Photo induced trans→cis isomerism studies of heteroleptic iridium complex with 8-quinolinol-5-phenylazo ligand: Photophysical and electrochemical studies and it's theoretical investigations

Free rotating azo type ligand in different types of metal complexes give trans-cis isomerism in presence of photon irradiation by UV light. For this connection one new iridium complex has been synthesized with 8-hydroxyquinoline-5-phenylazo ligand in which the azo part of the ligand is free from coordination with metal centre. UV light irradiation of the Ir complex with this type of 8-hydroxyquinoline-5-arylazo ligand at room temperature promotes the trans→cis photoisomerization of the N[dbnd]N bond with formation of a cis-isomer. The complex is characterised by single X-ray diffractometry, IR, mass and ¹ HNMR spectroscopy method. Here we report on the synthesis, the electrochemical properties and the photophysical characterization of donor-acceptor azobenzene derivative that possess 8-quinolinol group connected to a benzene moiety and it's cis-trans isomerisation reaction and stability of the isomers. Thoroughly DFT and TD-DFT calculations are performed to correlate experimental and theoretical interpretation.