Iron carbonyl complexes of N,C,S-pincer ligands with a pendant thioether arm: Synthesis, structures and reactivity

Abstract Thiolate-bridged diiron carbonyl complexes of N,C,S-pincer ligands with a pendant thioether arm were synthesized by treatment of [Fe(CO) 5 ] with Schiff bases, which were derived from 4-formyldibenzothiophene and 2-(methylthio or phenylthio)aniline. Cleavage of a C–S bond in the proligands occurred during metalation. A carbonyl ligand in the complex was reversibly replaced by the thioether S atom, allowing for interconversion between the N,C,S-tridentate and S,N,C,S-tetradentate coordination modes. The diiron carbonyl complex of the S,N,C,S-tetradentate ligand reacted with dimethylphenylphosphine and 4-(dimethylamino)pyridine under moderate conditions to afford a mononuclear complex and a thiolate-bridged dimeric complex, respectively, while maintaining the S,N,C,S-tetradentate coordination mode. The dimeric complex was converted to the mononuclear complex by the reaction with dimethylphenylphosphine.