DFT Studies on the Mechanism of Alcohol Oxidation Catalyzed by the Ni III /bipy Complex

On the basis of our previous DFT calculations on the catalytic reaction cycle catalyzed by Cu II /bipy (2,2′‐bipyridine), a new Ni III /bipy catalyst has been designed. By examining the mechanism of alcohol oxidation catalyzed by the Ni III /bipy catalyst, it was found that the barrier calculated for the rate‐determining step (16.3 kcal/mol) is 12.2 kcal/mol lower than that for the corresponding Cu II /bipy catalyst. This indicates that the Ni III /bipy catalyst might be a potential catalyst for green alcohol oxidation. In addition, the reasons for the higher activity of the Ni III /bipy catalyst relative to the Cu II /bipy catalyst are discussed. It was found that the unoccupied Ni III (d 7 ) d   x   2 – y   2orbital might be the reason for the higher activity of the Ni III /bipy catalyst. The singly occupied Ni III (d 7 ) d   z   2orbital plays a very important role in producing the final product (CH 3 CHO) in the absence of an oxidation auxilliary.