Reaction of CpW(CO)2(μ-PPh2)Mo(CO)5 and Fe2(μ-S2)(CO)6: Unusual Fragmentation and Coordination of Fe2(μ-S2)(CO)6

Reaction of Fe 2 (μ-S 2 )(CO) 6 with at dichloromethane reflux afforded heterotrimetallic clusters CpW(μ-PPh 2 )Mo(CO) 3 (μ-CO)(μ 3 -S) 2 Fe 2 (CO) 5 ( 1 ), Cp(CO)W(μ-PPh 2 )Mo(CO) 3 (μ 3 -S) 2 Fe(CO) 3 ( 2 ), CpW(μ-PPh 2 )Mo(CO) 3 (μ 3 -S) 2 Fe 2 (μ-CO)(CO) 4 ( 3 ), and CpW(CO)(μ 3 -S) 2 Fe(μ-PPh 2 )Fe(CO) 4 Mo(μ 3 -S) 2 Fe 2 (CO) 6 ( 4 ). Thermolysis of 1 in dichloromethane produced 3, which was also obtained by the reaction of 2 with Fe 2 (CO) 9 at dichloromethane reflux. Reflux of a benzene solution of 3 with norbornadiene (nbd) produced CpW(μ-PPh 2 )Mo(CO)(nbd)(μ 3 -S) 2 Fe 2 (μ-CO)(CO) 4 ( 5 ), but the typical reaction without nbd afforded a benzene substitution product, CpW(μ-PPh 2 )Mo(η 6 -C 6 H 6 )(μ 3 -S) 2 Fe 2 (μ-CO)(CO) 4 ( 6 ). Molecular structures of 1 − 6 were determined by single-crystal X-ray diffraction analyses. Cluster 1 has bitetrahedral geometry, where the Fe 2 MoW core is intercepted by an Fe−W bond to FeMoW and Fe 2 W units, and each unit is capped by a μ 3 -S atom. Cluster 2 is a rare example of square pyramidal geometry with the FeS 2 W plane capped by a Mo atom, whereas cluster 3 consists of an Fe 2 MoW tetrahedron core with each FeMoW face capped by a μ 3 -S atom. Clusters 4 − 6 possess an Fe 2 MoW core geometry similar to that of 3, where carbonyl ligands on the Mo site were replaced by Fe 2 (μ-S 2 )(CO) 6, nbd, and benzene, respectively.