Structural variability, unusual thermochromic luminescence and nitrobenzene sensing properties of five Zn(II) coordination polymers assembled from a terphenyl-hexacarboxylate ligand

摘要

Reactions of the terphenyl-hexacarboxylate ligand [1,1',4',1 '']terphenyl-3,5,2',5',3 '',5 ''-hexacarboxylic acid (H6L) with Zn(NO)(3) in the mixed solvents under low-temperature solvothermal conditions afforded five new coordination networks, namely, {[Me2NH2](2)[Zn-5(L)(2)(H2O)(4)]center dot 16H(2)O}(n) (1), {[Me2NH2][Zn(H3L)(H2O)]center dot C2H5OH center dot 5H(2)O}(n) (2), {[Me2NH2](2)[Zn-2(L)(H2O)(2)]center dot 2DMF center dot 2H(2)O}(n) (3), {[Zn-4(L)(COO)(2)(DMF)(2)(H2O)(2)]center dot 2C(2)H(5)OH center dot 2DMF center dot 2H(2)O}(n) (4), and {[Zn-4(L)(DMF)(4)(C2H5OH)(H2O)](OH)(2)center dot DMF center dot 2H(2)O}(n) (5) (DMF = N,N-dimethylformamide). Compounds 1 and 3-5 possess 3D frameworks, while compound 2 exhibits a 2D grid layer network. Photoluminescence properties of these five compounds have been investigated in solid state at room temperature and low temperature. These five compounds exhibit two kinds of emission modes at room temperature, and compounds 3-5 turn out to have interesting responses to temperature. The sensing properties of compound 1 also have been explored, which show high selectivity and sensitivity to trace amounts of nitrobenzene.