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), {[Zn3(PIDC)2(H2O)3]·0.5H2O}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 μ3 mode to generate 3D or 2D MOFs, displaying two coordination modes. The triply deprotonated HPIDC3 − coordinates in the μ4 mode to generate a 3D MOF. In 1 a (10^3) metal organic net was fabricated (srs SrSi2 topology). In 2, however, a ({6.8^2}{6^2.8^2.10^2}) framework was formed. In 3 a (8^2.10) metal organic net was fabricated. Complexes 1 and 3 are crystallized in the orthorhombic, a chiral space group (P212121). 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.