Synthesis and characterization of a nickel(II) unsymmetrical salencomplex as an efficient catalyst for selective oxidation of alcohols

Oxidation of alcohols to the carbonyl compounds is a major transformation in organicsynthesis because the carbonyl compounds such as aldehydes and ketones are versatileintermediates for synthesizing various drugs, chemicals, vitamins, and fragrances [۱]. Schiffbase transition metal complexes are interesting oxidation catalysts owing to their easysynthesis and their chemical and thermal stability. Unsymmetrical Schiff base ligands areimportant compounds and received much attention due to the bounding of central metal ionswith unsymmetrical ligands in natural systems [۲]. In the present work, unsymmetrical salenligand was synthesized in good yield according to the published procedure [۳], and thenmetallated with NiCl۲.۶H۲O to obtain complex ۱. The prepared complex ۱ was characterizedby FT-IR, UV-Vis, ۱HNMR, and elemental analysis. The synthesized complex ۱ wassuccessfully employed as a new and efficient homogeneous catalyst for selective oxidation ofvarious alchols to the corresponding aldehydes and ketones in acetionitrile under refluxconditions (Scheme۱). Good to excellent yields, short reaction times, and use of tert-BuOOH(TBHP) as a green oxidant can be mentioned as advantages of this method for oxidation ofalcohols.

کلیدواژه ها:

Unsymmetrical Schiff base ، Nickel(II) complex ، Homogeneous catalyst ، Selectiveoxidation ، Alcohol