Structural isomers and low-lying electronic states of gas-phase M(NO) (M = Co, Rh, Ir) ion-molecule complexes.

The structures of gas-phase group nine cation-nitrous oxide metal-ligand complexes, M(NO) (M = Co, Rh, Ir; n = 2-7) have been determined by a combination of infrared photodissociation spectroscopy and density functional theory. The infrared spectra were recorded in the region of the NO asymmetric (N[double bond, length as m-dash]N) stretch using the inert messenger technique and show spectroscopically distinct features for N- and O-bound isomers. The evolution of the spectra with increasing ligand number is qualitatively different for each of the metal ions studied here with only Co(NO) complexes behaving similarly to the coinage metal complexes studied previously. The rich variety of electronic and isomeric structures identified make these species attractive targets for infrared-driven, isomer selective intra-complex chemistry.