Robust Red-Absorbing Donor-Acceptor Stenhouse Adduct Photoswitches

Chemistry. 2024 Mar 27:e202400621. doi: 10.1002/chem.202400621. Online ahead of print.ABSTRACTDonor-Acceptor Stenhouse Adduct (DASA), a class of push-pull negative photochromes, has received large interest lately owing to its versatile synthesis, modularity and excellent photoswitching in solutions. From a technological perspective, it is imperative for this class of photoswitches to work robustly in solid state, e.g. thin films. We feature a molecular framework for the optimized design of DASAs by introducing a new thioindoline donor (D3) and assessing its performance against known 2nd generation indoline-based donors. The systematic structure-function investigations suggest that to achieve robust reversible photoswitching, a ground state with low charge separation is desired. DASAs with stronger electron donors and a larger charge separation in the ground state result in a low population of the photothermalstationary state (PTSS) and reduced photostability. The DASA with thioindoline donor (D3A3) seems to be a special case among the donor series as it causes a red shift (ca. 15 nm), however with less polarization of the ground state and marginally better photostability as compared to the unsubstituted 2-methyl indoline (D1A3). We also emphasize the consideration of the key additional factors that can modulate the red-light photoswitching properties of DASA chromophores in polymer thin films, which might not be dominant in homogenous solution state.PMID:38536207 | DOI:10.100...

Source: Chemistry - March 27, 2024 Category: Chemistry Authors: Abbey Meprathu Philip Marie Erskov Krogh Bo Wegge Laursen Source Type: research