Preparation of α1- and α2-isomers of mono-Ru-substituted Dawson-type phosphotungstates with an aqua ligand and comparison of their redox potentials, catalytic activities, and thermal stabilities with Keggin-type derivatives

摘要: Both the α1- and α2-isomers of mono-ruthenium (Ru)-substituted Dawson-type phosphotungstates with terminal aqua ligands, [α1-P2W17O61RuIII(H2O)]7− (α1-RuH2O) [α2-P2W17O61RuIII(H2O)]7− (α2-RuH2O), were prepared in pure form by cleavage Ru–S bond corresponding DMSO derivatives, [α1-P2W17O61Ru(DMSO)]8− (α1-RuDMSO) [α2-P2W17O61Ru(DMSO)]8− (α2-RuDMSO), respectively. Redox studies indicated that α1-RuH2O α2-RuH2O show proton-coupled electron transfer (PCET), RuIII(H2O) species was reversibly reduced to RuII(H2O) oxidized RuIV(O) further RuV(O) aqueous solution depending on pH. Their redox potentials thermal stabilities compared those α-Keggin-type derivatives ([α-XW11O39Ru(H2O)]n−; X = Si4+ (n 5), Ge4+ or P5+ 4)). The basic electronic features Ru(L)-substituted Keggin- heteropolytungstates (with L H2O O2−) analyzed means density functional calculations. Similar both catalytic activity for water oxidation.