Spatial Factors for Triplet Fusion Reaction of Singlet Oxygen Photosensitization
journal contributionposted on 2017-10-23, 00:00 authored by Shuming Bai, Mario Barbatti
First-principles quantum-chemical description of photosensitized singlet oxygen generation kinetics is challenging because of the intrinsic complexity of the underlying triplet fusion process in a floppy molecular complex with open-shell character. With a quantum-chemical kinetic model specifically tailored to deal with this problem, the reaction rates are investigated as a function of intermolecular incidence direction, orientation, and distance between O2 and the photosensitizer. The adopted photosensitizer, 6-azo-2-thiothymine, combines practical interest and prototypical variability. The study quantitatively determined maximum singlet oxygen generation rates for 15 incidence/orientation directions, showing that they span 5 orders of magnitude between the largest and the smallest rate. Such information may provide a hands-on guideline for the experimental molecular design of new photosensitizers as well as further higher-level theoretical research.
triplet fusion processphotosensitizeropen-shell characterspan 5 ordersreaction ratesSpatial Factorsphotosensitized singlet oxygen generation kineticsincidence directionSuch informationO 2singlet oxygen generation rates6- azo -2-thiothymineTriplet Fusion ReactionSinglet Oxygen Photosensitization First-principles quantum-chemical description