Reactions of dinuclear and polynuclear complexes XVI. Chemistry of hydrido-, thiolato-bridged complexes [Mo 2Cp 2(μ-H)(μ-SR)(CO) 4] (R  Me, Ph): Reactivity and electrochemical behaviour; crystal structure of [Mo 2Cp 2(μ-SPh) { μ- σ : η2-C(CH 3)  CHCH 3}(CO) 2

Abstract

Photolysis of [Cp 2Mo 2(μ-H)(μ-ER)(CO) 4] (ER  SMe ( 1) or SPh ( 2)) with MeCCMe gives the μ-vinyl complex [Cp 2Mo 2{ μ- σ : η 2-C(CH 3)CHCH 3}( μ-ER)(CO) 2] (ER  SMe ( 5) or SPh ( 6)) as the major product. Partial oxidation of 5 leads to the oxo compounds [Cp 2Mo 2(O) { μ- σ : η 2-C(CH 3)CHCH 3}( μ-SR)(CO] with a low yield. Compound 6 has been structurally characterized by X-ray diffraction. The structure contains μ- σ : η 2-C(CH 3)CHCH 3 bridging an MoMo double bond whose length is 2.644(1) Å. Chemical deprotonation of [Cp 2Mo 2(μ-H)(μ-ER)(CO) 4] ( 1 or 2) affords the anionic complex [Cp 2Mo 2(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.