Synthesis, characterization and benzene oxidation promoted by a new mononuclear copper(II) complex, [Cu(BTMEA)2Cl]Cl

Abstract

The aim of this work is to present the synthesis, crystal structure, electrochemical behavior, spectroscopic properties (FT-IR and UV-Vis) and catalytic activity toward benzene oxidation of a new mononuclear copper(II) complex [Cu(BMTEA)2Cl]Cl, (1) (BTMEA: bis(2-thienylmethyl)-1,2-ethylenediamine). The reaction between BTMEA and [Cu(OH2)2]Cl2, in methanol, resulted in 1, which crystallizes as an irregular blue crystal, space group Pnna, with a = 20.101(3), b = 12.094(6), c = 12.741(2) Å, V = 3097.4(17) ų, Z = 4. In 1, the copper ion is pentacoordinated, showing a distorted square pyramidal geometry. Complex 1 shows two irreversible redox processes at -0.35 V and at 0.456 V versus NHE, which are associated with the CuII/CuI redox couple and with a coupled reaction involving the chloride ligand. The catalytic activity of 1 was evaluated through benzene oxidation reaction, using hydrogen peroxide as oxidant. Reaction products (phenol and p-benzoquinone) were identified by gas chromatography.