Synthesis, physicochemical characterization, and crystal structures of Ni(II) and Cu(II) sulfadiazine and 2,2’-bipyridine complexes. Pharmacological assessment of related compounds

Abstract

In the present work, the biological properties (antitumoral and antimicrobial) and the toxicity of the sulfadiazine (SDZ) ternary complexes were assessed. Novel ternary complexes based on SDZ and 2,2’- bipyridine (bpy, secondary ligand) with nickel(II) and copper(II) have been synthesized and characterized by elemental analyses, X-ray diffraction, FTIR and Raman spectroscopies, UV-visible spectroscopy, and thermogravimetric techniques. Their congeners of cobalt(II) and zinc(II) were also included for the biological determinations. [Ni(SDZ)2(bpy)]·2EtOH and [CuCl(SDZ)(bpy)] complexes crystallize in the Pc monoclinic space group and the triclinic P-1 space group, respectively. The nickel(II), cobalt(II) and zinc(II) complexes are structurally similar, with MN6 hexacoordinated environment. The geometry of [Ni(SDZ)2(bpy)]·2EtOH complex is closer to an octahedral environment, whereas [Co(SDZ)2(bpy)] and [Zn(SDZ)2(bpy)] complexes are closer to a trigonal prismatic environment. On the other hand, [CuCl(SDZ)(bpy)] complex is pentacoordinated, with a CuN4Cl coordination sphere, and the geometry is closer to a distorted square-based pyramid. The cytotoxicity was evaluated against human osteosarcoma (MG-63) and human lung carcinoma (A549) cell lines. The antimicrobial activity was studied against bacteria and fungi derived from the American Type Culture Collection (ATCC) and clinical isolates. The biological activity of the SDZ ligand is enhanced upon complexation with metals, with the [CuCl(SDZ)(bpy)] complex showing the strongest activity. The complexes neither induce mutagenicity (frameshift or base-pair substitution mutations) on S. typhimurium strains nor acute toxicity on A. salina nauplii. Complexation offers potential for new drug development.