Co-reporter:Qin-Qin Dang, Hong-Jing Wan, and Xian-Ming Zhang
ACS Applied Materials & Interfaces June 28, 2017 Volume 9(Issue 25) pp:21438-21438
Publication Date(Web):June 6, 2017
DOI:10.1021/acsami.7b04201
A multifunctional carbazolic porous framework (Cz-TPM), with a tetrahedral core, has been synthesized by FeCl3 oxidative coupling polymerization. The Brunauer–Emmett–Teller surface area of the obtained polymers reaches 713.2 m2 g–1. Gas adsorption isotherms show that Cz-TPM exhibits large carbon dioxide (97.9 mg g-1, 9.8 wt %, 273 K, and 1 bar) and hydrogen uptake capacities (149.3 cm3 g-1, 1.34 wt %, 77 K, and 1 bar). Furthermore, Cz-TPM has been found to display tandem visual detection of iodide and mercury, respectively. The Cz-TPM dispersion turns to yellow in the presence of iodide salts and subsequently changes to nearly colorless on addition of Hg2+ salts that could be easily observed by the naked eye. Cz-TPM can detect I– via “turn off” fluorescence quenching, and then the in situ generated Cz-TPM@I complexes can recognize Hg2+ ions via “turn on” fluorescence recovery. More importantly, Cz-TPM is stable over common solvents and can be easily recovered by excessive water washing and centrifugation for further repeated use. As far as we know, carbazolic porous organic frameworks enabling detection of I– and Hg2+ have not been reported.Keywords: Carbazolic; gas uptake; iodide sensing; mercury sensing; regeneration; reversibility;
Co-reporter:Juan-Juan Hou, Xiao-Qing Li, Ping Gao, Han-Qi Sun, and Xian-Ming Zhang
Crystal Growth & Design July 5, 2017 Volume 17(Issue 7) pp:3724-3724
Publication Date(Web):June 12, 2017
DOI:10.1021/acs.cgd.7b00348
Stimuli-responsive solid-state crystal dynamics or flexibility in metal–organic frameworks (MOFs) showing multiple structure changes is an arising interest for understanding the structure–property relationship and designing functional materials. In this article, dehydration-induced stepwise single-crystal to single-crystal (SC–SC) transformations are observed in two-dimensional 63-topological coordination polymer [Co(H2L)(H2O)2]·H2O (1), where H4L is 3,5-bis(3′,5′-dicarboxylphenyl)-1H-1,2,4-triazole. Upon thermal dehydration at 130 °C for 2 h, half lattice water in 1 can be released to form [Co(H2L)(H2O)2]·0.5H2O (2). By increasing dehydration temperature to 150 °C for 3 h, the third phase [Co(H2L)(H2O)2] (3) that is free of lattice water molecule is gained. Further increasing the dehydration temperature to 160 °C for 6 h, one of coordination water molecule can be released, giving rise to dicobalt-based 2D (3,6)-connected kgd double layer [Co(H2L)(H2O)] (4). During stepwise dehydration SC–SC transformation courses, coordination sphere of Co(II) changes from penta-coordinate trigonal bipyramid to hexa-coordinate octahedra; H2L2– ligates from (κ1)–(κ1)–(κ1)−μ3–H2L2–, (κ1)–(κ1)–(κ2)−μ3–H2L2– to (κ1–μ2)–(κ1)–(κ2)−μ4–H2L2–; network topology ranges from 3-connected 63-hcb to (3,6)-connected kgd; magnetism changes from single-ion behavior of Co(II) to intradicobalt ferromagnetism.
Co-reporter:Yi-Gang Chen, Nan Yang, Xing-Xing Jiang, Yao Guo, and Xian-Ming Zhang
Inorganic Chemistry July 17, 2017 Volume 56(Issue 14) pp:7900-7900
Publication Date(Web):June 26, 2017
DOI:10.1021/acs.inorgchem.7b00647
The first lead tellurate–nitrate nonlinear-optical (NLO) crystal, Pb9Te2O13(OH)(NO3)3, featuring a 3D anionic diamondlike toplogical structural motif formulated as [Pb9O13]8– constructed by unique nonanuclear basket-shaped Pb@Pb8O14 clusters has been hydrothermally achieved, in which the Pb@Pb8O14 cluster shows a core–shell structure with one PbO10 polyhedron enclosed by eight PbOx (x = 3 and 4) polyhedera via edge and face sharing. The hexavalent Te in TeO5(OH) octahedra is linked to a [Pb9O13]8– cluster to form a rare [Pb9Te2O13(OH)]3+ cationic framework. The compound demonstrates a powder second-harmonic-generation (SHG) response of about 1.2 times that of KH2PO4 (KDP) as well as a wide transparency range. Calculations on the local dipole moment and SHG coefficient reveal that the net polarization is zero because of a Kleinman-forbidden point group. Further analysis shows that the SHG response results from structure-induced variations by thermal vibrations of the lattice rather than the intrinsic dipole moment, which offers another insight on the design of new NLO materials.
Co-reporter:Shi-Li Li, Jie Wang, Fu-Qiang Zhang, and Xian-Ming Zhang
Crystal Growth & Design February 1, 2017 Volume 17(Issue 2) pp:
Publication Date(Web):January 9, 2017
DOI:10.1021/acs.cgd.6b01598
Light and heat dually sensitive luminescent materials have promising applications such as light emitting diodes, bioimaging, and memories but are rather scarce due to simultaneous requirements of stimuli induced structural flexibility and the existence of multiple emissions. In continuation of our research interest in tunable photoluminescent materials with templated organic ligands, we report herein two isostructural organic templated CdSO4-topological halogeno(cyano)cuprates with disorder of halogenide and cyanide, formulated as [Me2DABCO]2Cu4Br5(CN)3 (1) and [Me2DABCO]2Cu4I4.5(CN)3.5 (2) (Me2DABCO = N,N′-dimethyl-1,4-diazabicyclo[2.2.2]octane). Both 1 and 2 show a very strong emission band upon photoexitation with microsecond lifetime and high quantum yield. With the increase of excitation wavelength, the strong main emission band in 1 is gradually red-shifted from 495 to 535 nm, seemingly breaking Kasha’s rule, and the strong main emission in 2 also significantly red-shifted. With the decrease of temperature, the low energy emission in 1 also is red-shifted, while this phenomenon is not found in 2. The photochromic luminescence for 1 and 2 might be caused by multiple emission centers associated with disorder of halogenide and cyanide.
Co-reporter:Zhi-Li Du, Qin-Qin Dang, and Xian-Ming Zhang
Industrial & Engineering Chemistry Research April 19, 2017 Volume 56(Issue 15) pp:4275-4275
Publication Date(Web):March 28, 2017
DOI:10.1021/acs.iecr.6b05039
A newly heterogeneous palladium catalyst has been synthesized by immobilizing Pd(OAc)2 onto a nitrogen-rich heptazine-based porous framework (Cy-pip). Highly dispersed Pd particles and abundant distributed N atoms in the framework make Pd/Cy-pip very efficient toward the Suzuki–Miyaura reaction in aqueous medium at 40 °C without inert atmosphere and phase transfer agents. Pd/Cy-pip catalytic system is superior to many POPs supported Pd catalysts such as Pd/COF-LZU1, Pd@CNPCs, Pd-CIN-1, and MsMOP-1 that required toxic organic solvents or high temperature. Furthermore, the strong interaction between N donor sites and Pd nanoparticles in the framework extends excellent recyclability without significant deactivation of the catalyst after five cycles.
Co-reporter:Yi-Gang Chen, Mei-Ling Xing, Peng-Fei Liu, Yao Guo, Nan Yang, and Xian-Ming Zhang
Inorganic Chemistry 2017 Volume 56(Issue 2) pp:
Publication Date(Web):January 3, 2017
DOI:10.1021/acs.inorgchem.6b02303
Two new phosphates—Cs6Mg6(PO3)18 (CMP) and Cs2MgZn2(P2O7)2 (CMZP)—have been obtained, using high-temperature molten methods. Crystals of CMP with the polar P21 space group display a new three-dimensional (3D) anionic framework possessing two one-dimensional (1D) [PO3]∞ chains that are interconnected by isolated MgO6 octahedra, while CMZP with centrosymmetric monoclinic space group P21/c possesses a new [MgZn2P4O20]14– structure unit consisting of two isolated P2O7 dimers, one ZnO4, and two disordered Mg/ZnO4 tetrahedral units. The polar phosphate CMP with deep-UV transparency (below 190 nm) shows weak second harmonic generation (SHG) response (0.1 × KDP), and the dipole moment analysis suggests that the weak SHG response mostly originates from much distorted CsOn polyhedron. Some related properties, such as optics, thermostability, and band structure derived from density functional theory, were explored.
Co-reporter:Xiao-Xia Jia, Ru-Xin Yao, Fu-Qiang Zhang, and Xian-Ming Zhang
Inorganic Chemistry 2017 Volume 56(Issue 5) pp:
Publication Date(Web):February 17, 2017
DOI:10.1021/acs.inorgchem.6b02872
Heavy-metal ions and nitroaromatic substances are highly toxic and harmful to human health and the ecological environment. It is an urgent issue to selectively detect and capture these toxic substances. By introducing the triazole ligand to the π-conjugated aromatic carboxylate system and borrowing the organic template open framework idea, a stable fluorescent framework [Me2NH2]4[Zn6(qptc)3(trz)4]·6H2O (1) (H4qptc = terphenyl-2,5,2′5′-tetracarboxylic acid, trz = 1,2,4-triazole) has been successfully synthesized, which features Zn4(trz)2 chain-based 3D anionic structure with channels filled by [Me2NH2]+ cations. It is worth noting that the material exhibits selective adsorption and recyclable detection of heavy-metal Cr3+ ion in aqueous solutions, which may be the synergy from the metal charge, bond ability of metal ions to carboxylate oxygen atom, and soft–hard acid–base properties. Furthermore, it can selectively sense of 2,4,6-trinitrophenol with a large quenching coefficient Ksv of 2.08 × 106 M–1.
Co-reporter:Ying-Jie Jia;Yi-Gang Chen;Xiao-Ni Yao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 44) pp:6644-6650
Publication Date(Web):2017/11/13
DOI:10.1039/C7CE01461A
A series of alkali earth cadmium selenites including MgCd3(SeO3)4 (1), Ca0.7Cd2.3(SeO3)3 (2), SrCd(SeO3)2 (3) and BaCd(SeO3)2 (4) are synthesized by hydrothermal reaction and studied in detail by single crystal and powdered X-ray diffractions, thermal analyses, IR and UV spectral measurements and dipole moment calculation. 1 features a 3D anionic [Cd3(SeO3)4]2− framework constructed from isolated SeO3 trigonal pyramids and 2D [Cd3O12]n layers, in which the [Cd3O12]n layer is composed of edge-shared [Cd2O10]16− dimers and butterfly-like [Cd4O20]32− tetramers. 2 shows a smooth 2D [Cd2(SeO3)3]n layer composed of unique [Cd(SeO3)]n double chains. 3 exhibits a wavelike 2D [Cd(SeO3)2]n layer constructed from corner-shared CdO6 octahedra and isolated SeO3 trigonal pyramids. 4 displays a windmill-like 1D [Cd(SeO3)2]n chain built from zigzag [CdO4]n chain motifs and isolated SeO3 trigonal pyramids. The alkali earth oxide motifs demonstrate interesting and regular changes from isolated MgO6 octahedra, CaO7 polyhedra, and SrO9 tri-capped trigonal prisms based on a ribbon chain to BaO12 icosahedra based on a brucite-like layer, and meanwhile the SeO3 groups are observed from variable tetradentate to hexadentate coordination modes. These flexible motifs reveal that cadmium selenites are strongly affected by the size of the alkali earth cations, providing a feasible approach to modulating their space structure via selection of template cation.
Co-reporter:Fu-Qiang Zhang;Jin-Ping Gao;Li-Kai Yan;Wei Guan;Ru-Xin Yao
Dalton Transactions 2017 vol. 46(Issue 46) pp:16145-16158
Publication Date(Web):2017/11/28
DOI:10.1039/C7DT03200E
Density functional theory calculations combined with the energy and building-block decomposition analyses have been carried out to investigate the structures, stability orders, redox potentials and proton binding of the six Baker–Figgis isomers (α, β, γ, α*, β* and γ*) of [(SbO6)W18O54(OH)2]9− {H2SbW18} and [(NaF6)W18O54(OH)2]7− {H2NaW18} anions at the level of PBEsol-D3/TZP. Both bonding energy and Gibbs free energy analyses exhibit that the two non-classical Wells–Dawson (WD) species behave quite differently from each other. The pyroanimonate {H2SbW18}, with a stability order of γ* > β* > α > α* > β > γ, is a non-classical WD species, while the hexafluoride {H2NaW18} (α > β > γ > γ* > β* > α*) is a transition intermediate between classical and non-classical WD types, possessing both non-classical ([XW18O60(OH)2]n−, X = I, Te and W) and classical [Si2W18O62]8− properties. Energy decomposition analyses (EDA) reveal that spatial arrangement (Ehost), host–guest fragment interaction energy (FIE), and structural distortion energy (DE) are three key factors governing the relative stability of isomers; among these, DE is always dominant, while FIE and Ehost are subordinated but are still important. Building-block decomposition analyses (BDA) disclose that the octahedral {MO6} units of the equatorial belt, particularly the staggered belt, are always more distorted than those of the two polar caps inside each structure. The theoretical redox potentials demonstrate that the oxidizing power increases with a trend of α < β < γ and α* < β* < γ* for both species, and the first redox potential is closely related to the energy level of the LUMO of each anion. Evaluation of the proton inclusion energies suggests that {H2NaW18} can only embed two protons, while {H2SbW18} may encapsulate four; the number of embedded protons is controlled by both the charge of the heteroatom X and the volume of the tetrahedral {O4}/{OF3} cavity.
Co-reporter:Lingjuan Zhang, Jie Liu, Fuqiang Zhang, Xian-Ming Zhang
Journal of Catalysis 2017 Volume 354(Volume 354) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.jcat.2017.08.013
•We studied butterfly-like Cu2(ophen)2 for dioxygen selective oxidation of alcohols.•DFT calculations and ESI-MS experiments were used to study the reaction mechanism.•Superoxide/peroxide and hydroperoxide in the cycle of oxidation were experienced.•“Stretched-folded-stretched” configuration changes of Cu-complex were experienced.•The role of H2O as proton mediator was revealed in the L2Cu2-O2 cyclical process.The selective catalytic oxidation of alcohols is important both in laboratory and industrial production, and traditional oxidants cause environmentally lethal wastes. The development of dioxygen selective oxidation efficient has been pursued from atom-efficient, economic and environmental view of points. Using DFT calculation and ESI-MS experiments, we studied the activation of the CuCu bonded planar complex Cu2(ophen)2 to dioxygen and the application of the dioxygen-copper system for the selective oxidation of alcohols. For practical application and green chemistry, this catalytic system avoided the use of a large excess of base and expensive nitroxyl derivatives. In the cycle of oxidation, two oxidative dehydrogenation processes featuring superoxide/peroxide (I) and hydroperoxide (II) occurred along with a series of conformational changes of the butterfly-like Cu-complex from stretched to folded to stretched. Additionally, we characterized the role of the water molecule as a proton mediator in the dioxygen-copper system.Download high-res image (84KB)Download full-size image
Co-reporter:Xuedong Wei, Na Li, Xianming Zhang
Applied Surface Science 2017 Volume 425(Volume 425) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.apsusc.2017.07.067
•TheCu@C nanoporous composites were synthesized by pyrolyzing MOF199 and DI-MOF199.•The structure is characterized by XRD, SEM, TEM, EDX, XPS, and N2 adsorption-desorption.•C-Cu-DI exhibits higher electrocatalytic activityby the addition of Dimethyl imidazole(DI).•The superior catalytic activity is attributed to the special composite structure.It remains a huge challenge to develop non precious electrocatalysts with high activity to substitute commercial Pt catalysts for hydrogen evolution reactions (HER). Here, the C-Cu-DI and C-Cu materials with the copper based nanoporous carbon structures were synthesized by carbonizing MOF199 and DI-MOF199. The composite structure and HER electrocatalytic properties of the C-Cu-DI and C-Cu materials are studied. The results show that C-Cu-DI and C-Cu samples exhibit good catalytic activity. And C-Cu-DI sample through the addition of Dimethyl imidazole(DI) in the DI-MOF199 precursor has higher electrocatalytic activity than the C-Cu sample. The superior catalytic activity is attributed to the special composite structure of nanoscale deposition particles on the framework with plenty of nano pores and nano copper and few copper oxidation particles distributed or wrapped into the amorphous porous carbon phase. The nano copper and few copper oxidation particles in the C-Cu and C-Cu-DI catalysts maybe provide the more effective catalytic activity sites. The C-Cu-DI composite with large size spherical hollow deposition particles has higher conductivity, better BET surface area and reasonable micro-meso-macro porous distribution, so the overpotentials at the current density of 1 mA cm−2 and 10 mA cm−2 are respectively 270 mV and 390 mV vs. RHE. Although the HER activity has a big gap with commercial platinum catalyst, this study can provide an important experimental exploration for the design of copper based non noble metal/nano porous carbon composite HER electrocatalyst.Download high-res image (152KB)Download full-size imageThe Schematic illustrations of the synthesis process of Cu@C nanoporous composites.
