A supramolecular assembly in which Ru(II) photosensitizer and Ru(II) catalyst units are connected by an ethylene linker (see figure) is among the most effective and robust photocatalysts for CO2 reduction to produce formate.1 Here, we investigated the mechanisms of photochemical CO2 reduction of mononuclear ruthenium carbonyl catalysts to later translate this knowledge to the study of the supramolecular catalyst. An important finding was that triethanolamine (TEOA) – a commonly used sacrificial electron donor in homogeneous photochemical experiments – was actively involved in determining reaction intermediates and played a crucial role in CO2 capture and formate selectivity. Time-resolved infrared experiments with the supramolecular assembly in argon- or CO2-saturated CH3CN solution containing BIH as an electron donor and TEOA as a proton relay allowed for kinetic investigation of the electron transfer and chemical transformation at the catalyst unit. At this meeting, we will discuss control results with the mononuclear ruthenium carbonyl catalyst and the intramolecular electron transfer of the supramolecular catalyst during the photocatalytic reduction of CO2 and how the presence of TEOA impacts the formation of reaction intermediates.

Roles of triethanolamine in photochemical CO2 reduction with [Ru(dmb)2(CO)2]2+ and Ru(II)-Ru(II) supramolecular systems

2019 Spring National Meeting

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