Synthesis and luminescent properties of Zn complex based on 8-hydroxyquinoline group containing 3,5-bis(trifluoromethyl) benzene unit with unique crystal structure

The use of a novel 2-substituted-8-hydroxyquinoline ligand (E)-2-{2-[3,5-bis (trifluoromethyl)phenyl]ethenyl}-8-hydroxyquinoline(4, BFHQ) characterized by EIMS, 1H NMR spectroscopy, elemental analysis, and FTIR spectroscopy enabled the isolation of a trimeric Zn(II) complex with the formula Zn3(BFHQ)6 (5, Scheme 1). X-ray structural analysis shows that 5 exhibits a trinuclear core, which is bridged by four 8-hydroxyquinoline rings. The trinuclear core is surrounded by three pairs of BFHQ ligands with offset π–π stacking, showing propeller-like molecular structure. The aggregation behavior of Zn(AcO)2 and the ligand 4 in solution was investigated by UV–vis. The luminescence properties of compound 5 were investigated by UV–vis and fluorescence spectra at room temperature. The experimental results show that the complex 5 emits yellow luminescence at 553 nm (λem, max) in DMSO solution and at 610 nm (λem, max) in solid state. The thermogravimetric analysis was carried out to examine the thermal stability.

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