First heterobimetallic AgI-CoIII coordination compound with both bridging and terminal -NO2 coordination modes: synthesis, characterization, structural and computational studies of (PPh3)2AgI-(μ-κ2O,O′:κN-NO2)-CoIII (DMGH)2(κN-NO2)

An unusual heterobimetallic bis(triphenylphosphane)(NO2)Ag-I-Co-III(dimethyl-glyoximate)(NO2) coordination compound with both bridging and terminal -NO2 (nitro) coordination modes has been isolated and characterized from the reaction of [CoCl(DMGH)(2)(PPh3)] (DMGH(2) is dimethylglyoxime or N,N'-dihydroxybutane-2,3-diimine) with excess AgNO2. In the title compound, namely bis(dimethylglyoximato-1 kappa O-2,O')(mu-nitro-1 kappa N:2 kappa O-2,O')(nitro-1 kappa N)bis(triphenylphosphane-2?P)cobalt(III)silver(I), [AgCo(C4H7N2O2)(2)(NO2)(2)(C18H15P)(2)], one of the ambidentate -NO2 ligands, in a bridging mode, chelates the AgI atom in an isobidentate kappa O-2,O'-manner and its N atom is coordinated to the CoIII atom. The other -NO2 ligand is terminally kappa N-coordinated to the Co-III atom. The structure has been fully characterized by X-ray crystallography and spectroscopic methods. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been used to study the ground-state electronic structure and elucidate the origin of the electronic transitions, respectively.