Dissecting the Roles of Optimal Tuning, Solvation, and Vibrational Corrections in Excited-State Redox Potential Prediction for Organic Photoredox Catalysts
- 1Department of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, GA, United States, 30097
Abstract
Department of Chemistry, Emory University Abstract Reliable computational prediction of excited-state redox potentials is central to the rational design of photoredox catalysts and requires accurate treatment of both ground-state redox thermochemistry and excited-state energetics. Although time-dependent density functional theory (TDDFT) provides a practical computational framework, it remains unclear whether these two components should use the same range-separation treatment and how the tuning of 2 range-separated hybrid (RSH) functionals, solvent response, and vibrational corrections affect that choice. We address these questions using a controlled benchmark of 16 structurally related N-aryl phenoxazine photocatalysts with experimental data obtained in dimethylacetamide, comparing default range-separation parameters with gas-phase tuning (GPγT) and two solution-phase tuning schemes based on equilibrium (PVγT) and nonequilibrium (SVγT) polarizable continuum models. The optimal treatment is quantity dependent: default ω values give the lowest errors for ground-state oxidation potentials, whereas solution-phase tuning with PVγT or SVγT reduces the mean absolute errors (MAEs) of transition energies to 0.10–0.13 eV; combining these component-specific treatments with zero-point or full vibrational corrections yields excited-state oxidation-potential MAEs of 0.11–0.13 V, although the required frequency calculations substantially increase the computational cost. These results reveal that applying a single range-separation treatment throughout the calculation is suboptimal and provide a physically motivated, quantity-specific computational strategy for solution-phase excited-state redox predictions that can now be tested across broader photocatalyst classes and solvent environments. 1 Introduction Photocatalysis has emerged as a versatile strategy for promoting chemical transformations through photoinduced electron transfer (PET) under mild conditions.1-8 Although ruthenium and iridium complexes have traditionally been widely used as photoredox catalysts (PCs),5, 9-12 organic PCs are emerging as cheaper and greener alternatives because their photophysical and redox properties can be systematically tuned through molecular design.2, 4, 8, 13-19
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BibTeX
@misc{gale2026dissecting,
title = {{Dissecting the Roles of Optimal Tuning, Solvation, and Vibrational Corrections in Excited-State Redox Potential Prediction for Organic Photoredox Catalysts}},
author = {Ariel Gale and Bushra Alam and Fang Liu},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009133/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009133/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Dissecting the Roles of Optimal Tuning, Solvation, and Vibrational Corrections in Excited-State Redox Potential Prediction for Organic Photoredox Catalysts
AU - Ariel Gale
AU - Bushra Alam
AU - Fang Liu
PY - 2026
DA - 2026/09/21
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009133/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009133/v1
AB - Department of Chemistry, Emory University Abstract Reliable computational prediction of excited-state redox potentials is central to the rational design of photoredox catalysts and requires accurate treatment of both ground-state redox thermochemistry and excited-state energetics. Although time-dependent density functional theory (TDDFT) provides a practical computational framework, it remains unclear whether these two components should use the same range-separation treatment and how the tuning of 2 range-separated hybrid (RSH) functionals, solvent response, and vibrational corrections affect that choice. We address these questions using a controlled benchmark of 16 structurally related N-aryl phenoxazine photocatalysts with experimental data obtained in dimethylacetamide, comparing default range-separation parameters with gas-phase tuning (GPγT) and two solution-phase tuning schemes based on equilibrium (PVγT) and nonequilibrium (SVγT) polarizable continuum models. The optimal treatment is quantity dependent: default ω values give the lowest errors for ground-state oxidation potentials, whereas solution-phase tuning with PVγT or SVγT reduces the mean absolute errors (MAEs) of transition energies to 0.10–0.13 eV; combining these component-specific treatments with zero-point or full vibrational corrections yields excited-state oxidation-potential MAEs of 0.11–0.13 V, although the required frequency calculations substantially increase the computational cost. These results reveal that applying a single range-separation treatment throughout the calculation is suboptimal and provide a physically motivated, quantity-specific computational strategy for solution-phase excited-state redox predictions that can now be tested across broader photocatalyst classes and solvent environments. 1 Introduction Photocatalysis has emerged as a versatile strategy for promoting chemical transformations through photoinduced electron transfer (PET) under mild conditions.1-8 Although ruthenium and iridium complexes have traditionally been widely used as photoredox catalysts (PCs),5, 9-12 organic PCs are emerging as cheaper and greener alternatives because their photophysical and redox properties can be systematically tuned through molecular design.2, 4, 8, 13-19
ER -