Synthesis and crystal structure of Cu(II) and Co(II) complexes with 1,3-dimethyl-pyrazole-5-carboxylic acid ligand

In the reaction of 1,3-dimethylpyrazole-5-carboxylic acid (HL) with M(OAc)2·4H2O, (M = Cu or Co), two novel complexes were prepared, the square-planar [CuL2(H2O)2] and the octahedral [CoL2(MeOH)4]. The crystal structures were determined by single-crystal X-ray diffraction. In both complexes, the deprotonated acid displays monodentate coordination to the metal ions. According to the results of a CSD survey, this is the first structural report on the metal complexes with an N1-substituted pyrazole-5-carboxylic ligand