Pyrazole‐Based Ligands for the [Copper–TEMPO]‐Mediated Oxidation of Benzyl Alcohol to Benzaldehyde and Structures of the Cu Coordination Compounds

Abstract

Abstract New pyrazole‐based ligands have been designed, and the catalytic performances of their copper(II) complexes for the [copper/TEMPO]‐mediated oxidation of benzyl alcohol to benzaldehyde have been examined. The pyridine‐pyrazole ligands give efficient catalysts, while the use of naphthol‐pyrazole ligands results in inactive catalytic systems. Single‐crystals of four Cu coordination compounds obtained from pyridine‐pyrazole ligands and a free ligand have been isolated and were characterized by X‐ray diffraction. Thus, the solid‐state structures of three copper(II) complexes are described, together with a copper(I) coordination chain, exhibiting luminescent properties. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)