Trithio-Chloro Molybdate [MoCIS sub(3)] super(-): A Versatile Precursor for Molybdenum Trisulfido Complexes

The reaction of trithiomolybdate [PPh sub(4)] sub(2)[MoOS sub(3)] (1) with 2 equiv of trimethylchlorosilane generated trithio-chloro molybdate [PPh sub(4)][MoCIS sub(3)] (2) in high yield, by way of a siloxy complex [PPh sub(4)][Mo(OSiMe sub(3))S sub(3)] (3). This intriguing reaction provided us with a convenient entry into a series of mononuclear molybdenum trisulfido complexes, [PPh sub(4)][MoS sub(3)X] (4, X = Cp*; 6a, X = S super()tu; 6b, X = SPh; 6c, X = SMes (Mes = mesityl); 6d, X = STip (Tip = 2,4,6-triisopropylphenyl); 6e, X = SDmp (Dmp = 2,6-dimesitylphenyl); 7, X = NPh sub(2); 8a, X = O super()tu; 8b, X = OPh; 8c, X = OC(CH sub(2)) super(()Bu; 8d, X = OC(CH sub(2))Ph), which were obtained by the reactions of 2 with the corresponding potassium salts. In a similar manner, a citrate complex [PPh sub(4)][MoS sub(3)(Me sub(3)cit)] (9, Me sub(3)cit = OC(CH sub(2)CO sub(2)Me) sub(2)(CO sub(2)Me)) was synthesized, which may model the molybdenum site of the nitrogenase FeMo-cofactor. The molecular structures of 2, 6c, 7, 8a, 8b, 8c, and 9 were determined by X-ray crystallography.