Structure, bonding, and reactivity of the organometallic 1,3,2,4-dithiadiazole complex CpCoS2N2

The bonding and spectroscopic properties of 5-(η5-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.