TRANSITION-METAL COMPLEXES WITH SULFUR LIGANDS .87. COORDINATION OF CO TO HIGH VALENT MOLYBDENUM SULFUR CENTERS - SYNTHESES, PROPERTIES AND STRUCTURE OF STABLE MOLYBDENUM(IV) THIOLATO CARBONYL-COMPLEXES

Thermal thioether-S-desalkylation of the molybdenum(II) carbonyl complexes [MO(CO)2(PR3)('buS4')] (R = Ph, Me; ('buS-4'2-) = 1,2-bis(2-mercapto-3,5-di-t-butylphenylthio)ethane(2-)) yields the molybdenum(IV) carbonyl complexes [Mo(CO)(PR3)(('buS2')2] (('buS-2'2-) =3,5-di-t-butyl-1,2-benzenedithiolate(2-)). X-ray structure analysis of [Mo(CO)(PPh3)(('buS2')2] (1) shows a pseudo trigonal prismatic coordination of the molybdenum center by a S4CP donor set. NMR spectra indicate that 1 and [Mo(CO)(PMe3)(('buS2')2] (2) possess trans octahedral structures in solution. Thermal desalkyation of [Mo(CO)3('buS4')] at room temperature in high vacuo yields [Mo(CO)2('buS2')2] (4), the first molybdenum(IV) carbonyl complex displaying only biologically relevant thiolate donors in its coordination sphere and being stable at room temperature.