](OH)2·22H2O displays a spin ground state of 73/2.
Co-reporter:Hui-Zhong Kou, Shoko Hishiya, Osamu Sato
Inorganica Chimica Acta 2008 Volume 361(Issue 8) pp:2396-2406
Publication Date(Web):2 June 2008
DOI:10.1016/j.ica.2007.12.018
Bidentate ligands 2,2′-biquinoline (biq) and 6,6′-dimethyl-2,2′-bipyridine (dmbpy) with steric hindrance substituents cis to the nitrogen atoms have been used in the synthesis of transition metal complexes. Six new doubly end-on azido-bridged binuclear complexes [M2(biq)2(μ1,1-N3)2(N3)2] (M = Ni (1), M = Co (2)), [M2(biq)2(μ1,1-N3)2Cl2] (M = Ni (3), M = Co (4)), [M2(dmbpy)2(μ1,1-N3)2(N3)2] (M = Ni (5), M = Co (6)) and one end-to-end thiocyanato-bridged polymeric [Ni(dmbpy)(μ1,3-SCN)(NCS)]n (7) have been synthesized and characterized by single crystal X-ray diffraction analysis and magnetic studies. Complexes 1–6 comprise five-coordinate M(II) ions bridged by two end-on azide ligands. The bridging M–N–M bond angles are in the small range 104.1–105.2°. Complex 7 consists of a singly thiocyanate-bridged Ni(II) chain in which Ni(II) ions are five-coordinate. This research suggests that the bulky ligands play a key role in the formation of five-coordinate coordination structure. All complexes display intramolecular intermetallic ferromagnetic coupling with JNiNi and JCoCo of ca. 23 or 13 cm−1 based on the Hamiltonian H^=-2JS^1S^2 (S1 = S2 = 1 for Ni2, or 3/2 for Co2). The singly SCN−-bridged chainlike complex 7 shows intrachain ferromagnetic interaction with J = 3.96(2) cm−1 and D = −4.55(8) cm−1 (H^=-2J∑i=1(SˆiS^i+1)-D∑i=1[(S^iZ)2-2/3]). Magneto-structural correlationship has been investigated.The employment of bulky ligands has been shown to be an effective approach to produce five-coordinate transition metal complexes. Ferromagnetic coupling exists in the end-on azide-bridged Co2 or Ni2 complexes and the novel end-to-end thiocyanate-bridged 1D Ni(II) complex. Significant structural-magneto correlationship has been investigated.
Co-reporter:Hui-Juan YANG;Ai-Li CUI;Ru-Ji WANG
Chinese Journal of Chemistry 2008 Volume 26( Issue 8) pp:1527-1531
Publication Date(Web):
DOI:10.1002/cjoc.200890277
Abstract
The reaction of benzene-1,3,5-tricarboxylic acid (H3BTC) with NiCO3 under hydrothermal conditions afforded a new 2D complex Ni3(BTC)2(µ-H2O)2·6H2O, which possesses an infinite double-layered structure. The layer is comprised of syn-syn carboxylate- and aqua oxygen-bridged Ni3 units that are connected further by BTC3−. Ferromagnetic exchange interaction is operative between the Ni2+ ions, experimentally showing the propagation of ferromagnetic coupling through the syn-syn carboxylate bridges because the magnetic exchange through the aqua bridges [Ni–O–Ni bond angle=122.8(3) °] is antiferromagnetic. On the basis of the present results and the previous reports on syn-syn carboxylate-bridged Ni(II) complexes, it was found that the coplanarity of Ni–O–C–O–Ni dominated the magnetism. The planar arrangement of Ni–O–C–O–Ni gives rise to strong antiferromagnetic coupling, whereas the deviation from planarity weakens the antiferromagnetic coupling, possibly resulting in weak ferromagnetic coupling. Therefore, similarly to the mixed ligand-bridged Cu(II) dimer the orbital complementary effect (OCE) is also operative in the aqua-/carboxylate-bridged Ni(II) dimer.
Co-reporter:Chong-Chao Zhao;Wei-Wei Ni;Ming-Ming Yu;Ai-Li Cui
Transition Metal Chemistry 2008 Volume 33( Issue 7) pp:
Publication Date(Web):2008 October
DOI:10.1007/s11243-008-9124-5
The hydrothermal synthesis of a heterocyclic quaternary nitrogen compound, namely, 6,7-dihydro-pyrido[2′,1′:3,4]pyrazino[1,2-a]imidazol-5-ium-bromide monohydrate (LBr · H2O) is reported. Various spectroscopic analyses were performed on the cationic heterocycle. CuII and ZnII halide complexes of this novel ligand were prepared. The heterocycle and its complexes were characterized by single crystal X-ray diffraction analysis. Both complexes contain neutral [MIILX3] molecules, where the cyclic ligand (L+) is coordinated to the metal as a monodentate ligand. The Cu2+ complex has a distorted tetrahedral geometry, indicating an obvious steric effect from L+ on the chloride co-ligand.
