Benzil/triethylamine: a photo-reducing system for Cu2+

Abstract

We have investigated the photo-induced reduction of Cu2+–Cu0 using benzil/triethylamine mixtures. The formation of elemental Cu is indicated by the appearance of its characteristic plasmon absorption peaks at 515 nm and 620 nm. Importantly, the nature of the counterion of the Cu2+ salt affects the reduction process. In the presence of Cl−, the reduction proceeds faster than with SO42-. Photo-induced electron transfer between excited benzil and triethylamine leads to the benzil radical anion, which acts as the reducing agent for Cu2+ and generates Cu0.Graphical abstract Electronic supplementary materialThe online version of this article (10.1007/s00706-017-2085-7) contains supplementary material, which is available to authorized users.

Bis(acyl)phosphine Oxides as Stoichiometric Photo‐Reductants for Copper Nanoparticle Synthesis: Efficiency and Kinetics

“…This reaction requires water as solvent, a pH range between 1–7, and rather long irradiation times (>1 h) to give good yields. Elemental analysis indicated that one BAPO‐OH molecule possibly serves as four electron reductant surpassing the efficiency of aromatic ketones and α‐hydroxyketones as photo‐reducing agents [23,48–52] …”

“…Elemental analysis indicated that one BAPO-OH molecule possibly serves as four electron reductant surpassing the efficiency of aromatic ketones and α-hydroxyketones as photo-reducing agents. [23,[48][49][50][51][52] We have recently identified the delocalized ketyl-type radical (C * ), which is rapidly formed from the primary radical phosphanoyl radical P * (Scheme 1). [53] Because the SOMO of C * is relatively high in energy, this electron-rich radical serves as an electron donor (reducing agent).…”