Hai-Yang Guo

Secondary organic moiety templated organic–inorganic polyoxometalate-based frameworks

Four new organic–inorganic hybrid compounds, namely, [Cu3(4,4′-bpy)3][HSiW12O40]·(C3H4N2) (1), [Cu3(4,4′-bpy)3][PMo12O40]·(C5H6N2)·0.5H2O (2), [Cu2(4,4′-bpy)2][HPMo12O40]·(C5H6N2) (3) and [Cu(Phen)(4,4′-bpy)(H2O)]2[PW12O40]·(4,4′-bpy) (4) (C3H4N2 = imidazole, C5H6N2 = 2-aminopyridine, bpy = bipyridine, Phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-vis, powder XRD, cyclic voltammetry analysis, photoluminescence analysis, elemental analyses and single crystal X-ray diffraction. The four compounds represent new examples of secondary organic moiety templated frameworks constructed from Keggin polyanions, metal ions and organic ligands. Compounds 1 and 2 present 3-D framework structures; compound 3 exhibits a 1-D ladder-like structure and compound 4 shows a 2-D layered framework structure. It is noted that the packing structures of compounds 1 and 2 are almost identical; however, the crystal space groups and cell parameters of the two are thoroughly different. Such a phenomenon has also been observed between compound 3 and a compound recently reported by us. Compound 4 is the first framework structure constructed from polyoxometalates, metal ions and mixed organic ligands. In addition, all the four frameworks are combined with dissociated organic moieties as templates.

Vanadoantimonates: from discrete clusters to high dimensional aggregates

Five new vanadoantimonates [Cd(en)3]3[Sb6V15O42(H2O)]·8H2O (1), [Ni(en)3]2[H2Sb6V15O42(H2O)]·5H2O (2), [Co(en)3]2[H2Sb6V15O42(H2O)]·5H2O (3), [H4Sb8V14O42(H2O)]·5H2O (4) and [Co(enMe)3]2[Sb8V14O42(H2O)]·4H2O (5) (en = ethylenediamine, enMe = 1,2-propanediamine) have been obtained under hydrothermal conditions and characterized by IR, UV-Vis, XRD, ESR and CD spectroscopy. Compound 1 is a chiral compound constructed from [Sb6V15O42(H2O)]6− (Sb6V15) and [Cd(en)3]2+. Compounds 2 and 3 are isostructural and isomorphous. Both compounds are chiral, each of which contains a 2-D inorganic layer formed by [H2Sb6V15O42(H2O)]4−via V–O⋯Sb contacts. Compound 4 contains a 2-D inorganic layer formed by [H4Sb8V14O42(H2O)], of which [H4Sb8V14O42(H2O)] is directed by both V–O⋯Sb and Sb–O⋯Sb interactions. Compound 5 contains a 1-D zigzag chain structure formed by [Sb8V14O42(H2O)]4− (Sb8V14) via Sb–O⋯Sb contacts.

The synthesis and characterization of three organic–inorganic hybrids based on different transition metal complexes and {As8V14O42(H2O)} clusters

Three new arsenic–vanadium compounds, [As8V14O42(H2O)][Cu(2,2′-bpy)2]4 (1) [As8V14O42(H2O)][Cu(1,10-Phen)2]4 (2) and [As8V14O42(H2O)][Ni(Biim)3]2·6H2O (3) (2,2′-bpy = 2,2′-bipyridine, 1,10-Phen = 1,10-phenanthroline and Biim = 2,2′-biimidazole), have been prepared hydrothermally and characterized by IR, UV-Vis, XRD, XPS, and single-crystal X-ray diffraction analyses. X-ray crystallographic studies showed that compounds 1–3 are all based on the cluster anion [As8V14O42(H2O)]4−. However, the crystal structures of the three are thoroughly different. It is obvious that the transition metal complex building blocks are the vital factor for the packing structures of the three. We carefully discussed the influence of transition metal complex building blocks on the crystal structures. Also we analyzed the catalytic properties of the compounds and discussed the influence of the crystal structures of transition metal complexes on the catalytic properties.