Co-reporter:Ming-Ming Yu;Zhong-Hai Ni;Chong-Chao Zhao;Ai-Li Cui
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 36) pp:
Publication Date(Web):29 OCT 2007
DOI:10.1002/ejic.200700680
Three azido-bridged MnII complexes of formulas [Mn2(N3)4(ttp)2] (1), [Mn2(N3)4(ttp-N3)2] (2) and [Mn2(N3)4(ttp-N3)2]3[MnIII(ttp-N3)(N3)3]2 (3), where ttp and ttp-N3 represent 4′-p-tolyl-2,2′:6′,2″-terpyridine and 4′-p-azidomethylphenyl-2,2′:6′,2″-terpyridine, were synthesized and characterized by single-crystal X-ray diffraction analysis and magnetic studies. The Mn ions in complexes 1 and 2 are coordinated by three N atoms of the ttp or ttp-N3 ligands, and they are connected by double end-on (EO) azide ligands; this forms a dinuclear MnII system with Mn–N–Mn bridging angles of 103.5 and 103.1°. The Br atoms of the –CH2Br ligands were replaced by azido groups during the formation of complexes 2 and 3. The structure of complex 3 comprises two structurally similar MnII dimers with double end-on bridging azide groups and one mononuclear MnIII structure. The bridging Mn–N–Mn angles in 3 are 104.2, 105.1, and 106.73°. Magnetic studies indicate the presence of intramolecular ferromagnetic superexchange. The strength of ferromagnetic coupling within the Mn2 cores in 1–3 is dependent on the Mn–N–Mn bridging angles. The magnetic coupling constants for intermolecular exchange are 2.46(4), 2.25(2), and 1.92(4) cm–1 for 1, 2, and 3, respectively, on the basis ofHamiltonian Ĥ = –2JŜ1Ŝ2.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Zhong-Hai Ni;Lei Zheng;Li-Fang Zhang;Ai-Li Cui;Wei-Wei Ni;Chong-Chao Zhao
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 9) pp:
Publication Date(Web):14 FEB 2007
DOI:10.1002/ejic.200600958
Four cyanido-bridged MnIII–CrI heterodimetallic complexes have been synthesized by the reactions of MnIII Schiff-base complexes with the [Cr(CN)5(NO)]3– building block. X-ray diffraction analysis reveals that [Mn(5-Cl-salen)(H2O)2][Mn2(5-Cl-salen)2(H2O)1.5Cr(CN)5(NO)] (1) has a trinuclear structure, and [Mn3(salen)3(H2O)(CH3CN)Cr(CN)5(NO)]·0.5CH3CN·0.5MeOH·2H2O (2) and [Mn(5-Br-salen)(H2O)(CH3OH)][Mn2(5-Br-salen)2(CH3OH)Cr(CN)5(NO)]·2H2O (3) have novel 1D chain topological structures, whereas [{Mn(saltmen)}4Cr(CN)5(NO)]ClO4·3H2O (4) displays a 2D layered network structure. Magnetic measurements show that the magnetic interaction between the MnIII and CrI ions bridged by a cyanido group is antiferromagnetic for complexes 1–4. The magnetic fitting for the trinuclear complex 1 gives the magnetic coupling constant J = –10.4(1) cm–1 and J′ = –1.29(2) cm–1 based on the isotropic Hamiltonian Ĥ = –2JŜCr[ŜMn(1) + ŜMn(2)] – 2J′ŜMn(1)ŜMn(2). Complex 2 exhibits 3D antiferromagnetic ordering (TN = 3.5 K) with a metamagnetic character below TN. Complex 3 exhibits an obvious frequency-dependent AC magnetic susceptibility below 4.0 K, which is due to the spin-glass behavior. The layered complex 4 displays 3D ferromagnetic ordering with Tc = 6.4 K due to the ferromagnetic interaction between the ferrimagnetic layers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Bing Zhang, Zhong-Hai Ni, Ai-Li Cui and Hui-Zhong Kou
New Journal of Chemistry 2006 vol. 30(Issue 9) pp:1327-1332
Publication Date(Web):07 Aug 2006
DOI:10.1039/B605521D
Three new trinuclear complexes based on [Cu(Ln)]2+ (L1 = 1,5,8,12-tetramethyl-1,3,6,8,10,13-hexaazacyclotetradecane, L2 = 1,3-propanediamine (tn)) and [M(bpb)(CN)2]− (bpb2− = 1,2-bis(pyridine-2-carboxamido)benzenate, M = Fe or Cr) have been synthesized and characterized structurally and magnetically. The Cu(II) ions adopt an axially-elongated octahedron with four N atoms from the Ln ligands occupying the equatorial plane and another two atoms (cyano nitrogen atoms or amide oxygen atoms) from two [M(bpb)(CN)2]− moieties at the axial positions, resulting in a neutral linear trinuclear complex. Magnetic studies show that the CuFe2 compound bridged by the amido group exhibits ferromagnetic behaviour. The two cyano-bridged CuFe2 or CuCr2 compounds show unusual magnetic properties: weak antiferromagnetic Cu(II)–Fe(III) coupling and negligible Cu(II)–Cr(III) magnetic exchange, proved by the results of the field dependence of magnetization.
