Peroxidative oxidation of alkanes and alcohols under mild conditions by Di- and tetranuclear copper (II) complexes of Bis (2-Hydroxybenzylidene) isophthalohydrazide

• Autor(a) principal: Sutradhar, Manas
• Data de Publicação: 2018
• Outros Autores: Alegria, Elisabete, Guedes Da Silva, M. Fátima C., Liu, Cai-Ming, Pombeiro, Armando
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.21/9081
• topic: Cu (II) complexes; Microwave assisted oxidation of alcohols; Oxidation of alkanes; Solvent free process; Magnetism

Bis(2-hydroxybenzylidene)isophthalohydrazide (H4L) has been used to synthesize the dinuclear [Cu2(1_NO2:2_N0O02-H2L)(NO3)2(H2O)2] (1) and the tetranuclear [Cu4(_-1_NO2:2_N0O2-H2L)2(_-NO3)2(H2O)4]_2C2H5OH (2) complexes. The solvent plays an important role in determining the ligand behaviour in the syntheses of the complexes. An ethanol-acetonitrile mixture of solventes favours partials enolization in the case of 2. Both complexes have been characterized by elemental analysis, infrared radiation (IR), single crystal X-ray crystallography and electrochemical methods. The variable temperature magnetic susceptibility measurements of 2 show strong antiferromagnetic coupling between the central nitrato-bridged Cu (II) ions. The catalytic activity of both 1 and 2 has been screened toward the solvent-free microwave-assisted oxidation of alcohols and the peroxidative oxidation of alkanes under mild conditions. Complex 1 exhibits the highest activity for both oxidation reactions, leading selectively to a maximum product yield of 99% (for the 1-phenylethanol oxidation after 1 h without any additive) and 13% (for the cyclohexane oxidation to cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone after 3 h).