Spontaneous Resolution of Zinc Coordination Polymers with 2-(4-Pyridyl)imidazole-4,5-dicarboxylic Acid

Solvothermal reaction between achiral 2-(4-pyridyl)imidazole-4,5-dicarboxylic acid (H2L) and zinc nitrate afforded two spontaneously resolved three-dimensional metal-organic frameworks formulated as ZnLn?2nH2O, with the space group being P41212 and P43212 respectively. The coordination polyhedral are - and -Zn(NO)2N trigonal bipyramidal geometries, respectively. There are about 0.2 nm wide ultramicroporous channels with different chiralities, among which are the right- and left-handed helix of water chains formed by hydrogen bonds. The main frameworks keep stable under 320 ℃. The fluorescence of the crystals is enhanced over two times than that of the free ligand. The present work is helpful for further studies on constructing chiral porous materials with achiral starting substances.