Co-reporter:Chun-Hua Ge, Hui-Zhong Kou, Zhong-Hai Ni, Yun-Bo Jiang, Ai-Li Cui
Inorganica Chimica Acta 2006 Volume 359(Issue 2) pp:541-547
Publication Date(Web):20 January 2006
DOI:10.1016/j.ica.2005.09.044
Three complexes of the composition {[Cu(μ1,5-dca)2(mppca)2] · H2O}n (1), [Cu(μ1,5-dca)2(nppca)2]n (2) and [Cu(μ-Cl)2(mppca)2]n (3) (dca = dicyanamide, N(CN)2-; mppca = N-(4′-methylphenyl)-4-pyridinecarboxamide; nppca = N-(4′-nitrophenyl)-4-pyridinecarboxamide) have been synthesized and characterized by single crystal X-ray crystallography and magnetic susceptibility studies. Different supramolecular structures of the complexes have been constructed by different non-covalent motifs in the crystalline solids. In complex 1, adjacent copper(II) atoms are connected by double μ1,5-dca(end-to-end) bridges to form a chain-like structure. The chains are linked by π–π interactions and hydrogen bonds between the ligands and water molecules to form a 3D network. In complex 2, copper(II) atom has a coordination environment similar to 1, but water molecules have not been found. Weak C–H⋯N hydrogen bonding and π–π interaction yield a 3D supramolecular network which is different from that of complex 1. Complex 3 is a 1D polymeric chain in which Cu(II) ions are bridged by Cl−, and only CH/π interactions had been found. Magnetic measurements revealed antiferromagnetic properties of 1, 3 and ferromagnetic behavior of 2.Three N(CN)2- or Cl− bridged 1D copper(II) complexes have been synthesized with the pyridinecarboxamide ligand. The pyridinecarboxamide ligands exhibit interesting intermolecular contacts. Temperature dependence of magnetic susceptibilities of the complexes has been studied.
Co-reporter:Ni Zhong-Hai;Zhao Yi-Hua;Zheng Lei;Kou Hui-Zhong;Cui Ai-Li
Chinese Journal of Chemistry 2005 Volume 23(Issue 6) pp:
Publication Date(Web):12 JUL 2005
DOI:10.1002/cjoc.200590786
A new hydroxo-bridged dimeric Cr(III) complex [Cr(saltn)OH]2·4H2O [H2saltn=N,N′-bis(salicylidene)trimethylenediamine] has been synthesized and its structural and magnetic properties have been investigated. The complex crystallizes in the triclinic space group P-1 with one dimeric formula unit in a cell of dimensions a=0.95828(19) nm, b=0.95926(19) nm, c=1.0437(2) nm, α=86.77(3)°, β=82.48(3)°, and γ=64.93(3)°. The geometry around each chromium(III) center is six-coordinate, distorted-octahedral. The bridging Cr2O2 unit is strictly planar, as required by the crystallographic symmetry. The CrOCr′ bridging angle is 99.94(16)°, and the distance between Cr…Cr′ is 0.3019 nm. The magnetic susceptibility of the complex has been examined in the range of 2-300 K. By using the spin-spin coupled model for an S1=S2=3/2 dimeric system , the magnetic data were fitted to give the parameters of g=2.01(1), J=-0.85(2) cm-1, and zJ' =0.18(3)cm-1, indicating the presence of a weak antiferromagnetic spin-exchange interaction between the Cr(III) ions in the binuclear complex.
Co-reporter:Zhong-Hai Ni Dr.;Li-Fang Zhang;Chunhua Ge Dr.;Ai-Li Cui Dr.;Ru-Ji Wang ;Yadong Li Dr.;Osamu Sato Dr.
Angewandte Chemie 2005 Volume 117(Issue 47) pp:
Publication Date(Web):3 NOV 2005
DOI:10.1002/ange.200502699
Heterometallrad: Ein Cyanid-verbrückter zwölfkerniger Heterometallkomplex mit der Form eines molekularen Rades wurde aus magnetisch anisotropen [Mn(salen)]+- und [Fe(bpmb)(CN)2]−-Baugruppen synthetisiert. Der Komplex weist ferromagnetische intramolekulare Kopplungen (siehe Bild) und frequenzabhängige magnetische AC-Suszeptibilität auf. H2bpmb=1,2-Bis(pyridin-2-carboxamido)-4-methylbenzol.
