Synthesis, crystal structure, spectroscopy and magnetism of a trinuclear nickel(II) complex with 3,5-pyrazoledicarboxylic acid as bridge ligands

A new complex of [Ni3(dcp)2(H2O)10] (1) (H3dcp = 3,5-pyrazoledicarboxylic acid) has been synthesized from H3dcp and Ni(NO3)2·6H2O by hydrothermal reaction. Complex 1 has the discrete trinuclear structure. Three Ni(II) ions are bridged by two dcp3− ligands, with 10 coordinated water molecules as terminal ligands. The molecules of [Ni3(dcp)2(H2O)10] extend into three-dimensional supramolecular architectures by intermolecular O–H···O hydrogen bonds as well as π-π stacking interactions. Magnetic susceptibility measurement shows that a weak antiferromagnetic interaction is operative between nickel(II) ions and an excellent simulation of the experimental data gives D = 5.27 cm−1, J = −2.19 cm−1 and g = 2.05.