Structure and photophysical properties of a dimeric Zn(II) complex based on 8-hydroxyquinoline group containing 2,6-dichlorobenzene unit

A novel 2-substituted-8-hydroxyquinoline ligand (E)-2-[2-(2,6-dichlorophenyl)ethenyl]-8-hydroxyquinoline (HL) was synthesized and characterized by ESI-MS, NMR spectroscopy, and elemental analysis. Using solvothermal method, a dimeric complex (ZnL2)2 (1) was fabricated by self-assembly of Zn(II) ions with ligand HL. X-ray structural analysis shows that 1 exhibits a binuclear core, which is bridged by two 8-hydroxyquinoline rings. The supramolecular structure of 1 features a lamellar solid constructed by aromatic stacking interactions, Cl⋯Cl interactions and nonclassical C–H⋯Cl hydrogen bonds derived from 2,6-dichlorophenyl group of the ligand HL. The aggregation behavior of zinc salts and HL in solutions was investigated with a variety of techniques, including 1H NMR, UV–vis, and photoluminescence (PL). In addition, we also studied the photophysical properties of compound 1 by UV–vis and PL. The experimental results show that the complex 1 emits yellow luminescence in the solid state.

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