Co-reporter:Zhong-Hai Ni, Hui-Zhong Kou, Li-Fang Zhang, Chunhua Ge, Ai-Li Cui, Ru-Ji Wang, Yadong Li,Osamu Sato
Angewandte Chemie International Edition 2005 44(47) pp:7742-7745
Publication Date(Web):
DOI:10.1002/anie.200502699
Co-reporter:Yun-Bo Jiang;Ru-Ji Wang;Ai-Li Cui
European Journal of Inorganic Chemistry 2004 Volume 2004(Issue 23) pp:
Publication Date(Web):7 OCT 2004
DOI:10.1002/ejic.200400449
Four new CuII complexes of formulae [Cu3(SE)2(H2O)2Cl3]Cl·6H2O (1), Cu3(SE)2(N3)4(DMF)2 (2), Cu(SE)N3·DMF (3) and Cu(SE)N3·Cu(SE)N3 (4) with tridentate Schiff-base ligands SE−, derived from condensation of N,N-dimethylethylenediamine with salicylaldehyde, have been synthesised and characterised by IR spectroscopy, X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Complex 1 has an alternating phenoxy- and chloro-bridged 1D chain structure. Complex 2 possesses trinuclear units in which the CuII ions are bridged by single end-on (µ-1,1) azido ligands. Uniformly spaced 1D chains with end-to-end (µ-1,3) azido bridges are found in 3 and 4. As expected, complexes 1 and 2 exhibit antiferromagnetic and ferromagnetic exchange, respectively. Compounds 3 and 4 show unusual ferromagnetic coupling though the 1,3-azido pathways. Theoretical simulations have been carried out in order to evaluate the magnitude of the magnetic exchange and the magneto-structural correlation has been investigated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Co-reporter:Hui-Zhong Kou;Bei Chuan Zhou;Shu-Feng Si;Ru-Ji Wang
European Journal of Inorganic Chemistry 2004 Volume 2004(Issue 2) pp:
Publication Date(Web):19 NOV 2003
DOI:10.1002/ejic.200300500
The synthesis, structure, and properties of the dimetallic complexes [CuLCr(CN)6]6·[{CuL(H2O)}6Cr(CN)6](ClO4)3· 16H2O (1), [CuLCr(CN)5(NO)]6·[{CuL(H2O)}6Cr(CN)5(NO)](ClO4)3·16H2O (2) and [CuL]3[W(CN)8]2·4H2O (3) {L = 3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo[3.3.2]decane} are presented. The structures of 1 and 2 are isomorphous and consist of novel cyano-bridged [CuL(μ-CN)2Cr(CN)4]6 dodecanuclear units and [CuL(H2O)(μ-CN)]6Cr heptanuclear moieties. Every cyclic dodecanuclear Cu6Cr6 group embeds a ClO4− anion. The heptanuclear and the dodecanuclear units are connected through hydrogen bonds to generate a vacant hole, in which another ClO4− anion is accommodated. Complex 3 contains cyano-bridged Cu2W trimers and CuW dimers. Magnetic studies have shown that the three complexes display ferromagnetic coupling across the Cr−CN−Cu or W−CN−Cu linkages. The best fit to the magnetic data gave for complex 1JCuCr = +2.40 cm−1, gCr = 1.99, gCu = 2.09, and an intermolecular coupling constant θ = +0.23 K while for complex 2JCuCr = +12 cm−1, g = 2.13, and θ = −0.49 K. Ferromagnetic CuII-WV coupling is operative in complex 3. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Co-reporter:Hui-Zhong Kou, Bei Chuan Zhou, Ru-Ji Wang
Journal of Organometallic Chemistry 2004 Volume 689(Issue 2) pp:369-373
Publication Date(Web):15 January 2004
DOI:10.1016/j.jorganchem.2003.10.024
A novel cyano-bridged three-dimensional mixed-valence Cu(II)/Cu(I) compound [Cu2(oxpn)][Cu(CN)2]2 (oxpn2− = dianion of N,N′-bis(3-aminopropyl)oxamide) has been synthesized and structurally characterized. Single crystals of 1 formed by diffusion of Cu2(oxpn)Cl2 and K3[Cr(CN)5(NO)] in H2O for two months. The structure of the title compound consists of threefold interpenetrating 3D frameworks. In each 3D network, oxamidato-bridged dimeric [Cu2(oxpn)]2+ units connect 1D polymeric [Cu(CN)2]− anions giving rise to a 3D structure. Room temperature magnetic measurement shows the presence of strong magnetic coupling between the Cu(II) ions. Electronic paramagnetic resonance spectrum measurements show the transitions due to the excited triplet state.A novel cyano-bridged three-dimensional mixed-valence Cu(II)/Cu(I) compound [Cu2(oxpn)][Cu(CN)2]2 (oxpn2−=dianion of N,N′-bis(3-aminopropyl)oxamide) has been synthesized and structurally characterized.
