Synthesis and Crystal Structures of Alkali and Alkaline Earth Metal Complexes of 3,5-Dinitropyrazolyl-4-carboxylate

摘要

The synthesis and crystal structures of 3,5-dinitro-1H-pyrazolyl-4-carboxylic acid (H2dnpzc) and its four complexes with Ca~(2+), Ba~(2+), Na~+ and K~+ are reported in this paper. Ca(dnpzc)·5H_2O exhibits a 1D polymeric structure, whereas Ba(dnpzc)·4H_2O possesses a 2D structure. The structure of Na_2(dnpzc)·4H_2O consists of 2D layers of [Na(dnpzc)]_n~– and 1D chains of [Na(H_2O)_3]_n~+. K2(dnpzc)·H_2O has a true 3D structure. It was observed that the doubly deprotonated ligand (dnpzc2–) can act as a versatile bridge to form polymeric structures by varying combinations of its 8 potential donor atoms (two carboxy O atoms, two pyrazolyl N atoms and four nitro O atoms). Particularly in the structure of K_2(dnpzc)·H_2O, all the 8 donor atoms of dnpzc2– take part in the coordination and as many as 10 potassium atoms are connected by one ligand.