"Alternating Orthogonal Switching in a Thiophenyl-Phenyl-Bis-Azobenzene Switch" in Chemistry – A European Journal
Abstract To design efficient molecular information storage systems with multi-photoswitchable entities, orthogonal isomerization of the different switchable moieties is essential. Various challenges, like unintentional energy transfer, spectral overlap, and other energy dissipation channels, have to be addressed by intelligent molecule design. In this context, we took advantage of calculations to design a bis-azobenzene switch, which consists of a phenyl- and a thiophenylazobenzene moiety in meta-connection to reduce π-conjugation. Ultrafast spectroscopy and computational studies confirmed that this bis-photoswitch exhibits alternating orthogonal switching behavior when irradiated with light of different wavelengths. These results represent a significant advancement toward the development of efficient and adaptable organic multi-photoswitches for applications, such as information storage, molecular machines, or smart materials.
"Breaking Bonds with Short-Wave Infrared Light: BODIPY Photocages for Two-Photon Activation in the 900–1500 nm NIR-II Window" in Journal of the American Chemical Society
In this collaborative study, we investigated 11 BODIPY-based photocages for two-photon excitation within the first and second biological windows, aiming to overcome the tissue penetration limits of UV/visible activation. By modifying the 3- and 5-positions, we identified structural motifs, such as strong charge-transfer character and increased vibrational freedom, that significantly enhance two-photon absorption in the 900–1500 nm range. These photocages enable photorelease using two SWIR photons carrying as little as 20 kcal/mol each, establishing key design principles for NIR-II photoactivatable systems.
"CryoRhodopsins: A comprehensive characterization of a group of microbial rhodopsins from cold environments" in Science Advances
Comprehensive study of a new group of microbial rhodopsins called CryoRhodopsins (CryoRs), whose members mainly originate from cold environments. By combination of insights gaining from single-particle cryo-EM, X-ray crystallography, and time-resolved spectroscopy we elucidated, that the characteristic arginine residue of this group (R57 in CryoR1) stabilizes the UV-absorbing M2 intermediate state, which causes the extremely slow photocycle dynamics of CryoRs at neutral and alkaline conditions. Furthermore, the mechanism causing the photoswitch-like behavior was elucidated. All in all, the data suggests that CryoRs function as sensors for UV irradiation, as illustrated by the population of the UV sensitive M2 intermediate upon irradiation by sunlight.
