New iridium complexes(III) bearing 2-phenylimidazo[4,5-f][1,10]-phenanthroline ligand: Synthesis, characterization, electrochemical and photoluminescence studies

• Published in: Journal of molecular structure 2021-02, Vol.1226, p.129415, Article 129415
• Main Authors: Sahin, Cigdem, Sahin, Murat
• Format: Article
• Language: English
• Subjects: Counterion; Iridium complex; Phenanthroline; Photoluminescence
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.129415

•Iridium complexes with 2-phenylimidazo[4,5-f][1,10]phenanthroline ligand were synthesized.•The effect of solvent and substituent on photophysical properties was investigated.•The counterions have an important influence on the quantum yield of the complexes.•The thermal and electrochemical properties of the complexes were investigated.•The redox potentials of complexes were correlated with Hammett Substituent Constants. Iridium complexes bearing 2-phenylimidazo[4,5-f]-[1,10]-phenanthroline with different substituents (-CH3, -CH(CH3)2, -OCH3, -C6H5) were synthesized and characterized. The effects of different substituents and solvents on the photoluminescence properties of the complexes with [Cl] and [PF6] counter anions have been investigated. The synthesized complexes show high photoluminescence quantum yield due to the extension of the π-electron conjugation of 2-phenylimidazo[4,5-f][1,10]-phenanthroline ligands. The results indicate that the choice of counter anions ([Cl] and [PF6]) has an important influence on the quantum yield of the complexes. In toluene, the compound 4 with phenyl substituent exhibits excimer emission with increasing solution concentrations in the presence of [Cl] counter anion. The linear correlation was observed between the redox potentials of the complexes and Hammett Substituent Constants. The linear correlation can allow the prediction of the effects of substituents on electrochemical studies. [Display omitted]