Preparation and properties of a 4Fe4S cluster complex chelated by pyridine-2-thiolato ligands, (Et4N)2[Fe4S4(S-2-(4-NO2)C5H3N)4]

A 4Fe4S cluster complex with pyridine-2-thiolato ligands, (Et4N)2[Fe4S4(S-2-(4-NO2)C5H3N)4], has been synthesized by the ligand exchange reaction. X-ray structure analysis revealed that the Fe atoms in the core are chelated by the ligands in a bidentate form. The four-membered chelate ring has a very small bite angle of NFeS=64.7°. The complex crystallizes in space group Fddd, displaying a highly symmetrical molecular structure. A quasi-reversible redox wave is observed at E1/2=−1.46 V (vs. SCE), showing a large negative shift relative to those in ordinary arenethio analogues.