Three new POM-based compounds constructed by rigid thiabendazole and flexible bis(pyrazole) ligands: structures and properties for Hg2+ recognition

摘要

By using mixed rigid and flexible organic ligands, three Keggin based compounds, [Ag-6(tbz)(4)(bmz)(2)-(H3PW12O40)]center dot 4H(2)O (1), [Ag(H(2)bdpm)(2)(H2PMo12O40)]center dot 7.5H(2)O (2), and [Ag-4(tbz)(2)(H(2)bdpm)(2)(HPMo12-O-40)]center dot 2H(2)O (3) (Htbz = thiabendazole, Hbmz = benzimidazole, H(2)bdpm = 1,1'-bis(3,5-dimethyl-1H-pyrazolate) methane), were hydrothermally synthesized and structurally characterized. Through adopting rigid Htbz ligands, compound 1 with hexa-nuclear Ag-I clusters has been obtained. These hexa-nuclear clusters are linked by Keggin anions alternately to form a one dimensional (1D) chain. In compound 2, the organic moiety is the flexible H2bdpm ligand. The Keggin anions are fused by [Ag(H(2)bdpm)(2)](+) subunits to form a 1D chain. In compound 3, the rigid Htbz and the flexible H(2)bdpm cooperate to modify the anions. Two tbz and two H2bdpm are fused by four AgI ions to construct a tetra-nuclear AgI cycle. The anions connect these cycles through Ag-O bonds alternately to form a 1D chain. Adjacent chains arrange parallel to build a 2D layer. The chains in the adjacent layers are vertically packed and linked by Ag-O bonds to construct a 3D framework. The electrochemical and photocatalytic properties of the title compounds have been studied. Furthermore, we have also studied the Hg2+ recognition properties in a suspension of compounds 1 and 3.