Electronic structures and population dynamics of excited states of xanthione and its derivatives

Direct CH/CH functionalization of 1,3-dihydroxy-9H-xanthen-9-one and 1,3-dimethoxy-9H-xanthen-9-one with 1,2,4-triazines and quinazoline

“…1,3-Dihydroxyxanthone 1 and 1,3-dimethoxyxantone 4 were prepared according to known procedures [3,4].…”

Spectral Dynamics of Nitro Derivatives of Xanthione in Solutions

“…Similar results were obtained earlier for methoxy derivatives of XT that manifest itself in the broadening of the absorption band, S 2 ← S 0 . 6 The experimental and simulated transient absorption spectra (TA) of DNXT are presented in Figure 5. The spectra of TNXT are shown in the Supporting Information.…”

“…20 Besides, it requires detailed studies of the mechanisms of pico-and femtosecond deactivation processes of highly excited singlet and triplet states of heterocyclic compounds. 6,20−22 A number of preliminary results obtained for XT and its derivatives 6,19,21 allows outlining the subsequent course of experimental and theoretical studies to construct a molecular model with the desired frequency and charge parameters. In particular, for 1,3-dimethoxy-9H-xanthene-9-thione (DXT) 6 significant charge transfer (about 0.1 of the electron charge) was observed from the methoxy group to the thiocarbonyl group, and the fitting of transient absorption spectra of XT and DXT showed an increase in the intersystem crossing probability of S 1 → T 1 upon attaching electron-donor methoxy groups to the xanthione molecule.…”

“…Considerable interest of researchers in thioketones during past decades is associated with their remarkable spectral and photophysical properties. − Spectral properties are closely related to the electronic structure of their highest excited electronic states . For the thioketones in solutions, experimentalists can distinguish separate S 1 , S 2 , and S 3 absorption bands, as well as direct absorption T 1 ← S 0 , thermally activated delayed fluorescence from S 1 state, fluorescence and phosphorescence from S 2 and T 2 , correspondingly .…”

“…A possibility to design optical switches operating in the frequency range up to tens of gigahertz and providing a high yield (up to 90%) of the charge separation process requires experimentalists and theorists to consider derivatives of thioketones with strong electron donor groups . Besides, it requires detailed studies of the mechanisms of pico- and femtosecond deactivation processes of highly excited singlet and triplet states of heterocyclic compounds. ,− …”