Dimethylcethrene: A Chiroptical Diradicaloid Photoswitch

Ravat, Prince and Šolomek, Tomáš and Häussinger, Daniel and Blacque, Olivier and Juríček, Michal. (2018) Dimethylcethrene: A Chiroptical Diradicaloid Photoswitch. Journal of the American Chemical Society, 140 (34). pp. 10839-10847.

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Official URL: https://edoc.unibas.ch/68486/

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We describe the synthesis and properties of 13,14-dimethylcethrene, a prototype of a chiral diradicaloid photochemical switch that can be transformed reversibly via conrotatory electrocyclization to its more stable closed form by light (630 nm) or heat and back to its open form by light (365 nm). This system illustrates how the chemical reactivity of a diradicaloid molecule can be translated into a switching function, which alters substantially all electronic parameters, namely, the HOMO-LUMO and the singlet-triplet (ST) energy gaps, and the degree of helical twist. As a result, distinct changes in the optical and chiroptical properties of this system were observed, which allowed us to monitor the switching process by a variety of spectroscopic techniques, including NMR, UV-vis, and CD. In comparison to the previously reported parent molecule cethrene, this system benefits from two methyl substituents installed in the fjord region, which account for the stability of the closed form against oxidation and racemization. The methyl substituents increase the ST energy gap of 13,14-dimethylcethrene by ∼4 kcal mol; -1; in comparison to cethrene. Our DFT calculations reveal that the larger ST gap is a result of electronic and geometric effects of the methyl substituents and show the potential of related systems to act as magnetic switches at room temperature.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Nuclear Magnetic Resonance (Häussinger)
UniBasel Contributors:Häussinger, Daniel
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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edoc DOI:
Last Modified:08 Feb 2020 15:06
Deposited On:23 Apr 2019 10:35

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