Phosphine-substituted derivatives of dodecacarbonyltetrairidium. Synthesis and X-ray characterization of [Ir4(CO)8(Ph2PCHCHPPh2)2] and of the hydrido ortho-metallated derivative [Hlr4(CO)7(Ph2PCHCHPPh2)(PhC6H4PCHCHPPh2)]

Abstract

Reaction of [Ir₄(CO)₁₂] with cis-1,2-bis(diphenylphosphino)ethane(dpp) in refluxing tetrahydrofuran (THF) gives first [Ir₄(CO)₁₀(dpp)] and then [Ir₄(CO)₈(dpp)₂] which is converted into the hydrido ortho-metallate [HIr₄(CO)₇(dpp)-(PhC₆H₄PCHCHPPh₂)] on standing; X-ray crystallography has shown that, in the latter species, dpp forms a new tridentate lignad upon ortho-metallation of a phenyl ring.