Copper(ii) complexes with 2,2′:6′,2′′-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine substituted with quinolines. Synthesis, structure, antiproliferative activity, and catalytic activity in the oxidation of alkanes and alcohols with peroxides

Abstract

A series of 2,2′:6′,2′′-terpyridine (terpy), 2,6-di(thiazol-2-yl)pyridine (dtpy) and 2,6-di(pyrazin-2-yl)pyridine (dppy) derivatives with n-quinolyl substituents (n = 2 and 4) was used to synthesize five-coordinate complexes [CuCl₂(n-quinolyl-terpy)] (1–2), [CuCl₂(n-quinolyl-dtpy)] (3–4) and [CuCl₂(n-quinolyl-dppy)] (5–6), respectively. The main emphasis of the research was to investigate the impact of the triimine skeleton (terpy, dtpy and dppy) and n-quinolyl pendant substituent on the antiproliferative and catalytic properties of 1–6. The obtained Cu(II) compounds were studied as antiproliferative agents against human colorectal (HCT116) and ovarian (A2780) carcinoma, and they were used as catalysts for the oxidation of alkanes and alcohols with peroxides under mild conditions. The kinetic characteristics of the oxidizing species generated by the catalytic system Cu(II) complex–H₂O₂ in CH₃CN were obtained from the dependence of the alkane oxidation rate on its initial concentration. A model of competitive interaction of hydroxyl radicals with CH₃CN and RH in the catalyst cavity has been proposed which is based on the simultaneous study of kinetics and selectivity in alkane oxidations.