Síntese e Caraterização do Complexo de Cobre [Cu(phen)(isn)(NO2)]Cl

Abstract

Copper is a trace element with a fundamental role in several biological systems, being present in several metalloenzymes, like superoxide dismutase and cytochrome oxidase. Copper complexes are of great importance in the field of medicinal inorganic chemistry, as they are capable of inducing DNA cleavage via intercalation and can be used as chemotherapeutic agents. For this reason, the study of copper-based coordination compounds that can be used as anticancer drugs has grown in recent decades due to their low toxicity and may be an effective alternative when compared to platinum-based compounds. In this context, the present work aims to synthesize and characterize the copper complex [Cu(phen)(isn)(NO2)]Cl where phen = 1,10'-phenanthroline, isn = isonicotinamide and NO2- = nitrite. The complex was obtained from the precursor cis-[Cu(phen)Cl2] complex dissolved in water with the addition of the ligand isonicotinamide in methanol and, later, addition of nitrite. Via the UV-Vis technique, in aqueous medium, it was possible to observe in the ultraviolet region bands at 204 and 272 nm attributed to the attributed to the intrabonding transitions of the π → π* type of both ligands (1,10'-phenanthroline and isonicotinamide) as also bands at 220 and 293 nm associated with the π → π* transitions of 1,10'-phenanthroline. Additionally, in the visible region of the spectrum it was possible to verify a band at 696 nm referring to the d-d transition of copper (II). Via IR spectroscopy, the complex presents bands at 3380 and 3166 cm-1 corresponding to the asymmetric and symmetric υ(N-H) of isonicotinamide, respectively, as well as a band at 1683 cm-1 referring to the υ(C=O) also of that binder. Furthermore, there are bands in the range of 1600-1475 cm-1 attributed to υ(C=C) and υ(C=N) present in the aromatic ring of phenanthroline as well as modes at 1396 and 1270 cm-1 associated with υ(NO2-) asymmetric and symmetrical, respectively, of the nitrite ligand, indicating the coordination of these ligands to the metallic center. Finally, in electrochemistry, the square wave voltammogram obtained in NaTFA 0.1 mol.L-1 and pH = 7.0 for the nitrocomplex showed a potential at 0.019 V attributing to the redox pair CuII/CuI, which is compatible with those affected in physiological processes. The data suggest that this complex has potential in a possible biological application.