Complexos de COBRE (II) contendo ligantes FENOLATO/ NAFTALATO-IMINA: Síntese, caracterização, estudos computacionais empregando DFT e avaliação da atividade antioxidante

Abstract

A new serie of Cu(II) complexes supported ONO- and ONS-donor Schiff base ligand (phenoxy/naphthoxy-imine) have been synthesized and characterized using various physico-chemical techniques.The dinucleares complexes of the Cu(II) designated Cu1-Cu4 were synthesized by reacting the pro-ligands with [CuCl2.2H2O]. In the solid state, Cu1, [bis[{(µ2-chloro)-2-MeO-Ph-CH2-(N=CH)- 2,4-tert-butyl-2-OC6H2)}Cu(II)] features κ2 coordination of the monoanionic phenoxy‐imine ligant onto the copper center. While in the bis[{(µ2-chloro)-2-MeS Ph-CH2-(N=CH)-2-(OC10H6)}Cu(II)] complex, Cu4 containing naphthoxy-imine ligant, with donor atoms ONS features κ3 coordination of the monoanionic naphthoxy‐imine ligant onto the copper center. The reaction of two equivalents of the ligand [2‐MeS‐Ph‐CH2‐(N=CH)‐2,4‐tert‐butyl‐2‐(HOC6H2)] with [Cu(OAc)2·H2O] led to the synthesis of a bis-ligand monomeric complex, with the ligand acting bidentate and coordinating donor atoms ON to the metallic center and quadratic geometry as show by X-ray diffraction characterization and high resolution electrospray ionization mass spectrometry. To investigate the antioxidant properties of all Cu(II) complexes obtained, it was performed spectrophotometric methods for the determination of the determination of free radical-scavenging compounds including the ABTS+ , the DPPH and the SOD-like assays. The dinucleares compounds Cu2-Cu4, from the concentration of 5 µM, presented a good activity in scavenging ABTS+ radical. Similarly, most of the Cu(II) complexes showed DPPH radical-scavenging activity except the compound bis[{2-MeS-Ph-CH2-(N=CH)-2,4-tert-butyl-2-(OC6H2)}Cu(II)]. Cu(II) complexes supported NNO, ONO- and ONS-donor Schiff base ligand (phenoxy imine) (Cu6-Cu9) have been synthesized and characterized using physico chemical techniques and theorical studies.