Making Charge Recombination Spin-Forbidden for Efficient Generation and Excitation of Perylene Diimide Radical Anion by Pump–Pump

Article Article scientifique Lettre Making Charge Recombination Spin-Forbidden for Efficient Generation and Excitation of Perylene Diimide Radical Anion by Pump–Pump–Probe Spectroscopy eng 2025-12-16 author Cruz Neto Daniel Herculano 0000-0002-5987-9369 Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland. 429580 Chimie physique (groupe 6) (CHIF6) author Sucre Rosales Estefania 0000-0002-5486-4264 Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland. 975471 Chimie physique (groupe 6) (CHIF6) author Vauthey Eric 0000-0002-9580-9683 Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland. 133895 Département de chimie physique (CHIFI) 13241-13246 10.1021/acs.jpclett.5c03240 41402235 1948-7185 https://pubs.acs.org/doi/10.1021/acs.jpclett.5c03240 The excited radical anion of perylene diimide (PDI) dyes is broadly used in thermodynamically challenging synthetic reactions via a consecutive photoinduced electron transfer (ConPET) mechanism. This approach relies on two sequential single-photon absorptions, in which the first triggers photoinduced electron transfer (PET) while the second populates the doublet excited state of the ensuing radical anion. Herein, we employ pump-pump-probe spectroscopy to investigate all of the elementary steps of this mechanism. We show that radical anion formation upon direct quenching of photogenerated 1 PDI* is an inefficient strategy due to ultrafast charge recombination of the generated geminate ion pair (GIP). Alternatively, we demonstrate that 3 PDI* can be populated via triplet charge recombination with a halogenated electron donor and, from there, it can be quenched with a second donor, generating a triplet GIP and rendering charge recombination spin-forbidden to efficiently accumulate PDI• - in solution. This anion can then be selectively excited by a second laser pump pulse, potentially triggering a catalytic reaction. Dewey 540 38 Département de chimie physique 142 false 686 Groupe Vauthey The journal of physical chemistry letters 4e58b0fd-65df-466e-a25d-6c048f908525 Article (Published version) Restricted Cruz_JPCL26.pdf 1934872 application/pdf 7624ce3793dbcd9868b5a42c0c77ba05a28561dceda247f5f4c3f5c86c932c21 restrictedAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

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Making Charge Recombination Spin-Forbidden for Efficient Generation and Excitation of Perylene Diimide Radical Anion by Pump–Pump–Probe Spectroscopy	The journal of physical chemistry letters			2025	6	0

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