Impacting the balance between CO2 and proton reduction by control over aggregation in a model π-conjugated N-heterocycle – proflavine

Reva Y, Färber J, Bo Y, Thiele M, Hanke C, Günay-Gürer A, Herm M, Barth J, Guldi DM (2026)

Publication Type: Journal article

Publication year: 2026

Journal

DOI: 10.1039/d5sc06873h

Abstract

In this study, we investigated the mechanistic factors that govern the selective photocatalytic reduction of CO2 over protons within a simple π-conjugated N-heterocycle, proflavine. Diluted conditions, where aggregates of 65 nm are formed, favored the selective CO2 photo-reduction, while the gradual transition to concentrated conditions enabled photo-reductive H2 generation. Proton reduction is coupled to larger aggregates, in which an alternative photo-relaxation pathway is active. We used transient absorption spectroscopy to corroborate that at low proflavine concentrations the presence of an electron donor triggers the one-electron reduced proflavine to perform the direct CO2 reduction. At high proflavine concentrations, protonation of the one-electron reduced proflavine was favored due to a positive shift in basicity in larger aggregates with sizes over 1 µm. In turn, H2 abstraction began with a pair of one-electron reduced, protonated, intermediates. Our study demonstrates an effective approach to limiting water reduction, a key challenge in advanced metal-free organic photocatalysis.

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How to cite

APA:

Reva, Y., Färber, J., Bo, Y., Thiele, M., Hanke, C., Günay-Gürer, A.,... Guldi, D.M. (2026). Impacting the balance between CO2 and proton reduction by control over aggregation in a model π-conjugated N-heterocycle – proflavine. Chemical Science. https://doi.org/10.1039/d5sc06873h

MLA:

Reva, Yana, et al. "Impacting the balance between CO2 and proton reduction by control over aggregation in a model π-conjugated N-heterocycle – proflavine." Chemical Science (2026).

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