Reactions of dinuclear and polynuclear complexes XVI. Chemistry of hydrido-, thiolato-bridged complexes [Mo2Cp2(μ-H)(μ-SR)(CO)4](R = Me, Ph): Reactivity and electrochemical behaviour; crystal structure of [Mo2Cp2(μ-SPh) {μ-σ:η2-C(CH3) =CHCH3}(CO)2]1

Article abstract of DOI:10.1016/0022-328X(95)05902-2

Photolysis of [Cp₂Mo₂(μ-H)(μ-ER)(CO)₄] (ER = SMe (1) or SPh (2)) with MeC≡CMe gives the μ-vinyl complex [Cp₂Mo₂{μ-σ:η²-C(CH₃)=CHCH₃}(μ-ER)(CO)₂] (ER = SMe (5) or SPh (6)) as the major product. Partial oxidation of 5 leads to the oxo compound [Cp₂Mo₂(O) {μ-σ:η²-C(CH₃)=CHCH₃}(μ-SR)(CO)] (7) with a low yield. Compound 6 has been structurally characterized by X-ray diffraction. The structure contains μ-σ:η²-C(CH₃)=CHCH₃ bridging an Mo=Mo double bond whose length is 2.644(1) A. Chemical deprotonation of [Cp₂Mo₂(μ-H)(μ-ER)(CO)₄] (1 or 2) affords the anionic complex [Cp₂Mo₂(μ-ER)(CO)₄]^- (R = SMe (8) and SPh (9)), which is also obtainable by electrochemical reduction. The fluxional behaviour of 8 and 9 and the mechanism of reduction of 1-4 (ER = S^tBu(3) or SePh(4)) are described.