Organosilyl derivatives of trivacant tungstophosphate of general formula α-A-[PW9O34(RSiO)3(RSi)]3−: Synthesis and structure determination by X-ray crystallography

In the presence of NBu4nBr acting as phase-transfer reagent, organosilicon trichloride RSiCl3 reacts in acetonitrile with the trivacant tungstophosphate sodium salt β-A-Na8H[PW9O34]·24 H2O to give hybrid organosilyl polyoxotungstate derivatives α-A-[NBu4n]3[PW9O34(RSiO)3(RSi)] (R=C2H3 (1), CH3 (2)). These compounds are characterized by X-ray crystallography. Each of the two hybrid anions consists of one α-A-PW9O349− framework on which is grafted by three RSiO groups through six SiOW bridges, each of which is attached to the fourth RSi through three SiOSi bridges. Both hybrid anions become saturated, close cage structure and display C3v symmetry.