Copper (II) complexes with tridentate Schiff bases of the ONN type and with symmetric and asymmetric tetradentate schiff bases: synthesis, characterization e studies as catalysts in the oxidation of catechols

• Grant number: 08/10143-5
• Support type: Regular Research Grants
• Duration: February 01, 2009 - January 31, 2011
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal researcher: Edward Ralph Dockal
• Grantee: Edward Ralph Dockal
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Transition metal complexes participate in many chemical processes. The study of these complexes is very interesting because of the diversified chemistry and for their great utility. Transition metal complexes act as catalysts in various homogenous and heterogeneous systems. The catalytic activity of these complexes is due to the presence of only one active site for the catalytic reaction. Thus this type of reaction can be advantageous due to the elevated selectivity of the metal center. For these reasons, the object of this project is the systematic study involving three series of salen-type Schiff base copper (II) complexes. The Schiff bases are tridentate, of the type ONN, and symmetrical and asymmetrical tetradentates, ONNO. The new catalysts will be initially characterized by various techniques such as their visible-ultraviolet and infrared spectra, melting points, elemental analysis, solubility in various solvents and conductivity. The catalytic reactions of catechol oxidations will be carried out in flasks and the progress of the reaction monitored by gas chromatography. The kinetics of the catalytic reactions also will be followed in the visible-ultraviolet region. The products of the reactions also will characterized by their vibration and electronic spectra, NMR, 1H e 13C, and what other techniques deemed necessary. A correlation between electronic effects, the Hammett value, and steric effects of the groups on the aromatic rings of the Schiff bases and the efficiency of the copper (II) complexes as catalysts in the oxidation of catechols. From the kinetic data, the rate constants, concentrations effects of the substrate and catalysts, activation parameters and a possible reaction mechanism will be determined. (AU)