Co-reporter:Zhou Bei-Chuan;Kou Hui-Zhong;He Yi;Wang Ru-Ji;Li Ya-Dong;Wang Hong-Gen
Chinese Journal of Chemistry 2003 Volume 21(Issue 3) pp:352-355
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20030210326
A new cyano-bridged binuclear 4f-3d complex Sm(DMSO)4-(H2O)3Cr(CN)6 was synthesized and characterized by single crystal structure analysis. It crystallizes in monoclinic, space group P21 with a=0.9367(2) nm, b = 1.3917(3) nm, c = 1.1212(2) run, β = 99.88(3)° and Z = 2. In this binuclear complex, Sm atom is eight coordinated and linked to the Cr atom by a cyano bridge. The molecules packs to form 3D structure due to the hydrogen bonds among them. [K3(18-C-6)3(H2O)4]Cr(CN)6·3H2O (18-C-6 represents 18-crown-6-ether) that was synthesized as a byproduct in the preparation of a Gd—Cr complex is also structurally characterized. Crystal data: triclinic, space group P-l with a = 1.0496(7) nm, b= 1.1567(14) nm, c = 1.3530(13) nm, a = 94.15(9)°, β = 96.04(8)°, γ = 95.25(9)° and Z = l. [K3(18-C-6)3(H2O)4]-Cr(CN)6·3H2O consists of ionic [K3(18-C-6)3(H2O)4]3+ and [Cr(CN)6]3- pairs, of which the [K3(18-C-6)3(H2O)4]3+ ion is a trinuclear duster connected by water, and K atoms are eight coordinated by eight oxygen atoms of one 18-C-6 and two water molecules.
Co-reporter:Bei-Chuan Zhou;Yong Li;Ming Xiong;Ru-Ji Wang
Chinese Journal of Chemistry 2003 Volume 21(Issue 9) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20030210911
Three new complexes [Ni(H2L)][Fe(CN)5(NO)]2 ± 6H2O (1), [Ni(H2L)][Fe(CN)5(NO)]2 ± 4H2O (2) and [Cu(H2L)][Fe-(CN)5(NO)]2 ± 4H2O (3) (L = 3,10-bis(2-aminoethyl)-1,3,5, 8,10,12-hexaazacyclotetradecane) are prepared and characterized by IR, elemental analyses and single-crystal X-ray analyses, indicating that they are the first examples of trinuclear nitroprusside-bridged MFe2 (M = Cu and Ni) complexes. In the three complexes, the central metal atoms (M) are all six-coordinated by the nitrogen atoms from the macrocyclic ligand and two cyano-bridges at the trans-positions to form distorted octahedral configurations. The axial N-M-N linkage is nearly vertical to the equatorial plane defined by four coordinating N atoms of macrocyclic ligand. The C ± N-Ni bond angle of 172.6° in complex 1 is apparently larger than those in complexes 2 and 3 (152.57° and 136.37°, respectively). The three complexes are all connected by hydrogen bonds into 3D networks. This study shows that the cyano-bridged trinuclear species could be generated via the control of the charge of the building blocks.
Co-reporter:Hui-Zhong Kou Dr.;Bei Chuan Zhou;Song Gao ;Ru-Ji Wang
Angewandte Chemie 2003 Volume 115(Issue 28) pp:
Publication Date(Web):16 JUL 2003
DOI:10.1002/ange.200351248
Violette Plättchen eines Koordinationspolymers mit drei verschiedenen Metallionen (siehe Bild; C=schwarz, Cr=rosa, Cu=blau, Gd=grün, N=violett, O=rot) und verbrückenden [Cr(CN)6]3−-Komplexionen entstehen durch langsame Diffusion einer Lösung von GdCl3 und einem CuII-Oxamidokomplex in eine [Cr(CN)6]3−-Lösung. Der magnetische Grundzustand (S=7) der Verbindung ergibt sich aus der zweidimensionalen ferromagnetischen Kopplung innerhalb der Schichten.
Co-reporter:Hui-Zhong Kou Dr.;Bei Chuan Zhou;Song Gao ;Ru-Ji Wang
Angewandte Chemie International Edition 2003 Volume 42(Issue 28) pp:
Publication Date(Web):16 JUL 2003
DOI:10.1002/anie.200351248
Ion bridge: A unique mixed heterotrimetallic coordination polymer (depicted) with a bridging [Cr(CN)6]3− ion is synthesized by the slow diffusion of a macrocyclic oxamido-CuII complex, and gadolinium trichloride into potassium hexacyanochromate(III). Intermetallic ferromagnetic coupling is operative within the 2D layer, giving rise to an S=7 ground state. C=black, Cr=pink, Cu=blue, Gd=green, N=violet, O=red.
Co-reporter:Zhong-Hai Ni, Jun Tao, Wolfgang Wernsdorfer, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2009(Issue 15) pp:NaN2794-2794
Publication Date(Web):2009/02/23
DOI:10.1039/B814860K
The reaction of trans-[Fe(R-bpb)(CN)2]− (R-bpb2− = R-substituted-1,2-bis(pyridine-2-carboxamido)benzenate) with trans-Mn(III) Schiff base complexes [Mn(5-X-saltn)]ClO4 (5-X-saltn2− = N,N′-propanolbis(5-X-substituted-salcylideneiminato) dianion) gave rise to cyanide-bridged neutral binuclear [MnFe] compounds [Mn(saltn)(MeOH)][Fe(bpb)(CN)2]·3H2O (1), [Mn(saltn)(H2O)Fe(bpmb)(CN)2]·H2O (2), [Mn(saltn)(MeOH)Fe(bpClb)(CN)2]·2H2O (3), and ionic [Mn2Fe]+-[Fe]− complexes [Mn2(5-Br-saltn)2(H2O)(EtOH)Fe(bpb)(CN)2][Fe(bpb)(CN)2]·6H2O (4) and [Mn2(5-Cl-saltn)2(CH3OH)(EtOH)Fe(bpb)(CN)2][Fe(bpb)(CN)2]·5H2O·MeCN (5). Four binuclear units of complexes 1–3 assemble in a head-to-tail way viahydrogen bonding giving rise to a metallo-supramolecular [MnFe]4 square, while two [Mn2Fe]+-[Fe]− units of complexes 4–5 form a metallo-supramolecular macrocyclic structure. Magnetic studies reveal that complexes 1–3 and 5 exhibit intermetallic ferromagnetic coupling, while complex 4 displays antiferromagnetic interaction between low-spin Fe(III) and high-spin Mn(III) through the cyanide bridges. Complexes 1, 4 and 5 display frequency dependent of current-alternating (ac) magnetic susceptibility, typical of the presence of slow magnetization relaxation. Because of the existence of intermolecular magnetic interaction, complex 4 shows an exchange-biased single-molecule magnet (SMM) behavior below 0.5 K.
