Issue 34, 2023

How do donor and acceptor substituents change the photophysical and photochemical behavior of dithienylethenes? The search for a water-soluble visible-light photoswitch

Abstract

Dithienylethenes are a type of diarylethene and they constitute one of the most widely studied classes of photoswitch, yet there have been no systematic studies of how electron-donor or -acceptor substituents affect their properties. Here we report eight dithienylethenes bearing push–push, pull–pull and push–pull substitution patterns with different lengths of conjugation in the backbone and investigate their photophysical and photochemical properties. Donor–acceptor interactions in the closed forms of push–pull dithienylethenes shift their absorption spectra into the near-infrared region (λmax ≈ 800 nm). The push–pull systems also exhibit low quantum yields for photochemical electrocyclization, and computational studies indicate that this can be attributed to stabilization of the parallel, rather than anti-parallel, conformations. The pull–pull systems have the highest quantum yields for switching in both directions, ring-closure and ring-opening. The chloride salt of a pull–pull DTE, with alkynes on both arms, is the first water-soluble dithienylethene that can achieve >95% photostationary state distribution in both directions with visible light. It has excellent fatigue resistance: in aqueous solution on irradiation at 365 nm, the photochemical quantum yields for switching and decomposition are 0.15 and 2.6 × 10−5 respectively, i.e. decomposition is more than 5000 times slower than photoswitching. These properties make it a promising candidate for biological applications such as super-resolution microscopy and photopharmacology.

Graphical abstract: How do donor and acceptor substituents change the photophysical and photochemical behavior of dithienylethenes? The search for a water-soluble visible-light photoswitch

Supplementary files

Article information

Article type
Edge Article
Submitted
20 mar 2023
Accepted
28 jul 2023
First published
31 jul 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 9123-9135

How do donor and acceptor substituents change the photophysical and photochemical behavior of dithienylethenes? The search for a water-soluble visible-light photoswitch

S. Qiu, A. T. Frawley, K. G. Leslie and H. L. Anderson, Chem. Sci., 2023, 14, 9123 DOI: 10.1039/D3SC01458D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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