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

The new diamagnetic carbonyl-containing sulfide complex [CpMo-2(2)(CO )(2) (mu-SMe)(2)(mu-S)] (8) has been obtained by the thermal reaction of the pentamethylcyclopentadienyl compound [CpMo-2(2)(CO)(4)] (1) wi th MeSSMe; the other predominant product of the reaction, [CpMo-2(2)( CO)(4)(mu-SMe)(2)] (3), results from the oxidative addition of dimethy l disulfide across the Mo-2 center. Monitoring this thermal reaction b y IR spectroscopy indicated that 8 arises from decarbonylative dimeriz ation of [CpMo(CO)(3)(SMe)] (2). Reactions with other dialkyl and dia ryl chalcogenides, REER (ER = SPh, SeMe), and with thiol (HSBz) and se lenol (HSePh) led only to the formation of tetracarbonyl chalcogenato- bridged derivatives [CpMo-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 [CpMo-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 reactio n between 8 and electrophilic reagents showed that dinuclear molybdenu m(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 catio n 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 th e dicationic product [CpMo-2(2)(CO)(4)(mu-SMe)(2)][BF4](2) (21). All new thiolato-bridged complexes have been characterized by spectroscopi c analyses.