Co-reporter:Zhenzhen Wu;Juan Li
RSC Advances (2011-Present) 2017 vol. 7(Issue 82) pp:52321-52326
Publication Date(Web):2017/11/07
DOI:10.1039/C7RA10535E
In this study, we introduced 1H-1,2,4-triazole into the ordered nanochannels of propyl amino functioned MCM-41 and then investigated the hybrids' proton conducting performance. A high proton conductivity of 8.34 × 10−3 S cm−1 has been obtained at 120 °C, with 5 mol% mole ratio of dangling propyl amino and fully loaded 1H-1,2,4-triazole in the silica. The activation energy is 0.55 eV and 1.303 eV in the temperature range below and above 80 °C respectively, indicating that the charge transfer mechanism of the material involved both vehicle and Grotthuss process. The above results showed that loading of 1-H-1,2,4-triazole molecules into silica's ordered mesopores is a good strategy for excellent proton conductivity under intermediate temperature.
Co-reporter:Xian-Ming Zhang; Debajit Sarma; Ya-Qin Wu; Li Wang; Zhi-Xue Ning; Fu-Qiang Zhang;Mercouri G. Kanatzidis
Journal of the American Chemical Society 2016 Volume 138(Issue 17) pp:5543-5546
Publication Date(Web):April 15, 2016
DOI:10.1021/jacs.6b02959
The new ion-exchange oxy-sulfide material has a three-dimensional open framework comprising the pseudo-T4 supertetrahedral [In4Sn16O10S34]12– cluster. This material has large pores and is a fast ion exchanger. It exhibits high selectivity in sequestering heavy metal ions from aqueous solutions including solutions containing heavy concentrations of sodium, calcium, ammonium, magnesium, zinc, carbonate, phosphate, and acetate ions. Moreover, the ion-exchange efficiency in competitive ion-exchange experiments involving mixtures of metal ions is significantly higher than for solutions of single metal ions.
Co-reporter:Yan-Wu Zhao, Fu-Qiang Zhang, and Xian-Ming Zhang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 36) pp:24123
Publication Date(Web):August 25, 2016
DOI:10.1021/acsami.6b07724
Near-UV single-phase white-light phosphor (Eu0.045Tb0.955CPOMBA/La0.6Eu0.1Tb0.3CPOMBA) based on metal–organic framework was prepared by in situ doping isostructural lanthanide MOF with Eu3+ and Tb3+, and it is found that the energy can effectively transfer from organic ligand to lanthanides, which can overcome weak absorption under direct excitation of lanthanide ions due to the forbidden f–f transitions. The photoluminescence and thermostability of the new MOF phosphor are investigated, and effective white-light emission is achieved under 365 and 380 nm excitations. By employing Eu0.045Tb0.955CPOMBA as phosphor, we fabricated a near-ultraviolet white-light-emitting diode (n-UV WLED) (365 nm) with low CCT (5733 K), high CRI (Ra = 73.4), and CIE chromaticity coordinate (0.3264, 0.3427). This approach may open new perspectives for developing single-phase UV phosphors.Keywords: lanthanide; metal−organic framework; phosphors; single-phase; UV white-light-emitting diode
Co-reporter:Jie Wang, Shi-Li Li, and Xian-Ming Zhang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 37) pp:24862
Publication Date(Web):August 30, 2016
DOI:10.1021/acsami.6b06551
Photochromic and nonphotochromic luminescent bipyridinium-based supramolecular isomers [Cd(CPBPY)(BDC)(H2O)]n (1) and {[Cd(CPBPY)(BDC)]·H2O}n (2) (CPBPY = N-(3-carboxyphenyl)-4,4′-bipyridinium, BDC= terephthalate) have been successfully obtained by solvothermal reactions at 100 °C via tuning stoichiometric ratios of starting reagents. Isomer 1 features (4,4)-topological layer constructed by edge-shared Cd2 SBUs and BDC linkers attached by N-pendent CPBPY groups. Isomer 2 has (6,3)-topological layers with Cd atoms as nodes and BDC and double CPBPY as linkers, which are 4-fold interpenetrated into 3D network. Although both 1 and 2 contain bipyridinium ligands, only isomer 1 possesses reversible photochromic behavior with quick-switchable luminescence in the solid state. Compound 2 does not show photochromic behavior even after exposure to UV light for more than 2 h. Photochromism process of 1 originates from photostimulated reduction of CPBPY ligands to generate CPBPY•– radicals after irradiation, confirmed by EPR spectra. Careful check on structure reveals that the offset π–π stacking interaction between the pyridine ring of CPBPY and benzene ring of BDC with inter-ring shortest C···C distance of 3.214 Å in 1 is responsible for electron transfer to form the CPBPY•– radicals. The speculation is further supported by DFT calculation of frontier orbital matching of electron donor and acceptor. HOMO and HOMO–2 orbitals of BDC involve the carbon atoms of benzene ring while LUMO and LUMO+1 orbitals of CPBPY involve the carbon atoms of pyridinium ring. Importantly, the photoinduced formed CPBPY•– radicals in 1 have a long-lived lifetime (at least six months in air and room temperature condition), which is mainly attributed to the close packing mode.Keywords: air-stable; bipyridinium; long-lived lifetime; luminescent; photochromic; supramolecular isomers
Co-reporter:Qin-Qin Dang, Xiao-Min Wang, Yu-Fen Zhan and Xian-Ming Zhang
Polymer Chemistry 2016 vol. 7(Issue 3) pp:643-647
Publication Date(Web):23 Nov 2015
DOI:10.1039/C5PY01671A
An azo-linked porous organic network (Azo-Trip), in which triptycene is incorporated as a building block, has been prepared via a facile Zn-induced reductive homo-coupling reaction. The Azo-Trip exhibits a BET surface area of 510.4 m2 g−1, large carbon dioxide uptake (119.6 mg g−1, 10.8 wt% at 273 K and 1 bar), as well as good CO2/N2 (38.6) selectivity. The resulting polymer also displays an excellent guest uptake of 238 wt% in iodine vapor and outstanding reversible adsorption of iodine in solution, which is better than the functionalized MIL-53-NH2 and metalloporphyrin-based NiP-CMP.
Co-reporter:Ru-Xin Yao, Xin Cui, Xiao-Xia Jia, Fu-Qiang Zhang, and Xian-Ming Zhang
Inorganic Chemistry 2016 Volume 55(Issue 18) pp:9270-9275
Publication Date(Web):August 31, 2016
DOI:10.1021/acs.inorgchem.6b01312
A porous luminescent zinc(II) metal–organic framework (MOF) with a NbO net [Zn2(tptc)(apy)2–x(H2O)x]·H2O (1) (where x ≈ 1, apy = aminopyridine, H4tptc = terphenyl-3,3″,5,5″-tetracarboxylic acid), constructed using paddlewheel [Zn2(COO)4] clusters and π-electron-rich terphenyl-tetracarboxylic acid, has been solvothermally synthesized and characterized. Interestingly, the material displays efficient, reversible adsorption of radioactive I2 in vapor and in solution (up to 216 wt %). The strong affinity for I2 is mainly due to it having large porosity, a conjugated π-electron aromatic system, halogen bonds, and electron-donating aminos. Furthermore, luminescent study indicated that 1 exhibits high sensitivity to electron-deficient nitrobenzene explosives via fluorescence quenching.
Co-reporter:Kai Yang, Shi-Li Li, Fu-Qiang Zhang, and Xian-Ming Zhang
Inorganic Chemistry 2016 Volume 55(Issue 15) pp:7323-7325
Publication Date(Web):July 19, 2016
DOI:10.1021/acs.inorgchem.6b00922
A chiral C3-symmetric cubane cluster, [Cu4I4(TMP)4], with enough long Cu–Cu distances to eliminate the presence of Cu–Cu interaction has been synthesized and characterized, which shows simultaneous luminescent thermochromism, solvatochromism, vapochromism, and mechanochromism and is a multiply stimuli-responsive chromic luminescent material. This complex could partly transform into a yellow-emissive bicapped cubane cluster, [Cu6I6(TMP)4(MeCN)2], in acetonitrile (MeCN) vapor and solution, which provides some insight into vapochromism and solvatiochromism. This work challenges and makes us reconsider the conventional viewpoint that Cu–Cu interaction is involved in thermochromism and mechanochromism of copper complexes.
Co-reporter:Juan-Juan Hou, Xiao-Qing Li, Bao-Qiang Tian and Xian-Ming Zhang
CrystEngComm 2016 vol. 18(Issue 12) pp:2065-2071
Publication Date(Web):28 Jan 2016
DOI:10.1039/C5CE02284C
Three genuine supramolecular isomers with an identical formula of [Co(cpna)(H2O)2] (1a, 1b and 1c) [H2cpna = 5-(4′-carboxyl-phenyl) nicotinic acid] have been synthesized by adjusting the relative molar ratio of Y-shaped ligand H2cpna:CoCl2 under solvothermal conditions. Isomer 1a possesses a two-dimensional (2D) 63-hcb layer, in which the central Co(II) adopts trigonal bipyramidal geometry. 1b and 1c contain the same edge-shared dimeric SBUs, which are further ligated by cpna2− ligands to form 2D (3,6)-connected (43)2(46·66·83)-kgd layers and a 3D (3,6)-connected (4·62)2(42·610·83)-rtl net, respectively. The coordination modes of the cpna2− ligand in 1b and 1c are the same, indicating that only the difference in the dihedral angles of the pyridine and phenyl rings contributes to different isomers. Magnetic investigation indicates ferromagnetic interactions between Co(II) ions in edge-shared dimeric SBUs.
Co-reporter:Hai-Yun Ren and Xian-Ming Zhang
Energy & Fuels 2016 Volume 30(Issue 1) pp:526-530
Publication Date(Web):December 18, 2015
DOI:10.1021/acs.energyfuels.5b02393
As society’s demand for energy increases and more CO2 emissions are produced, it becomes imperative to selectively capture CO2 and decrease the amount emitted to the atmosphere. Here, we present a flexible and porous metal–organic framework (MOF), [Co3(OH)2(btca)2] (1) (where btca = benzotriazole-5-carboxylic acid), which exhibits excellent CO2 uptake (223.7 mg g–1 at 273 K and 104.7 mg g–1 at 298 K) and better selectivity for CO2/N2 (46.3 at 273 K) . During the sample preparation or after an exchange process, compound 1 could trap guest molecules [dimethylformamide (DMF)] into the channels and then yield an isostructural product [Co3(OH)2(btca)2]·0.5DMF (1·0.5DMF). 1·0.5DMF hardly adsorbs N2, O2, and H2 but favorably captures CO2 in the entire pressure range measured, responded by highly selective CO2/N2 gas separation with Henry’s law selectivity of 79.6.
Co-reporter:Ling-Juan Zhang, Yan-Hong Wang, Jie Liu, Mei-Chen Xu and Xian-Ming Zhang
RSC Advances 2016 vol. 6(Issue 34) pp:28653-28657
Publication Date(Web):14 Mar 2016
DOI:10.1039/C6RA01262K
An efficient catalytic system with dinuclear complex [Cu2(ophen)2] 1 and tetranuclear complex [Cu4(ophen)4(tp)] 2 as catalysts has been developed for the Glaser coupling reaction, which adopts environmentally friendly water as the solvent at room temperature under air/O2 atmosphere and avoids the utilization of any base. Satisfyingly, due to its poor solubility in common solvents, tetranuclear compound 2 served as a molecular heterogeneous catalyst and could be reused five times without loss of activity. Both catalysts could be prepared in high yield via simple hydrothermal reactions with cheap ligands, which in combination with the environmentally friendly water medium and mild catalytic reaction conditions makes the approach accord with the concept of green chemistry in the synthesis of 1,3-diynes.
Co-reporter:Ying-Lian Qin, Ya-Qin Wu, Juan-Juan Hou, Xian-Ming Zhang
Inorganic Chemistry Communications 2016 Volume 63() pp:101-106
Publication Date(Web):January 2016
DOI:10.1016/j.inoche.2015.11.016
•Two mixed-valence Cu(II/I) complexes were synthesized via different cyanide resources under solvothermal reaction conditions.•Compound 1 containing uncommon semi-closed {Cu2(CN)3} dimer, and showing the first example of uninodal 7-connected sev-like cyanide-bridged network.•Compound 2 is a honeycomb-like 2D anionic layer, in which [CuII(H2O)4]2 + cations are encapsulated into alternate interlamellar space.•Two compounds show differently characteristic properties related with their unique whole structure.Reactions of CuCl2, K2[Ni(CN)4]/K3[Co(CN)6], and 5-amino-1H-tetrazole led to cyanide-bridged mixed-valence Cu(II/I) complexes, [Cu(H2O)3Cu3(CN)5] (1) and [Cu(H2O)4][Cu4(CN)6] (2).The uncommon semi-closed {Cu2(CN)3} dimmers in 1 are bridged by μ3-C,C,N cyanide ligands to afford rare 1D centipedal-like chain motifs, which are further bridged by μ2-C,N and metalloligand “CN–Cu(4)–CN” to finish sophisticated zeolite-like 3-D structure. Topologically, 1 is the first example of uninodal 7-connected sev-like cyanide-bridged network. Compound 2 consists of two-dimensional honeycomb-related anionic layers [Cu4(CN)6]2 −, within which the [Cu(H2O)4]2 + cations are intercalated into alternate interlamellar space. Compound 1 shows antiferromagnetic couple arising from pure ground-state configuration of Cu(II) mediated by diamagnetic bridges –CN–CuI–CN −. The inclusion compound 2 shows blue photoluminescence originated from Cu(I) center to the unoccupied π* orbital of the cyanide ligand (MLCT) charge transfer.Cyanide-bridged mixed-valence Cu(II/I) complexes [Cu(H2O)3Cu3(CN)5] (1) and [Cu(H2O)4][Cu4(CN)6] (2) have been synthesized and characterized. Compound 1 is the first example of uninodal 7-connected sev-like open framework, constructed by uncommon semi-closed trinuclear subunits and bridging cyanide ligands, and representing weak antiferromagnetic coupling of the CuII ions mediated by the –NC–CuI–CN– diamagnetic bridges. For compound 2, unique cationic guests [Cu(H2O)4]2 + are encapsulated in the anionic host framework [Cu4(CN)6]2 −, which shows photoluminescence property induced from MLCT.
Co-reporter:Guo-Xiang He, Yi-gang Chen, Nan Yang, Mei-Ling Xing, Xian-Ming Zhang
Inorganic Chemistry Communications 2016 Volume 65() pp:13-15
Publication Date(Web):March 2016
DOI:10.1016/j.inoche.2016.01.006
•The alkali metal antimony iodate KSbI6O18 was first synthesized.•A novel cyclic S6-symmetric chiral I6O186 − hexaiodate was revealed.•The antimony iodate KSbI6O18 is a potential semiconductor material.The antimony iodate KSbI6O18 which contains cyclic S6-symmetric chiral hexaiodate has been successfully synthesized through hydrothermal reaction. It crystallizes in trigonal space group R-3 with cell parameters of a = 11.3057(6) Å, c = 11.3340(8) Å, γ = 120° and z = 3. Six corner-shared IO4 groups form cyclic S6-symmetric chiral I6O18 groups that are linked by Sb5 + to form anionic [Sb(I6O18)]− framework with cavities filled by K+ ions. Optical diffuse reflectance spectra indicate that KSbI6O18 is a potential semiconductor with optical band gap of 2.96 eV.The semiconducting antimony iodate KSbI6O18 has been hydrothermally synthesized, which contains cyclic S6-symmetric chiral hexaiodate linked by Sb5 + to form an anionic [Sb(I6O18)]− framework with cavities filled by K+ ions.
