Dohmen, Christoph
Preferred name
Dohmen, Christoph
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Publication Access status: Metadata only , Photoinduced [2+2] and [4+4] Cycloaddition and Cycloreversion Reactions for the Development of Photocontrollable DNA Binders(2024); In the current field of photopharmacology, molecular photoswitches are applied whose interactions with DNA can be triggered or controlled by light. And although several photochromic reactions have been shown to serve this purpose well, the reversible photocycloaddition and photocycloreversion reactions have been largely neglected. This absence of research is surprising because especially the photodimerization of a DNA ligand leads to products with significant change of the size and shape which, in turn, leads to strongly diminished or even suppressed DNA association. Therefore, photocycloaddition–cycloreversion sequences have a huge potential for the photoinduced, reversible deactivation and activation of ligand–DNA interactions, as will be shown with selected examples in this Concept Article . Specifically, heterostyryl and ‐stilbene derivatives are presented whose DNA–binding properties are efficiently switched in reversible [2+2] photocycloaddition reactions. In addition, the photocontrolled DNA–binding of anthracene derivatives and their heterocyclic benzo[ b ]quinolizinium analogues in a [4+4] photocycloaddition, as well as the use of this reaction as part of dual–mode switches in combination with redox‐active functionalities, are highlighted. Furthermore, examples of conjugates are provided, in which the photochromic unit is bound covalently to nucleic acids or proteins, such that the photocycloaddition reaction can be used for reversible photoinduced crosslinking, ligation, or inhibition of gene expression.Source Type:Article3 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Reversible Restrain and Release of the Dynamic Valence Isomerization in a Shape‐shifting Bullvalene by Complex FormationIn search for structural features that enable the control of the valence isomerization of the fluxional bullvalene, a bullvalene‐bis(harmane) conjugate is identified that acts as chelating ligand in complexes with metal ions. Spectrometric titrations show that this ligand forms 1 : 1 complexes with Ag + , Cu + , Cu 2+ , and Zn 2+ . Most importantly, detailed NMR‐spectroscopic analysis at different temperatures reveals that the complexation with Ag + strongly affects the dynamic isomerization of the bullvalene unit of the ligand such that only one predominant valence isomer is formed, even at 5 °C. Detailed 1 H‐NMR‐spectroscopic studies disclose an increased barrier (~11 kJ mol −1 ) of the Cope rearrangement. Furthermore, the addition of hexacyclene displaces the Ag + from the complex, so that the valence isomerization is accelerated and an equilibrium with two predominant isomers is formed. In turn, repeated addition of Ag + regains the complex with the restrained isomerization of the bullvalene unit. This method to control the valence isomerism by straightforward chemical stimuli may be used to simplify structural analysis at elevated temperatures, i. e. a feature not available so far with bullvalenes, and it may be employed as functional element in dynamic supramolecular assemblies.Source Type:Article1 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Switching between DNA binding modes with a photo- and redox-active DNA-targeting ligand(2023); The combination of a photochromic benzo[ b ]quinolizinium and a redox-active disulfide linker enables the control of DNA-binding properties by shifting between three different binding modes.Source Type:Article1 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Switching between DNA binding modes with a photo- and redox-active DNA-targeting ligand, part II: the influence of the substitution pattern(2023); A disulfide-functionalized photochromic system enables the control of DNA-binding properties by a combination of a photocycloaddition reaction, the redox reactions of the disulfide functionality, and an irreversible chemical degradation.Source Type:Article1
