Synthesis, structure and fluorescent properties of 2-(1H-benzoimidazol-2-yl)quinolin-8-ol ligands and their zinc complexes

A series of 2-(1H-benzoimidazol-2-yl)quinolin-8-ol ligands (L1−L5) and their Zn(II) complexes (C1−C6) were synthesized and characterized by spectroscopic and elemental analyses. The molecular structures of C1 and C6 were confirmed by single-crystal X-ray diffraction; the zinc centre in complex C1 was found to be five-coordination as a distorted tetrahedral geometry, meanwhile the zinc centre in complex C6 adopted as six-coordination as a octahedral geometry. UV–Vis absorption and fluorescent spectra in different solvent were measured, and the substituent effects as well as those of the solvents on the luminescent properties were analyzed. The maximum emission wavelengths of all complexes were generally blue-shifted compared to the free ligands.