Synthesis and characterizations of three layered Zn^II, Cd^II and Mn^II 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 Mn^II complex have also been measured.

Graphical 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.

Keywords:

• Coordination polymer
• Hydrolysis of DMF
• [3-(2-Pyridyl)-1-pyrazolyl] acetic acid
• Carboxylate

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [grant number 21101116]; Tianjin Normal University [grant number 52XQ1104].