Transient spectra, kinetics and mechanism of Rhodamine 700 dye precursor photoreaction

Protonation of meso-Tetraphenylporphyrin and Its β-Functionalized Derivatives by Photogenerators of Acidity in Toluene and Polymer Film

“…It can also be useful in the design of novel media for optical information recording, since one of the trends there is the use of substrates that possess sharp fluorescence change under irradiation. [32,33] In addition, results of this study are of interest for biochemical applications, since protonated forms of porphyrins are widely studied in antibacterial photodynamic therapy. [34][35][36]…”

Molecular Coherent Three-Quantum Two-Dimensional Fluorescence Spectroscopy

“…Moreover, the energy of state |f⟩ is in the vicinity of the first excited singlet state of the possible adduct that is facilitating population transfer to adduct states. We do not observe resonances of the photoproduct in the experimental 2D spectra because of its very low fluorescence quantum yield of 0.06 with a fluorescence spectrum located in the ultraviolet (around 350 nm), where the employed photodetector has a low responsivity.…”

“…There can be several reasons for the negligibly small quantum yield of |f⟩. We find that the most likely reason is a photoreaction of the doubly excited rhodamine 700 molecule with solvent molecules forming an adduct (Figure b, right) because of the highly electron-withdrawing trifluoromethyl group . Further possible reasons that we deem to be less likely are a high rate of intersystem crossing from |f⟩ to a highly excited triplet state with subsequent relaxation to the ground state (however, potential phosphorescence cannot be captured because emission can be detected only in an interval of <1 ms in our experiment) and other fast nonradiative deactivation pathways via multiple intermediate excited singlet states, possibly via conical intersections.…”

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

“…The few studies along this line are represented by the development of organic photoluminescent layers [13][14][15]. Irreversible light-sensitive recording media with photoinduced fluorescence have been developed, based on irreversible photochemical reactions of aromatic azides, diarylamine and tetrabromomethane, as well as haloacridine and naphthacenequinone derivatives [16][17][18][19].…”

“…The DP molecules are colorless and stable in neutral media, however they become strongly colored and fluorescing in the presence of an acid produced by the lightsensitive PAG molecules when they are exposed to light [20,21]. Rhodamine dyes in their passive forms are often used as dye precursors [17,[22][23][24]. For example, lactone forms of these dyes have no fluorescence in neutral media, but easily undergo into strong fluorescent open forms in the presence of acid.…”