REACTIONS OF DINUCLEAR AND POLYNUCLEAR COMPLEXES .14. SYNTHESIS OF PERMETHYLATED-CYCLOPENTADIENYL CHALCOGENO-BRIDGED COMPOUNDS - A ROUTE TO THE STABLE THIOLATOSULFIDOCARBONYLDIMOLYBDENUM(III) COMPLEX [CP-ASTERISK-MO-2(2)(CO)(2)(MU-SME)(2)(MU-S)] - CRYSTAL-STRUCTURE DETERMINATION OF [CP-ASTERISK-MO-2(2)(CO)(2)(MU-SME)(2)(MU-SH)][BF4]

The new diamagnetic carbonyl-containing sulfide complex [Cp*Mo-2(2)(CO)(2) (mu-SMe)(2)(mu-S)] (8) has been obtained by the thermal reaction of the pentamethylcyclopentadienyl compound [Cp*Mo-2(2)(CO)(4)] (1) with MeSSMe; the other predominant product of the reaction, [Cp*Mo-2(2)(CO)(4)(mu-SMe)(2)] (3), results from the oxidative addition of dimethyl disulfide across the Mo-2 center. Monitoring this thermal reaction by IR spectroscopy indicated that 8 arises from decarbonylative dimerization of [Cp*Mo(CO)(3)(SMe)] (2). Reactions with other dialkyl and diaryl chalcogenides, REER (ER = SPh, SeMe), and with thiol (HSBz) and selenol (HSePh) led only to the formation of tetracarbonyl chalcogenato-bridged derivatives [Cp*Mo-2(2)(CO)(4)(mu-ER)(2)] (ER = SPh (4), SBz (5), SeMe (6), SePh (7)). A thermolysis study showed the degradation of 3 to [Cp*Mo-2(2)(mu-SMe)(4)] (12) via [Cp*Mo-2(2)(CO)(2)(mu-SMe)(2)] (9); 8 was decarbonylated directly to 12. Investigation of the reaction between 8 and electrophilic reagents showed that dinuclear molybdenum(III) complexes [Cp(2)*Mo-2(CO)(2)(mu-SMe)(2)(mu-SH)]X [X = BF4 (16), Cl (17), F(18)] were formed stereospecifically as the cis isomers. 16 has been structurally characterized by X-ray diffraction. Crystals of 16 are orthorhombic, space group Pcab, a = 15.655(5) Angstrom, b = 16.173(3) Angstrom, c = 23.662(5) Angstrom, and Z = 8. The complex cation has approximate C-2 upsilon symmetry and the Mo-Mo bond length is 2.772(2) Angstrom. Complex 3 was readily oxidized by Ag[BF4] to yield the dicationic product [Cp*Mo-2(2)(CO)(4)(mu-SMe)(2)][BF4](2) (21). All new thiolato-bridged complexes have been characterized by spectroscopic analyses.