Self-Assembly of Five 8-Hydroxyquinolinate-Based Complexes: Tunable Core, Supramolecular Structure, and Photoluminescence Properties

Five new Zn-II complexes, namely [Zn-3(L)(6)] (1), [Zn-2(Cl)(2)(L)(2)(py)(2)] (2), [Zn-2(Br)(2)(L)(2)(py)(2)] (3), [Zn(L)(2)(py)] (4), and [Zn-2(OAc)(2)(L)(2)(py)(2)] (5), were prepared by the solvothermal reaction of ZnX2 (X- = Cl-, Br-, F-, and OAc-) salts with a 8-hydroxyquinolinate ligand (HL) that contained a trifluorophenyl group. All of the complexes were characterized by elemental analysis, IR spectroscopy, and powder and single-crystal X-ray crystallography. The building blocks exhibited unprecedented structural diversification and their self-assembly afforded one mononuclear, three binuclear, and one trinuclear Zn-II structures in response to dif-ferent anions and solvent systems. Complexes 1-5 featured four types of supramolecular network controlled by non-covalent interactions, such as pi center dot center dot center dot pi-stacking, C-H center dot center dot center dot pi, hydrogen-bonding, and halogen-related interactions. Investigation of their photoluminescence properties exhibited disparate emission wavelengths, lifetimes, and quantum yields in the solid state.