The photochemical trans → cis and thermal cis → trans isomerization pathways of azobenzo-13-crown ether: A computational study on a strained cyclic azobenzene system.

The isomerization of azobenzo-13-crown ether can be expected to be hindered due to the polyoxyethylene linkage connecting the 2,2'-positions of azobenzene. The mixed reference spin-flip time-dependent density functional theory results reveal that the planar and rotational minima of the first photo-excited singlet state (S1) of the trans-isomer pass through a barrier (2.5-5.

To Quench or Not: Extending a β-Carboline Fluorophore for TNT Detection in Aqueous Media via Simultaneous ESPT Destabilization and AIE.

Molecules relying on the excited-state intramolecular proton transfer/excited-state proton transfer (ESIPT/ESPT) mechanism are widely used in material science. In the current work, a known β-carboline-based probe TrySy was used to selectively detect explosive trinitrotoluene (TNT) in water. Compared to conventional TNT sensing, which relies mainly on the quenching of the fluorescence signal, TrySy could perform nanomolar detection of TNT via ESPT destabilization and AIE, with a significant fluorescence output.

Unexplored Isomerization Pathways of Azobis(benzo-15-crown-5): Computational Studies on a Butterfly Crown Ether.

Computational studies on → and → isomerizations of photoresponsive azobis(benzo-15-crown-5) have been reported in this work. The photoexcited ππ* state (S) of the isomer relaxes through the planar S minimum and the planar S/S conical intersection (both situated around 9 kcal/mol below the vertically excited S state) arising along the N═N stretching coordinate. The nπ* state (S) of this isomer has both planar and rotated (clockwise and anticlockwise) minima, which may lead to a torsional conical intersection (S/S) geometry having a View Article and Find Full Text PDF