The 4-phenyl-1,2,3,5-dithiadiazole complex [Fe2(CO)6(PhCN2S2)]: its preparation, crystal structure, and an extended-Hückel molecular-orbital study of the bonding

Abstract

The dithiadiazole (PhCN₂S₂)₂ reacts with [Fe₂(CO)₉] or [Fe₃(CO)₁₂] to give [Fe₂(CO)₆(PhCN₂S₂)]. The butterfly structure of this complex is similar to that of other Fe₂S₂ complexes, with Fe–Fe 2.533(2), S–S 2.930(2), and mean Fe–S 2.225(10)Å. Extended-Hückel molecular-orbital (m.o.) calculations, supported by X-ray structural data, indicate that the unpaired electron (in an antibonding m.o. largely concentrated on the dithiadiazole ligand) is responsible for the very weak S ⋯ S and intermolecular N ⋯ N interactions.