Photochemistry of rose bengal in water and acetonitrile: a comprehensive kinetic analysis

Abstract

The photophysical and photochemical properties of rose bengal (RB) in degassed aqueous and acetonitrile solutions were studied using steady-state and transient absorption spectroscopies. This comprehensive investigation provides detailed information about the kinetics and the optical properties of all intermediates involved: the triplet excited state and the oxidized and reduced forms of RB. A full kinetic description is used to control the concentrations of these intermediates by changing the initial experimental conditions.

Photosensitizing properties of hollow microcapsules built by multilayer self-assembly of poly(allylamine hydrochloride) modified with rose Bengal

“…Such spectral shis are expected for RB in a less protic and polar environment. 41 In addition, the uorescence quantum yield (F F ) value of PAH-RB is more than one-order of magnitude lower than that corresponding to free RB (Table 1), which can be explained assuming a strong static quenching of RB uorescence as a consequence of the intense dye-dye interactions in the functionalized polymer. In time-resolved experiments, uorescence lifetime (s F ) of RB in aqueous environments showed a mono-exponential decay with a s F 98 AE 10 ps, as expected for monomeric RB in water (see Fig.…”

“…Summary of the results obtained for RB in aqueous medium, bound to the polymer (PAH-RB) and in hollow microcapsules (HM-RB) À1 s À1 ) Â 10 9 AE 0.02 Ratio of the absorbance at the maximum of the RB peak to the absorbance at the absorption shoulder. b Quantum yield corresponds to RB in the monomeric form in solution 41. …”

Visible‐Light‐Driven C−H Oxidation of Cyclic Tertiary Amines: Access to Synthetic Strychnos Alkaloids with Antiviral Activity

“…We startedo ur investigation by exploring as elected model reactiono fN-phenyl-tetrahydroisoquinoline( 1a)t owards corresponding d-lactam 1b ( Table 1). According to the absorption maximum of Rose Bengal (RB; l = 558 nm in CH 3 CN) [25] and previously reported visible-light-mediated transformations, in which RB wass uccessfully applied as ap hotocatalyst, [23] green LED was chosen for irradiation. The oxidation reaction in DMF in the presence of RB (2 mol %) as ap hotocatalyst at room temperature delivered desired product in 18 %y ield ( Table 1, entry 1).…”

Optically-generated Overhauser dynamic nuclear polarization: A numerical analysis

“…where Φ is the quantum yield for intersystem crossing (ISC), which equals 0.786 for rose bengal in aqueous solution, 33 and A is the probability of a photon being absorbed by the sample. From the Beer-Lambert law:…”

“…The photochemistry of rose bengal was modelled according to a study by Ludvíková et al, 33 with the following triplet deactivation processes known to occur: [34][35][36]…”