Iridium(III) salen complexes with a formal tetradentate coordination: Synthesis, structure and photophysical properties

[Ir( Cod )Cl] 2 reacts with salen ligand L 1 to give a trans iridium complex [Ir III (salenL 1 )Cl(CO)] (1) . Subsequent ligand substitution reactions of complex 1 with various ancillary ligands enabled the synthesis of a novel series of neutral Ir(III) complexes bearing diverse axial ligands. Complexes [Ir III (salenL 1 )Cl(2,6-dimethylphenyl-isocyanide)] ( 2 ), [Ir III (salenL 1 )(2,6-dimethylphenyl-isocyanide)(4-methylphenylacetylide)] ( 4 ) and [Ir III (salenL 1 ) (2-naphthyl-isocyanide)(4-methylphenylacetylide)] ( 5 ) are emissive in degassed dichloromethane. The axial ligands were found to play a pivotal role in the photophysical and electronic properties of these Ir(III) complexes, as elucidated through a combination of spectroscopic studies and theoretical calculations.