The Evolution of Reactive Ligands in the Catalysis of Radical Processes by Copper Complexes

Non-innocent ligands in copper complexes catalyzed oxidation of thiols

“…Thus, it is ascertained that, as in the systems of copper complexes with aliphatic amines that we studied previously, [32,33] in the case of complexes with heterocycles and amides, too, a mixed-ligand copper complex is formed as an intermediate. It is also noteworthy that by analogy with systems containing aliphatic amines, heterocyclic ligands also participate in redox processes that occur in the metal ion coordination sphere.…”

“…For the catalytic reaction to proceed, it is necessary to use compositions containing copper complexes and excess ligand. In our previous works, [32,33] we have established the mechanism of the process, the schematic view of the mechanism in a simplified way is presented in Scheme 1.…”

“…The cycle of ligand transformation is interrupted due to low efficiency of dimethyl sulfide oxidation to DMSO and, as a consequence, the copper complexes with DMSO show low operational stability [33].…”

“…Copper complexes were obtained by the reaction of an ethanolic solution of copper(II) chloride with ligands as described in [32,33]. All complexes with nitrogen compounds were insoluble in ethanol.…”

“…The solid catalyst (5×10 −5 mole of copper) was placed in a flask and 25 ml of dodecane-1-thiol solution in isooctane was added ([RSH] = 5×10 −2 M). [33] To estimate the role of copper, analogous experiments were performed without copper (the sample consisted of isooctane, thiol ([RSH] = 5×10 −2 M) and the ligand (concentration 2×10 −2 M)).…”