Synthesis, characterization and antimicrobial activity of Ni(II) and Zn(II) complexes with N′,N′2-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide. Crystal structures of two highly solvated bimetallic complexes of Ni(II)

The bimetallic [Ni2(H2L2)2](ClO4)4 (1), [Ni2(HL2)(H2L2)](ClO4)3 (2) and [Zn2(H2L2)2](BF4)4 (3) complexes (H2L2 = N′,N′2-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide) were synthesized and characterized. The structure of complexes (1) and (2) was established by X-ray analysis. NMR spectroscopy was used for the characterization of complex (3). The complexes (1) and (2) were obtained from the same synthetic reaction and two crystal types of these complexes have been isolated during the fractional crystallization process.In complex (1) each Ni(II) ion is coordinated with two NNO donor atom sets from two H2L2 ligands forming an octahedral geometry. Similarly, in complex (2) the octahedral geometry of each Ni(II) ion is attained by coordination of two NNO donor atom sets, one from the neutral and the other from the monoanionic form of the ligand. The antimicrobial activity of the ligand and complexes is also presented.

Graphical abstractThe bimetallic Ni(II) complexes with N′,N′2-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide (H2L2), [Ni2(H2L2)2](ClO4)4 (1) and [Ni2(HL2)(H2L2)](ClO4)3 (2), were isolated during the fractional crystallization process. The less stable green crystals of (1) with a layered structure converted slowly to brown crystals of (2) having a channel structure while being kept in the solution.Figure optionsDownload full-size imageDownload as PowerPoint slide