Synthesis and characterizations of three layered ZnII, CdII and MnII coordination polymers with a flexible ligand [3-(2-pyridyl)-1-pyrazolyl] acetic acid

Abstract

Self-assembly of flexible [3-(2-pyridyl)-1-pyrazolyl] acetic acid (Hpypza) with ZnCl2·4H2O, CdCl2·4H2O, and Mn(OAc)2·4H2O affords three new coordination polymers [M(pypza)(HCOO)]n (M = Zn for 1; Cd for 2) and [Mn(pypza)(OAc)]n (3), which are significantly different from the previously reported complexes [Zn(pypza)Cl]2, [Cd(pypza)Cl]n, [Mn(pypza)Cl]2, and [Mn(pypza)Cl]n. These structural differences may be ascribed to the use of different solvents and anions. Single-crystal X-ray diffraction analyses of these polymers indicate that 1 and 2 are isostructural with a 2-D coordination network via bridging pypza− and HCOO− resulting from the hydrolysis of DMF, and 3 also displays a 2-D network connected via pypza− and OAc−. These complexes have been characterized by IR, microanalysis, and powder X-ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of 1–3 have also been investigated. Magnetic properties of the MnII complex have also been measured.