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Phptotophysics and kinetics of naphthopyran derivatives, part 4: Investigation of [3H]‐naphthopyran kinetics considered as an ABC(2k, 6ϕ) system yielding a monoexponential trace

“…Indeed, computational studies have shown that extremely fast (hundreds of fs) photochemical reactions are likely to occur via (ground and excited state) energy surface crossings where the nodal (or intersection) point represents a common intermediate structure, ultimately leading to more than one possible product. A similar mechanism can be anticipated for NPY because it is neither fluorescent nor phosphorescent 12,26,27 and no triplet state is involved in the reaction 20,23; this rules out any competition of photophysical or internal conversion processes for the deactivation of the singlet‐excited state of NPY toward B and C, and accordingly, fulfills the requirements for the conical intersection mechanism rather than an avoided crossing. The magnitude of the overall photochemical yields is, however, difficult to predict due to the fact that the regeneration of the initial species (A* → A) can be important (90% of the excited molecules in the case a spiropyran derivative 28) and between 70–98% of the initial concentration of A is estimated at the PSS for all the mechanisms given in Table I.…”

Probing Metal Ion Complexation of Ligands with Multiple Metal Binding Sites: The Case of Spiropyrans

“…The isomer formed, called merocyanine (MC), displays a planar conformation, as well as an extended delocalized π‐electron system. This allows the molecule to absorb visible light and also to display fluorescence in the same wavelength range …”

Aryl(hetaryl)pyrazolines as new photoacid generators for optical information recording

“…The progress in information technologies calls for an increase in the information capacity of recording media, and the rate of information processing demands an extension of their functional capabilities [1][2][3][4][5][6][7]. Analysis of the state-of-the-art research into the design of recording media shows that the limiting information capacity of magnetic disks can be increased to 20 GB.…”

“…Electronic absorption spectra of pyrazoline 1 (c = 24 mM) in toluene in the presence of hexachloroethane (c = 8.2 mM) before (1) and after(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) irradiation at 420 nm. Electronic absorption spectra of pyrazoline 1 (c = 48 mM) and Rhodamine B (c = 50 mM) in CCl 4 before (1) and after (2-11) irradiation at 420 nm.…”