Ni(II) and Cu(II) complexes of pyridyl-pyrazole ligands: syntheses, crystal structures and influence of metal ion

The ligand 3-(2-pyridyl)pyrazol-1-yl acetic acid (HL) has been prepared and the complexes [Ni(L)(N-3)](n) and [Cu(L')(2)(H2O)(2)](n) [HL' = 3-(2-pyridyl) pyrazole] have been synthesised by reaction of HL and NaN3 with NiCl2 center dot 6H(2)O and CuCl2 center dot 2H(2)O under hydrothermal condition. Single-crystal X-ray diffraction analysis shows that [Ni(L)(N-3)](n) possesses a 1D infinite chain structure, which further forms a 2D supramolecular framework connected by pi center dot center dot center dot pi weak interactions, and [Cu(L')(2)(H2O)(2)](n) is linked to form a 1D chain by pi center dot center dot center dot pi weak interactions, then to a 2D supramolecular structure by weak C-H center dot center dot center dot O interactions.