The Reaction of Ruthenium(II) Octaethylporphyrin and Ruthenium(II) Tetraphenylporphyrin Complexes with Carbon Monoxide.

Abstract The reactions of Ru II OEP(L) 2 and Ru II TPP(L) 2 with carbon monoxide, where OEP and TPP are the dianions of octaethylporphyrin and tetraphenylporphyrin, respectively, are reported for various ligands (L=dimethyl formamide, acetonitrile, aniline and substituted benzonitriles). The first-order rate constants for the loss of XC 6 H 4 CN from Ru II OEP(XC 6 H 4 CN) 2 increase with increasing electron-withdrawing ability of X. The best Hammett σ/ϱ correlation is obtained when both σ + and σ − values are employed. It is concluded that sigma donation from ligand-to-metal is the major mode of bonding in ruthenium-porphyrin-benzonitrile complexes.