Co-reporter:Qin-Qin Dang, Yu-Fen Zhan, Xiao-Min Wang, and Xian-Ming Zhang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 51) pp:28452
Publication Date(Web):December 7, 2015
DOI:10.1021/acsami.5b09441
A new heptazine-based polymer network (Cy-pip) with highly rich nitrogen sites has been synthesized via catalyst-free direct coupling of cyameluric chloride (Cy) and piperazine (Pip). Cy-pip exhibits large CO2 uptake capacity (103.4 mg/g, 9.4 wt %, 1 bar/273 K) with high selectivity (117) toward CO2 over N2. Furthermore, this framework with high Lewis basic nitrogen sites has also been exploited as heterogeneous catalyst for Knoevenagel reaction of aromatic and heterocyclic aldehydes with active methylene compounds. Moreover, the catalyst can recycle up to four times with only a minor loss of activity.Keywords: catalysis; CO2 adsorption; heptazine; Knoevenagel condensation; piperazine
Co-reporter:Shi-Li Li, Fu-Qiang Zhang and Xian-Ming Zhang
Chemical Communications 2015 vol. 51(Issue 38) pp:8062-8065
Publication Date(Web):13 Apr 2015
DOI:10.1039/C5CC01154J
An organic-ligand-free cuprous iodide trinuclear cluster with significant temperature-dependent structural distortion has been synthesized and characterized, which shows thermochromic luminescence originating from a single cluster-centered triplet due to the absence of an organic ligand. This compound also shows interesting reversible temperature dependent phase transition from chiral to centrosymmetric space groups.
Co-reporter:Jiang Liu, Mei Qu, Rodolphe Clérac and Xian Ming Zhang
Chemical Communications 2015 vol. 51(Issue 34) pp:7356-7359
Publication Date(Web):20 Mar 2015
DOI:10.1039/C5CC01199J
An unprecedented two-dimensional honeycomb network based on fused triacontanuclear heterometallic wheels of 3.4 nm, {[Co2(Mn3O)(N3)2(pic)6(NO3)]−}6 (Hpic = picolinic acid), has been assembled. The hexagonal {Co12Mn18} wheel motif is composed of six oxo-centered {Mn3} trinuclear and six {Co2} dinuclear moieties acting as nodes and linkers, respectively. The paramagnetic properties of this compound observed down to 1.8 K result from the competition of Mn⋯Mn, Mn⋯Co and Co⋯Co interactions in combination with spin–orbit coupling and single-ion behavior of the Co(II) centers.
Co-reporter:Ru-Xin Yao, Xin Cui, Jun Wang and Xian-Ming Zhang
Chemical Communications 2015 vol. 51(Issue 24) pp:5108-5111
Publication Date(Web):25 Feb 2015
DOI:10.1039/C5CC00003C
A pair of novel enantiomeric 3D magnetic complexes [NaCo3(IA)6](NO3)·H2O (1Δ and 1Λ) have been synthesized using an achiral ligand HIA via spontaneous resolution, which crystallize in the hexagonal crystal system with a chiral P63 space group, and diamagnetic sodium cations are located at the center of D3 symmetric clusters. This kind of spontaneous resolution is uncontrollable and dependent on batches. By utilizing cheap enantiopure mandelic acid as a chiral inducing agent, they are driven to controllable homochiral crystallization of the desired enantiomorph, confirmed by circular dichroism spectra.
Co-reporter:Hai-Yun Ren, Ru-Xin Yao, and Xian-Ming Zhang
Inorganic Chemistry 2015 Volume 54(Issue 13) pp:6312-6318
Publication Date(Web):June 5, 2015
DOI:10.1021/acs.inorgchem.5b00606
Hydrothermal reaction of Co(NO3)2 and terphenyl-3,2″,5″,3′-tetracarboxyate (H4tpta) generated Co3(OH)2 chains based 3D coordination framework Co3(OH)2(tpta)(H2O)4 (1) that suffered from single-crystal-to-single-crystal dehydration by heating at 160 °C and was transformed into dehydrated Co3(OH)2(tpta) (1a). During the dehydration course, the local coordination environment of part of the Co atoms was transformed from saturated octahedron to coordinatively unsaturated tetrahedron. Heterogenous catalytic experiments on allylic oxidation of cyclohexene show that dehydrated 1a has 6 times enhanced catalytic activity than as-synthesized 1 by using tert-butyl hydroperoxide (t-BuOOH) as oxidant. The activation energy for the oxidation of cylcohexene with 1a catalyst was 67.3 kJ/mol, far below the value with 1 catalysts, which clearly suggested that coordinatively unsaturated CoII sites in 1a have played a significant role in decreasing the activation energy. It is interestingly found that heterogeneous catalytic oxidation of cyclohexene in 1a not only gives the higher conversion of 73.6% but also shows very high selectivity toward 2-cyclohexene-1-one (ca. 64.9%), as evidenced in high turnover numbers (ca. 161) based on the open Co(II) sites of 1a catalyst. Further experiments with a radical trap indicate a radical chain mechanism. This work demonstrates that creativity of coordinatively unsaturated metal sites in MOFs could significantly enhance heterogeneous catalytic activity and selectivity.
Co-reporter:Reshalaiti Hailili, Li Wang, Junzhang Qv, Ruxin Yao, Xian-Ming Zhang, and Huwei Liu
Inorganic Chemistry 2015 Volume 54(Issue 8) pp:3713-3715
Publication Date(Web):April 7, 2015
DOI:10.1021/ic502861k
A planar tetracoordinated oxygen containing a homochiral metal–organic framework (MOF) has been synthesized and characterized that can be used as a new chiral stationary phase in high-performance liquid chromatography to efficiently separate racemates such as pharmaceutically important (±)-ibuprofen and (±)-1-phenyl-1,2-ethanediol.
Co-reporter:Xian-Ming Zhang, Juan-Juan Hou, Cai-Hong Guo, and Chun-Fang Li
Inorganic Chemistry 2015 Volume 54(Issue 2) pp:554-559
Publication Date(Web):December 29, 2014
DOI:10.1021/ic5024168
Although a variety of functional metal–organic frameworks (MOFs) have been synthesized, post-modified, and applied in various areas, there is little knowledge about how molecular cluster building units are stepwise evolved into MOFs via intermediates. Coordination bonds are generally stronger than hydrogen bonds, and thus equivalent replacement of X–H···Y hydrogen bonds by X–M–Y coordination bonds can transform hydrogen bond networks into MOFs. In this work, solvothermal in situ reduction reactions of CuBr2 and 1,4-diazoniabicyclo[2,2,2]octane (DABCO) generated a myriad of tunable photoluminescent cuprous body-centered cubic bromide cluster-based networks with the general formula [Cu4+xH4–xBr6(DABCO)4](HCO2)2·S (x = 0, 0.56, 0.81, 1.27, 1.39, 2.56, 2.78, and 4 for compounds 1–8, respectively). All of these compounds crystallize in the cubic space group with the largest volume difference being only 5.2%, but they belong to three remarkably different kinds of crystals. Complex 1 is a molecular crystal and consists of tetrahedral [Cu4Br6(HDABCO)4]2+ clusters with monodentate HDABCO groups that are supported via N–H···Br synthons in the hydrogen bond network. Compound 8 is a [Cu8Br6]2+ cube cluster-based MOF with bridged DABCO ligands. Complexes 2–7 are seemingly impossible Cu/H-substituted solid solutions of 1 and 8. The CuBr framework components in 1–8 are Cu4Br6, Cu4.56Br6, Cu4.81Br6, Cu5.27Br6, Cu5.39Br6, Cu6.56Br6, Cu6.78Br6, and Cu8Br6, respectively. Crystallization kinetics studies revealed that the [Cu4Br6(HDABCO)4]2+ cluster-based hydrogen bond network (1) was initially formed such that N–H···Br hydrogen bonds could be stepwise replaced by N–Cu–Br coordination bonds to form the [Cu8Br6]2+ cube cluster-based MOF (8) via solid solutions. These observations directly reveal the equivalence and transformation between the N–H···Br hydrogen bond and the N–Cu–Br coordination bond and the evolutionary mechanism of a molecular crystal to a MOF via solid solutions, which is of fundamental importance in materials but has never before been revealed. DFT calculations suggest that equivalent replacement of a N–H···Br hydrogen bond by a N–Cu–Br coordination bond is exothermic and exergonic, which also supports the transformation from molecule 1 to MOF 8.
Co-reporter:Xin Cui, Mei-Chen Xu, Ling-Juan Zhang, Ru-Xin Yao and Xian-Ming Zhang
Dalton Transactions 2015 vol. 44(Issue 28) pp:12711-12716
Publication Date(Web):18 Jun 2015
DOI:10.1039/C5DT01456E
The butterfly-like tetranuclear cobalt cluster based 3D MOF [Me2NH2][Co2(bptc)(μ3-OH)(H2O)2] (1) underwent a reversible thermally triggered single-crystal-to-single-crystal transformation via Co–Owater weakened intermediate 1a to produce a partly dehydrated phase [Me2NH2][Co2(bptc)(μ3-OH)(H2O)] (2), which was confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and IR spectroscopy. During the dehydration course, the local coordination environment of one Co2+ ion was changed from the saturated octahedron to a coordinately unsaturated square-pyramid, accompanied by a crystal color change from red to purple. Compared with pristine hydrated 1, dehydrated 2 exhibits highly efficient and recyclable catalytic activity for cyanosilylation of carbonyl compounds with a low catalyst loading of 0.1 mol% Co at room temperature under solvent-free conditions, which due to the open Co2+ sites as catalytically activated sites played a significant role in the heterogeneous catalytic process.
Co-reporter:Li-Na Duan, Qin-Qin Dang, Cai-Yun Han and Xian-Ming Zhang
Dalton Transactions 2015 vol. 44(Issue 4) pp:1800-1804
Publication Date(Web):18 Nov 2014
DOI:10.1039/C4DT02672A
A new interpenetrated bioactive nonlinear optical metal–organic framework [Zn2(ppa)2(1,3-bdc)(H2O)] has been designed and synthesized, which shows both a high drug content of 63.9% and a good slow release effect in simulated physical conditions compared to other non-interpenetrated bioactive MOFs. It also shows a large powder second-harmonic generation (SHG) efficiency of 5.6 times that of KH2PO4 (particle size: 150–200 μm).
Co-reporter:Qin-Qin Dang, Yu-Fen Zhan, Li-Na Duan and Xian-Ming Zhang
Dalton Transactions 2015 vol. 44(Issue 46) pp:20027-20031
Publication Date(Web):16 Oct 2015
DOI:10.1039/C5DT01943E
An expanded pyridyl-decorated MOF-505 analogue[Cu2(L)(H2O)2]·Gx (H4L = 5,5′-(pyridine-2,5-diyl)diisophthalic acid, G = solvent molecule) has been solvothermally synthesized and reported. It exhibited rare hierarchical meso- and microporosity. With exposed unsaturated CuII sites and Lewis basic pyridyl sites, the material shows both large CO2-uptake capacity (123.4 cm3 g−1 at 273 K, 1 bar) and high selectivity for CO2 over N2 (55.7) at 273 K. Furthermore, for the first time the compound has been exploited for its heterogeneous catalytic performance toward the cyanosilylation reaction under solvent-free conditions. The compound can be recycled up to five times with only a minor loss of activity.
Co-reporter:Ru-Xin Yao, Reshalaiti Hailili, Xin Cui, Li Wang and Xian-Ming Zhang
Dalton Transactions 2015 vol. 44(Issue 7) pp:3410-3416
Publication Date(Web):20 Jan 2015
DOI:10.1039/C4DT03657C
A perfectly aligned 63 helical tubular cuprous bromide single crystal has been synthesized and characterized, which can selectively decompose negatively charged dyes of Methyl Orange (MO) and Kermes Red (KR), and the photocatalytic efficiency is higher than that of nanosized (∼25 nm) TiO2 and ZnO. The direction and magnitude of the dipole moments as well as the band structure were calculated to reveal high photocatalytic efficiency. Moreover, luminescence studies indicate that the CuBr tube materials show very strong yellowish green emissions in the solid state and emulsion even at room temperature, and exhibit extremely high detection sensitivity towards nitro-explosives via fluorescence quenching. Detectable luminescence responses were observed at a very low concentration of 20 ppm with a high quenching efficiency of 94.90%. The results suggest that they may be promising multifunctional materials for photo-catalysis, luminescence and sensing of nitro-explosives.
Co-reporter:Min-Min Liu, Yan-Lin Bi, Qin-Qin Dang and Xian-Ming Zhang
Dalton Transactions 2015 vol. 44(Issue 46) pp:19796-19799
Publication Date(Web):29 Oct 2015
DOI:10.1039/C5DT03570H
The reversible crystal transformation between the mononuclear complex [Cu(tzbc)2(H2O)4] (1) and the 4-fold interpenetrated diamondoid MOF [Cu(tzbc)2] (2) was chemically implemented and structurally interpreted. Interestingly, despite 4-fold interpenetration, desolvated 2 with 1D channels and rich N-groups shows exclusive CO2 adsorption of up to 12.5 wt% at room temperature and low pressure, indicating potential application in the separation of industrial and automobile exhaust.
Co-reporter:Ling-Juan Zhang, Cai-Yun Han, Qin-Qin Dang, Yan-Hong Wang and Xian-Ming Zhang
RSC Advances 2015 vol. 5(Issue 31) pp:24293-24298
Publication Date(Web):23 Feb 2015
DOI:10.1039/C4RA16350H
Solvothermal reaction of Cu(OAc)2 and H3BTT·2HCl generated a sodalite-type metal–organic framework [(Cu4O0.27Cl0.73)3(H0.5BTT)8(H2O)12]·3MeOH·9DMF (1) (BTT3− = 1,3,5-benzene tristetrazolate), which features a porous 3D (3,8)-connected framework constructed by square [Cu4(μ4-O/Cl)] units and triangular BTT ligands and can be dehydrated to form [(Cu4O0.27Cl0.73)3(H0.5BTT)8] (1′) with coordinatively unsaturated Cu2+ centers. Compared with related M–BTT MOFs, partial replacement of μ4-Cl with μ4-O at the square Cu4 cluster and the absence of irremovable guest [M(DMF)6]2+ cations in 1′ enhance the Lewis acidity of coordinatively unsaturated metal centers and the effective pore volume. Open Cu(II) sites with stronger Lewis acidity give rise to 1′ being an active, stable and reusable solvent-free heterogeneous catalyst for C–C bond-forming reaction by cyanosilylation of carbonyl compounds. The loading of 1 mol% of catalyst 1′ is as low as one eleventh of that used in related Mn–BTT but leads to as high as 96% conversion of benzaldehyde, indicating that the catalytic activity of M–BTT MOFs was significantly improved via post-modification. In addition, the larger pore volume makes 1′ selectively adsorb N2 and O2 gases with hysteresis loops over CO2 and H2 gases without hysteresis loops, which did not appear in related M–BTT MOFs.
Co-reporter:Yan-Hong Wang, Mei-Chen Xu, Jie Liu, Ling-Juan Zhang, Xian-Ming Zhang
Tetrahedron 2015 Volume 71(Issue 52) pp:9598-9601
Publication Date(Web):30 December 2015
DOI:10.1016/j.tet.2015.11.001
An efficient synthesis of biphenyls via three-coordinate planar dinuclear Cu2(ophen)2 complex catalyzed homocoupling of arylboronic acids under air condition and in the condition of alkali-free was demonstrated. Uniquely, this catalyst shows high selectivity towards biphenyls when the reaction was conducted in aqueous solution, which is significantly different from selectivity towards phenols in related Cu-catalysts. Utilization of environmentally friendly water as main solvent, reaction at room temperature and in the absence of base, cheapness, low loading and easy bulk preparation of catalyst make it potential in green synthesis of biphenyls.
Co-reporter:Jiang Liu, Mei Qu, Mathieu Rouzières, Xian-Ming Zhang, and Rodolphe Clérac
Inorganic Chemistry 2014 Volume 53(Issue 15) pp:7870-7875
Publication Date(Web):July 24, 2014
DOI:10.1021/ic500420u
A new homonuclear single-chain magnet self-assembles as a one-dimensional coordination network of defective dicubane {CoII4} complexes linked by single CoII ions with the assistance of azido and picolinate ligands. Dominating intrachain ferromagnetic interactions, intrinsic Ising-like CoII anisotropy, and negligible interchain magnetic interactions lead to a thermally activated relaxation time of the magnetization below 8 K. Two thermally activated regimes above and below 3.5 K are observed with the following energy barriers: Δτ1/kB = 66 K (τ0 = 3.7 × 10–11 s) and Δτ2/kB = 51 K (τ0 = 2.3 × 10–9 s), respectively. The difference between the two energy barriers of the relaxation time, 15 K, agrees well with the experimental energy, Δξ, to create a domain wall along the chain.
