Construction of variable dimensional cadmium(<scp>ii</scp>) coordination polymers from pyridine-2,3-dicarboxylic acid

Abstract

Five variable dimensional cadmium(II) coordination polymers, {[Cd2(bpy)2(NO3)4·H2O]}n (1), [Cd(2,3-Pydc)]n (2), {[Cd2(2,3-Pydc)(bpy)2(NO3)(H2O)2]·(NO3)·3H2O}n (3), [Cd2(2,3-Pydc)2(H2O)]n (4) and {[Cd(NA)(NO3)(H2O)2]}n (5), have been synthesized by hydrothermal reaction of pyridine-2,3-dicarboxylic acid (2,3-H2Pydc) and 4,4′-bipyridine (bpy) with cadmium nitrate under different temperatures. At 80 °C, the mixture A of a 1-D compound 1 containing only a ligand of 4,4′-bpy and 2-D 36·46·53 topological compound 2 with a single ligand of 2,3-Pydc2− were obtained. At 120 °C or so, the 3-D 64·102 topological compound 3 containing mixed ligands of 2,3-Pydc2− and 4,4′-bpy was assembled. However, as the temperature increased to 170 °C, partial 2,3-H2Pydc in situ decarboxylated into nicotinic acid (HNA) and consequently another mixture B of 3-D 316·423·53·63 topological compound 4 reported previously and 1-D chain-like compound 5 containing NA− were constructed. Meanwhile, the complexes 1–3 and 5 exhibited good luminescent properties.