Ya-Li Ning

Influence of N-donor sites in 5-(x-pyridyl)-1H-tetrazole ligands (x = 2, 4) on assembly of polyoxometalate-based compounds modified by multinuclear metal clusters and infinite chains

Through tuning the N-donor site of the pyridyl group in 5-(x-pyridyl)-1H-tetrazole ligands (x = 2, 4), four new Keggin-based compounds, [Cu7(2-ptz)8(OH)2(H2O)2(HPMoVI10MoV2O40)]·4H2O (1), [Cu5(2-ptz)6(HPMoVI10MoV2O40)(H2O)4]·4H2O (2), [Ag6(4-ptz)4(H2SiMo12O40)] (3) and [Ag5(4-ptz)4(H2PMo12O40)]·5H2O (4) (2-ptzH = 5-(2-pyridyl)-1H-tetrazole, 4-ptzH = 5-(4-pyridyl)-1H-tetrazole), were successfully synthesized under hydrothermal conditions and structurally characterized. Compound 1 possesses two kinds of CuII subunits: penta-nuclear clusters and mono-nuclear subunits, which connect with each other to form a one dimensional (1D) stair-like metal–organic chain. The adjacent 1D stair-like chains are further linked by tetradentate Keggin anions to construct a 2D layer. In compound 2, the tetra-nuclear CuII clusters and mono-nuclear CuII subunits construct a 2D metal–organic layer, which is further linked by bidentate Keggin anions to build a 3D framework. In compound 3, the 4-ptz ligand links AgI ions with tetrazole groups to form 1D infinite Ag–ptz chains, which are extended by the pyridyl group of 4-ptz and the tetrazole groups of other 4-ptz molecules to construct a 2D layer. The adjacent 2D layers are further linked by 6-connected Keggin anions to build a 3D framework. In compound 4, the 4-ptz ligands are linked by AgI ions to form 1D infinite Ag–ptz belts. The Keggin anions are linked by AgI ions to construct another infinite inorganic chain, in which each Keggin anion provides six oxygen atoms to coordinate with the AgI ions from adjacent Ag–ptz belts to construct a 2D layer. The roles of the ptz ligands with different N-donor sites in the construction of multinuclear clusters and 1D chains are discussed. The electrochemical and photocatalytic properties of the title compounds were investigated as well.

Subtly tuning one N site of benzyl-1H-triazole ligands to build mono-nuclear subunits and tri-nuclear clusters to modify polyoxometalates

By using two kinds of organic ligands (1-benzyl-1H-(1,2,4)triazole (2-btz) and 1-benzyl-1H-(1,3,4)triazole (3-btz)), six polyoxometalate (POM)-based compounds were hydrothermally synthesized and structurally characterized, [Ag4(2-btz)4(HPMo2VMo10VIO40)] (1), [Ag4(2-btz)4(SiW12O40)] (2), [Ag4(2-btz)5K(SiWVW11VIO40)]·13H2O (3), [Cu4(2-btz)16(Mo8O26)2] (4), [Cu3(3-btz)8(H2O)4](PMo12O40)2·4H2O (5) and [Cu7(3-btz)16(OH)2(H2O)4(P2W18O62)2]·16H2O (6). Compounds 1 and 2 are isostructural with two sets of Ag–(2-btz) chains linked by Keggin anions to construct a “ladder”. Adjacent “ladders” are further connected by Ag1–O13 bonds to build a 3D framework. In compound 3, the anion dimers are linked by Ag5–O9 bonds to form a 1D chain. The chains are fused by Ag3 and K ions and a 3D framework of 3 is built. In compound 4, the Mo8 anions are linked by [Cu(2-btz)4]2+ subunits to construct a 3D structure. By changing 2-btz to 3-btz, we obtained a linear tri-nuclear cluster [Cu3(3-btz)8(H2O)4]6+ in compound 5. The discrete PMo12 anions combine with tri-nuclear clusters through hydrogen bonding interactions to construct a 2D supramolecular layer. Compound 6 contains a cycle tri-nuclear cluster-supporting anion [Cu3(3-btz)6(OH)(H2O)2(P2W18O62)]−, which is further connected by one [Cu(3-btz)4]2+ subunit to construct a discrete anion dimer. The title compounds show good electrocatalytic activities for reducing nitrite, hydrogen peroxide and bromate. These compounds also exhibit excellent photocatalytic activities for the degradation of methylene blue (MB, 1–6 as catalysts) and Rhodamine B (RhB, 5 and 6 as catalysts). Additionally, the magnetic properties of compounds 5 and 6 have been investigated.