Co-reporter:Shi-Li Li and Xian-Ming Zhang
Inorganic Chemistry 2014 Volume 53(Issue 16) pp:8376-8383
Publication Date(Web):July 25, 2014
DOI:10.1021/ic500822w
Solvothermal reactions of CuI, 1,4-diazabicyclo[2.2.2]octane (DABCO), and HI in an ethanol solution at 140 °C/150 °C for 7 days resulted in two 24-membered-ring-based layered semiconducting iodocuprate open-network polymorphs formulated as [deDABCO]2[meDABCO]Cu11I17 (deDABCO = N,N′-diethyl-1,4-diazabicyclo[2.2.2] octane and meDABCO = N-methyl-N′-ethyl-1,4-diazabicyclo[2.2.2]octane). The deDABCO and meDABCO templates were in situ generated via alkylation of DABCO during solvothermal reactions. The formation of layered Cu11I176– polymorphs can be rationalized via analyses of hierarchical building units. There are four hierarchical building units in polymorphs, namely, primary CuI3 triangle and CuI4 tetrahedron, secondary Cu3I7 trimer and Cu4I8 tetramer, tertiary Cu6I12 hexamer, and quaternary Cu12I22 dodecamer. The trimeric Cu3I7 secondary building unit (SBU) is constructed by three edge-shared CuI4 tetrahedra, while the tetrameric Cu4I8 SBU with an inversion center is formed by edge-shared two CuI3 triangles and two CuI4 tetrahedra. Two Cu3I7 SBUs are fused together via the sharing of two iodine atoms to form a Cu6I12 tertiary building unit (TBU), and two TBUs are further fused via the sharing of two iodine atoms into a Cu12I22 quaternary building unit (QBU). In colorless polymorph 1, each Cu3I7 SBU is connected to three neighbors via one Cu4I8 and two Cu6I12 linkers to form a 6,3-connected layer with 24-membered ring window. Different from 1, each Cu6I12 TBU in yellowish polymorph 2 is connected to four neighbors via two Cu4I8 and two Cu12I22 linkers to form a (4,4) topological layer also with 24-membered-ring window. These two compounds are very rare examples of copper halide polymorphs that exhibit similar local coordination geometries of copper(I) but different layered open networks. Electrical conductivity, band structure calculation, and UV–vis diffuse-reflectance spectrometry indicate that 1 and 2 are potential semiconductor materials, and the performance on the photocatalytic degradation of organic pollutants upon UV-light irradiation reveals that both 1 and 2 are highly efficient photocatalysts. Two polymorphs exhibit very similar green photoluminescence at room temperature in the solid state, and the study of the luminescent response to solvent on two polymorphs exhibits highly sensitive sensing of nitro explosives via quenching.
Co-reporter:Min-Min Liu, Juan-Juan Hou, Zhi-kai Qi, Li−Na Duan, Wen-Juan Ji, Cai-yun Han, and Xian-Ming Zhang
Inorganic Chemistry 2014 Volume 53(Issue 8) pp:4130-4143
Publication Date(Web):April 8, 2014
DOI:10.1021/ic5001232
Seven cupric halide coordination polymers, namely [Cu5(OH)3Br3(ina)4] (1), [Cu5(OH)3Cl3(ina)4] (2), [Cu2(OH)Cl(ina)2] (3), [Cu3(OH)2Cl2(ina)2]·2H2O (4), [Cu3(OH)2Br2(ina)2]·2H2O (5), [Cu2Cl2(ina)2(H2O)2] (6), [Cu2Cl(ina)2(gca)(H2O)] (7), cupric complex templated cuprous halide [CuII(Me-ina)2(H2O)][CuI5Br7] (8), and organic templated cuprous halide Me2-ina[Cu2Br3] (9) (Hina = isonicotinic acid), were prepared from the starting materials of cupric halide and Hina via fine-tuning solvothermal reactions. According to valence states of copper, 1–7 are copper(II) complexes, 8 is a mixed-valent Cu(I,II) complex, while 9 is a Cu(I) compound. According to bonding types of halides, nine complexes can be classified as three types: complexes 1–3 include only normal X–Cu bond (X = halide); complexes 4–7 include normal X–Cu bond and X···Cu weak bond; complexes 8 and 9 include normal X–Cu bond and X···H–C halogen hydrogen bonds. Complexes 1 and 2 are isomorphic three-dimensional (3D) pcu topological metal organic frameworks (MOFs) with butterfly-like Cu4(μ3-OH)2X2 and steplike Cu6(μ3-OH)4 cores as nodes, showing strong ferromagnetic couplings. Complex 3 also is a pcu topological MOF with only butterfly-like Cu4(μ3-OH)2Cl2 clusters as nodes, presenting spin canting antiferromagnetic behavior. Isostructural 4 and 5 are Cu3(OH)2 clusters based two-dimensional (2D) (4,4) layers, which are extended into 3D eight-connected networks via weak Cu···X bonds, showing ferromagnetic coupling. Antiferromagnetic 6 is a simple one-dimensional coordination polymer, which is extended via weak Cu···Cl bonds into 3D (3,4)-connected networks. Paramagnetic 7 is a ladderlike polymer, which is extended into 2D (3,4)-connected layer via weak Cu···Cl bonds. The syntheses of polymeric cupric complexes 1–7 mainly result from differences in reactant ratio and pH value. Utilization of reducing methanol generated novel cubane-containing [Cu5Br7]2– chain templated by paddlewheel-like [CuII(Me-ina)2]2+ 8 and face-shared dimer-containing [Cu2Br3]− chain templated by N-methylated and O-esterificated Me2-ina 9. Complex 9 exhibits a strong red emission and a weaker green emission upon excitation.
Co-reporter:Zhi-Kai Qi, Jun-Liang Liu, Juan-Juan Hou, Min-Min Liu, and Xian-Ming Zhang
Crystal Growth & Design 2014 Volume 14(Issue 11) pp:5773-5783
Publication Date(Web):October 9, 2014
DOI:10.1021/cg5010402
Five new polyoxometalate-based metal organic frameworks, [Cu4(ppz)4(PO4)]·[CuBr2] (1), [Cu4(ppz)4(MoO4)2(H2O)]·2H2O (2), [Cu(Hppz)(Mo2O7)] (3), [Cu2(ppz)2(Mo3O10)] (4), and [Cu6(ppz)6(PMo3VMo9VIO40)] (5) (Hppz = 2-(1H-pyrazol-3-yl)pyrazine), have been hydrothermally synthesized and fully characterized, in which a planar Cu2(ppz)2 dimer acts as a secondary building unit (SBU) and provides up to six potential binding sites. In virtue of the strong Jahn–Teller (JT) effect of Cu(II) ions, the potential binding sites in the Cu2(ppz)2 SBU can facilely be occupied by auxiliary oxygen-donor anions and/or outward pyrazine nitrogen atoms of neighboring SBUs. The auxiliary oxygen-donor anions in compounds 1–5 range from simple phosphate and molybdate, zonal Mo2O72– and Mo3O102– to a spherical three-electron reduced Keggin anion [PMo12O40]6–, respectively. Compound 1 contains an unprecedented 3D (4,6)-connected cationic open framework [Cu4(ppz)4(PO4)]+ with 1D channels filled by linear CuBr2– anions, where the Cu2(ppz)2 SBUs and PO4 groups act as nodes and the outward Cu–N bonds and oxo bridges act as linkers. 2 possesses a complicated trinodal (3,4)-connected topological framework, in which μ3-MoO4 and Cu2(ppz)2 groups act as 3- and 4-connected nodes and the outward Cu–N bonds and double μ2-MoO4 groups act as linkers. Differing from 1 and 2, compound 3 shows a 2D organic–inorganic hybrid sheet constructed by a [Mo2O7]2– ribbon of cyclic hexameric edge-shared [MoO6]-octahedra and Cu2(ppz)2 SBUs. Similar to 3, compound 4 also shows 2D organic–inorganic hybrid sheets constructed by zigzag [Mo3O10]2– ribbons and Cu2(ppz)2 SBUs, and adjacent sheets are extended by weak Mo–N bonds into the 3D network. 5 has a 3D 6-connected pcu topological framework constructed by Cu2(ppz)2 SBUs and [PMo12O40]6– anions, which also can be viewed as cationic of the NbO topological [Cu6(ppz)6]6+ network with cavities filled by [PMo12O40]6– anions. Magnetic measurements show that there is strong antiferromagnetic coupling within the Cu2(ppz)2 dimer and only one unpaired electron within the three-electron reduced Keggin anion.
Co-reporter:Ru-Xin Yao, Xia Xu and Xian-Ming Zhang
RSC Advances 2014 vol. 4(Issue 96) pp:53954-53959
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4RA07436J
Hydrothermal reaction of Dy(NO3)3, 2-amino-5-mercapto-1,3,4-thiadiazole and (NH4)2C2O4 in the presence of triethylamine resulted in two dysprosium hydroxysulfates, namely [Dy4(OH)4(SO4)4(H2O)3] (1) and [Dy4(OH)4(SO4)3(ox)(H2O)6] (2) (ox = oxalate), in which the sulfates came from in situ oxidized conversion of the organosulfur of 2-amino-5-mercapto-1,3,4-thiadiazole. Both 1 and 2 are constructed from cubane-like Dy4O4 clusters, which extend via sulfate and oxalate into 3D highly-connected networks. Compound 1 crystallizes in the orthorhombic chiral space group P212121 and has 3D (12,3)-connected Au4Ho-like topology in which Dy4(μ3-OH)4 cubane clusters serve as twelve-connected nodes and sulfates serve as three-connected nodes, while compound 2 crystallizes in the orthorhombic centrosymmetric space group Pbcm and shows a 3D (10,3)-connected unprecedented network with coordinated oxalates in which Dy4(μ3-OH)4 cubane clusters act as ten-connected nodes and sulfates act as three-connected nodes. Detailed comparison of experimental parameters indicated that the amount of lanthanide ions played a significant role in tuning the nuclearity of metal clusters and the local connectivity number of specific networks. Differing from antiferromagnetic coupling observed in known Dy4(μ3-OH)4 cubane-like compounds, 1 and 2 exhibit unusual ferromagnetic coupling.
Co-reporter:Hai-Yun Ren, Cai-Yun Han, Mei Qu and Xian-Ming Zhang
RSC Advances 2014 vol. 4(Issue 90) pp:49090-49097
Publication Date(Web):16 Sep 2014
DOI:10.1039/C4RA05275G
Hydrothermal in situ decomposition of DMF generated three [NH2(CH3)2]+ cation templated anionic zinc and cadmium terphenyl-3,2′′,5′′,3′-tetracarboxylate (tpta) frameworks. Compound 1 shows a kgd topological layer constructed by 6-connected paddlewheel-type [Zn2(CO2)4] SUBs and 3-connected tpta groups. Compound 2 has a 3D sra network constructed by the zigzag chains of metal centers and tpta groups. Compound 3 adopts a new (4,7)-connected topological network with four types of nodes. Compounds 1–3 show two blue phosphorescent emission bands attributed to ligand centered transitions perturbed by metal ions, which displays significant temperature-dependent behavior. The higher energy emissions are red-shifted and weakened with increasing temperature, while the lower energy emissions increase in intensity and finally become the main emission bands; the CIE coordinates for 1 are changed with decreasing temperature from blue to greenish blue. Interestingly, 1 could selectively detect traces of Ca2+ ions at ppm level in a pyridine suspension, which makes it more suitable to be a luminescent probe for sensing Ca+ ions.
Co-reporter:Zhi-Kai Qi, Fu-Qiang Zhang, Ru-Xin Yao, Jun-Liang Liu, Xian-Ming Zhang
Inorganic Chemistry Communications 2014 Volume 39() pp:21-25
Publication Date(Web):January 2014
DOI:10.1016/j.inoche.2013.10.032
•The rare geometric isomerism between two dinuclear complexes is reported.•The computed Gibbs free energy difference is 4.52 kcal/mol.•Both isomeric compounds show the same transition behavior(dp→π*) in DMA solution corresponding to the calculated results.The solvothermal reaction of CoCl2 and 2-(4-thiazolyl)-benzimidazole (Htbi) in ethanol solution at 160 °C and 72 h gave rise to a majority of green crystals of [Co2(Htbi)2Cl4] 1 and minor isomeric blue crystals of 2. Two isomers show quite different isolated dinuclear structures bridged by two chlorides. Complex 1 consists of edge-sharing CoN4Cl2 octahedron and CoCl4 tetrahedron, while 2 is composed of two edge-sharing CoN2Cl3 square pyramids. The intra- and inter-molecular halogen hydrogen bonds play an important role at the stabilization in the solid state. Density functional theory calculations manifest that the optimized geometric parameters match very well with the experimental ones for both isomers. The difference of calculated Gibbs free energies demonstrates that intrinsic stability of 1 is superior to 2, in agreement with their relative yields under experimental conditions. The experimental UV–vis absorption spectra in N, N-dimethyl acetamide for 1 and 2 show the same absorption bands and match the computed results. Magnetic studies of 1 reveal that strong antiferromagnetic interactions were detected between octahedral and tetrahedral Co(II) atoms.The rare geometric isomerism in a pair of dinuclear complexes is reported. The computed Gibbs free energy difference is 4.52 kcal/mol. The high energy isomer 2 can transform into more stable 1 in DMA solution.
Co-reporter:Mei Qu;Minmin Liu;Jiang Liu ;Xianming Zhang
Chinese Journal of Chemistry 2014 Volume 32( Issue 12) pp:1259-1266
Publication Date(Web):
DOI:10.1002/cjoc.201400424
Abstract
Five chiral (P21) isostructural lanthanide coordination complexes Ln(pic)3 [pic=picolinic acid, Ln=La (1), Gd (2), Nd (3), Sm (4) and Eu (5)] have been hydrothermally generated, featuring one dimensional right-handed 21 helical chains constructed from LnN3O6 of square antiprism geometry and N,O-chelated pic− groups, in which 3, 4 and 5 have been reported, but we explore undiscovered properties of their own systematically. In special, 1 undergoes an abnormal transformation of symmetry as the temperature cooling to 100 K. TG-DSC studies demonstrated that all isologues have good thermal stability with the decomposition temperature up to 400°C. Then, UV-Vis-NIR transmission spectroscopy measurements indicated that they possess a short-wavelength absorption edge onset at 377 nm, corresponding to the optical band gap of 3.29 eV. Meanwhile, powder second harmonic generation (SHG) measurements revealed that the SHG intensity of 1, 2, 4 and 5 may be about 1.2, 2.0, 0.9 and 0.75 times that of KH2PO4, respectively. Interestingly, 1 and 3 exhibit efficient photocatalytic degradation for MB (Methylene Blue) upon UV-light irradiation. Moreover, both 1 and 2 show strong blue luminescence.
Co-reporter:Min-Min Liu, Cai-Yun Han, Ying-Lian Qin, and Xian-Ming Zhang
Crystal Growth & Design 2013 Volume 13(Issue 4) pp:1386-1389
Publication Date(Web):March 11, 2013
DOI:10.1021/cg400165v
A novel body-centered cubic antiferromagnetic heterometal-coordination network Na4Mn8(μ4-OMe)6(μ4-MeCO2)12 ·2MeCO2 based on Mn8@Na8 cube-in-cube supramolecular building blocks has been synthesized, in which the unprecedented cubic (39.46)8 topological Mn8(μ4-OMe)6 cube with capped oxygen of five coordination is first revealed. Interestingly, the cube-in-cube Mn8@Na8 in combination with coordinated oxygen atoms makes up the unique nested Mn8O6@O24@Na8 triple-shell structure, in which the inner Mn8 cube is penetrated by the O6 octahedron but is enclosed by a larger O24 truncated cube that is further surrounded by a still larger Na8 cube.
Co-reporter:Juan-Juan Hou, Rong Zhang, Ying-Lian Qin, and Xian-Ming Zhang
Crystal Growth & Design 2013 Volume 13(Issue 4) pp:1618-1625
Publication Date(Web):March 5, 2013
DOI:10.1021/cg301827p
Four novel coordination polymers based on asymmetric triangular 5-(4′-carboxylphenyl) nicotinic acid (H2cpna), namely, Ni(cpna)(H2O)2 (1), M2(cpna)2(H2O)3·0.5H2O·DMF [M = Ni for (2), Co for (3)] and Ni3(Hcpna)2(cpna)2(H2O)4·2H2O (4), have been synthesized under solvothermal conditions. All of the four compounds contain low nuclear metal clusters as secondary building units (SBUs). Complex 1 exhibits two-dimensional (3,6)-connected (43)2(46.66.83)-kgd topology, in which cpna ligands and edge-shared dinuclear SBUs act as 3-connected and 6-connected nodes, respectively. Compounds 2 and 3 are constructed by corner-shared dinuclear SBUs and show an unprecedented (3,6)-connected chiral (42.6)2(44.62.88.10)-anh (flu-3, P6222) topology. In 4, linear trimers are ligated by six cpna ligands to form a planar (43)2(46.66.83)-kgd layer, and adjacent layers are further linked by Hcpna– ligands through Ni–O and Ni–N bonds to form three-dimensional (3,8)-connected (43)2(46.618.84)-tfz-d net. Both 1 and 4 crystallize in the triclinic crystal system with symmetric space group P̅1, which result in an equal ratio of (R)- and (S)-cpna isomers. Isostructural 2 and 3 crystallize in a trigonal crystal system with the chiral space group P3221, and a single crystal contains a sole optical isomer of cpna, although bulk crystals are a racemic mixture. Variable-temperature magnetic susceptibility measurements reveal ferromagnetic coupling of edge-shared dimers in 1, antiferromagnetic coupling of corner-shared dimers in 2 and 3, and ferrimagnetic coupling of linear trimers in 4.
