Synthesis and X-ray Characterization of Tetraphenylphosphonium Tetrathiocyanatodioxomolybdate(VI): A Remarkable Oxo Transfer Agent

Abstract

The tetraphenylphosphonium salt of the anion [Mo VI (O) 2 (NCS) 4 ] is prepared from sodium molybdate and potassium thiocyanate in acidic medium, followed by cation exchange under phase transfer conditions. The crystalline compound belongs to the tetragonal space group P4 1 2 1 2, with a=b=12.802(3) A and c=31.820(4) A. The volume of the unit cell is 5215 A 3 with Z=4. The structure was refined to R=8.9%. The title compound is found to catalyze the oxygen transfer from dimethyl sulfoxide to triphenylphosphine approximately 20 times more efficiently than the known dioxobis(N,N'-diethyldithiocarbamato)molybdenum(VI) complex