Construction of diverse CdII/ZnII coordination polymers based on 5-(quinolyl)tetrazolate generated via in situ hydrothermal synthesis

By variation of reaction parameters such as metal salts and secondary ligands, a series of new coordination polymers, [Cd(QTZ)(2)] (1), [Cd(QTZ)N-3 center dot H2O] (2), [Zn(QTZ)Cl] (3), [Cd-2(QTZ)(2)(INA)(2)]center dot 0.25H(2)O (4), [Cd-2(QTZ)(btrc)center dot 2(H2O)]center dot 1.67H(2)O (5), 2[Cd-3(QTZ)(2)(btec)center dot H2O]center dot H2O (6) (QTZ = 5-(quinolyl)tetrazole; HINA = isonicotinic acid; H(3)btrc = 1,3,5- benzenetricarboxylic acid; H(4)btec = 1,2,4,5- benzenetetracarboxylic acid) were successfully synthesized under hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction. The QTZ ligands in these compounds are in situ generated from a [2 + 3] cycloaddition reaction of 3-quinolinecarbonitrile and NaN3 in water with the acid of Cd-II/Zn-II salt. Compound 1 displays a three-dimensional (3D) 2-fold interpenetrating diamond network with Schlafli symbol 6(6). Compound 2 represents a two-dimensional (2D) coordination framework constructed of infinite Cd-N-3(-) chains and QTZ ligands. Compound 3 exhibits a 4-connected 2D (4,4) net built up by interconnection of Zn-2(QTZ)(2)Cl-2 subunits. Compound 4 is a 2D framework constructed by interconnection of Cd-2(QTZ) 2(INA) 2 subunit and Cd-2(QTZ)(2) subunit. Compound 5 exhibits a 2D layered structure with the Cd-2-QTZ chain extended by btrc ligands. In compound 6, trinuclear CdII clusters link each other by pairs of QTZ ligands to form an infinite zigzag Cd-3-QTZ chain; furthermore the adjacent Cd-3-QTZ chains are extended by the btec ligands to form a 3D network. These results indicate that QTZ is a powerful functional ligand and the nature of secondary ligands and transition metal ions also play significant roles in dominating molecular self-assembled structure. In addition, the luminescent properties of all compounds have been investigated in the solid state at room temperature.