Crystal structure and luminescent mechanochromism of a quinoline-appended acylhydrazone ligand and its Zn(II) complex

In the work, a quinoline-appended acylhydrazone H2L was designed and prepared via a Schiff base condensation reaction of quinoline-2-formaldehyde and salicylhydrazide. Further, a new zinc(II) complex, [Zn(HL)2]·H2O was synthesized by the reacting of the ligand H2L and Zn(NO3)2·6H2O in dichloromethane/ethanol solution. The ligand and its Zn(II) complex were elucidated via UV–Vis, FT-IR, DFT calculation, Hirshfeld surfaces, MEP & IRI analyses, and X-ray single-crystal diffractions. The results of Hershfield surface analysis showed that there are obvious hydrogen bond interactions and CH···π mutual effect in the Zn(II) complex. In addition, solid-state photoluminescence properties indicated that H2L and its Zn(II) complex represent uncommon luminescent mechanochromism tuned via intermolecular hydrogen bonds.