Co-reporter:Ru-Xin Yao, Ying-Lian Qin, Fang Ji, Yan-Fei Zhao and Xian-Ming Zhang
Dalton Transactions 2013 vol. 42(Issue 18) pp:6611-6618
Publication Date(Web):19 Feb 2013
DOI:10.1039/C3DT32539C
Three novel tetrazole-based frustrated magnets, namely, Co3(OH)2(3-ptz)2(SO4)(H2O)4 (1), Co2(OH)(tzba)(H2O)4 (2) and [Co(OH)(tta)] (3) (3-ptz = 5-(3-pyridyl) tetrazole, H2tzba = 4-(1H-tetrazol-5-yl) benzoic acid, Htta = 1H-tetrazole) were hydrothermal synthesized and magnetically characterized. Compound 1 is a 2D (4,4) layered structure assembled by sulfate capped triangular [Co3(μ3-OH)(μ3-SO4)] clusters and in situ synthesized μ3-3-ptz ligands. Compound 2 features Co3(μ3-OH) triangle based magnetic Δ-chains linked with in situ generated μ5-tzba ligands to form a 2D layer. Compound 3 is a uninodal eight-connected body-centered-cubic (bcu) 3D network with square Co4O4 clusters as nodes and μ4-tta ligands as linkers. Interestingly, spin frustration was observed in these complexes due to inherent spin competition in triangle, Δ-chain and square. Magnetic studies show that 1 behaves as antiferromagnet, while 2 and 3 exhibits spin canting and long-range magnetic ordering.
Co-reporter:Jiang Liu, Ying-Lian Qin, Mei Qu, Rodolphe Clérac and Xian-Ming Zhang
Dalton Transactions 2013 vol. 42(Issue 32) pp:11571-11575
Publication Date(Web):30 May 2013
DOI:10.1039/C3DT51363G
A novel two-dimensional (2D) azido-based CuII network, [Cu11(pic)6(N3)16] (1), was prepared using picolinic acid (Hpic) as coligand. Interestingly, 1 is composed of symmetric double azido EO-bridged [Cu(N3)2]n chains linked by [Cu(pic)2] units making a regular ladder with a missing rung. These rung-defected ladders are assembled in a layered structure by long azido-CuII contacts between neighboring [Cu(N3)2]n chains. The magnetic properties of 1 are dominated by significantly strong antiferromagnetic coupling (J/kB = −15.4(2) K) between CuII spins through the double EO azido-bridges along the [Cu(N3)2]n chains.
Co-reporter:Dong-Ping Jiang;Ru-Xin Yao;Fang Ji
European Journal of Inorganic Chemistry 2013 Volume 2013( Issue 4) pp:556-562
Publication Date(Web):
DOI:10.1002/ejic.201200949
Abstract
Five tetrazolate-based coordination polymers with cationic copper(I) halide motifs, namely, Cu4(tta)2Cl2 (1, tta = tetrazolate), Cu4(tta)2Br2 (2), Cu2(tta)I (3), Cu3(mtta)2Cl (4, mtta = 5-methyltetrazolate), and Cu2(tta)Br (5) were prepared by hydro(solvo)thermal reactions of CuX2 or CuX with tetrazolato ligands in the presence of HX. Compounds 1, 2, and 3 show eight-connected square-planar layered structures constructed with butterfly-like [Cu4X2]2+ (X = Cl, Br, I) clusters and μ4-tta groups. Isomorphs 1 and 2 crystallize in the orthorhombic space group Pbca, but 3 crystallizes in the orthorhombic space group Pbam, because each μ4-tta group is coordinated to three butterfly-like clusters rather than four in 1 and 2. To the best of our knowledge, 1, 2, and 3 represent the only 2D coordination polymers with eight-connected square planar topology to date. Compound 4 is a [Cu3Cl]2+ cluster based on the undocumented ten-connected ZrIn2 topological framework. Compound 5 has a 3D pillar layered framework constructed with [Cu2Br]nn+ cationic layers. Compounds 1, 2, 4, and 5 exhibit strong green-blue emission in the solid state at room temperature, whereas cuprous iodide complex 3 shows strong red luminescence.
Co-reporter:Shi-Li Li, Rong Zhang, Juan-Juan Hou, Xian-Ming Zhang
Inorganic Chemistry Communications 2013 Volume 32() pp:12-17
Publication Date(Web):June 2013
DOI:10.1016/j.inoche.2013.03.002
•Two cuprous iodide polymorphs were synthesized via in situ templation.•X-ray crystallography reveals that two polymorphs have different conformations.•The UV–vis spectra exhibit that polymorphs belong to optional semiconductors.•Two polymorphs show different photoluminescent emission and excitation.Two cuprous iodide polymorphs formulated as [N(CH3)4][Cu2I3] α and β were synthesized, in which N(CH3)4+ template that never existed in the reaction materials are in situ generated via cleavage of CN bonds and N-alkylation reactions. Solvothermal reaction of copper source, hexamethylenetetramine and HI in methanol solution at 150 °C led to α and β polymorphs. Two polymorphs have been synthesized via subtle modification of the experimental condition, which indicates that the small force is also sufficient for energy difference for polymorphs. α polymorph contains one-dimensional Cu2I3− chain in which the copper atoms are arranged into a zigzag lattice; β polymorph is composed of novel ladder-like chains which can be considered as being built up by Cu12I18 and Cu2I3 two types of secondary building units. The UV–vis absorption spectra for α and β polymorphs were investigated in reflectance mode in the solid state at room temperature, exhibiting that they belong to potential semiconductors. The excitation and emission in α and β are very distinct, which highlight that the molecular packing in polymorphs is critical to photophysical properties.Two cuprous iodide polymorphs formulated as [N(CH3)4][Cu2I3] α and β were synthesized, in which N(CH3)4+ template that never existed in the reaction materials are in situ generated via cleavage of CN bonds and N-alkylation reactions. α contains one-dimensional Cu2I3− chain in which the copper atoms are arranged into a zigzag lattice; β is composed of novel ladder-like chains which can be considered as being built up by Cu12I18 and Cu2I3 two types of units. Two polymorphs have been synthesized via subtle modification of the experimental condition, which indicates that the small force is also sufficient for energy difference for polymorphs.
Co-reporter:Ying-Lian Qin;Ru-Xin Yao;Guo-Xing Wu;Min-Min Liu ;Dr. Xian-Ming Zhang
Chemistry – An Asian Journal 2013 Volume 8( Issue 7) pp:1587-1595
Publication Date(Web):
DOI:10.1002/asia.201300143
Abstract
By using environmentally friendly [Ni(CN)4]2− as a cyanide source, three new heterometallic cyano-bridged mixed-valence CuI/CuII coordination polymers with three different electronic configurations (d8–d10), that is, [Cu2Ni(CN)5(H2O)3] (1), [Cu2Ni(CN)5(pn)H2O] (2), and [Cu3Ni(CN)6(pn)2] (3, pn=1,2-propane diamine) have been synthesized by gradually increasing the amount of pn. Compound 1, which was hydrothermally synthesized in the absence of pn ligand, exhibits the famous 2D Cairo pentagonal tiling, in which the CuI, CuII, and NiII atoms act as trigonal, T-shaped, and square-planar nodes, respectively. Notably, there are three water molecules located at the meridianal positions of the octahedrally coordinated CuII atom in compound 1. A similar reaction, except for the addition of a small amount of pn, generated a similar Cairo pentagonal tiling layer in which two of the water molecules that were located at the meridianal positions of the octahedrally coordinated CuII atom were replaced by a chelating pn group. Another similar hydrothermal reaction, with the addition of a larger amount of pn, yielded compound 3, which showed a related two-fold-interpenetrated (3,4)-connected 3D framework with an unprecedented {83}2{86} topology in which the CuII atom was chelated by two pn groups. These structural changes between compounds 1, 2, 3 can be explained by the chelating effect of the pn group. The replacement of two meridianally coordinated water molecules on the octahedral CuII atom in compound 1 by a pn group gives compound 2, which shows similar Cairo tiling, and a further increase in the amount of pn results in the formation of the [Cu(NC)2(pn)2] unit and the two-fold-interpenetrated 3D framework of compound 3. The mixed-valence properties of compounds 1, 2, and 3 were confirmed by variable-temperature magnetic-susceptibility measurements.
Co-reporter:Ru-Xin Yao, Xia Xu, and Xian-Ming Zhang
Chemistry of Materials 2012 Volume 24(Issue 2) pp:303
Publication Date(Web):December 13, 2011
DOI:10.1021/cm202876r
A series of isostructural metal-carboxylate frameworks [Me2NH2][M2(bptc)(μ3-OH)(H2O)2] (H4bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, M = Co, Co0.83Ni0.17, Co0.55Ni0.45, Co0.13Ni0.87, and Ni for 1–5, respectively) have been synthesized, which feature (4,8)-connected scu topological anionic frameworks constructed by a butterfly-like [M4(OH)2(RCO2)8] cluster and have three-dimensional (3D) channels filled by in situ generated [Me2NH2]+ cations. Flame atomic absorption spectroscopy (FAAS), scanning electron microscope energy-disperse X-ray spectroscopy (SEM-EDS), infrared spectroscopy (IR), Raman spectroscopy, and powder X-ray diffraction (PXRD) measurements reveal that 1 can selectively exchange alkali metal cations. Magnetic properties display that monometallic 1 and 5 are characteristic of a antiferromagnet and a ferromagnet, respectively. Incorporation of Co and Ni into the system produced heterometallic compounds 2, 3, and 4. Compound 2 with a very low ratio of Ni to Co shows antiferromagnetic behavior similar to 1, while compounds 3 and 4 with a large ratio of Ni to Co are characteristic of ferrimagnetic-like behavior. This work demonstrates that magnetic tuning from antiferromagnetic, ferrimagnetic-like, to ferromagnetic behaviors can be achieved by heterometallic substitution in isostructural magnetic frameworks.Keywords: anionic framework; butterfly-like cluster; cation-exchange; magnetic tuning;
Co-reporter:Hui Gao and Xian-Ming Zhang
Dalton Transactions 2012 vol. 41(Issue 5) pp:1562-1567
Publication Date(Web):29 Nov 2011
DOI:10.1039/C1DT11258A
Three novel bismuth(III) complexes with in situ synthesized dihydroxybenzoquinone (anilic acid) ligands, namely [Bi(H3dhbqdc)(H2dhbqdc)]·2.5dmf (1), [Bi2(mdhbqdc)(ox)2(dmf)4] (2) and [Bi2(mdhbqdc)2(ox)(dmf)4] (3) (H4dhbqdc = 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylic acid; H2mdhbqdc = dimethyl 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylate, ox = oxalate, dmf = dimethyl formamide) were prepared under ambient conditions. 1 features 3-D diamond-like structure with 2-D channels filled by dmf molecules. 2 and 3 are geometrically different but topologically identical. 2 shows a brick-wall layer in which ratio of mdhbqdc to ox is 1:2 while 3 has a herringbone layer in which the ratio of mdhbqdc to ox is 2:1. Bismuth-assisted aerobic in situoxidation of dimethyl 1,4-cyclohexanedione-2,5-dicarboxylate (H2dmchddc) gave H2mdhbqdc, which underwent either ester hydrolysis to give H4dhbqdc or carbon–carbon cleavage to form oxalate. Comparative experiments revealed that both Bi(III) and nitrate are important in the unusual oxidation. Possible reaction pathways for the formation of the dihydroxy benzoquinone (dhbq) ligands from their cyclohexanedione precursor were proposed.
Co-reporter:Ying-Lian Qin, Jiang Liu, Juan-Juan Hou, Ru-Xin Yao, and Xian-Ming Zhang
Crystal Growth & Design 2012 Volume 12(Issue 12) pp:6068-6073
Publication Date(Web):October 23, 2012
DOI:10.1021/cg301192y
Reactions of CuCl2, K3[Fe(CN)6]/K4[Fe(CN)6], and pyrazine (pyz) in water solution at 160 °C/170 °C for 6 days led to two luminescent supramolecular isomers with stoichiometry [Cu2(pyz)(CN)2]·[CuCN] (1 and 2), which show 3D pseudopolyrotaxane structures with 1D [Cu(CN)]∞ chains penetrating 2D [Cu2(pyz)(CN)2] sheets. Isomer 1 contains linear, trigonal, and tetrahedral Cu(I) atoms, which are linked by pyz and cyanide groups into unprecedented (3,4)-connected Shubnikov-type (5,34) sheets, and these sheets are penetrated by [Cu(CN)]∞ chains via unsupported CuI–CuI interactions. In contrast, the [Cu2(pyz)(CN)2] sheets in isomer 2 can be viewed as a classical (6,3)-topological brick wall layer, which are also penetrated by [Cu(CN)]∞ chains in the absence of cuprophilicity. Schematically, the brick wall and Shubnikov-type (5,34) nets can be formed via arrangement of brick rows in ABAB and ABBA modes, respectively. It is worth noting that cyanide sources played a crucial role in the formation of supramolecular isomers. 1 and 2 show strong photoluminescence related to the various local coordination geometries of copper atoms and weak cuprophilic interactions.
Co-reporter:Qinqin Dang;Fang Ji ;Xianming Zhang
Chinese Journal of Chemistry 2012 Volume 30( Issue 9) pp:2232-2236
Publication Date(Web):
DOI:10.1002/cjoc.201200392
Abstract
Solvent-induced structural transformation was observed in two layered supramolecular isomers of [Zn2(H2O)(Hdtim)2] (H3dtim=4,5-ditetrazoyl-imidazole). Structural analyses revealed that the two isomers have the similar geometry of Zn, coordination mode of Hdtim2−, and topology. Their structural differences only arise from different arrangement of the layers which seemingly corresponds to cooperative clockwise and counter-clockwise 90° rotation of the adjacent layers. This is a quite unique solvent-dependent supramolecular isomerism in coordination polymers.
Co-reporter:Xian-Ming Zhang ; Jin Lv ; Fang Ji ; Hai-Shun Wu ; Haijun Jiao ;Paul v. R. Schleyer
Journal of the American Chemical Society 2011 Volume 133(Issue 13) pp:4788-4790
Publication Date(Web):March 7, 2011
DOI:10.1021/ja201525a
A perfectly square-planar, D4h-symmetric, tetracoordinated oxygen has been observed in a tetracopper cluster-based coordination polymer that shows an unusual magnetic moment and ESR signal. The stabilization factor of the square-planar tetracoordinated oxygen has been revealed using DFT calculations.
Co-reporter:Ying-Lian Qin, Juan-Juan Hou, Jin Lv, and Xian-Ming Zhang
Crystal Growth & Design 2011 Volume 11(Issue 7) pp:3101
Publication Date(Web):May 16, 2011
DOI:10.1021/cg200362c
By using environmental friendly K3[Fe(CN)6] as a cyanide source, hydrothermal reactions of CuCl2 and diamines resulted in four Cu2(1,1,2-μ3-CN)2(CN)4 dimer-based organic templated cuprous cyanide open frameworks, namely, [H1.5mepip]2[Cu4(CN)7] (1), [H1.5etpip]2[Cu4(CN)7] (2), [H2me2pip][Cu3(CN)5] (3), and [H2dmpa][Cu4(CN)6] (4) (mepip = N-methylpiperazine; etpip = N-ethylpiperazine, me2pip = N,N-dimethylpiperazine, dmpa = 3-dimethyl-aminopropylamine). Isomorphic 1 and 2 show three-dimensional (3-D) (4,6)-connected FeS2-like open frameworks constructed by 4-connected Cu(CN)4 monomers and 6-connected Cu2(CN)6 dimers. Complex 3 shows an unprecedented 3-D (4,6)-connected open framework in which the ratio of 4-connected Cu(CN)4 monomers to 6-connected Cu2(CN)6 dimers is 1:1. Complex 4 shows a 3-D (3,6)-connected AgIn2-like open framework constructed by 3-connected Cu(CN)3 monomers and 6-connected Cu2(CN)6 dimers. Different from CuCN/amine coordination polymers, the protonated organic diamines in 1–4 act as templates in the formation of cuprous cyanide open frameworks. Even at ambient temperature, 1, 2, 3, and 4 show strong blue-green photoluminescence related to Cu2(CN)6 dimer, which is mainly assigned to metal-to-ligand charge-transfer (MLCT) by time-dependent density functional theory (TD-DFT) and electronic band structure calculations.
