Xueliang Zhai

Copper-organic cationic ring with an inserted arsenic-vanadium polyanionic cluster for efficient catalytic Cr(VI) reduction using formic acid.

Polyanionic cluster [β-As8V14O42(H2O)](4-) is well embedded in a large porous eight-membered cationic ring of the copper ligand, giving a stable host-guest supramolecular system. The assembly exhibits an efficient heterogeneous catalytic performance for the reduction of Cr(VI) using formic acid at ambient temperature.

An unusual metallic oxygen cluster consisting of a {AlMo12O40(MoO2)}.

A novel aluminum-containing, bimolybdenum-capped Keggin-type polyoxomolybate cluster of the {AlMo12O40(MoO2)2} anion has been synthesized and characterized. This is the first experimentally determined Keggin-type {AlMo12O40} polyoxoanion. The polyoxometalate crystal exhibits high selectivity toward the heterogeneous catalytic oxidation of cyclohexanol to cyclohexanone.

Polyanionic clusters embedded in lattice-type hydrogen bonding networks involving in situ bond activation and coupling of organic cations

Two inorganic–organic supramolecular polyoxometalates, (H2chtpy)2[SiW12O40] (1) (chtpy = 1,3,4,6-tetra(4-pyridyl)cyclohexane-1,3-diol) and [Co(Hbztpy)2]H[AlW12O40]·3H2O (2) (bztpy = 1,2,4,5-tetra(4-pyridyl)benzene), have been hydrothermally synthesized and characterized. Both of them consist of complex supramolecular interactions between inorganic polyanions and organic cations. During the formation process of 1 and 2, in situ organic reactions involving C–C coupling through dehydrogenative cyclodimerization of two flexible 1,3-bis(4-pyridyl)propane (bpp) molecules were observed. The tetradentate pyridyl chtpy and bztpy molecules serve as 4-connected nodes to enrich the structural topologies of 1 and 2. The typical centered N–H⋯N (N⋯N = 2.6–2.7 A) hydrogen bonding interactions link the organic cations to form grid-type networks for capturing the pseudo-spherical Keggin-type anions. The pH values of the reaction solutions are important for the intermolecular C–C coupling of the organic molecules, and their transformation mechanisms are discussed.

Phosphotungstic salt used as an efficient catalyst to rapidly remove RhB from water solution

Abstract Ag-modified polyoxometalate [Na(H2O)]2[Ag(bpf)]3[PW12O40] (1) (bpf = 2,4-di(4-pyridyl)furan) was synthesized through a hydrothermal reaction. Single-crystal X-ray diffraction analysis revealed that 1 consists of a hybrid 3D MOF constructed from Keggin-type polyanionic [PW12O40]3- and cationic Ag-bpf units. Ligand bpf in 1 was in situ transferred from 1,3-bis(4-pyridyl)propane under the higher temperature and pressure of hydrothermal conditions. Catalytic performance of 1 as a heterogeneous catalyst for degradation of organic dye Rhodamine B (RhB) was investigated. Experimental results showed that hybrid 1 was especially active to catalytically degrade RhB under room temperature and natural light. RhB-containing solution (5.0 mg·L−1) could be quickly bleached in a short time, and the high removal efficiency (97%) could be reached in a mere 30 min. The degradation mechanism of RhB was discussed.