Experimental and theoretical studies of structural and photophysical properties of a novel heteroleptic cyclometalated iridium(III) complex with 8-hydroxyquinoline-phenylazo ligand

One novel heteroleptic iridium(III) complex with cyclometalated 2-phenylquinoline(2-phq) was synthesized by the stoichiometric reaction of [Ir(2-phq)₂Cl]₂, i.e, Bis-[μ-chlorodi-(2-phenylquinoline)iridium(III)] and HL ligand, where L⁻ is deprotonated form of azo ligand prepared from 8-hydroxyquinoline and aniline in a 1:1 proportion of dichloromethane and ethanol solvent at argon atmosphere in presence of mild base triethylamine in stoichiometric ratio. The prepared complex was characterized by ¹H NMR, ESI-mass spectrometry, IR spectroscopy and most accurately by X-ray single crystallography. The photo physical properties like absorption and emission, i.e, photoluminescence in liquid state as well as solid state were studied exclusively. The experimental electrochemical study was also done with cyclic voltammetry. The theoretical investigations of the photo physical properties were done by DFT and TDDFT calculations. The ground state excitation transitions of the complex arise from ¹ILCT and ¹MLCT transition. The UV–Vis and photoluminescence transition was also investigated by NTO analysis. The triplet state emission transition was characterized by ³MLCT and some portion of ³ILCT transition.