Nickel complexes of aroylhydrazone ligand: synthesis, crystal structure and DNA binding properties

Abstract In this work, three aroylhydrazone ligands ((E)-2-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL1; (E)-3-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL2; and (E)-4-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL3) and their complexes with nickel (Ni(L1)2, NiL1; Ni(L2)2∙2DMF, NiL2; Ni(L3)2∙2DMF, NiL3) were prepared. The single crystal X-ray structures analysis of three compounds showed that they were neutral. The ligand adopts tridentate chelating mode. The nickel ion is six-coordinate with two O atoms and four N atoms from two ligands, and forms an octahedral arrangement. The investigation of DNA binding ability by ultraviolet and fluorescence titrations showed that NiL2 and NiL3 exhibit moderate binding affinity toward calf Thymus DNA. Spectroscopy, molecular docking, and molecular dynamics simulation indicated that NiL2 and NiL3 bind at the minor groove of DNA through intercalation.