Baibin Zhou

Inorganic–organic hybrids constructed from heteropolymolybdate anions and copper–organic fragments: syntheses, structures and properties

A series of inorganic–organic complexes based on polymolybdate anions and copper–organic subunits, [Cu(H2O)(bim)2]{[Cu(Hbim)2][P2Mo5O23]}·2H2O (1), [Cu(Hbim)2]{[Cu(bim)(H2O)2]2[Cu(bim)2]2[(P2Mo5O23)2]}·20H2O (2), [Cu(phen)(H2O)][Cu(bim)2]2[P2Mo5O23]·H2O (3) and Mg[Cu(bim)(H2O)]2[P2Mo5O23]·4H2O (4) (bim = 2,2′-biimidazole, phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions and their crystal structures have been determined by single-crystal X-ray diffraction analysis. All of these compounds contain the [P2Mo5O23]6− polyoxoanions as building units. The structure determination shows that the polyoxoanion of compound 1 is mono-supported by one copper complex subunit. In compound 2, the [P2Mo5O23]6−cluster is supported by two distinct [Cu(bim)(H2O)2]2+ and [Cu(bim)2]2+ fragments. Compound 3 presents a tri-supported polyoxometalate cluster structure, where each [P2Mo5O23]6− anion is decorated by two [Cu(bim)2]2+ and one [Cu(phen)(H2O)]2+ cations. In compound 4, the [P2Mo5O23]6− anion is supported by four symmetry [Cu(bim)(H2O)]2+ units. The cyclic voltammetry results for 1–4 indicate the known fingerprint of the [P2Mo5O23]6− anion. Although compounds 1–4 contain similar polyoxometalate anions, the mean peak potentials are slightly different, due to their different chemical environments. The magnetic behaviours of 1–4 were also investigated, in the temperature range of 2–300 K.

New extended poly(oxomolybdophosphates) based on strontium(II) linkers

Four new poly(oxomolybdophosphates), Na[FeIII(2,2′-bpy)3]2[FeII2Sr2MoV12O24(OH)6(H2O)8(H2PO4)2(HPO4)2(PO4)4]·[PO4]·9H2O 1, [H2(bpp)]2[MnII2Sr2Mo12O24(OH)6(H2O)8(H2PO4)2(HPO4)2(PO4)4]·8H2O 2, [H2(4,4′-bpy)]2[CdII2Sr2Mo12O24(OH)6(H2O)6(H2PO4)2(HPO4)2(PO4)4]·5H2O 3 and [H2(4,4′-bpy)][MnII2Sr4Mo12O24(OH)6(H2O)12(HPO4)4(PO4)4]·8H2O 4 (2,2′-bpy = 2,2′-bipyridine, bpp = 1,3-bi(4-pyridyl)-propane, 4,4′-bpy = 4,4′-bipyridine), have been hydrothermally synthesized and structurally characterized by elemental analysis, TG, IR, UV-vis and single-crystal X-ray diffraction. All the compounds are based on the [P4Mo6O31]12− (abbreviated as [P4Mo6]) polyoxometalate units, which are further connected into sandwich-type dimeric units by various transition metal (TM) ions. In compounds 1–3, the dimeric {(TM)[P4Mo6]2} units are linked by new {Sr2TM} trinuclear fragments into one-dimensional (1-D) chains. These 1-D chains are further packed into various three-dimensional (3-D) supramolecular assemblies due to the use of different bipyridine-based structure-directing agents. In compound 4, the dimeric {(TM)[P4Mo6]2} units are linkered by an unprecedented {Sr4Mn} pentanuclear unit into new 3-D open framework, exhibiting a 64.82-nbo (niobium-oxide-like) topology. The electrochemical properties of these compounds were investigated.