Co-reporter:Hui-Zhong Kou, Guang-Yu An, Cong-Min Ji, Bing-Wu Wang and Ai-Li Cui
Dalton Transactions 2010 - vol. 39(Issue 40) pp:NaN9610-9610
Publication Date(Web):2010/08/27
DOI:10.1039/C0DT00528B
Single-, double- and triple-decker oximato-bridged Ni(II) clusters based on pyridine-2-amidoxime (H2pyaox) have been synthesized and characterized. The decks have the same tetranuclear cationic units [Ni4(Hpyaox)2(pyaox)2]2+ that are stably present in the reaction solution. Magnetic studies show that uncommon ferromagnetic exchange between the adjacent Ni(II) ions through the oxime bridges is operative in the compounds with the magnetic coupling constant (J) in the range 0.6–6.3 cm−1 (H = −2JSNi1SNi2). Density function theoretical (DFT) calculations and the experimental data confirm that the N–O bond distances of the bridging oxime group have a decisive effect in magnetic coupling. For the present Ni(II) species, the elongation of N–O bond distances are responsible for the switching from antiferromagnetic to ferromagnetic exchange with the critical bond distance of 1.394 Å.
Co-reporter:Qi-Wei Xie, Ai-Li Cui, Jun Tao and Hui-Zhong Kou
Dalton Transactions 2012 - vol. 41(Issue 35) pp:NaN10595-10595
Publication Date(Web):2012/06/22
DOI:10.1039/C2DT30785E
The synthesis and characterizations of a family of isomorphous [MnIII2MIII4L2(μ4-O)2(N3)2(CH3O)2(CH3OH)4(NO3)2]·2H2O (M = Y(1), Gd(2), Tb(3), Dy(4)) are reported, where H4L = N,N′-dihydroxyethyl-N,N′-(2-hydroxy-4,5-dimethylbenzyl)ethylenediamine. They were obtained from the reactions of H4L with M(NO3)3·6H2O, Mn(ClO4)2·6H2O, NaN3 and NEt3 in a 1:1:1:2:2 molar ratio. The core structure consists of a Mn2M4 unit. The four MIII ions that are held together by two μ4-bridging oxygen atoms form a butterfly M4 moiety. The M4 core is further connected to the two five-coordinate trigonal-bipyramidal MnIII ions via one μ4-O2−, two alkyloxo and one methoxo triple bridges. Magnetic susceptibility measurements indicate the presence of intramolecular antiferromagnetic interactions in complex 2, and overall intramolecular ferromagnetic interactions in complexes 3 and 4. The alternating current (AC) magnetic susceptibility studies revealed that complexes 3 and 4 showed frequency-dependent out-of-phase signals, which indicates that they exhibit slow relaxation of the magnetization.
Co-reporter:Qi-Wei Xie, Shu-Qi Wu, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 - vol. 42(Issue 31) pp:NaN11233-11233
Publication Date(Web):2013/05/31
DOI:10.1039/C3DT50818H
The synthesis and characterization of three isomorphous complexes [NiII(L)LnIII(DBM)3] (Ln = Gd (1·2.5CH3CN·0.5H2O), Tb (2·2CH3CN·0.5MeOH), and Dy (3·2CH3CN·0.5MeOH·0.5H2O)) are reported (H2L = N,N′-dimethyl-N,N′-(2-hydroxy-3-methoxy-5-methylbenzyl)ethylenediamine, DBM− = anion of 1,3-diphenylpropane-1,3-dione). The flexible ligand L2− contains an N2O2-inner and an O4-outer coordination site. There are diphenoxo bridges between NiII and LnIII ions in these complexes. The remaining coordination sites are occupied by DBM− anions. Direct current (dc) magnetic susceptibility measurements indicate the presence of intramolecular ferromagnetic interactions in desolvated complexes 1–3. The magnetic coupling constant JNiGd in complex 1 is estimated to be 1.11 cm−1 (H = −2JNiGdSNiSGd). Alternating current (ac) magnetic susceptibility studies reveal that complexes 2 and 3 show frequency-dependent out-of-phase signals, which indicate that they exhibit SMM behavior. The energy barriers for complexes 2 and 3 under a 2 kOe applied direct current (dc) magnetic field are estimated from Arrhenius plots to be 14.4 and 11.3 K, respectively.
