Synthesis of a series of Iridium(III) salen complexes: Axial ligand substitution and catalytic reactivity

A panel of trans-Ir(III)-salen complexes bearing axial alkyl, alkynyl, acyl, pyridine, and NHC-carbene ligands were synthesized through diverse ligand substitution methodologies, including carbonyl dissociation, CH bond activation of p-tolualdehyde, CN bond activation of triethylamine, and coupling reaction with 4-ethynyltoluene. Subsequent investigation of their catalytic properties revealed notable reactivity: the alkyl-Ir(III)-salen complex exhibited high catalytic activity for intermolecular carbene insertion into NH bonds, while the alkynyl-Ir(III) analogue demonstrated excellent performance in intramolecular carbene transfer reactions.