In new research, carried out in University of Bern, we have shown that triazolium iodides are excellent catalysts for the oxidative coupling of benzylamines, due to a synergistic cation/anion effect, with iodide acting as I−/I2 redox manifold and the triazolium cation facilitating the iodine reduction and concomitant substrate oxidation. Oxygen was is the terminal oxidant for this process.
The research emerged from the dual interest in the Albrecht group in catalysis and the use of triazolium salts – typically as precursors to organometallic complexes. Joe followed up on some unexpected catalytic activity of triazolium iodides with a series of experiments and control experiments to determine the origins of the reactivity, the role of atmospheric oxygen as terminal oxidant, the importance of the iodide/iodine redox couple and the accelerating effect of the triazolium ion. We hope this work will inspire others to look at the role of heterocylcic compounds in other processes catalysed by iodine.