Co-reporter:Zheng-Ming Hao and Xian-Ming Zhang
Dalton Transactions 2011 vol. 40(Issue 10) pp:2092-2098
Publication Date(Web):31 Jan 2011
DOI:10.1039/C0DT00979B
Single-crystal-to-single-crystal (SCSC) transformations have recently been found in some molecular magnets, which involve rearrangement or dynamic movement of molecular components of the crystals. Various stimuli such as guest removal, guest exchange, ligand exchange as well as redox reactions may induce SCSC transformations. To date, only a few molecular magnets are known to exhibit SCSC transformations, which often show high-dimensional robust structures. This review mainly focuses on magnetic complexes that are robust enough to experience SCSC transformations and show magnetic changes induced by solvents in due course. This contribution is organized according to the means of solvent treatment of molecular magnets, aiming at revealing magneto-structural correlation in such SCSC transformations.
Co-reporter:Xu-Hui Zhang;Zheng-Ming Hao ;Dr. Xian-Ming Zhang
Chemistry - A European Journal 2011 Volume 17( Issue 20) pp:5588-5594
Publication Date(Web):
DOI:10.1002/chem.201003199
Abstract
Hydrothermal reactions generated a cobalt–hypoxanthine framework [Co3(OH)4(Hpxt)2]⋅2 H2O (H2pxt=6-hydroxypurine, 1⋅2 H2O), which became a microporous framework [Co3(OH)4(Hpxt)2] (1) through a single-crystal-to-single-crystal transformation. Compound 1⋅2 H2O shows a three-dimensional umr topological structure with two types of spiral channels constructed by rod-shaped {Co3(μ-OH)4(N-C-N)2(N-C-C-O)2} second building units (SBUs). The larger channel is filled by fourfold spiral water chains. An unprecedented μ5-O6,N3,N7,N9 coordination mode of the Hpxt anion was observed. Both complexes 1⋅2 H2O and 1 qualitatively show similar metamagnetism from anti-parallel to parallel ferromagnetic cobalt-hydroxide chains. Compared with 1⋅2 H2O, a smaller Curie constant and more negative Weiss constant in 1 indicate that the helical water chains tend to suppress antiferromagnetic coupling between Co3(OH)4 ferromagnetic chains. Detailed magnetic studies of 1⋅2 H2O revealed that the competitive interactions between interchain antiferromagnetic exchange coupling and single-ion anisotropy of CoII resulted in a partly canted antiferromagnetic sate in low fields. Anti-parallel arrangement of adjacent ferromagnetic chains in middle fields gives 3D antiferromagnetic ordering, and magnetic ground states in high fields are a parallel arrangement of ferromagnetic chains.
Co-reporter:Juan-Juan Hou, Shi-Li Li, Cui-Rui Li and Xian-Ming Zhang
Dalton Transactions 2010 vol. 39(Issue 10) pp:2701-2707
Publication Date(Web):02 Feb 2010
DOI:10.1039/B922583H
Five new cuprous halides formulated as [etpy][Cu3I4] 1, [mepy][Cu2Br3] 2, [mepy][Cu2I3] 3 [dmebpp][Cu7Br9] 4 and [dmeDABCO]4[Cu8I16] 5 (etpy = N-ethylpyridyl; mepy = N-methylpyridyl; dmebpp = N,N′-dimethyl-1,3-bis(4-pyridyl)propane; dmeDABCO = N,N′-dimethyl-1,4-diazabicyclo-[2.2.2]octane) have been prepared by solvothermal reactions of a copper source, halides and N-heterocyclic ligands in alcoholic solution. 1 contains an unprecedented trigonal two-dimensional cuprous halide layer Cu3I4− constructed from trimeric Cu3I8 units via sharing peripheral μ3-iodines; isostructural 2 and 3 contain infinite Cu2X3− chains in which the copper atoms are arranged into a ladder; 4 is composed of novel twofold helical cuprous halide chains Cu7Br92− built up by CuBr4 and CuBr3; 5 contains an infinite edge-sharing tetrahedral chain with a periodic sequence of eight CuI4 tetrahedra. In situ alkylation reactions of N-heterocycles with alcohols generated organic cationic templates, which played an important role in the control of the structures of anionic cuprous halides. A possible alkylation mechanism of N-heterocycles in the system has been proposed. The fluorescence properties of 1 and 4 were investigated. Time-dependent density functional theory (TD-DFT) calculations were carried out on the excited electronic states of 1 in order to understand the emission mechanism.
Co-reporter:Zheng-Ming Hao, Jun Wang and Xian-Ming Zhang
CrystEngComm 2010 vol. 12(Issue 4) pp:1103-1109
Publication Date(Web):30 Nov 2009
DOI:10.1039/B915615A
Hydro(solvo)thermal treatment of Cu(II) and pyrimidine-2-thione (pymtH) in the presence of halide/pseudohalide has generated four phosphorescent cuprous pyrimidine-2-thiolate complexes, namely Cu2(pymt)Cl (1) and Cu3(pymt)2(SCN) (2), Cu3(pymt)2I (3) and Cu11(pymt)4I7 (4). Complex 1 has a layered structure constructed by a [Cu2SCl]∞ staircase chain; 2 contains helical chains [Cu3(pymt)2]nn+ that are further linked by μ3-1,2κS:3κN SCN into a 2-D layer, in which two adjacent helical chains are heterochiral; 3 is structurally related to 2 because it also contains a helical chain [Cu3(pymt)2]nn+. Differently the helical chain in 3 is attached by iodides to form a neutral two-fold screw chain; 4 consists of linear, trigonal and tetrahedral copper(I) sites, some of which are half occupied and has a complicated layered structure. Two unprecedented coordination modes of μ4-1κS:2,3κS:4κN′ and μ5-1,κN:2,3,4,κS:5,κN′ of pymt are observed. The presence of helical [Cu3(pymt)2]nn+ chains in both 2 and 3 leads us to guess that the [Cu3(pymt)2]nn+ chain is possibly an elementary structural species in solution. In the solid state and at ambient temperature, 1–4 all show interesting phosphorescent emissions: a strong red emission and a weak higher energy blue emission band. The weak higher energy blue emissions are tentatively assigned as originating from the halides/pseudohalides to aromatic pyrimidine π* charge transfer while the low-energy red emissions are tentatively assigned as from ligand-to-metal charge transfer (LMCT) and/or metal-to-ligand charge-transfer (MLCT) characters, mixed with metal-centered (ds/dp) states modified by Cu–Cu interactions.
Co-reporter:Zheng-Ming Hao, Cai-Hong Guo, Hai-Shun Wu and Xian-Ming Zhang
CrystEngComm 2010 vol. 12(Issue 1) pp:55-58
Publication Date(Web):25 Sep 2009
DOI:10.1039/B918159H
Solvothermal treatment of copper halides and 3-amino-5-mercapto-1,2,4-triazole (H2amtz) produced three isostructural complexes [Cu31X4(H1.55amtz)24](SO4)8·xDMF [X = Cl, Br and I, x ∼ 32], which show 3-D networks with bor topology constructed by Cu-centered CuCu4 tetrahedra and CuCu3 triangles with an acentric cubic superlarge cell.
Co-reporter:Fu-Qiang Zhang, Xian-Ming Zhang, Rui-Qin Fang and Hai-Shun Wu
Dalton Transactions 2010 vol. 39(Issue 35) pp:8256-8260
Publication Date(Web):05 Aug 2010
DOI:10.1039/C000606H
The non-classical KP6Mo18O73 heteropolyanion has been studied by the density functional theory (DFT) method, and the calculated geometry compares well with the experimental one. In fully oxidized [KP6Mo18O73]7− state, the dxy-orbitals centered at eight “belt” Mo sites in the lower part of the “basket” are the major contributors to the LUMO and LUMO+1, while the LUMO+2 orbital is mostly focused on the two polar parts. In contrast, the HOMOs indicates that the coordination of the KP6Mo18 heteropolyanion to metal ions favorably occurs at the oxygen atoms from four external phosphates and two molybdates of the handle of the “basket”. Compared with Wells–Dawson [P2Mo18O62]6−, the HOMO–LUMO gap in fully oxidized [KP6Mo18O73]7− is much smaller, indicating much easier reduction that is consistent with the cyclic voltammogram. Both frontier orbitals and Mulliken analysis indicate that two of three blue electrons in [KP6Mo18O73]10− (KP6Mo18-3e) have spin alpha while third blue electron has spin beta, in agreement with magnetic data. The four-copper complex of the non-classical KP6Mo18-3e heteropolyanion has been synthesized and structurally characterized; its structure supports the theoretical results such as reactivity and basicity of external oxygen sites.
Co-reporter:Guo-Xing Wu, Hai-Shun Wu and Xian-Ming Zhang
Dalton Transactions 2010 vol. 39(Issue 5) pp:1179-1181
Publication Date(Web):13 Nov 2009
DOI:10.1039/B919966G
An ionothermal reaction has generated a cobalt hydroxyacetate magnet that contains a three-dimensional Co–O–Co framework consisting of vertex-sharing octahedral chains bridged by another octahedra via edge-sharing and shows spin glass behavior.
Co-reporter:Zheng-Ming Hao, Shi-Li Li, Xian-Ming Zhang
Inorganic Chemistry Communications 2010 Volume 13(Issue 9) pp:1100-1102
Publication Date(Web):September 2010
DOI:10.1016/j.inoche.2010.06.036
Hydrothermal treatment of cobalt chloride, 2,2′-biimidazole (H2biim), oxalate acid and NaOH at 160 °C for five days produced a three-dimensional mixed-valence metal-organic framework [CoIII(Hbiim)3]2[CoII3(ox)3]·4H2O (1). Compound 1 exhibits a 3D network with tri-nodal (3-c)2(4-c)3 topology, in which [CoIII(Hbiim)3] building blocks as 3-connected nodes, and CoII ions as 4-connected nodes. The magnetic measurements reveal that compound 1 exhibits a spin canting antiferromagnetic coupling between adjacent CoII ions.Hydrothermal treatment of cobalt chloride, 2,2′-Biimidazole (H2biim), oxalate acid and NaOH produced a three-dimensional mixed-valence metal-organic framework [CoIII(Hbiim)3]2[CoII3(ox)3]·4H2O (1) with tri-nodal (3-c)2(4-c)3 topology. The study on magnetic properties indicates spin-canting anitiferromagnetic coupling between the adjacent CoII sites.
Co-reporter:Xian-Ming Zhang, Tao Jiang, Hai-Shun Wu and Ming-Hua Zeng
Inorganic Chemistry 2009 Volume 48(Issue 10) pp:4536-4541
Publication Date(Web):April 6, 2009
DOI:10.1021/ic9002912
Solvothermal treatment of a mixture of Co(OAc)2, NaN3, NaN(CN)2, HF, MeCN, and H2O generated an AlB2-like metal-organic framework, namely, [{(Co3F)3(trta)2(H2O)9}{Co(Hbta)3}2]·11H2O (1) (H3trta = N,N,N-tris-tetrazol-5-yl-amine; H3bta = N,N-bis-tetrazol-5-yl-amine), in which supertrianglar supramolecular building blocks (SBBs) {(Co3F)3(trta)2} act as 12-connected nodes of hexagonal prisms. The unprecedented ligand N,N,N-tris-tetrazol-5-yl-amine is in situ generated via metal-assisted reactions of NaN(CN)2, MeCN, and NaN3, and a possible mechanism involves both 1,3-dipolar cycloaddition and nucleophilic addition. The F-centered Co3 triangles are bridged by trta groups to result in supertriangular {(Co3F)3(trta)2} SBBs that are further arranged in a frustrated triangular lattice. The long-range ordering temperature is reduced to 4.8 K due to strong spin frustration.
Co-reporter:Cui-Rui Li, Shi-Li Li and Xian-Ming Zhang
Crystal Growth & Design 2009 Volume 9(Issue 4) pp:1702-1707
Publication Date(Web):February 12, 2009
DOI:10.1021/cg800522h
Solvothermal treatment of metal sulfate and oxalic acid in DMF solution generated three isostructural 3D homonchiral (10,3)-a metal oxalates {(Me2NH2)3(SO4)}2[MII2(ox)3] (M = Fe in 1, Co in 2, Ni in 3) in which D3-symmetric supramolecular cation {(Me2NH2)6SO4}4+ formed via electrostatic attractions and 24 N−H···O hydrogen bonds functions as template. The overall structure of 1−3 can be described as interpenetration of coordinate [MII2(ox)3]2− and supramolecular {(Me2NH2)3(SO4)}+ (10,3)-a nets. Thermal analyses reveal that compounds 1−3 show two-stepped decomposition via metal sulfate intermediates. The magnetic behavior of 1 and 2 exhibits antiferromagnetic coupling between M(II) ions, and magnetic ordering is observed in 2.
Co-reporter:Zheng-Ming Hao, Hu-Ping Liu, Huan-Huan Han, Wan-Ting Wang, Xian-Ming Zhang
Inorganic Chemistry Communications 2009 Volume 12(Issue 5) pp:375-377
Publication Date(Web):May 2009
DOI:10.1016/j.inoche.2009.02.020
Solvothermal treatment of silver nitrate, pyridine-4-thione (4-pdtH) and NH4SCN at 140 °C for 3 days produced a three-dimensional metal–organic framework [Ag3(4-pdt)(SCN)2] (1) in which [Ag3S3]n tubes act as secondary building units and pyridine rings and CN groups act as linkers. At ambient temperature, 1 shows a blue emission band assigned as from a ligand-centred n → π∗ or π → π∗ process.Solvothermal treatment of silver nitrate, pyridine-4-thione (4-pdtH) and NH4SCN at 140 °C for 3 days produced a three-dimensional metal–organic framework [Ag3(4-pdt)(SCN)2] (1) in which [Ag3S3]n tubes act as building units and pyridine rings and CN groups act as linkers.
Co-reporter:Xian-Ming Zhang, Cui-Rui Li, Xu-Hui Zhang, Wei-Xiong Zhang and Xiao-Ming Chen
Chemistry of Materials 2008 Volume 20(Issue 6) pp:2298
Publication Date(Web):February 21, 2008
DOI:10.1021/cm7032542
Two cobalt hydroxysulfates Na2Co3(OH)2(SO4)3(H2O)4 (1) and Co3(OH)2(HSO4)2(SO4)(H2O)4 (2) have been prepared and characterized by single-crystal X-ray diffraction, thermal analysis, and magnetic measurements. The structure of 1 consists of helical Co3(OH)2 ferrimagnetic chains that are connected by μ3- and μ4-sulfates into a two-dimensional anionic [Co3(OH)2(SO4)3(H2O)2]2− layer. The adjacent [Co3(OH)2(SO4)2(H2O)2]2−layers in 1 are further linked by Na+ ions into a three-dimensional framework. The related compound 2 also consists of helical Co3(OH)2 ferrimagnetic chains but has a two-dimensional layered structure due to the absence of Na+ ions and partial replacement of sulfates by hydrosulfates. Preliminary magnetic measurements show that 1 and 2 have similar behavior. A detailed magnetic study of 1 reveals a stepped hysteresis loop at 2 K with a coercive field of 1800 Oe and remnant magnetization of 2.8 Nβ attributed to the different anisotropy axes of Co(II) spins in the helical Co3(OH)2 chain. Field-cooled (FC) and zero-field-cooled (ZFC) magnetization measurements show that 1 has a blocking temperature ca 28 K. The study of frequency dependence of real χm′ component of ac susceptibility by the equation φ = ΔTf/[TfΔ(log ω] exhibits that 1 is close to a spin glass. The fitting of Arrhenius law reveals that τ0 seems a little longer but the U/kB is normal for a typical single-chain magnet following Glauber dynamics. The −zν value of 3.3 obtained by the conventional critical scaling law of the spin dynamics τ = τ0 (Tp − Tf/Tf)−zν is out of the range for various spin glasses. The plot of dlog(T)/dlog(χT)ferro versus T eliminates the phase transition to long-range ordering and suggests that 1 is a real one-dimensional system. The unusual slow magnetic relaxation behavior of 1 is tentatively ascribed to be a ferrimagnetic chain with spin-glass-like dynamic relaxation, possibly arising from the movement of the domain walls.
