Banca de DEFESA: JHONATHAN ROSA DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JHONATHAN ROSA DE SOUZA
DATE: 30/10/2023
TIME: 14:00
LOCAL: Auditório 801, 8º andar, Bloco B, Campus Santo André da Universidade Federal do ABC
TITLE:

Benchmarking electronic structure methods for photophysical properties of potential photosensitizers for photodynamic therapy

PAGES: 160
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Química Teórica
SUMMARY:

Photosensitizers hold great promise in the field of photodynamic therapy, a treatment method relying on their unique photophysical properties. The choice of suitable computational tools and benchmarks is crucial for a deep understanding of these photosensitizers. In this context, two distinct studies explore the electronic characteristics of photosensitizer. The first study investigates the absorption spectrum of cobalt(II) porphyrin using density functional (DFT) and multireference n-electron valence perturbation (NEVPT) theories. By delving into the lowest-energy states of doublet and quartet spin multiplicities, Q and B bands' origins, higher-energy π-π* excitations, and charge-transfer states, the research unveils intriguing insights. While the position of the B band remains independent of the DFT functional, the Q band is better described by pure functionals. However, other excitation energies, orbital energies, and ionization potentials significantly depend on the chosen functional, emphasizing the need for careful functional selection in electronic structure calculations. The second study focuses on pyranoflavylium cations, akin to pyranoanthocyanidins found in the maturation process of red wine, showcasing potent characteristics for potential application as photosensitizers in photodynamic therapy. The electronic structure of these molecules is pivotal for the treatment's success. The research benchmarks seven commonly used density functionals for assessing the photophysical properties of these compounds, revealing that global-hybrid functionals offer an excellent description of absorption and emission energies. In contrast, range-separated functionals excel in predicting phosphorescence energies. These findings guide practitioners in selecting appropriate computational tools for modeling the photophysical properties of photosensitizers, advancing the field of photodynamic therapy. In conclusion, both studies shed light on the intricate world of electronic structure calculations in the realm of photosensitizers. The investigation of cobalt(II) porphyrin's absorption spectrum underscores the consistency of DFT results, particularly in the case of B bands. However, a word of caution emerges from the broader picture: the choice of density functionals remains a crucial factor, as they can lead to significant variations in excitation energies, orbital energies, and ionization potentials, at times exceeding 2 eV. These findings underscore the need for meticulous consideration when employing density functionals for benchmarking and electronic structure calculations. 

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1544394 - PAULA HOMEM DE MELLO
Membro Titular - Examinador(a) Interno ao Programa - 1544403 - MAURICIO DOMINGUES COUTINHO NETO
Membro Titular - Examinador(a) Externo ao Programa - 3944999 - ROMARLY FERNANDES DA COSTA
Membro Titular - Examinador(a) Externo à Instituição - CLEITON DOMINGOS MACIEL - IFSP
Membro Titular - Examinador(a) Externo à Instituição - ATAUALPA ALBERT CARMO BRAGA - USP
Membro Suplente - Examinador(a) Interno ao Programa - 1544379 - ANDERSON ORZARI RIBEIRO
Membro Suplente - Examinador(a) Externo à Instituição - LUIS GUSTAVO DIAS - USP
Membro Suplente - Examinador(a) Externo à Instituição - FABRICIO DE CARVALHO