Green-light ionization of 3-aminoperylene in SDS micelles—a promising access to hydrated electrons despite a myth debunked

Abstract

Using an improved methodology, we have carefully reinvestigated the title reaction by laser flash photolysis and disproved an earlier study (J. K. Thomas and P. Piciulo, J. Am. Chem. Soc., 1978, 100, 3239), which claimed this green-light ionization to be monophotonic, the only instance of such a scenario ever reported for a stable compound. We show it to be biphotonic instead, in accordance with thermodynamic considerations, and present a photokinetic model that accurately represents the intensity dependences throughout the whole excitation range in the green (532 nm) and the near UV (355 nm), up to near-quantitative electron release in the latter case. A major artifact deceptively similar to a chemical decay arises from an SDS-related laser-induced turbidity but can be eliminated by difference experiments or careful selection of excitation intensities and temporal windows. The ionization step is not accompanied by side processes, and affords an extremely long-lived (0.35 s) radical cation remaining solubilized. The micelles completely block attacks of hydrated electrons or hydroxyl radicals on the starting material and its radical cation but allow a post-ionization regeneration by high concentrations of the hydrophilic ascorbate monoanion.

Micellized Tris(bipyridine)ruthenium Catalysts Affording Preparative Amounts of Hydrated Electrons with a Green Light‐Emitting Diode

“…We studied that process by two‐pulse experiments, in which we used a high‐intensity first pulse to achieve quantitative formation of MLCT, ensured completion of the OER generation by an interpulse delay of 5 μs (compare, left half of Figure a), and varied the intensity of the second pulse. Furthermore, we observed in isolation by difference experiments without and with N 2 O saturation (SI‐1), a procedure that succeeds even in the presence of strongly absorbing other transients and/or “pathological” background artifacts in micellar systems …”

Resveratrol Radical Repair by Vitamin C at the Micelle–Water Interface: Unexpected Reaction Rates Explained by Ion–Dipole Interactions

“…[36] This allowsaf acile quantification of the photoionization yield provided that the calibrated e À aq spectrum in the reaction mediumi sk nown. This leaves the key question of how the surfactants influence the ionization.…”

Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)

“…[13] Pooling two photons,s imilar to photosynthesis,i sanatural solution. [13] Pooling two photons,s imilar to photosynthesis,i sanatural solution.…”