Search results for "PHOTOISOMERIZATION"
showing 3 items of 73 documents
Large Azobenzene Macrocycles : Formation and Detection by NMR and MS Methods
2023
Azobenzene macrocycles are widely investigated as potential drug delivery systems and as part of molecular machines due to their photo-responsive properties. Herein, we detect the formation of a series of new azobenzene macrocycles that feature up to eight switchable repeating units. High-resolution mass spectrometry and ion mobility (IM) mass spectrometry experiments and 1H and diffusion-ordered spectroscopy (DOSY) NMR are used to detect the presence of the macrocycles that contain 10 to 40 aromatic rings in the gas phase and solution, respectively. The responsiveness of the Z-to-E photo-switching of the smallest of the macrocycles, exhibiting two azobenzene units and in total 10 aromatic …
Kinetics of photochemical isomerization of TFA-Gly-ZΔPhe into TFA-Gly-EΔPhe
2017
The kinetics of photoisomerization of trifluoroacetyl-(Z)-dehydrophenylalanylglycine into trifluoroacetyl-(E)- dehydrophenylalanylglycine was studied in the hope that light-induced reaction could be useful as a means of preparation of the E-dehydropeptides. The obtained results indicate that if this reaction carried out under irradiation with light of wavelength 360 nm it is practically irreversible and gave nearly quantitatively pure Eisomer Significantly, expected cyclic side-products were not observed in the reaction mixture, thus proving the preparative potential of the elaborated procedure.
Theoretical Study of the Electronic Spectrum of trans-Stilbene
1997
The electronic spectrum of trans-stilbene in the energy range up to 6 eV has been studied using multiconfigurational second-order perturbation theory (CASPT2). The study includes a geometry determination of the ground state. In all, 12 singlet and one triplet excited states were studied. The calculated spectrum makes it possible to assign the valence excited singlet states corresponding to the three bands observed in the low-energy region of the one-photon absorption spectrum. The most intense feature of the calculated spectrum corresponds to the 11Ag → 21Bu transition at 4.07 eV. The weakly allowed 11Bu state was found 0.3 eV below 21Bu. Transition to the 31Ag state, computed at 4.95 eV, i…