A Series of Green Light Absorbing Organic Photosensitizers Capable of Oxidative Quenching Photocatalysis

Abstract

In order to design a series of photoredox compounds with a broad range of reactivity, eosin Y, a xanthene derivative, was chosen as a precursor to synthesize a new series of organic photocatalysts. The synthesis and characterization of these four new organic photocatalysts was undertaken. Redox potentials of this series of photocatalysts varied by 110 mV, which shows that these catalysts can be tuned for specific reactions. The measured fluorescence quantum yields ranged from 0.33 to 0.65 which outperform most transition metal photocatalysts. The excited state lifetimes (ns) of the new photocatalysts are comparable to those of the parent complex, but the λ max value for absorption was red-shifted into the green light region of the solar spectrum. Despite the absorbance shift to lower energy wavelengths, the new photocatalysts were more potent reductants compared to the parent complex and were able to undergo oxidative quenching and promote the photocatalytic enol arylation reaction.

Photomediated core modification of organic photoredox catalysts in radical addition: mechanism and applications

“… 5,23,44,45 So, it is meaningful to gain insights into the effects of these core modifications on the photon absorption of OPCs. 46 …”

“…5,23,44,45 So, it is meaningful to gain insights into the effects of these core modifications on photon absorption of OPCs. 46 TD-DFT calculations at the uM06/6-311+G**(CPCM, SOL=H 2 O)//uM06/6-31G** level of theory were performed to investigate the orbitals involved in photoexcitation of OPCs at their corresponding λ max, abs . As shown in Fig.…”

Tunable Redox‐Neutral Photocatalysis: Visible Light‐Induced Arylperfluoroalkylation of Alkenes Regulated by Protons

“…For example, the photocatalyst‐dependent redox potentials are intrinsic, generally fixed, and relatively low [1] . In addition, in oxidative quenching [5] ‐triggered redox‐neutral transformations, matched reduction and oxidation rates are usually essential. Mismatched ones, partially arising from the mismatched reducing and oxidizing potentials of the photoredox catalyst (PC), often enough lead to undesired by‐products, complicating the reaction and hampering the development of such reactions.…”

Benchmarking Computational Approaches to Predict the UV-Vis Spectra of Organic Photocatalysts

“…34 Nevertheless, with the increasing number of In this work, we benchmark several exchange-correlation functionals against handpicked reference data that consists of experimental spectra extracted then digitized from recent literature. [35][36][37][38][39][40][41][42][43][44][45] The main novelties in our strategy are: i) the spectral fitting procedure takes into account full spectral shapes, not only individual excitations; ii) during the fitting we scale the excitation energies instead of shifting them resulting in proportional changes throughout the fitted range; iii) the benchmark focuses on organic photocatalysts. The molecules in the dataset are shown in Scheme 1.…”