Using a flexible bis(pyrazol) ligand to construct four new Keggin-based compounds: syntheses, structures and properties†
Abstract
Using a flexible bis(pyrazol) ligand, four new compounds based on Keggin anions, namely [Cu(H2bdpm)2(H2O)2(HPW12O40)] (1), [Cu(H2bdpm)2(H2PW12O40)]2·2H2O (2), [Cu2(H2bdpm)3(H2O)2(SiW12O40)]·2H2O (3), and [Cu2(H2bdpm)4(H2O) (SiW12O40)]·16H2O (4) (H2bdpm = bis(3,5-dimethyl-1H-pyrazol-4-yl)methane), have been synthesized under hydrothermal conditions. Compound 1 is a zero dimension (0D) structure, showing a [Cu(H2bdpm)2]2+ mono-supporting [PW12O40]3− anion. Compound 2 shows a 1D supramolecular chain, with bi-supporting anions lined by discrete [PW12O40]3− anions. Compound 3 contains bi-nuclear Cu2+ cycles, which are linked by O4W to form a cycle-connecting-cycle chain. The [SiW12O40]4− anions connect adjacent chains to construct a 2D structure. Compound 4 contains a nested cycle subunit [Cu4(H2bdpm)6]8+, with two bi-nuclear cycles [Cu2(H2bdpm)2]4+ linked by two H2bdpm ligands. The nested cycle subunits are connected by H2bdpm molecules to construct a 2D metal–organic layer. The Keggin anions link adjacent layers to form a 3D framework. The electrochemical and photocatalytic properties of compounds 1–4 are studied.