Evidence for Photochemical Linkage Isomerism of the Phenylazo Ligand in M(CO)₂(N₂Ph)(PPh₃)₂ Cations (M = Fe and Ru)

Abstract Frozen‐matrix photolysis studies of M(CO) 2 (N 2 Ph)(PPh 3 ) 2 cations (M = Fe and Ru) have revealed end‐on/side‐on photochemical linkage isomerism of the phenylazo ligand. The previously reported solvent‐dependent vibrational bands of the Ru(CO) 2 (N 2 Ph)(PPh 3 ) 2 cation have now been identified as an equilibrium between the two linkage isomers. DFT calculations have been performed on the end‐on and side‐on isomers of the iron and ruthenium complexes.