Hydro(solvo)thermal synthesis, structures, luminescence of 2-D zinc(ii) and 1-D copper(ii) complexes constructed from pyridine-2,6-dicarboxylic acid N-oxide and decarboxylation of the ligand

Two new coordination polymers [Zn(pydco)(H2O)]n (1) and [Cu(pyco)2]n (2) (pydco = pyridine-2,6-dicarboxylic acid N-oxide, pyco = 2-pyridine carboxylic acid N-oxide) have been synthesized by hydro(solvo)thermal reaction of pydco and two transition metal ions in one pot. Complex 1 is a 2-D network structure containing double helical chains with a strong emission. Complex 2 displays a 1-D infinite ladder-like chain arrangement. Interestingly, pyco came from the in situ decarboxylation of pydco in the hydrothermal reactions. Through a comparison study in a series of hydro(solvo)thermal reaction of pyridine-2,6-dicarboxylic acid N-oxide and transition metal ions, we confirm that the decarboxylations was catalyzed by Mn(II) ions.