Co-reporter:Xian-Ming Zhang ; Ying-Lian Qing ;Hai-Shun Wu
Inorganic Chemistry 2008 Volume 47(Issue 7) pp:2255-2257
Publication Date(Web):February 26, 2008
DOI:10.1021/ic702394w
Hydrothermal reactions generated two cuprous cyanide polymorphs with similar hexagonal [Cu2(CN)3]− layers but different supramolecular arrays.
Co-reporter:Zheng-Ming Hao ; Rui-Qin Fang ; Hai-Shun Wu
Inorganic Chemistry 2008 Volume 47(Issue 18) pp:8197-8203
Publication Date(Web):August 9, 2008
DOI:10.1021/ic800709w
Hydrothermal reaction of Cu(MeCO2)2, (4-pyridylthio)acetic acid and NH4SCN resulted in a twelve-connected face-centered cubic topological metal-organic framework [Cu3(pdt)2(CN)] (pdt = pyridinethiolate) in which Cu6S4 clusters act as twelve-connected nodes and pyridine rings and cyanides act as connectors. As an extension, an unprecedented fourteen-connected body-centered cubic coordination polymer [Cu19I4(pdt)12(SH)3] has been synthesized by three methods, in which nanosized chiral Cu19I4S12 clusters act as fourteen-connected nodes and triple pyridine rings and hydrosulfides act as connectors. The in situ S−C(sp3), S−C(sp2), and S−C(sp) cleavage reactions have been observed in the work.
Co-reporter:Xian-Ming Zhang ; Xu-Hui Zhang ; Hai-Shun Wu ; Ming-Liang Tong ;Seik Weng Ng
Inorganic Chemistry 2008 Volume 47(Issue 17) pp:7462-7464
Publication Date(Web):August 5, 2008
DOI:10.1021/ic8012014
A hybrid material constructed of 3/19 site-modified Brucite-like cobalt hydroxide and cobalt-oxalate, two types of new layered structural motifs, has been synthesized that shows rare 3D Co−O−Co connectivity and ferrimagnetic ordering.
Co-reporter:Zheng-Ming Hao and Xian-Ming Zhang
Crystal Growth & Design 2008 Volume 8(Issue 7) pp:2359-2363
Publication Date(Web):June 7, 2008
DOI:10.1021/cg701208g
Three phosphorescent acentric cuprous halide coordination polymers, namely, [Cu2(pyt)Cl] (1), [Cu2(pyt)Br] (2), and [Cu5(pytH)3Cl5] (3) have been synthesized through the treatment of copper halides with achiral ligand pyridine-4-thiol (pyHt) by the hydro(solvo)thermal method. Complexes 1 and 2 are isostructural and exhibit three-dimensional (3-D) pillar-layered structures constructed by [Cu2SCl]∞/[Cu2SBr]∞ layers and pyridine pillars. The [Cu2SCl]∞ layer can be viewed as a fusion of zigzag [CuS]∞ and [CuCl]∞ chains. Alternately, the [Cu2SCl]∞ layers can be viewed as a fusion of six-membered Cu3S2Cl and Cu3Cl2S rings. Complex 3 shows a [Cu5S3Cl]∞ chain decorated by terminal chlorides and pyridine rings, in which the six Cu(I) atoms are linked by three μ3-S atoms and one μ3-Cl into a Cu6S3Cl cage, and a fusion of Cu6S3Cl cages via sharing Cu sites results in a one-dimensional [Cu5S3Cl]∞ chain. At ambient temperature, 1, 2, and 3 show a strong yellow or red emission assigned from ligand-to-metal charge transfer (LMCT) and/or metal-to-ligand charge-transfer (MLCT) character and a weak higher energy blue emission band assigned from halide to pyridine π* charge transfer. Their noncentrosymmetric structures are confirmed by measurement of second harmonic generation efficiency.
Co-reporter:Tao Jiang and Xian-Ming Zhang
Crystal Growth & Design 2008 Volume 8(Issue 8) pp:3077
Publication Date(Web):June 26, 2008
DOI:10.1021/cg800248b
Hydrothermal in situ [2 + 3] cycloaddition reaction of dicyanamide and azide in the presence of Zn(II) ions at 120, 150, and 180 °C generated [Zn4O(Hbta)3(H2O)6] 1, [Zn7(OH)2(Hbta)6(H2O)6] 2, and [Zn5(OH)4(bta)2]·2H2O 3 (H3bta = N,N-bis-(1(2)H-tetrazol-5-yl)-amine), respectively. 1crystallizes in hexagonal space group P6̅2c and shows a layered structure with 3-connected 63-hcb topology in which Zn3O clusters and unsaturated three-coordinate Zn(II) ions function as 3-connected nodes; 2crystallizes in trigonal space group P3̅c1 and also shows a layered structure with (3,6)-connected (43)2(46)-kgd topology in which Zn3O clusters and six-coordinated Zn(II) sites function as 3-connected nodes as 6-connected nodes, respectively; 3 is a 3D organic−inorganic hybrid open framework constructed by Zn5(OH)4 chains. The triply deprotonated bta3− anion is first observed in 3, and rare three-coordinate Zn(II) ions are revealed in 1. Analysis of relationship between structure and synthesis condition reveals that 1 is a metastable kinetic phase whose structure is closely related to that of 2. Both 1 and 2 are constructed by Zn3O(Hbta)3 units and discrete Zn ions. The coordination mode of doubly deprotonated Hbta in 1 and 2 are also same. This study reveals that a higher reaction temperature is helpful to remove amine-hydrogen of H3bta to form triply deprotonated bta anion. The emergence of triply deprotonated bta species may explain why structure of 3 is significantly different from those of 1 and 2. Compounds 1−3 show strong blue-green emission, assigned as ligand-centered π→π* excitation.
Co-reporter:X.-M. Zhang;Y.-F. Zhao;X.-M. Chen;X.-W. Zhang
Advanced Materials 2007 Volume 19(Issue 19) pp:2843-2846
Publication Date(Web):6 SEP 2007
DOI:10.1002/adma.200602410
A solvothermal reaction of a cupric salt and tetrazole in acetonitrile generates a tetrazolate (tta)- and cyano-bridged homometallic mixed- valence copper(I,II) molecular ferrimagnet, [Cu5(tta)6(CN)2] (see figure), that exhibits a field-induced transition from a 3D antiferromagnetic state to a ferrimagnetic state at 7.9 K.
Co-reporter:Xian-Ming Zhang Dr.;Zheng-Ming Hao;Wei-Xiong Zhang;Xiao-Ming Chen Dr.
Angewandte Chemie 2007 Volume 119(Issue 19) pp:
Publication Date(Web):27 MAR 2007
DOI:10.1002/ange.200604284
Auf Wasserentzug: Bei der Dehydratisierung geht ein poröses organisch-anorganisches 3D-Gerüst (siehe Struktur, Co rosa, O rot, N blau, C grau) aus {Co3(OH)2}-Ketten vom Einzelkettenmagneten in einen Metamagneten über. Abgesehen vom Verlust des solvatisierenden Wassers bleibt das Gerüst dabei weitgehend unverändert.
Co-reporter:Xian-Ming Zhang Dr.;Zheng-Ming Hao;Wei-Xiong Zhang;Xiao-Ming Chen Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 19) pp:
Publication Date(Web):27 MAR 2007
DOI:10.1002/anie.200604284
A change for the meta: On dehydration, a 3D homometallic porous organic–inorganic framework constructed from {Co3(OH)2} chains (see structure, pink Co, red O, blue N, gray C) undergoes a transition from being a single-chain magnet into a metamagnet. Apart from the loss of solvent water molecules, the dehydration leaves the framework structure largely unchanged.
Co-reporter:Xian-Ming Zhang, Yan-Fei Zhao, Hai-Shun Wu, Stuart R. Batten and Seik Weng Ng
Dalton Transactions 2006 (Issue 26) pp:3170-3178
Publication Date(Web):06 Apr 2006
DOI:10.1039/B518052J
Two salts and seven copper(I/II) and silver(I) coordination polymers containing tetrazolyl ligands have been hydro(solvo)thermal synthesized by metal salts, NaN3 and various nitriles generated via [2 + 3] cycloaddition reactions of organonitriles and sodium azide. The study also shows that in some cases the azide can play a dual role in the in situ syntheses of metal tetrazole complexes, namely, starting material for tetrazole ligand and co-ligand in the tetrazole-based coordination complexes. Compounds 1 and 2 are simple salts of ammonium and sodium 5-methyltetrazolate. Compound 3 has a 3-D framework with intersecting channel and unprecedented (49.66) topology constructed from mixed-valent Cu8 clusters. Compounds 4 and 5 are isomorphous, and have 3-D organic–inorganic frameworks constructed by [M2(mtta)]+ (Hmtta = 5-methyltetrazole) ribbon and [M2(N3)]+ (M = Cu, Ag) layer two types of structural motifs, which contains an µ4-1,1,1,3 azide. Compound 6 is a 3-D four-connected chiral complex with (42.84)Cu(42.82.102)tta topology. The structure of 7 consists of 2-D three-connected layers that are linked by ligand-unsupported Ag(I)⋯Ag(I) interactions to form a 3-D supramolecular array. Compound 8 shows a 3-D chiral framework containing tetrahedrally and linearly coordinated Ag(I) ions and µ3- and µ4-two types of 5-propyltetrazolate. Compound 9 has a 2-D layered structure formed by linkage of [Ag(tetrazolyl)] ribbons via C–C and N–Ag bonds. Magnetic measurement confirmed that there are two Cu(II) ions and six Cu(I) ions per Cu8 unit consistent with a mixed-valent Cu(I,II) complex.
Co-reporter:Juan-Juan Hou, Cai-Hong Guo, Xian-Ming Zhang
Inorganica Chimica Acta 2006 Volume 359(Issue 12) pp:3991-3995
Publication Date(Web):1 September 2006
DOI:10.1016/j.ica.2006.04.034
Hydrothermal reaction of CuBr2, 4,4′-bipyridine and ethanol/methanol generated two copper (I) bromide complexes with in situ alkylated 4,4′-bipyridium, namely [C14H18N2][Cu5Br7] (1) and [C12H14N2][Cu4Br6] (2). The structure of 1 consists of Cu5Br72- chains and N,N ′-diethyl-4,4′-bipyridinium. The underlying structural motif in Cu5Br72- of 1 is the Cu5Br capped square pyramid, which is different from the Cu5Br2 pentagonal bipyramidal structural motif in various documented Cu5Br72- anions. The Cu5Br72- in 1 contains untypical μ5-bromide, with which five copper atoms forms a capped square pyramid rather than a pentagonal pyramid as predicted by Subramanian and Hoffmann. Compound 2 is isostructural with [C12H14N2][Cu4Cl6] reported by Willett, and consists of Cu4Br62- chains and N,N ′-dimethyl-4,4′-bipyridinium. The Cu4Br62- chain is composed of alternating Cu6Br6 and Cu2Br6 units.Hydrothermal reaction of CuBr2, 4,4′-bipyridine and ethanol/methanol generated two copper(I) halide complexes with in situ synthesized alkylated bipyridine-like cations.
Co-reporter:Rui-Qin Fang, Yan-Fei Zhao, Xian-Ming Zhang
Inorganica Chimica Acta 2006 Volume 359(Issue 7) pp:2023-2028
Publication Date(Web):25 April 2006
DOI:10.1016/j.ica.2006.01.003
Hydrothermal reaction of molybdenum oxide and copper(II) source in the presence of 4,4′-bipyridine (4,4′-bpy) afforded three-dimensional covalent framework [CuII(4,4′-bpy)(MoO4)] (1), while reaction with 1,4-diazoniabicyclo[2,2,2]octane (DABCO) in place of 4,4′-bpy and addition of metal molybdenum resulted in one-dimensional chain-like compound [Cu2I(HDABCO)2(Mo8(OH)2O25)]·4H2O(2). The copper in 1 is divalent and approximately shows trigonal bipyramidal geometry, while in 2 is monovalent and approximately shows T-shaped geometry. The structure of 1 has a three-dimensional pillar-layered framework constructed from bimetallic {CuMoO4} layers bridged by bifunctional ligand 4,4′-bpy. Interestingly, the {CuMoO4} layer in 1 consists of 16-membered {Cu4Mo4O8} rings and 8-membered {Cu2Mo2O4} rings, different from other reported {CuMoO4} layers. The structure of 2 consists a one-dimensional {H2Mo8O27}n4n- chain that is attached by peripheral {Cu(HDABCO)}2+ units. The {H2Mo8O27}n4n-chain is constructed from octamolybdates through common corners.Hydrothermal reaction of molybdenum source, copper(II) source and organic amines generated three-dimensional covalent framework [CuII(MoO4)(4,4′-bpy)] (1) and one-dimensional chain-like compound [Cu2I(HDABCO)2(H2Mo8O27)]·4H2O(2).
Co-reporter:Guo-Xing Wu, Hai-Shun Wu and Xian-Ming Zhang
Dalton Transactions 2010 - vol. 39(Issue 5) pp:NaN1181-1181
Publication Date(Web):2009/11/13
DOI:10.1039/B919966G
An ionothermal reaction has generated a cobalt hydroxyacetate magnet that contains a three-dimensional Co–O–Co framework consisting of vertex-sharing octahedral chains bridged by another octahedra via edge-sharing and shows spin glass behavior.
Co-reporter:Ru-Xin Yao, Xiao-Hui Qiao, Xin Cui, Xiao-Xia Jia and Xian-Ming Zhang
Inorganic Chemistry Frontiers 2016 - vol. 3(Issue 1) pp:NaN85-85
Publication Date(Web):2015/11/04
DOI:10.1039/C5QI00159E
Two hydrophobic 3D cobalt-cluster based magnetic MOFs, [Co3(pimdc)2(H2O)6]·5H2O (1) and Co2(Hpimdc)2 (2) (H3pimdc = 2-propyl-imidazole-4,5-dicarboxylic acid), have been hydrothermally synthesized and magnetically characterized. Both of them exhibit a regular pcu net with hexagonal Co6 and zigzag Co4 clusters as 6-connected nodes, respectively. The magnetic studies indicate that 1 displays predominant antiferromagnetic interactions within the Co3(pimdc) triangle, while 2 shows spin-canting antiferromagnetic behaviour with larger canting angles. Furthermore, after heating under vacuum conditions, activated 1 exhibits an excellent catalytic selectivity in the allylic oxidation reaction of cyclohexene to form an α,β-unsaturated ketone, which indicates that the opened Co(II) sites play a significant role in the heterogeneous catalytic process.
Co-reporter:Jiang Liu, Mei Qu, Rodolphe Clérac and Xian Ming Zhang
Chemical Communications 2015 - vol. 51(Issue 34) pp:NaN7359-7359
Publication Date(Web):2015/03/20
DOI:10.1039/C5CC01199J
An unprecedented two-dimensional honeycomb network based on fused triacontanuclear heterometallic wheels of 3.4 nm, {[Co2(Mn3O)(N3)2(pic)6(NO3)]−}6 (Hpic = picolinic acid), has been assembled. The hexagonal {Co12Mn18} wheel motif is composed of six oxo-centered {Mn3} trinuclear and six {Co2} dinuclear moieties acting as nodes and linkers, respectively. The paramagnetic properties of this compound observed down to 1.8 K result from the competition of Mn⋯Mn, Mn⋯Co and Co⋯Co interactions in combination with spin–orbit coupling and single-ion behavior of the Co(II) centers.
Co-reporter:Ru-Xin Yao, Xin Cui, Jun Wang and Xian-Ming Zhang
Chemical Communications 2015 - vol. 51(Issue 24) pp:NaN5111-5111
Publication Date(Web):2015/02/25
DOI:10.1039/C5CC00003C
A pair of novel enantiomeric 3D magnetic complexes [NaCo3(IA)6](NO3)·H2O (1Δ and 1Λ) have been synthesized using an achiral ligand HIA via spontaneous resolution, which crystallize in the hexagonal crystal system with a chiral P63 space group, and diamagnetic sodium cations are located at the center of D3 symmetric clusters. This kind of spontaneous resolution is uncontrollable and dependent on batches. By utilizing cheap enantiopure mandelic acid as a chiral inducing agent, they are driven to controllable homochiral crystallization of the desired enantiomorph, confirmed by circular dichroism spectra.