Preparation, structure and characterization of a series of vanadates

A series of compounds based on vanadate, [Zn(1,10-phen)3][Zn(dap)2]0.5[Zn(dap)2(H2O)]2[VV6VIV10O38Cl]·2H2O (1), [Ni(im)6]3[VV7VIV8O36Cl]·17H2O (2), [Zn(2,2′-bpy)3]2[H2VV10O28]·6H2O (3), [Fe(Phen)3]3[V16O39Cl]·8.5H2O (4), [Zn(2,2′-bpy)]3[V15O36Cl] (5), [Co(2,2′-bpy)]3[V15O36Cl] (6), [Ni(en)2]3[V18O42Cl]·18H2O (7), [Cd(2,2′-bpy)2]2[V4O12]·0.5H2O (8), [Ni(2,2′-bpy)3]2[V4O12]·11H2O (9), [Zn(2,2′-bpy)3][V4O12]·11H2O (10) and [Ni(phen)3]2[V4O12]·12H2O (11) (1,10-phen = 1,10-phenanthroline, dap = 1,2-propanediamine, 2,2′-bpy = 2,2′-bipyridine, im = imidazole), has been synthesized under hydrothermal conditions and characterized using IR, UV-vis, XRD, ESR, elemental analysis and crystal structure analysis. Out of the eleven compounds, 1–3 and 11 are novel. Compound 1 is based on [V16O38Cl]7− anions and [Zn(dap)2]2+ and [Zn(dap)2(H2O)]2+ cations, forming a novel dimer of cluster supported coordination complexes. Compound 2 has a supramolecular structure based on [V15O36Cl]6− anions (V15) and [Ni(im)6]2+ cations. Compound 3 also has a supramolecular structure, which is constructed from [H2V10O28]4− and [Zn(2,2′-bpy)3]2+ cations. Compound 11 is formed by [V4O12]4− clusters and [Ni(phen)3]2+ cations. Compounds 4–10 are also based on vanadate and are not new compounds. Here, we investigate the catalytic properties of these eleven compounds, and the photocatalytic properties of some of these compounds.

pH-controlled assembly of two new supramolecular hybrid compounds based on Keggin polyoxotungstates

Two supramolecular compounds based on Keggin polyoxotungstates, (4,4′-H2bpy){[Cu(4,4′-bpy)]2[SiW12O40]} (1) and (4,4′-H2bpy)2[SiW12O40]·2H2O (2) have been synthesized and characterized by elemental analyses, IR, UV, XPS spectra, TG analyses, and single crystal X-ray diffraction analyses. Compound 1 exhibits an infinite 1-D ladder like structure, which is further interconnected into a 3-D supramolecular framework via hydrogen bonding interactions. Compound 2 contains 4,4′-bipyridine (4,4′-bpy), pseudo-Keggin polyoxoanions [SiW12O40]4−, and water molecules. Polyoxoanions together with water molecules in 2 construct a 3-D inorganic supramolecular network through O···O and O···Ow(1) interactions. The electrochemical behaviors and photocatalytic properties of 1 and 2 have been investigated.

Two new halide-containing polyoxometalate-based compounds

Two new compounds, [CuCl(Phen)(H2O)][PW12O40][4,4′-H2bpy]·1.5H2O (1) and [Cd2(Phen)4Cl2][HPMo12O40](4,4′-bpy) (2) (bpy = bipyridine, Phen = phenanthroline), have been hydrothermally prepared and characterized by IR, UV–vis, XPS, XRD, elemental analysis, cyclic voltammetry analysis, and single-crystal X-ray diffraction analysis. Compound 1 exhibits a 1-D chain structure constructed from polyoxometalates (POMs) and transition metal complexes, whereas 2 presents a supramolecular structure constructed from POMs, metal halide clusters, and organic ligands. Graphical Abstract

Polyoxometalate tri-supported transition metal complexes containing mixed-valent transition metal ions

Three compounds, [AsMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·4H2O (1), [PMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·3H2O (2) and [PMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·3.5H2O (3), have been synthesized under hydrothermal conditions and characterized by IR, UV–vis, XRD, TG, elemental analysis, and X-ray diffraction analysis. Single-crystal X-ray structure analysis reveals that 1 and 2 are isostructural and isomorphous, whereas 2 and 3 are polymorphs. Polymorphs of 1 have not been synthesized yet. The mixed-valent transition metal ion in 1–3 has been further confirmed by TG analyses. Catalytic properties of 1 and 2 have also been studied.

Two novel structures based on an organic ligand with two different coordination modes

Two novel organic–inorganic hybrid compounds, namely [Ag6(bzmd)2][SiW12O40] ·H2O (1) and [Ag2(Hbzmd)2][HPW12O40] (2) (Hbzmd = 1-(p-(tetrazol-5-yl)benzyl)-2-(pyrid-2-yl)benzimidazole), have been synthesized and characterized by IR, UV, powder XRD, EDS, TG, cyclic voltammetry analysis, photoluminescent analysis, elemental analyses and single crystal X-ray diffraction. The two compounds represent two novel 3-D structures constructed from Keggin polyanions, metals and organic ligands. It should be noted that compound 1 is based on polyoxometalates, silver and bzmd− ligands, whereas, compound 2 is based on polyoxometalates, silver and Hbzmd ligands. The bzmd− ligand in compound 1 and the Hbzmd ligand in 2 exhibit distinctly different coordination modes. Silver and bzmd− ligands form a 3-D framework via Ag–N and Ag–π interactions in compound 1. Compound 1 also contains a pure inorganic 3-D framework, and then the two kinds of frameworks in compound 1 are fused into an unprecedented 3-D structure. Silver and Hbzmd ligands form a 2-D framework via only Ag–N interactions in compound 2, moreover, polyoxometalates in compound 2 are linked by silver into a novel pure inorganic 2-D framework, and then two kinds of frameworks are further fused into a novel 3-D structure. In conclusion, two different 3-D frameworks and two different 2-D frameworks are respectively fused into two novel 3-D structures constructed from polyoxometalates, metals and organic ligands (POMMOFs).