Far-red triplet sensitized<i>Z</i>-to-<i>E</i>photoswitching of azobenzene in bioplastics

Bharmoria, Pankaj; Ghasemi, Shima; Edhborg, Fredrik; Losantos, Raúl; Wang, Zhihang; Mårtensson, Anders; Kimizuka, Nobuo; Morikawa, Masaaki; İşçi, Ümit; Dumoulin, Fabienne; Albinsson, Bo; Moth‐Poulsen, Kasper

doi:10.1039/d2sc04230d

Cited by 23 publications

(26 citation statements)

References 65 publications

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“…3D shows the energy diagram for 1 ⋅ ps1 . These results led us to hypothesize that the experimentally observed TET might be facilitated by thermal fluctuations of molecules, as suggested previously for other triplet donor–acceptor pairs ( 25 , 26 , 45 , 46 ). Therefore, we studied the dependence of the 1 ⋅ ps1 excited-state energies on the C–N=N–C dihedral angle (Φ) in azobenzene 1 (which is substantially more flexible than ps1 ).…”

Section: Time-resolved Spectroscopic and Computational Studies Of Descsupporting

confidence: 76%

Disequilibrating azobenzenes by visible-light sensitization under confinement

Gemen,

Church,

Ruoko

et al. 2023

Science

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Photoisomerization of azobenzenes from their stable E isomer to the metastable Z state is the basis of numerous applications of these molecules. However, this reaction typically requires ultraviolet light, which limits applicability. In this study, we introduce disequilibration by sensitization under confinement (DESC), a supramolecular approach to induce the E -to- Z isomerization by using light of a desired color, including red. DESC relies on a combination of a macrocyclic host and a photosensitizer, which act together to selectively bind and sensitize E -azobenzenes for isomerization. The Z isomer lacks strong affinity for and is expelled from the host, which can then convert additional E- azobenzenes to the Z state. In this way, the host–photosensitizer complex converts photon energy into chemical energy in the form of out-of-equilibrium photostationary states, including ones that cannot be accessed through direct photoexcitation.

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Section: Time-resolved Spectroscopic and Computational Studies Of Descsupporting

confidence: 76%

Disequilibrating azobenzenes by visible-light sensitization under confinement

Gemen,

Church,

Ruoko

et al. 2023

Science

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show abstract

“…3d for the energy diagram of 1⋅ps1). These results led us to hypothesize that the experimentally observed TET might be facilitated by thermal fluctuations of molecules, as suggested previously for other triplet donor-acceptor pairs 32,34,49,50 . Therefore, we studied the variation of the 1⋅ps1 excited state energies on the C-N=N-C dihedral angle (Φ) in azobenzene 1 (which is significantly more flexible than ps1).…”

supporting

confidence: 76%

“…ii) once generated, the triplet state of azobenzene relaxes preferentially 29,30 (by a factor of >50) to the thermodynamically stable E isomer. Therefore, whereas triplet sensitizers can rapidly and efficiently facilitate the equilibration of the high-energy Z isomer into the stable E state 31,32,33,34 , the reverse reaction-i.e., sensitized disequilibration-is far more demanding and has remained unknown.…”

mentioning

confidence: 99%

Disequilibrating azoarenes by visible-light sensitization under confinement

Gemen

Church

Ruoko

et al. 2023

Preprint

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The process of vision begins with the absorption of light by retinal, which triggers isomerization around a double bond and, consequently, a large conformational change in the surrounding protein opsin. However, certain organisms evolved different visual systems; for example, deep-sea fishes employ chlorophyll-like antennas capable of capturing red light and sensitizing the nearby retinal molecule via an energy-transfer process. Similar to retinal, most synthetic photochromic molecules, such as azobenzenes and spiropyrans, switch by double-bond isomerization. However, this reaction typically requires shortwavelength (ultraviolet) light, which severely limits the applicability of these molecules. Here, we introduce DisEquilibration by Sensitization under Confinement (DESC) – a supramolecular approach to switch various azoarenes from the E isomer to the metastable Z isomer using visible light of desired color, including red. DESC relies on a combination of a coordination cage and a photosensitizer (PS), which act together to bind and selectively sensitize E-azoarenes. After switching to the Z isomer, the azoarene loses its affinity to—and is expelled from—the cage, which can convert additional copies of E into Z. In this way, the cage⋅PS complex acts as a light-driven supramolecular machine, converting photon energy into chemical energy in the form of out-of-equilibrium photostationary states, including ones that cannot be accessed via direct photoexcitation.

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“…Conventional azobenzenes are known to undergo indirect Z / E photoisomerization even if the sensitizer E T is substantially lower than the azobenzene. 40,45 This is due to the ultrashort lifetime of azobenzene triplet state and thus negligible probability of back energy transfer to the sensitizer. 40 This was also the case with E-diazocine, as Pdtetraphenyltetranaphthoporphyrin (PdTPNP, E T = 1.30 eV, Fig.…”

Section: Resultsmentioning

confidence: 99%