Cu (II) and Ni (II) complexes of 1-(N-phenylthiocarbamoyl)-pyrazolines: Synthesis, electrochemistry and cytotoxic properties

Abstract

Two series of novel Cu (II) (4a–e) and Ni (II) (5a–e) complexes bearing 1-(N-phenylthiocarbamoyl)-pyrazoline ligands (3a–e) were synthesized and characterized. The structures of Ni (II) complexes 5a, c were confirmed by X-ray crystallography; both complexes have a distorted octahedral coordination environment of the Ni (II); metal atoms are coordinated by pyridyl and pyrazoline nitrogen atoms and thiocarbonyl sulfur of two ligand moiety, with two chloride anions in the outer sphere. The Cu (II) complex 4a derived from ligand 3a demonstrate a non-typical electrochemical behavior indicating Cu (I) complex formation which can be explained either by pyrazoline ligand ring opening in DMF solution or by a non-innocent nature of 3a. All of the synthesized complexes were cytotoxic against HCT116 and К562 cell lines; the most cytotoxic ligand was 3d, which is structurally related to combretastatin A4.

Keywords

• Cu (II) complexes
• Ni (II) complexes
• Cyclic voltammetry
• X-ray diffraction
• Cytotoxicity