Syntheses and Reactions of Dimolybdenum Alkyne Compounds Containing Functionally Substituted Ligands. The Crystal Structure of [Co2Mo2(μ4-CHCH)(μ-CO)4(CO)4-(η5-C5H4C(O)Me)2

Abstract

Three dimolybdenum alkyne complexes containing functionally substituted ligands [Mo2(μ-CHCH)(CO)4(η5‒C5H4C(O)R)2] [R ˭ OEt, (1a); R ˭ Me, (1b); R ˭ Ph, (1c)] were synthesized by reactions of acetylene with in situ generated metal-metal triply bonded complexes [Mo(CO)2(η5‒C5H4C(O)R)]2 (R ˭ OEt, Me, Ph). Further reaction of (1a), (1b) or (1c) with Co2(CO)8 in refluxing toluene gave another three new butterfly compounds [Co2Mo2-(μ4-CHCH)(μ-CO)4(CO)4(η5-C5H4C(O)R)2] [R ˭ OEt, (2a); R ˭ Me, (2b); R ˭ Ph, (2c)]. The resulting compounds were characterized by elemental analyses, IR, 1H NMR and MS. The crystal structure of (2b) was determined by single-crystal X-ray analysis. The results indicate that the existence of functional groups on the cyclopentadienyl ring has an influence on the reactivity of this type of complex.