Co-reporter:Shu-Qi Wu, Qi-Wei Xie, Guang-Yu An, Xi Chen, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 - vol. 42(Issue 13) pp:NaN4372-4372
Publication Date(Web):2013/02/14
DOI:10.1039/C3DT50265A
A supramolecular strategy has been applied to construct two tetranuclear lanthanide complexes for investigating the magnetic properties of individual lanthanide ions. The LnIII complexes (Ln = Dy, Tb) display field-induced slow magnetization relaxation, typical of single-molecule magnet behavior. The four lanthanide ions in the molecules are well separated by distances of ca. 9 Å, and thus the slow magnetization relaxation should be assigned to single-ion magnet (SIM) behavior. Therefore, the present complexes are novel supramolecular aggregates of four isolated SIMs.
Co-reporter:Kong-Qiu Hu, Shu-Qi Wu, Guang-Yu An, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2013 - vol. 42(Issue 4) pp:NaN1108-1108
Publication Date(Web):2012/10/09
DOI:10.1039/C2DT31708G
The compartmental Schiff base ligands N,N′-ethylenebis(3-hydroxysalicylidene) (H4L) and N,N′-propylenebis(3-hydroxysalicylidene) (H4L′) have been employed in the synthesis of a cyclic tetranuclear Cu(II) complex [Cu4(L′)2(MeOH)3(H2O)]·[Cu4(L′)2(MeOH)3] (1), a novel octanuclear Cu(II) complex [Cu8(L–L)2(H2O)4(μ2-H2O)]·3DMF·3H2O (2) and a hetero-octanuclear Cu(II)–Fe(III) complex [Cu4Fe4(L)4(H2O)3(μ3-O)2]·3DMF·3H2O (3). During the formation of the Cu8 complex (2), a new bis-Schiff base ligand (L–L)8− forms via the ortho–para C–C coupling of two H4L ligands. The bicyclic complex (2) is comprised of two cyclic Cu4 units that are similar to that of complex 1. In the Cu4 unit, the alternate Cu(II) ions are singly bridged by phenoxo groups. The three complexes display overall antiferromagnetic coupling, and the Cu(II)–Cu(II) magnetic coupling constant falls in the range −117.2 to −473.6 cm−1 for complexes 1 and 2 corresponding to the bridging Cu–Ophenoxide–Cu bond angles of 124.3–131.0°.
Co-reporter:Kong-Qiu Hu, Xiang Jiang, Shu-Qi Wu, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2015 - vol. 44(Issue 35) pp:NaN15416-15416
Publication Date(Web):2015/07/30
DOI:10.1039/C5DT02175H
Two cyano- and phenoxo-bridged octanuclear complexes ZnII4DyIII2CoIII2 (complex 1) and ZnII4DyIII2CrIII2 (complex 2) with diamagnetic Zn(II) and Co(III) are reported. Dy(III) is surrounded by nine oxygen atoms of two [Zn(Me2valpn)] (Me2valpn2− = dianion of N,N′-2,2-dimethylpropylenebis(3-methoxysalicylideneimine)) and one water molecule. Magnetic studies reveal that both exhibit single-ion magnet (SIM) behavior with the energy barrier of 85.9 K for complex 1 and 100.9 K for complex 2.
Co-reporter:Xiang Jiang and Hui-Zhong Kou
Chemical Communications 2016 - vol. 52(Issue 14) pp:NaN2955-2955
Publication Date(Web):2016/01/08
DOI:10.1039/C5CC09808D
Herein, we present an exceptional structural transformation from a porous supramolecular network to a porous coordination polymer. The transformation involves a change of interpenetrating dimensionality from 6-fold to 5-fold. Simultaneously, the spin state of nickel(II) is altered from S = 0 to S = 1, which is concomitant with the formation of the Ni–Ocarboxylate coordination bonds.
Co-reporter:Qi-Wei Xie, Shu-Qi Wu, Wen-Bo Shi, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2014 - vol. 43(Issue 29) pp:NaN11316-11316
Publication Date(Web):2014/04/29
DOI:10.1039/C4DT00740A
The synthesis and characterization of four dinuclear 3d–4f complexes [MIILnIII(L)(DBM)3] (ZnDy = 1, CoY = 2, CoDy = 3·3.5CH3CN, CoGd = 4·3.5CH3CN) are reported (H2L = N,N′-dimethyl-N,N′-(2-hydroxy-3-methoxy-5-methyl-benzyl)ethylenediamine, DBM− = anion of 1,3-diphenyl-propane-1,3-dione). In each of the four complexes, the MII ion occupies the internal N2O2 site whereas the LnIII ion occupies the external O4 site. There are diphenoxo bridges between the MII and LnIII ions in these complexes. The remaining coordination sites are occupied by three DBM− anions. Direct current (dc) magnetic susceptibility measurements indicate the presence of intramolecular ferromagnetic interactions in complexes 3 and 4. The magnetic coupling constant, JCoGd, of complex 4 is estimated to be 0.26 cm−1 (H = −2JCoGdSCoSGd). Alternating current (ac) magnetic susceptibility studies reveal that complexes 1 and 2 show field-induced single molecule magnet behavior, with ΔE values of 36.5 K and 8.56 K, respectively. Complex 3 shows frequency dependent out-of-phase signals, indicating the presence of a slow relaxation of the magnetization, whereas complex 4 does not display slow magnetization relaxation.
