Four Hybrid Materials Based on Preyssler P5W30 Polyoxometalate and First-Row Transition-Metal Complex

Four Preyssler P5W30 based inorganic–organic hybrids, formulated as {[Cu12(pbtz)2(Hpbtz)2­(OH)4(H2O)16]­[Na­(H2O)­P5­W30O110]}·16H2O (1; H2pbtz = 5′-(pyridin-2-yl)-1H,2′H-3,3′-bi­(1,2,4-triazole)), {[Cu10(ttbz)2(Httbz)4­(OH)6(H2O)8]­[K­(H2O)­H2P5W30O110]}·30H2O (2; Httbz = 1-(tetrazo-5-yl)-4-(triazo-1-yl)­benzene), {[Ni6(bpz)6(H2O)16]­[Na­(H2O)­H2P5W30O110]}·36H2O (3; bpz = 3,3′,5,5′-tetramethyl-4,4-bipyrazole), {[Co4(bpz)6(H2O)9]­[K­(H2O)­H6P5­W30O110]}·46H2O (4), have been isolated and structurally identified via microanalysis, thermogravimetry (TG), infrared (IR) spectroscopy, and X-ray single-crystal diffraction. Compound 1 exhibits a 3D binodal (3,6)-connected ant framework composed of dodeca-supported P5W30 polyoxometalate (POM) clusters and discrete [Cu6(pbtz)­(Hpbtz)­(OH)2(H2O)8] subunits. Compound 2 is a pillared-layer 3D network constructed from [Cu5(ttbz)­(Httbz)2­(OH)3(H2O)4] sheets pillared by individual P5W30 clusters. Compound 3 contains octa-supporting P5W30 POM clusters and novel [Ni6(bpz)6] crown-like metallamacrocycles, which construct a (4,4)-connected pts network. Compound 4 displays a complicated 3D (5,5)-connected {45·64·8}­{45·65} network built by pentasupporting P5W30 POM clusters and discrete [Co4(bpz)6(H2O)9] subunits. In 1–4, the unified features are the Preyssler-type [P5W30O110] POM as the fundamental building block, which supports the transition-metal compounds with different modes to give the resultant diverse networks. The magnetism studies indicated antiferromagnetically coupled systems for the hexa- and pentanuclear Cu­(II) units in 1 and 2, respectively. The electrochemical properties demonstrate that all compounds have electrocatalytic abilities toward the reduction of hydrogen peroxide. Furthermore, the catalytic activities of 1 in the cyanosilylation of aldehydes reaction have been investigated.