Co-reporter:Zheng-Ming Hao and Xian-Ming Zhang
Dalton Transactions 2011 - vol. 40(Issue 10) pp:NaN2098-2098
Publication Date(Web):2011/01/31
DOI:10.1039/C0DT00979B
Single-crystal-to-single-crystal (SCSC) transformations have recently been found in some molecular magnets, which involve rearrangement or dynamic movement of molecular components of the crystals. Various stimuli such as guest removal, guest exchange, ligand exchange as well as redox reactions may induce SCSC transformations. To date, only a few molecular magnets are known to exhibit SCSC transformations, which often show high-dimensional robust structures. This review mainly focuses on magnetic complexes that are robust enough to experience SCSC transformations and show magnetic changes induced by solvents in due course. This contribution is organized according to the means of solvent treatment of molecular magnets, aiming at revealing magneto-structural correlation in such SCSC transformations.
Co-reporter:Fu-Qiang Zhang, Xian-Ming Zhang, Rui-Qin Fang and Hai-Shun Wu
Dalton Transactions 2010 - vol. 39(Issue 35) pp:NaN8260-8260
Publication Date(Web):2010/08/05
DOI:10.1039/C000606H
The non-classical KP6Mo18O73 heteropolyanion has been studied by the density functional theory (DFT) method, and the calculated geometry compares well with the experimental one. In fully oxidized [KP6Mo18O73]7− state, the dxy-orbitals centered at eight “belt” Mo sites in the lower part of the “basket” are the major contributors to the LUMO and LUMO+1, while the LUMO+2 orbital is mostly focused on the two polar parts. In contrast, the HOMOs indicates that the coordination of the KP6Mo18 heteropolyanion to metal ions favorably occurs at the oxygen atoms from four external phosphates and two molybdates of the handle of the “basket”. Compared with Wells–Dawson [P2Mo18O62]6−, the HOMO–LUMO gap in fully oxidized [KP6Mo18O73]7− is much smaller, indicating much easier reduction that is consistent with the cyclic voltammogram. Both frontier orbitals and Mulliken analysis indicate that two of three blue electrons in [KP6Mo18O73]10− (KP6Mo18-3e) have spin alpha while third blue electron has spin beta, in agreement with magnetic data. The four-copper complex of the non-classical KP6Mo18-3e heteropolyanion has been synthesized and structurally characterized; its structure supports the theoretical results such as reactivity and basicity of external oxygen sites.
Co-reporter:Hui Gao and Xian-Ming Zhang
Dalton Transactions 2012 - vol. 41(Issue 5) pp:NaN1567-1567
Publication Date(Web):2011/11/29
DOI:10.1039/C1DT11258A
Three novel bismuth(III) complexes with in situ synthesized dihydroxybenzoquinone (anilic acid) ligands, namely [Bi(H3dhbqdc)(H2dhbqdc)]·2.5dmf (1), [Bi2(mdhbqdc)(ox)2(dmf)4] (2) and [Bi2(mdhbqdc)2(ox)(dmf)4] (3) (H4dhbqdc = 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylic acid; H2mdhbqdc = dimethyl 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylate, ox = oxalate, dmf = dimethyl formamide) were prepared under ambient conditions. 1 features 3-D diamond-like structure with 2-D channels filled by dmf molecules. 2 and 3 are geometrically different but topologically identical. 2 shows a brick-wall layer in which ratio of mdhbqdc to ox is 1:2 while 3 has a herringbone layer in which the ratio of mdhbqdc to ox is 2:1. Bismuth-assisted aerobic in situoxidation of dimethyl 1,4-cyclohexanedione-2,5-dicarboxylate (H2dmchddc) gave H2mdhbqdc, which underwent either ester hydrolysis to give H4dhbqdc or carbon–carbon cleavage to form oxalate. Comparative experiments revealed that both Bi(III) and nitrate are important in the unusual oxidation. Possible reaction pathways for the formation of the dihydroxy benzoquinone (dhbq) ligands from their cyclohexanedione precursor were proposed.
Co-reporter:Shi-Li Li, Fu-Qiang Zhang and Xian-Ming Zhang
Chemical Communications 2015 - vol. 51(Issue 38) pp:NaN8065-8065
Publication Date(Web):2015/04/13
DOI:10.1039/C5CC01154J
An organic-ligand-free cuprous iodide trinuclear cluster with significant temperature-dependent structural distortion has been synthesized and characterized, which shows thermochromic luminescence originating from a single cluster-centered triplet due to the absence of an organic ligand. This compound also shows interesting reversible temperature dependent phase transition from chiral to centrosymmetric space groups.
Co-reporter:Min-Min Liu, Yan-Lin Bi, Qin-Qin Dang and Xian-Ming Zhang
Dalton Transactions 2015 - vol. 44(Issue 46) pp:NaN19799-19799
Publication Date(Web):2015/10/29
DOI:10.1039/C5DT03570H
The reversible crystal transformation between the mononuclear complex [Cu(tzbc)2(H2O)4] (1) and the 4-fold interpenetrated diamondoid MOF [Cu(tzbc)2] (2) was chemically implemented and structurally interpreted. Interestingly, despite 4-fold interpenetration, desolvated 2 with 1D channels and rich N-groups shows exclusive CO2 adsorption of up to 12.5 wt% at room temperature and low pressure, indicating potential application in the separation of industrial and automobile exhaust.
Co-reporter:Ru-Xin Yao, Reshalaiti Hailili, Xin Cui, Li Wang and Xian-Ming Zhang
Dalton Transactions 2015 - vol. 44(Issue 7) pp:NaN3416-3416
Publication Date(Web):2015/01/20
DOI:10.1039/C4DT03657C
A perfectly aligned 63 helical tubular cuprous bromide single crystal has been synthesized and characterized, which can selectively decompose negatively charged dyes of Methyl Orange (MO) and Kermes Red (KR), and the photocatalytic efficiency is higher than that of nanosized (∼25 nm) TiO2 and ZnO. The direction and magnitude of the dipole moments as well as the band structure were calculated to reveal high photocatalytic efficiency. Moreover, luminescence studies indicate that the CuBr tube materials show very strong yellowish green emissions in the solid state and emulsion even at room temperature, and exhibit extremely high detection sensitivity towards nitro-explosives via fluorescence quenching. Detectable luminescence responses were observed at a very low concentration of 20 ppm with a high quenching efficiency of 94.90%. The results suggest that they may be promising multifunctional materials for photo-catalysis, luminescence and sensing of nitro-explosives.
Co-reporter:Jiang Liu, Ying-Lian Qin, Mei Qu, Rodolphe Clérac and Xian-Ming Zhang
Dalton Transactions 2013 - vol. 42(Issue 32) pp:NaN11575-11575
Publication Date(Web):2013/05/30
DOI:10.1039/C3DT51363G
A novel two-dimensional (2D) azido-based CuII network, [Cu11(pic)6(N3)16] (1), was prepared using picolinic acid (Hpic) as coligand. Interestingly, 1 is composed of symmetric double azido EO-bridged [Cu(N3)2]n chains linked by [Cu(pic)2] units making a regular ladder with a missing rung. These rung-defected ladders are assembled in a layered structure by long azido-CuII contacts between neighboring [Cu(N3)2]n chains. The magnetic properties of 1 are dominated by significantly strong antiferromagnetic coupling (J/kB = −15.4(2) K) between CuII spins through the double EO azido-bridges along the [Cu(N3)2]n chains.
Co-reporter:Juan-Juan Hou, Shi-Li Li, Cui-Rui Li and Xian-Ming Zhang
Dalton Transactions 2010 - vol. 39(Issue 10) pp:NaN2707-2707
Publication Date(Web):2010/02/02
DOI:10.1039/B922583H
Five new cuprous halides formulated as [etpy][Cu3I4] 1, [mepy][Cu2Br3] 2, [mepy][Cu2I3] 3 [dmebpp][Cu7Br9] 4 and [dmeDABCO]4[Cu8I16] 5 (etpy = N-ethylpyridyl; mepy = N-methylpyridyl; dmebpp = N,N′-dimethyl-1,3-bis(4-pyridyl)propane; dmeDABCO = N,N′-dimethyl-1,4-diazabicyclo-[2.2.2]octane) have been prepared by solvothermal reactions of a copper source, halides and N-heterocyclic ligands in alcoholic solution. 1 contains an unprecedented trigonal two-dimensional cuprous halide layer Cu3I4− constructed from trimeric Cu3I8 units via sharing peripheral μ3-iodines; isostructural 2 and 3 contain infinite Cu2X3− chains in which the copper atoms are arranged into a ladder; 4 is composed of novel twofold helical cuprous halide chains Cu7Br92− built up by CuBr4 and CuBr3; 5 contains an infinite edge-sharing tetrahedral chain with a periodic sequence of eight CuI4 tetrahedra. In situ alkylation reactions of N-heterocycles with alcohols generated organic cationic templates, which played an important role in the control of the structures of anionic cuprous halides. A possible alkylation mechanism of N-heterocycles in the system has been proposed. The fluorescence properties of 1 and 4 were investigated. Time-dependent density functional theory (TD-DFT) calculations were carried out on the excited electronic states of 1 in order to understand the emission mechanism.
Co-reporter:Qin-Qin Dang, Yu-Fen Zhan, Li-Na Duan and Xian-Ming Zhang
Dalton Transactions 2015 - vol. 44(Issue 46) pp:NaN20031-20031
Publication Date(Web):2015/10/16
DOI:10.1039/C5DT01943E
An expanded pyridyl-decorated MOF-505 analogue[Cu2(L)(H2O)2]·Gx (H4L = 5,5′-(pyridine-2,5-diyl)diisophthalic acid, G = solvent molecule) has been solvothermally synthesized and reported. It exhibited rare hierarchical meso- and microporosity. With exposed unsaturated CuII sites and Lewis basic pyridyl sites, the material shows both large CO2-uptake capacity (123.4 cm3 g−1 at 273 K, 1 bar) and high selectivity for CO2 over N2 (55.7) at 273 K. Furthermore, for the first time the compound has been exploited for its heterogeneous catalytic performance toward the cyanosilylation reaction under solvent-free conditions. The compound can be recycled up to five times with only a minor loss of activity.
Co-reporter:Li-Na Duan, Qin-Qin Dang, Cai-Yun Han and Xian-Ming Zhang
Dalton Transactions 2015 - vol. 44(Issue 4) pp:NaN1804-1804
Publication Date(Web):2014/11/18
DOI:10.1039/C4DT02672A
A new interpenetrated bioactive nonlinear optical metal–organic framework [Zn2(ppa)2(1,3-bdc)(H2O)] has been designed and synthesized, which shows both a high drug content of 63.9% and a good slow release effect in simulated physical conditions compared to other non-interpenetrated bioactive MOFs. It also shows a large powder second-harmonic generation (SHG) efficiency of 5.6 times that of KH2PO4 (particle size: 150–200 μm).
Co-reporter:Ru-Xin Yao, Ying-Lian Qin, Fang Ji, Yan-Fei Zhao and Xian-Ming Zhang
Dalton Transactions 2013 - vol. 42(Issue 18) pp:NaN6618-6618
Publication Date(Web):2013/02/19
DOI:10.1039/C3DT32539C
Three novel tetrazole-based frustrated magnets, namely, Co3(OH)2(3-ptz)2(SO4)(H2O)4 (1), Co2(OH)(tzba)(H2O)4 (2) and [Co(OH)(tta)] (3) (3-ptz = 5-(3-pyridyl) tetrazole, H2tzba = 4-(1H-tetrazol-5-yl) benzoic acid, Htta = 1H-tetrazole) were hydrothermal synthesized and magnetically characterized. Compound 1 is a 2D (4,4) layered structure assembled by sulfate capped triangular [Co3(μ3-OH)(μ3-SO4)] clusters and in situ synthesized μ3-3-ptz ligands. Compound 2 features Co3(μ3-OH) triangle based magnetic Δ-chains linked with in situ generated μ5-tzba ligands to form a 2D layer. Compound 3 is a uninodal eight-connected body-centered-cubic (bcu) 3D network with square Co4O4 clusters as nodes and μ4-tta ligands as linkers. Interestingly, spin frustration was observed in these complexes due to inherent spin competition in triangle, Δ-chain and square. Magnetic studies show that 1 behaves as antiferromagnet, while 2 and 3 exhibits spin canting and long-range magnetic ordering.
Co-reporter:Xin Cui, Mei-Chen Xu, Ling-Juan Zhang, Ru-Xin Yao and Xian-Ming Zhang
Dalton Transactions 2015 - vol. 44(Issue 28) pp:NaN12716-12716
Publication Date(Web):2015/06/18
DOI:10.1039/C5DT01456E
The butterfly-like tetranuclear cobalt cluster based 3D MOF [Me2NH2][Co2(bptc)(μ3-OH)(H2O)2] (1) underwent a reversible thermally triggered single-crystal-to-single-crystal transformation via Co–Owater weakened intermediate 1a to produce a partly dehydrated phase [Me2NH2][Co2(bptc)(μ3-OH)(H2O)] (2), which was confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and IR spectroscopy. During the dehydration course, the local coordination environment of one Co2+ ion was changed from the saturated octahedron to a coordinately unsaturated square-pyramid, accompanied by a crystal color change from red to purple. Compared with pristine hydrated 1, dehydrated 2 exhibits highly efficient and recyclable catalytic activity for cyanosilylation of carbonyl compounds with a low catalyst loading of 0.1 mol% Co at room temperature under solvent-free conditions, which due to the open Co2+ sites as catalytically activated sites played a significant role in the heterogeneous catalytic process.
![Benzoic acid, 3,5-bis[(4-carboxyphenyl)methoxy]-](/data/chemimg/3716200/1431457-73-6.png)
![Benzoic acid, 3,5-bis[(4-carboxyphenyl)methoxy]-](/data/chemimg/3716200/1431457-73-6_b.png)
![Hexanenitrile, 2-[(trimethylsilyl)oxy]-](http://img.cochemist.com/ccimg/107000/106942-21-6.png)
![Hexanenitrile, 2-[(trimethylsilyl)oxy]-](http://img.cochemist.com/ccimg/107000/106942-21-6_b.png)
![(2E)-3-[6-HYDROXY-2-(2-HYDROXY-2-PROPANYL)-2,3-DIHYDRO-1-BENZOFUR<WBR />AN-5-YL]ACRYLIC ACID](http://img.cochemist.com/ccimg/71200/71190-35-7.png)
![(2E)-3-[6-HYDROXY-2-(2-HYDROXY-2-PROPANYL)-2,3-DIHYDRO-1-BENZOFUR<WBR />AN-5-YL]ACRYLIC ACID](http://img.cochemist.com/ccimg/71200/71190-35-7_b.png)
![1-FLUORO-4-[4-(4-FLUOROPHENYL)BUTA-1,3-DIYNYL]BENZENE](http://img.cochemist.com/ccimg/55700/55606-94-5.png)
![1-FLUORO-4-[4-(4-FLUOROPHENYL)BUTA-1,3-DIYNYL]BENZENE](http://img.cochemist.com/ccimg/55700/55606-94-5_b.png)
![1-ETHYL-4-[4-(4-ETHYLPHENYL)BUTA-1,3-DIYNYL]BENZENE](http://img.cochemist.com/ccimg/35700/35672-48-1.png)
![1-ETHYL-4-[4-(4-ETHYLPHENYL)BUTA-1,3-DIYNYL]BENZENE](http://img.cochemist.com/ccimg/35700/35672-48-1_b.png)
![Poly[(8-amino-1,3,4,6,7,9,9b-heptaazaphenalene-2,5-diyl)imino]](http://img.cochemist.com/ccimg/32600/32518-77-7.png)
![Poly[(8-amino-1,3,4,6,7,9,9b-heptaazaphenalene-2,5-diyl)imino]](http://img.cochemist.com/ccimg/32600/32518-77-7_b.png)
![Cyclopentanecarbonitrile, 1-[(trimethylsilyl)oxy]-](http://img.cochemist.com/ccimg/25500/25438-35-1.png)
![Cyclopentanecarbonitrile, 1-[(trimethylsilyl)oxy]-](http://img.cochemist.com/ccimg/25500/25438-35-1_b.png)
![Propanedinitrile,2-[(4-methoxyphenyl)methylene]-](http://img.cochemist.com/ccimg/2900/2826-26-8.png)
![Propanedinitrile,2-[(4-methoxyphenyl)methylene]-](http://img.cochemist.com/ccimg/2900/2826-26-8_b.png)
![2-[(4-methylphenyl)methylidene]propanedinitrile](http://img.cochemist.com/ccimg/2900/2826-25-7.png)
![2-[(4-methylphenyl)methylidene]propanedinitrile](http://img.cochemist.com/ccimg/2900/2826-25-7_b.png)
![Propanedinitrile,2-[(4-chlorophenyl)methylene]-](http://img.cochemist.com/ccimg/1900/1867-38-5.png)
![Propanedinitrile,2-[(4-chlorophenyl)methylene]-](http://img.cochemist.com/ccimg/1900/1867-38-5_b.png)
