Halogeno-carbonyl and -nitrosyl complexes of the platinum metals, and their vibrational spectra

Decarbonylation reactions of formic acid by Group VIII halide complexes have been used to prepare new halogenocarbonyl complexes of the form cis-[M(CO)2X4]2– and cis-[M(CO)3X3]–(M = Os or Ru; X = Cl, Br, or l), [Os(CO)X5]3– and [M(CO)3X2]2(M = Os or Ru; X = Cl or Br), [M(CO)X5]2–(M = lr, Rh, or Ru; X = Cl or Br), and [Pt(CO)X3]–(X = Cl or Br). A number of triphenylphosphine derivatives of these products were also made, e.g. M(CO)2X2(PPh3)2(M = Os or Ru; X = Cl or Br). The vibrational spectra of the halogenocarbonyls were measured and assignments of fundamental modes proposed. The spectra of pentahalogeno-carbonyl and -nitrosyl species were compared and 13C and 15N substitution used to confirm the assignments.