The Transfer Hydrogenation of Cinnamaldehyde Using Homogeneous Cobalt(II) and Nickel(II) (E)-1-(Pyridin-2-yl)-N-(3-(triethoxysilyl)propyl)methanimine and the Complexes Anchored on FeO Support as Pre-Catalysts: An Experimental and In Silico Approach.

The imino pyridine Schiff base cobalt(II) and nickel(II) complexes ( and ) and their functionalised γ-FeO counterparts ( and ) were synthesised and characterised using IR, elemental analysis, and ESI-MS for and , and single crystal X-ray diffraction for , while the functionalised materials and were characterized using IR, XRD, SEM, TEM, EDS, ICP-OES, XPS and TGA. Complexes , and the functionalised materials and were tested as catalysts for the selective transfer hydrogenation of cinnamaldehyde and all four pre-catalysts showed excellent catalytic activity. Complexes and acted as homogeneous catalysts with high selectivity towards the formation of hydrocinnamaldehyde (88.7% and 92.6%, respectively) while and acted as heterogeneous catalysts with high selectivity towards cinnamyl alcohol (89.7% and 87.7%, respectively). Through in silico studies of the adsorption energies, we were able to account for the different products formed using the homogeneous and the heterogeneous catalysts which we attribute to the preferred interaction of the C=C moiety in the substrate with the Ni centre in (-0.79 eV) rather than the C=O (-0.58 eV).