Synthesis of new tripodal ligand 5-(bis(3,5-dimethyl-1H-pyrazol-1-ylmethyl)amino)pentan-1-ol, catecholase activities studies of three functional tripodal pyrazolyl N-donor ligands, with different copper (II) salts

A new tripodal ligand, 5-(bis(3,5-dimethyl-1H-pyrazol-1-ylmethyl)amino)pentan-1-ol, has been synthesized. Three functional, N-donor tripodal pyrazolyl ligands, L1: 2-(bis(3,5-dimethyl-1H-pyrazol-1-ylmethyl)amino)ethan-1-ol; L2: 4-(bis(3,5-dimethyl-1H-pyrazol-1-ylmethyl)amino)butan-1-ol and L3: 5-(bis(3,5-dimethyl-1H-pyrazol-1-ylmethyl)amino)-pentan-1-ol have been examined for their catalytic oxidative activities. The dioxygen complexes of copper (II) were generated in situ by stirring copper salts and the tridentate pyrazole ligands. It has been found that these compounds are very efficient to give quinone. The lengths of the lateral chain carrying the hydroxyl group and the nature of the anion copper (II) salts have been investigated. These two parameters play an important effect on the oxidation reaction rate.