Photocontrolled Isomerization Pathways of Tolylsulfonyl- and Pyrene-Linked Norbornadiene Systems Driven by Absorption Band Targeting

Sun D, Krappmann D, Oleszak C, Lienert J, Slavov C, Hirsch A, Wachtveitl J (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Journal of the American Chemical Society American Chemical Society

Book Volume: 148

Pages Range: 38500-38510

Journal Issue: 35

DOI: 10.1021/jacs.6c14776

Abstract

Norbornadiene (NBD) photoswitches are promising for molecular solar energy and information storage, as they isomerize to quadricyclane (QC) after absorbing irradiation energy. Here, we report pyrene-linked tolylsulfonyl-substituted NBD hybrids that enable wavelength-selective back-isomerization from QC to NBD. Using femtosecond-to-microsecond transient absorption spectroscopy in the deep-UV range, direct observation of QC formation could resolve the temporal windows of competing mechanisms, which confirm that the wavelength-dependent isomerization proceeds through two ultrafast charge-transfer (CT) pathways and longer-lived radical ion pair intermediates. Furthermore, chromophore coupling converts charge recombination from a loss channel into a productive process by enabling triplet energy transfer, leading to comparatively high quantum yields in both the switching directions. In a symmetric bis-NBD architecture, early CT productivity is reduced, and the mechanism shifts toward triplet-dominated isomerization, demonstrating how molecular symmetry redistributes pathway branching. Selective excitation of the QC unit or the pyrene chromophore biases singlet versus triplet channels, providing wavelength-dependent control over reaction efficiency. These results establish pathway engineering across singlet and triplet manifolds as a strategy for designing NBD systems for solar energy storage and optically addressable molecular information technologies.

Authors with CRIS profile

Daniel Krappmann Lehrstuhl für Organische Chemie II Christoph Oleszak Sonderforschungsbereich 953/3 Synthetische Kohlenstoffallotrope Andreas Hirsch Lehrstuhl für Organische Chemie II

Involved external institutions

Goethe-Universität Frankfurt am Main DE Germany (DE) University of South Florida (USF) US United States (USA) (US)

How to cite

APA:

Sun, D., Krappmann, D., Oleszak, C., Lienert, J., Slavov, C., Hirsch, A., & Wachtveitl, J. (2026). Photocontrolled Isomerization Pathways of Tolylsulfonyl- and Pyrene-Linked Norbornadiene Systems Driven by Absorption Band Targeting. Journal of the American Chemical Society, 148(35), 38500-38510. https://doi.org/10.1021/jacs.6c14776

MLA:

Sun, Dazhong, et al. "Photocontrolled Isomerization Pathways of Tolylsulfonyl- and Pyrene-Linked Norbornadiene Systems Driven by Absorption Band Targeting." Journal of the American Chemical Society 148.35 (2026): 38500-38510.

BibTeX: Download