A new mixed pyrazole-diamine/Ni(II) complex, Crystal structure, physicochemical, thermal and antibacterial investigation

The new mixed complex {[2Ni(L1)2.2Ni(L1)(L2)].2(NO3)4•2H2O} was obtained from a mixture, under aerobic conditions, of a solution of Ni(NO3)2,6H2O and the two diamine pyrazolic ligands L1, N1-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)propane-1,2-diamine, and L2, N2-((3,5-dimethyl-1H-pyrazol-1-yl)-methyl)propane-1,2-diamine. Obtained in very good yield, this complex was identified and characterized by FT-IR, EDX, ultraviolet-visible spectroscopies and single-crystal X-ray diffraction (XRD). The structural peculiarity is that two isomeric forms of molecules C18H36N8Ni have co-crystallized with H2O and NO3 molecular units. The triclinic structure of P1 symmetry is stabilized by the numerous hydrogen bonds that occur in the crystal lattice. The thermal behavior of this Ni(II) complex was studied in an open atmosphere via TG/DTG. The L1, L2 ligands and the Ni(II) complex were evaluated for their antibacterial activity against a series of Gram-negative and Gram-positive bacteria.