Mechanistic insights on the catalytic hydrogenation of cyclohexene by ruthenium(III) N2O2 tetradentate Schiff-base complex

Abstract

The work aimed at the mechanistic investigation of the catalytic hydrogenation of cyclohexene by a newly synthesized ruthenium(III) Schiff base complex, [RuLCl(H2O)], where L represents tetradentate N2O2 naphthaldiimine. Several physicochemical methods were used to characterize the target complex. Furthermore, it was observed that the catalytic activity relies mainly on solvent composition. On the other hand, the density functional theory (DFT) was applied to explore the mechanistic story of the catalytic reaction. The findings showed that the complex has two stable isomers (trans and cis), which serve as platforms for the destination toward the hydrogenation journey through the in-situ generation of the active catalysts. Accordingly, one can imagine them as robust and weak machines for cyclohexane production in the reaction vessel. Interestingly, the experimental and the theoretical total activation energies are so comparable which supports the validity of the mechanistic insights.