Rethinking uncaging: a new antiaromatic photocage driven by a gain of resonance energy

  • Photoactivatable compounds for example photoswitches or photolabile protecting groups (PPGs, photocages) for spatiotemporal light control, play a crucial role in different areas of research. For each application, parameters such as the absorption spectrum, solubility in the respective media and/or photochemical quantum yields for several competing processes need to be optimized. The design of new photochemical tools therefore remains an important task. In this study, we exploited the concept of excited-state-aromaticity, first described by N. Colin Baird in 1971, to investigate a new class of photocages, based on cyclic, ground-state-antiaromatic systems. Several thio- and nitrogen-functionalized compounds were synthesized, photochemically characterized and further optimized, supported by quantum chemical calculations. After choosing the optimal scaffold, which shows an excellent uncaging quantum yield of 28 %, we achieved a bathochromic shift of over 100 nm, resulting in a robust, well accessible, visible light absorbing, compact new photocage with a clean photoreaction and a high quantum product (ϵ⋅Φ) of 893 M−1 cm−1 at 405 nm.

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Author:Volker HermannsGND, Maximilian Scheurer, Nils Frederik Kersten, Chahinez Abdellaoui, Josef WachtveitlORCiDGND, Andreas DreuwORCiDGND, Alexander HeckelORCiDGND
Parent Title (English):Chemistry - a European journal
Place of publication:Weinheim
Document Type:Article
Date of Publication (online):2021/08/07
Date of first Publication:2021/08/07
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/12/21
Tag:Baird's rule; excited state aromaticity; photochemistry; photolabile protecting groups; substituent effects
Page Number:7
First Page:14121
Last Page:14127
This work was supported by the Deutsche Forschungsgemeinschaft (DFG) by means of the research training group “CLiC” (GRK 1986, Complex Light Control). Open Access funding enabled and organized by Projekt DEAL.
Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0