Bioinspired covalently grafted Cu(II)–C protected amino acid complexes: selective catalysts in the epoxidation of cyclohexene

Abstract

In this work, the syntheses of covalently grafted C-protected Cu(II)-amino acid (methylesters of L-histidine and L-cystine) uniform and mixed ligand complexes with two different amino acid esters are described using chloropropylated silica gel as the support. The conditions of the syntheses were systematically altered. The structural features of the substances obtained were studied by the Kjeldahl method, ICP-MS, X-ray absorption and mid/far infrared spectroscopies. The superoxide dismutase-like activities of the materials were determined in a biochemical test reaction and these substances were also tested as catalysts in the oxidation of cyclohexene. It was possible to prepare metal ion-amino acid complexes grafted with covalent bonds onto the supports. All the covalently anchored materials displayed superoxide dismutase-like activity and most of them were active in the oxidation of cyclohexene, providing the epoxide with high selectivity.