The electro-oxidation of dimethylamine borane: Part 1, polycrystalline substrates

The oxidation of dimethylamine borane (DMAB) on polycrystalline gold electrodes has been investigated using a number of electrochemical techniques. The oxidation of borohydride has been studied to provide a comparison: for DMAB we observe two, sequential oxidation processes on gold. At low potentials, three electrons are extracted from the molecule, implying that hydrogen is not oxidised, whereas at high potential a six electron oxidation occurs. The dimethylamine fragment is also oxidised on gold, albeit at higher potentials, in contrast to assumptions made in previous literature. DMAB oxidation is also studied on platinum and glassy carbon: the data suggests that only part of the amine–borane dissociates in alkaline solution, in particular cleavage of the B−N bond requires prolonged exposure to metallic surfaces.

Research highlights► We have studied the oxidation of dimethylamine borane (DMAB) on Au electrodes. ► The results have been compared with oxidation of dimethylamine and borohydride. ► Further comparison is made with DMAB oxidation on glassy carbon and Pt electrodes. ► The mechanism of DMAB electro-oxidation is hereby proposed.