TRANSITION-METAL COMPLEXES WITH SULFUR LIGANDS .71. SYNTHESIS OF MOLYBDENUM(II) COMPLEXES WITH STERICALLY CONGESTED TETRADENTATE THIOETHER THIOLATE LIGANDS

In order to obtain well soluble molybdenum sulfur carbonyl complexes [Mo(CO)2(PR3)('buS4')] (R = Me, Ph; 'buS4'2- = 1,2-bis(2-mercapto-3,5-di-t-butylphenylthio)ethane(2-)) was synthesized by reaction of 'buS4'-Li2 with [Mo(CO)2(PMe3)3(Cl)2] and [Mo(CO)3(PPh3)2(Cl)2], respectively. Reaction of [Mo(CO)4(Cl)2] with 'buS4'-H2 yields [Mo(CO)3('buS4')], which is also formed slowly in solutions of [Mo(CO)2(PPh3)('buS4')] at room temperature. Although the [Mo(CO)2(L)('buS4')] complexes (L = CO, PMe3, PPh3) have overall C1 symmetry, according to the NMR spectra, the [Mo('buS4')] cores exhibit in solution undisturbed C2 symmetry and, consequently, the [Mo(CO)2(L)] fragments have to fluctuate.