SYNTHESES AND STRUCTURES OF DINUCLEAR MOLYBDENUM COMPLEXES CONTAINING REACTIVE MU-THIOLATE THIOETHER LIGANDS

Certain thiolate-bridged cationic complexes of the formula [(CpMo)2(S2CH2)(mu-S)(mu-SR)]SO3CF3 react reversibly with olefins: [GRAPHICS] The resulting adduct contains a thiolate-thioether bridging ligand. The stability of the olefin adduct varies significantly as the R substituent on the thiolate ligand and the substituents on the olefin are varied. Equilibrium constants have been determined for the formation of selected olefin adducts. The reaction of allene with [(CpMo)2(S2CH2)(mu-S)(mu-SR)]SO3CF3, where R = 2-propenyl, led to the formation of an isolable thiolate-thioether complex, [(CpMo)2(S2CH2)(SC(= CH2)CH2SC(CH3)(= CH2))]SO3CF3 (3). Complex 3 crystallized in space group P2(1)/c with a = 15.498 (6) angstrom, b = 14.132 (6) angstrom, c = 24.130 (10) angstrom, beta = 100.68 (3)degrees, V = 5193 (3) angstrom 3, and Z = 8. The structural study shows that the symmetrical Cp2Mo2S4 core is retained; the coordination geometry about the bridging thioether sulfur atom is highly distorted tetrahedral. Complex 3 dissociates allene when heated. The reaction of [(CpMo)2(S2CH2)(mu-S)(mu-SR)]SO3CF3 (2; R = tert-butyl) with acetylene led to the isolation of a product of the formula [(Cp Activated Mo)(SCH = CHSCMe3)(S2CH2)MoCp]SO3CF3 (4). Complex 4 crystallized in space group P2(1)/c with a = 11.983 (7) angstrom, b = 13.839 (6) angstrom, c = 15.200 (6) angstrom, beta = 109.71 (4)degrees, V = 2373 (2) angstrom 3, and Z = 4. The cation contains a thiolate-thioether ligand as a result of acetylene interaction with sulfur ligands. The double bond of the coordinated alkyne has inserted into the molybdenum-sulfur bond of the thioether ligand and undergoes a pi-interaction with one metal ion: [GRAPHICS] The complex represents the first structurally characterized Cp2Mo2S4 derivative in which a Mo-S bond has been cleaved.