Benchmarking DFT functionals for photophysics of pyranoflavylium cations

Author(s)

Souza, Jhonathan R. ; Curutchet, Carles ; Aoto, Yuri A. ; Homem-De-Mello, Paula

• Document type: Journal article
• Source: JOURNAL OF MOLECULAR GRAPHICS & MODELLING; v. 122, p. 11-pg., 2023-03-31.

Abstract

An intense absorption, phosphorescence, a long triplet excited state lifetime and singlet oxygen generation ca-pabilities are characteristics of pyranoflavylium cations, analogues to pyranoanthocyanidins originated in the maturation process of red wine. Such properties make these compounds potential photosensitizers to be applied in photodynamic therapy. In this context, the photophysical processes underlying that treatment critically depend on the electronic structure of the pyranoflavylium molecules. When employing density functional theory to describe the electronic structure of molecules, the choice of the most suitable functional is not trivial, and benchmark studies are needed to orient practitioners in the field. In this work, a benchmark of seven of the most commonly used density functionals in addressing the photophysical properties of a set of eight pyranoflavylium cations is reported. Ground and excited state geometries, molecular orbitals, and absorption, fluorescence and phosphorescence transition energies were calculated using density functional theory approaches, and evaluated and compared to experimental data and monoreferential wave function-based methodologies. Statistical analysis of the results indicates that global-hybrid functionals allow an excellent description of absorption and emission energies, with errors around 0.05 eV, while range-separated variants led to somewhat larger errors in the range 0.1-0.2 eV. In contrast, range-separated functionals display excellent phosphorescence energies with errors close to 0.05 eV, in this case global-hybrids showing increased discrepancies around 0.5-0.1 eV. (AU)

• FAPESP's process: 17/21199-0 - The differentiable manifolds of the electronic structure theory
• Grantee: Yuri Alexandre Aoto
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 21/09841-4 - Environment effects on photosensitizer properties and energy transfer processes studied by means of QMMM approaches
• Grantee: Jhonathan Rosa de Souza
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 18/25576-6 - Studies on photophysical and energy transfer processes of photosensibilizers with emphasis in photodynamic therapy: an approach of first principles
• Grantee: Jhonathan Rosa de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)