Anionic halogenocarbonyls of rhodium, iridium, and platinum

Abstract

The decarbonylation of formic acid by platinum metal halogeno-complexes in the presence of the appropriate halogen acid provides a simple method for the preparation of salts containing the anions [M^III(CO)l₅]^2–, [Ru^III(CO)Br₅]^2–, [Os^III(CO)Y₅]^2–, [Ir^III(CO)Br₄(MeOH)]^–, [Ir^III(CO)Br₄]₂^2–, [Rh^III(CO)X₄(MeOH)]^–, [Rh^III(CO)X₄]₂^2–, cis-[Ir^III(CO)₂X₄]^–, [Pt^II(CO)X₃]^–, cis-[Ir^II(CO)₂Y₃]₂^2–, [Ir₄^{II, I}(CO)₈X₈]^2–, cis-[Ir^I(CO)₂Br₂]^– and cis-[Rh^I(CO)₂Y₂]^–(M = Rh or Ir; X = Cl, Br, or I; Y = Cl or Br). Raman and i.r. spectra of these complexes have been studied and assignments of fundamental modes suggested. The structures of the complexes are discussed.