Direct Structural Determination of Conformations of Photoswitchable Molecules by Laser Desorption–Electron Diffraction

Anfractuous paths: Electron diffraction reveals the involvement of multiple structures in the complex photochemistry of photoswitchable nitro-substituted 1,3,3-trimethylindolinobenzospiropyran. The spiropyran-to-merocyanine isomerization due to ring opening produces primarily the cis–trans–cis structure (see picture; red O, blue N, yellow C), while competing nonradiative pathways lead to other structures, namely the closed forms in their triplet and singlet ground states.