Synthesis, crystal structure, and properties of three supramolecular compounds based on Keggin-type phosphomolybdate and different flexible ligands

Abstract Three supramolecular compounds based on Keggin phosphomolybdate and different flexible ligands, Cu3(bei)6(PMo12O40)2·6H2O (1), (H2bbi)(Hbbi)(PMo12O40)·2H2O (2), and (H2bpp)3(PMo12O40)2·6H2O (3) (bei = 1,1’-(1,2-ethanediyl)bis(imidazole), bbi = 1,1’-(1,4-butanediyl)bis(imidazole), bpp = 1,3-bi(4-pyridyl)propane)), have been hydrothermally prepared and characterized by elemental analysis, IR, TG, XRD, and single-crystal X-ray diffraction. Crystal data analysis reveals that 1–3 are composed of discrete [Cu(bei)2]2+ complex cations, protonated bbi and bpp cations, respectively, with [PMo12O40]3-. All three compounds exhibit interesting supramolecular frameworks via electrostatic interactions and hydrogen bonds. Their electrochemistry, electrocatalytic behavior, and solid state fluorescence at room temperature have been investigated.

Synthesis, crystal structure, and properties of a new 1-D “heteropoly blue”-modified nickel complex

A new reduced molybdenum phosphate, [Ni(bpy)2(H2O)2]{[Ni(H2O)2][Ni0.5(MoO2)6(OH)3(PO4)(HPO4)3[Ni(bpy)2(H2O)]2][Ni0.5(MoO2)6(OH)3(PO4)(H2PO4)2(HPO4)]} · 14H2O (1) (2,2′-bpy = 2,2-bipyridine), has been hydrothermally synthesized and characterized by elemental analysis, IR, UV-Vis, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P-1, with lattice parameters a = 17.0459(9) Å, b = 19.2643(11) Å, c = 19.9357(11) Å, β = 79.9500(10)°, V = 5804.9(6) Å, Z = 2, and R 1(wR 2) = 0.0460(0.1228). Structural analysis indicates that neighboring Ni[P4Mo6]2 and nickel-complex polyanions are interconnected by [Ni(H2O)2] subunits via P–O–Ni(2) bridges, generating a 1-D infinite chain “heteropoly blue” structure. Furthermore, 1 shows photoluminescence in the solid state at room temperature. Compound 1 was used as a solid bulk modifier to fabricate a carbon paste electrode (1-CPE) by direct mixing. The electrochemical and electrocatalytic behaviors of 1-CPE have been studied.

A 2-D organic–inorganic supramolecular layer based on a {P2Mo5} cluster bridged by Mn(II) and pentanuclear fragment linker

An organic–inorganic hybrid based on {P2Mo5} clusters, (H2bim)3[{Na0.5(H2O)0.5}2{Mn(OH)4(H2O)2}{Na0.5(H2bim)}2{Mn(H2O)4(P2Mo5O23)2}]·4H2O (1) (bim = 2,2′-biimidazole), was hydrothermally synthesized and characterized by elemental analyses, IR, TG, UV, and single crystal X-ray diffraction analyses. In 1, four Na ions, one Mn, and two bim ligands are linked by four μ–O bridges to form unusual pentanuclear fragments [{Na0.5(H2O)0.5}2{Mn(OH)4(H2O)2}{Na0.5(H2bim)}2]. Each pentanuclear segment links adjacent to four Standberg units to form supramolecular dimer chains, which are further connected by Mn(H2O)4 linkers to yield infinite 2-D layer. Two kinds of cage-like pores are observed in alternating type along the crystallographic b axis in which protonated H2bim ligands fill one sort of pores. Electrochemical and fluorescent properties of 1 have been investigated. Graphical Abstract Mn2+ and unusual pentanuclear fragments {[Na0.5(H2O)0.5]2Mn(OH)4(H2O)2[Na0.5(H2bim)]2} are introduced into {P2Mo5} system to yield an infinite 2-D supramolecular layer with two cage-like pores. Compound 1 displays good electrocatalytic activity on reduction of hydrogen peroxide, and fluorescent properties in the solid state at room temperature.