Alcohol oxidation by O2 to carboxylic acid can be operated in water using noble-metal catalysts, but relies on the undesirable addition of a base such as sodium hydroxide. Using periodic density functional theory (DFT), we built a model including the chemisorption of hydroxide anion at the metal/water interface to rationalize the pivotal role of the added base on the catalytic activity. We demonstrate that the role of the base is to polarize the surface and that a similar promotion could be obtained by tuning the electronic properties of additives, alloy, and support.

Among the best-performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron-poor amine derivatives, metal triflates, such as aluminum triflate, Al(OTf)₃ , stand out. Herein we report the extension of this reaction to electron-rich amines and activated primary alcohols. We provide detailed insight into the structure and reactivity of the catalyst under working conditions in both nitromethane and toluene solvent, through experiment (cyclic voltammetry, conductimetry, NMR spectroscopy), and density functional theory (DFT) simulations. Competition between aniline and benzyl alcohol for Al in the two solvents explains the different reactivities. The catalyst structures predicted from the DFT calculations were validated by the experiments. Whereas a S_N 1-type mechanism was found to be active in nitromethane, we propose a S_N 2 mechanism in toluene to rationalize the much higher selectivity observed when using this solvent. Also, unlike what is commonly assumed in homogeneous catalysis, we show that different active species may be active instead of only one.