Catalytic efficacy of Schiff-base copper(II) complexes: Synthesis, X-ray structure and olefin oxidation

• Published in: Polyhedron 2008-04, Vol.27 (6), p.1556-1562
• Main Authors: Adhikary, Chandan, Bera, Rajesh, Dutta, Buddhadeb, Jana, Sreyashi, Bocelli, Gabriele, Cantoni, Andrea, Chaudhuri, Siddhartha, Koner, Subratanath
• Format: Article
• Language: English
• Subjects: Catalytic oxidation; Copper(II) complex; Olefins; Schiff-base ligand; tert-Butyl-hydroperoxide; X-ray structure
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2008.01.030

Copper(II) complexes containing tridentate and tetradentate Schiff-bases have been synthesized and characterized. Olefin oxidation reactions catalyzed by these complexes, in different solvent media, have been studied by using tert-BuOOH as an oxidant. Three copper(II) Schiff-base complexes, [Cu(L 1)(H 2O)](ClO 4) ( 1), [Cu(L 2)] ( 2) and [Cu(L 3)] ( 3) have been synthesized and characterized [where HL 1 = 1-( N- ortho-hydroxy-acetophenimine)-2-methyl-pyridine], H 2L 2 = N, N′-(2-hydroxy-propane-1,3-diyl)-bis-salicylideneimine and H 2L 3 = N, N′-(2,2-dimethyl-propane-1,3-diyl)-bis-salicylideneimine]. The structure of complex 1 has been determined by single crystal X-ray diffraction analysis. In complex 1, the copper(II) ion is coordinated to one oxygen atom and two nitrogen atoms of the tridentate Schiff-base ligand, HL 1. The fourth coordination site of the central metal ion is occupied by the oxygen atom from a water molecule. All the complexes exhibit high catalytic activity in the oxidation reactions of a variety of olefins with tert-butyl-hydroperoxide in acetonitrile. The catalytic efficacy of the copper(II) complexes towards olefin oxidation reactions has been studied in different solvent media.