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

Frozen-matrix photolysis studies of M(CO)(2)(N2Ph)(PPh3)(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)(N2Ph)(PPh3)(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.