Rare and Nonexistent Nitrosyls: Periodic Trends and Relativistic Effects in Ruthenium and Osmium Porphyrin-Based {MNO}7 Complexes

Abstract

Relativistic and nonrelativistic density functional theory calculations were used to investigate rare or nonexistent ruthenium and osmium analogues of nitrosylhemes. Strong ligand field effects and, to a lesser degree, relativistic effects were found to destabilize {RuNO}⁷ porphyrins relative to their {FeNO}⁷ analogues. Substantially stronger relativistic effects account for the even greater instability and/or nonexistence of {OsNO}⁷ porphyrin derivatives.