Novel intercluster compound between a heptakis{triphenylphosphinegold(i)}dioxonium cation and an α-Keggin polyoxometalate anion

Abstract

A novel intercluster compound, [{{Au(PPh(3))}(4)(μ(4)-O)}{{Au(PPh(3))}(3)(μ(3)-O)}][α-PW(12)O(40)]·EtOH (1) constructed between a heptakis{triphenylphosphinegold(i)}dioxonium cation and an α-Keggin polyoxometalate (POM) is synthesized and unequivocally characterized by elemental analysis, TG/DTA, FTIR, X-ray crystallography, solid-state CPMAS (31)P NMR and solution ((1)H, (31)P{(1)H}) NMR. The heptagold(i) cluster was formed during the course of carboxylate elimination of a monomeric phosphinegold(i) carboxylate precursor, i.e., [Au((RS)-pyrrld)(PPh(3))] ((RS)-Hpyrrld = (RS)-2-pyrrolidone-5-carboxylic acid), in the presence of the sodium salt of an α-Keggin POM, Na(3)[α-PW(12)O(40)]·9H(2)O. Compound 1 was formed by ionic interaction between the heptagold(i) cluster cation and the α-Keggin POM anion. The heptagold(i) cluster unit was formed by four inter-cationic aurophilic interactions between the tetragold(i) cluster unit and trigold(i) cluster unit. The tetragold(i) cluster unit and trigold(i) cluster unit contained μ(4)-O and μ(3)-O atoms, respectively.