Subtle difference of [SiMo12O40]4− and [PMo12O40]3− inducing two new distinct Keggin-Ag-(1H-Pyrazole) compounds

Abstract Two new inorganic-organic hybrid compounds based on α-Keggin clusters and Ag-(1H-Pyrazole) subunits, [AgL2]4[SiMo12O40] (1) and [AgL2]3[PMo12O40] (2) (L = pyrazole), have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. In 1, there are two kinds of chains, the chains linked by two [AgL2]+ clusters and the other linked only by one [AgL2]+, which further connect by sharing [SiMo12O40]4− anions to construct a 2-D layer. In 2, four-supporting [PMo12O40]3− anions are fused by [Ag(1)L2]+ subunits to form a 1-D chain. Through weak interactions of Ag⋯O (3.091 Å) a 2-D supramolecular layer is constructed. Additionally, the electrochemical properties of title compounds and the photocatalytic properties of 2 have been studied.

A series of polyoxometalate-based compounds including infinite Ag belts and circles constructed by two tolyl-1H-tetrazole isomers

In this paper, three new polyoxometalate (POM)-based metal–organic compounds containing silver cycles/belts, namely, [K2Ag15(L1)10(H2O)2][H(PMo11VIMoVO40)2] (1), [Ag7(L1)4][PW12O40]·2H2O (2) and [Ag10(L2)8(H2O)][PW12O40] (3) (L1 = 5-o-tolyl-1H-tetrazole, L2 = 5-m-tolyl-1H-tetrazole), have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectra and powder X-ray diffraction (PXRD). The organic molecules L1 and L2 are isomeric. In compound 1, there exist two dimensional (2D) Ag-L1 layers including Ag belts, which are further linked by Ag5 to form a 3D metal–organic framework (MOF). The inorganic chain in 1 with Keggin anions linked by Ag1 ions insert into the channels of this 3D MOF. In compound 2, the Ag-L1 belts are connected by Keggin anions to construct a 2D layer. Adjacent layers link with each other through Ag–O bonds and the 3D framework of 2 is thus built. In compound 3, the 2D Ag-L2 layer possesses Ag cycles. Adjacent layers are linked by Ag–N bonds and Keggin anions to form the 3D structure of 3. The influence of the types of POM anions and organic ligands on the final structures was discussed. Furthermore, the electrochemical, photocatalytic and fluorescent properties of compounds 1–3 were investigated.

A New Wells-Dawson-based Organic-Inorganic Honeycomb Hybrid Compound with Cadmium Bis(2,2´-biimidazole) Spacers

A new Wells-Dawson-based organic-inorganic honeycomb hybrid compound, namely [Cd3(H2biim)6P2W18O62]·2H2O (1) (H2biim=2,2´-biimidazole), was hydrothermally synthesized by using a cadmium salt, the biimidazole ligand and the Wells-Dawson-type POM, and characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. In compound 1, each polyoxoanion cluster [P2W18O62]6- is coordinated by six [Cd(H2biim)2]2+ subunits via six of its terminal oxygen atoms on two equatorial sites. Each [Cd(H2biim)2]2+ subunit links two adjacent polyoxoanions. Thus, the linking styles of the [P2W18O62]6- and [Cd(H2biim)2]2+ subunits induce a honeycomb-like layer. The electrochemical and photocatalytic properties of the title compound have been studied. Graphical Abstract A New Wells-Dawson-based Organic-Inorganic Honeycomb Hybrid Compound with Cadmium Bis(2,2´-biimidazole) Spacers