Structure, Bonding, and Reactivity of the Organometallic 1,3,2,4-Dithiadiazole Complex CpCOS₂N₂

The bonding and spectroscopic properties of 5-(eta(5)-cyclopentadienyl)-5-cobalta-1,3,2,4-dithiadiazole (i.e., a structure having a Co-N-S-N-S five-membered ring, abbreviated CpCoS2N2) have been studied, based on the results of theoretical calculations at the DFT/ B3LYP level with the 6-311+G* basis set and on a redetermination of the single-crystal structure and experimental NMR spectra. A description of the bonding is provided based on a combination of geometrical data, electron densities, bond orders, and valencies, and a critical evaluation of the aromaticity of the compound is given based on several aromaticity criteria. In addition, a dipole analysis is performed and the reactive sites in this complex are located by means of atomic charges, molecular electrostatic potentials, Fukui functions, and local softnesses.