Synthesis, characterization and properties of chiral and non-chiral coordination polymers in a zinc 2-(pyridine-3-yl)-1H-imidazole-4, 5-dicarboxylic acid system

Three different structural metal-organic frameworks (MOFs), [Zn(HPIDC)](n) (1), {[Zn-3(PIDC)(2)(H2O)(3)]center dot 0.5H(2)O}(n) (2), and [Zn(HPIDC)(H2O)](n) (3), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction, X-ray powder diffraction, circular dichroism spectrum, and thermogravimetric analysis (H3PIDC=2-(pyridine-3-yl)-1H-imidazole-4, 5-dicarboxylic acid). Single crystal X-ray diffractions show that ligands H3PIDC are doubly deprotonated in complexes 1 and 3, while ligand H3PIDC is triply deprotonated in complex 2. The doubly deprotonated HPIDC2- coordinates in the mu 3 mode to generate 3D or 2D MOFs, displaying two coordination modes. The triply deprotonated HPIDC3- coordinates in the mu 4 mode to generate a 3D MOF. In 1 a (10(boolean AND)3) metal organic net was fabricated (srs SrSi2 topology). In 2, however, a ({6.8(boolean AND)2}{6(boolean AND)2.8(boolean AND)2.10(boolean AND)2}) framework was formed. In 3 a (8(boolean AND)2.10) metal organic net was fabricated. Complexes 1 and 3 are crystallized in the orthorhombic, a chiral space group (P2(1)2(1)2(1)). Complex 3 is a chiral compound. Solid-state fluorescence emission spectra: complex 1 shows stronger luminescence than complexes 2 and 3. Absolute quantum yield of complex 2 is 3.60%, which is larger than that of the ligand by more than almost 1.7 folds. (c) 2013 Elsevier B.V. All rights reserved.