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)(CO)2MoFe2(μ3-O)(μ-t-BuS)(CO)6 and (η5-EtO2CC5H4)(CO)2WFe2(μ3-O)(μ-EtS)(CO)6

The complex salts [Et 3 NH][(μ-RS)(μ-CO)Fe 2 (CO) 6 ] ( 1: R = Et, t -Bu, Ph), prepared from Fe 3 (CO) 12, RSH, and Et 3 N, react in situ with the triply bonded dimers [(η 5 -R‘C 5 H 4 )(CO) 2 M] 2 ( 2: M = Mo, W; R‘ = H, MeCO, MeO 2 C, EtO 2 C) followed by treatment with air to give the series of novel clusters (η 5 -R‘C 5 H 4 )(CO) 2 MoFe 2 (μ 3 -O)(μ-RS)(CO) 6 (compound, R, R‘: 3a, Et, H; 3b, t -Bu, H; 3c, Et, MeCO; 3d, t -Bu, MeO 2 C; 3e, Ph, MeO 2 C; 3f, Et, EtO 2 C; 3g, t -Bu, EtO 2 C; 3h, Ph, EtO 2 C) in 26−37% yields and (η 5 -R‘C 5 H 4 )(CO) 2 WFe 2 (μ 3 -O)(μ-RS)(CO) 6 (compound, R, R‘: 3i, Et, MeO 2 C; 3j, t -Bu, MeO 2 C; 3k, Et, EtO 2 C) 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 MFe 2 SO with the M atom occupying its apical position and the Fe 2 OS 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.