6-Benzhydryl-4-methyl-2-(1H-benzoimidazol-2-yl)phenol ligands and their zinc complexes: Syntheses, characterization and photoluminescence behavior

The series of 6-benzhydryl-4-methyl-2-(1H-benzoimidazol-2-yl)phenol derivatives (HL) and their zinc complexes (ZnL2) were synthesized and fully characterized. Single-crystal X-ray diffraction studies were conducted on representative complexes (C1 and C4), which revealed a distorted tetrahedral geometry at zinc. By comparison with these organic compounds (HL), the fluorescent quantum yields of the corresponding zinc complexes were increased. The fluorescence intensities of zinc complexes were affected by the solvents used, and enhanced intensities in methanol were observed compared with those observed in other solvents such as dichloromethane and toluene. The fluorescence decay mainly followed a single exponential in toluene, whereas a double exponential decay was observed in the presence of two active species in methanol and dichloromethane.