Synthesis and crystal structures of mononuclear CuII/CoII coordination complexes from pyrazole-dicarboxylate acid derivatives

Three novel pyrazole-dicarboxylate acid derivatives namely 1-(carboxymethyl)-5-methyl-1H-pyrazole3-carboxylic acid [L1], 1-[(3-carboxy-5-methyl-1H-pyrazol-1-yl) methyl]-5-methyl-1H-pyrazole-3 -carboxylic acid [L2] and 1-[3-(3-carboxy-5-methyl-1H-pyrazol-1-y1) propy1]-5-methyl-1H-pyrazole-3carboxylic acid [L3] were synthesized and characterized by H-1 NMR and ESI-MS. The coordination/chelation and crystallization property of these organic molecules with Cu-II/Co-II/Zn-II were studied and single crystals were obtained with L1 and L3 on reaction with Cu(NO3)(2) and Co(NO3)(2), respectively. Single crystal X-ray diffraction experiments revealed that both resulted in mononuclear chelate complexes of formula [Cu(L1)(2)(H2O)center dot 2H(2)O (A) and [Co(L3)(H2O2] (B). A and B consist of 2D hydrogen bonded networks with and without lattice included water molecules, respectively. The crystal structure of the free derivative 1.2 is also presented. (C) 2014 Elsevier Ltd. All rights reserved.