Synthesis of the Novel Thiolato-Bridged and Oxo-Capped Trimetallic Clusters (η⁵-R‘C₅H₄)(CO)₂MFe₂(μ₃-O)- (μ-RS)(CO)₆ via Reactions of [Et₃NH][(μ-RS)(μ-CO)- Fe₂(CO)₆] with Triply Bonded Dimers [(η⁵-R‘C₅H₄)(CO)₂M]₂ (M = Mo, W) and Subsequent Treatment with Air. Crystal Structures of (η⁵-MeO₂CC₅H₄

The complex salts [Et₃NH][(μ-RS)(μ-CO)Fe₂(CO)₆] (1:  R = Et, t-Bu, Ph), prepared from Fe₃(CO)₁₂, RSH, and Et₃N, react in situ with the triply bonded dimers [(η⁵-R‘C₅H₄)(CO)₂M]₂ (2:  M = Mo, W; R‘ = H, MeCO, MeO₂C, EtO₂C) followed by treatment with air to give the series of novel clusters (η⁵-R‘C₅H₄)(CO)₂MoFe₂(μ₃-O)(μ-RS)(CO)₆ (compound, R, R‘:  3a, Et, H; 3b, t-Bu, H; 3c, Et, MeCO; 3d, t-Bu, MeO₂C; 3e, Ph, MeO₂C; 3f, Et, EtO₂C; 3g, t-Bu, EtO₂C; 3h, Ph, EtO₂C) in 26−37% yields and (η⁵-R‘C₅H₄)(CO)₂WFe₂(μ₃-O)(μ-RS)(CO)₆ (compound, R, R‘:  3i, Et, MeO₂C; 3j, t-Bu, MeO₂C; 3k, Et, EtO₂C) in 12−17% yields. Single-crystal X-ray diffraction analyses of 3d and 3k confirmed that (i) these clusters consist of the M−S (M = Mo, W) edge-opened square-pyramidal cluster skeleton MFe₂SO with the M atom occupying its apical position and the Fe₂OS atoms constructing its pyramid base and (ii) clusters 3d and 3k are single isomers in which the t-Bu and Et groups are bonded to the bridged S atoms by an equatorial type of bond.