Nickel(<scp>ii</scp>) riboflavin complex as an efficient nanobiocatalyst for heterogeneous and sustainable oxidation of benzylic alcohols and sulfides

In this paper, a novel nickel–riboflavin nanocomplex has been prepared via the incorporation of Ni(OAc)2 with riboflavin. This new heterogeneous nanocatalyst showed high catalytic activity towards green oxidation reactions. The structural and morphological characterization of the as-prepared nanocomplex was carried out using different techniques such as FT-IR, ICP-AES, TGA, SEM, EDX, TEM, UV-vis and elemental analysis. The nano-biocatalyst showed high oxidation stability and desired activity in the aerobic benzylic oxidation of a structurally diverse set of alcohols in ethyl acetate as a safe solvent. Further, oxidation of sulfides in the presence of H2O2 was successfully achieved, producing the corresponding sulfoxides in high yields and with excellent selectivity. The facile and practical reusability of the solid catalyst at the end of the reaction was also observed.