The influence of hindered rotation on electron transfer and exchange interaction in triarylamine-triptycene-perylene diimide triads

The influence of hindered rotation on electron transfer and exchange interaction in triarylamine-triptycene-perylene diimide triads Научная публикация

Журнал

Physical Chemistry Chemical Physics
ISSN: 1463-9076

Вых. Данные

Год: 2024, Том: 26, Номер: 6, Страницы: 4954-4967 Страниц : 14 DOI: 10.1039/d3cp05785b

Авторы

Roger Chantal ¹ , Schmiedel Alexander ¹ , Holzapfel Marco ¹ , Lukzen Nikita N. ² , Steiner Ulrich E. ³ , Lambert Christoph ^4,1

Организации

1	Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
2	International Tomography Center, Russia and Novosibirsk State University, Institutskaya 3a, Novosibirsk, Novosibirsk 630090, Russia
3	Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
4	Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, D-97074 Würzburg, Germany

Stretched electron-donor-bridge-acceptor triads that exhibit intramolecular twisting degrees of freedom are capable of modulating exchange interaction (J) as well as electronic couplings through variable π-overlap at the linear bond links, affecting the rate constants of photoinduced charge separation and recombination. Here we present an in-depth investigation of such effects induced by methyl substituents leading to controlled steric hindrance of intramolecular twisting around biaryl axes. Starting from the parent structure, consisting of a triphenyl amine donor, a triptycene (TTC) bridge and a phenylene-perylene diimide acceptor (Me0), one of the two phenylene linkers attached to the TTC was ortho-substituted by two methyl groups (Me2, Me3), or both such phenylene linkers by two pairs of methyl groups (Me23). Photoinduced charge separation (kCS) leading to a charge-separated (CS) state was studied by fs-laser spectroscopy, charge recombination to either singlet ground state (kS) or to the first excited local triplet state of the acceptor (kT) by ns-laser spectroscopy, whereby kinetic magnetic field effects in an external magnetic field were recorded and analysed using quantum dynamic simulations of the spin dependent kinetics of the CS state. Kinetic spectra of the initial first order rate constants of charge recombination (k(B)) exhibited characteristic J-resonances progressing to lower fields in the series Me0, Me2, Me3, Me23. From the quantum simulations, the values of the parameters J, kS, kT and kSTD, the singlet/triplet dephasing constant, were obtained. They were analysed in terms of molecular dynamics simulations of the intramolecular twisting dynamics based on potentials calculated by density functional theory. Apart from kT, all of the parameters exhibit a clear correlation with the averaged cosine square products of the biaryl angles.

Roger C. , Schmiedel A. , Holzapfel M. , Lukzen N.N. , Steiner U.E. , Lambert C.
The influence of hindered rotation on electron transfer and exchange interaction in triarylamine-triptycene-perylene diimide triads
Physical Chemistry Chemical Physics. 2024. V.26. N6. P.4954-4967. DOI: 10.1039/d3cp05785b WOS Scopus РИНЦ OpenAlex

Поступила в редакцию:	27 нояб. 2023 г.
Принята к публикации:	17 янв. 2024 г.
Опубликована online:	26 янв. 2024 г.
Опубликована в печати:	14 февр. 2024 г.

≡ Web of science:	WOS:001149540300001
≡ Scopus:	2-s2.0-85184516781
≡ РИНЦ:	65984406
≡ OpenAlex:	W4391263781