Substantial improvement of pyridine-carbene iridium water oxidation catalysts by a simple methyl-to-octyl substitution

Ilaria Corbucci, Ana Petronilho, Helge Müller-Bunz, Luca Rocchigiani, Martin Albrecht, Alceo Macchioni

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Abstract

The substitution of a methyl to an octyl group in the ancillary triazolylidene ligand—an apparently simple variation—induces a more than 10-fold increase of activity of the corresponding iridium complex in water oxidation catalysis when using cerium(IV) as sacrificial oxidant. Detailed NMR studies suggest that various different molecular species form, all bearing the intact triazolylidene ligand. The octyl substituent is essential for inducing the association of the iridium species, thus generating extraordinarily active multimetallic catalytic sites. Their accessibility and steady-state concentration is critically dependent on the type of sacrificial oxidant and specifically on the cerium ammonium nitrate versus catayst ratio.
Original languageEnglish
Pages (from-to)2714-2718
JournalACS Catalysis
Volume5
Issue number5
Early online date23 Mar 2015
DOIs
Publication statusPublished - 1 May 2015

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