Co-reporter:Mei-Jiao Liu, Kong-Qiu Hu, Cai-Ming Liu, Ai-Li Cui and Hui-Zhong Kou
Dalton Transactions 2017 - vol. 46(Issue 20) pp:NaN6552-6552
Publication Date(Web):2017/04/24
DOI:10.1039/C7DT00948H
We herein report the synthesis, crystal structure and magnetic properties of nine new heterotrimetallic complexes. [Ni(Me2valpn)] (H2Me2valpn = N,N′-bis(3-methoxysalicylidene)-2,2-dimethyl-1,3-diaminopropane) was used as the precursor to construct phenoxo-bridged [Ni2Ln]3+ (Ln3+ = Dy, Tb, Gd and Y) species that were respectively connected by two [M(CN)6]3− (M = Cr, Fe or Co) anions to form octanuclear cyclic complexes, i.e. {[Ni(Me2valpn)]2Ln(H2O)M(CN)6}2 in which Ln = Y, Gd, Tb and Dy and M = Cr, Fe or Co (1–9). Each of the complexes contains many lattice-bound molecules of solvation. The Ni(II) ions are penta-coordinate, while the Ln(III) ions are nine coordinated with a muffin geometry. The fitting to the χmT vs. T curves of complexes 6–9 gave the parameters of JNiCr = 11.82 cm−1, JNiGd = 0.94 cm−1 and g = 2.04 for complex 6, JNiFe = 10.58 cm−1, JNiGd = 1.24 cm−1 and g = 2.03 for complex 7, JNiCr = 9.4(1) cm−1, zJ′ = −0.050(2) cm−1 and g = 2.06(1) for complex 8 and JNiFe = 4.9(7) cm−1, zJ′ = −0.35(2) cm−1 and g = 2.24(1) for complex 9, respectively. The dynamic magnetic investigations demonstrate that complexes 1–5 display single-molecule magnet properties with an effective energy barrier (Ueff) of 38.9 K (1, M1 = Dy, M2 = Cr), 37.2 K (2, M1 = Dy, M2 = Cr), 24.4 K (3, M1 = Dy, M2 = Co), 21.9 K (4, M1 = Tb, M2 = Cr) and 29.6 K (5, M1 = Tb, M2 = Fe), respectively. Complex 1 shows the highest energy barrier among the octanuclear [Ni4LnM2] (Ln = Dy or Tb, M = Fe, Cr, Co or W) system. Although the [Ni4Dy2Cr2] complexes have Ueff higher than that of [Ni4Dy2Fe2], complex [Ni4TbCr2] shows lower Ueff than that of [Ni4TbFe2]. The results indicate that besides the M–CN–Ni magnetic coupling the lanthanide ions can significantly affect the magnetic performances of heterotrimetallic SMMs as well. Moreover, the SMMs are achieved when diamagnetic Co(III) was substituted by paramagnetic Cr(III) or Fe(III) in the [Ni4Tb2 M2] system, suggesting that the trimetallic strategy is effective in the construction of new 3d–4f SMMs.
Co-reporter:Hui-Zhong Kou, Kong-Qiu Hu, Hao-Yan Zhao, Junkui Tang and Ai-Li Cui
Chemical Communications 2010 - vol. 46(Issue 35) pp:NaN6535-6535
Publication Date(Web):2010/08/12
DOI:10.1039/C0CC01628D
Novel tetranuclear Cu(II)–Ln(III)–Cr(III) complexes with oxamidate and oxalate bridges have been prepared using [Cu(L)], LnCl3·6H2O and K3[Cr(ox)3] components (ox2− = oxalate) during the development of new multimetallic complexes as molecular magnets. Overall ferromagnetic properties have been observed in the Cu2GdCr compound, and no single-magnet behavior has been found in the Cu2TbCr and Cu2DyCr compounds.
Co-reporter:Xi Chen, Shu-Qi Wu, Ai-Li Cui and Hui-Zhong Kou
Chemical Communications 2014 - vol. 50(Issue 17) pp:NaN2122-2122
Publication Date(Web):2013/12/10
DOI:10.1039/C3CC48117D
The chains in complex [Mn(TPP)][Mn(TPP)(CN)2] (H2TPP = meso-tetra(4-phenyl)-porphyrin) demonstrate perfect linearity, and are well isolated with the nearest interchain Mn–Mn separation of 12.95 Å. Ferromagnetic coupling is present among adjacent Mn(III) ions, and single-chain magnet (SCM) behaviour is verified.
