Professora Paula Homem-de-Mello

@article{doi:10.1021/acs.joc.3c02079,

title = {Chemiluminescence of a Firefly Luciferin Analogue Reveals that Formation of the Key Intermediate Responsible for Excited State Generation Occurs on a Fully Concerted Step},

author = {Diego Ulysses Melo and Henrique Bergonzini de Lima and Roberta Albino Reis and Andreia Boaro and Alexander Garreta Gonçalves Costa Pinto and Luiz Francisco Monteiro Leite Ciscato and Paula Homem-de-Mello and Fernando Heering Bartoloni},

url = {https://doi.org/10.1021/acs.joc.3c02079},

doi = {10.1021/acs.joc.3c02079},

year  = {2023},

date = {2023-12-19},

urldate = {2024-01-01},

journal = {The Journal of Organic Chemistry},

volume = {89},

number = {1},

pages = {345-355},

abstract = {The chemiluminescence (CL) reaction of eight different 2-(4-hydroxyphenyl)-4,5-dihydrothiazole-4-carboxylate esters with an organic superbase and oxygen was investigated through a kinetic and computational study. These esters are all analogues to the luciferin substrate involved in efficient firefly bioluminescence. The kinetic data obtained from CL emission and light absorption assays were used in the context of linear free energy relationships (LFER); we obtained the Hammett reaction constant ρ = +1.62 ± 0.09 and the Brønsted constant βlg = −0.39 ± 0.04. These observations from LFER, together with activation parameters obtained from Arrhenius plots, suggest that the formation of the high-energy intermediate (HEI) 1,2-dioxetanone occurs via a concerted mechanism during the rate-determining step of the reaction. Calculations performed using density functional theory support a late transition state for HEI formation within the reaction mechanism pathway, which was described considering geometric parameters, Wiberg bond indices from natural bond order analysis, and the atomic charges derived from the electrostatic potential.},

note = {PMID: 38113466},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1021/acs.jpcb.3c01707,

title = {Synergistic Interaction of Hyperbranched Polyglycerols and Cetyltrimethylammonium Bromide for Oil/Water Interfacial Tension Reduction: A Molecular Dynamics Study},

author = {James M. de Almeida and Conny Cerai Ferreira and Lucas Bandeira and Renato D. Cunha and Maurício Domingues Coutinho-Neto and Paula Homem-de-Mello and Ednilsom Orestes and Regina Sandra Veiga Nascimento},

url = {https://doi.org/10.1021/acs.jpcb.3c01707},

doi = {10.1021/acs.jpcb.3c01707},

year  = {2023},

date = {2023-10-23},

journal = {The Journal of Physical Chemistry B},

volume = {0},

number = {0},

pages = {null},

abstract = {Applying surfactants to reduce the interfacial tension (IFT) on water/oil interfaces is a proven technique. The search for new surfactants and delivery strategies is an ongoing research area with applications in many fields such as drug delivery through nanoemulsions and enhanced oil recovery. Experimentally, the combination of hyperbranched polyglycerol (HPG) with cetyltrimethylammonium bromide (CTAB) substantially reduced the observed IFT of oil/water interface, 0.9 mN/m, while HPG alone was 5.80 mN/m and CTAB alone IFT was 8.08 mN/m. Previous simulations in an aqueous solution showed that HPG is a surfactant carrier. Complementarily, in this work, we performed classical molecular dynamics simulations on combinations of CTAB and HPG with one aliphatic chain to investigate further the interaction of this pair in oil interfaces and propose the mechanism of IFT decrease. Basically, from our results, one can observe that the IFT reduction comes from a combination of effects that have not been observed for other dual systems: (i) Due to the CTAB-HPG strong interaction, a weakening of their specific and isolated interactions with the water and oil phases occurs. (ii) Aggregates enlarge the interfacial area, turning it into a less ordered interface. (iii) The spread of individual molecules charge profiles leads to the much lower interfacial tension observed with the CTAB+HPG systems.},

note = {PMID: 37871185},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Corrêa2023,

title = {Diving into the optoelectronic properties of Cu(II) and Zn(II) curcumin complexes: a DFT and wavefunction benchmark},

author = {Raissa Lohanna Gomes Quintino Corrêa and Matheus Morato Ferreira de Moraes and Kléber Thiago de Oliveira and Yuri Alexandre Aoto and Maurício Domingues Coutinho-Neto and Paula Homem-de-Mello},

doi = {10.1007/s00894-023-05560-1},

issn = {0948-5023},

year  = {2023},

date = {2023-05-00},

journal = {J Mol Model},

volume = {29},

number = {5},

publisher = {Springer Science and Business Media LLC},

keywords = {Catalysis, Computational Theory and Mathematics, Computer Science Applications, Inorganic Chemistry, Organic Chemistry, Physical and Theoretical Chemistry},

pubstate = {published},

tppubtype = {article}

}

@article{SOUZA2023108460,

title = {Benchmarking DFT functionals for photophysics of pyranoflavylium cations},

author = {Jhonathan R. Souza and Carles Curutchet and Yuri A. Aoto and Paula Homem-De-Mello},

url = {https://www.sciencedirect.com/science/article/pii/S109332632300058X},

doi = {https://doi.org/10.1016/j.jmgm.2023.108460},

issn = {1093-3263},

year  = {2023},

date = {2023-01-01},

journal = {Journal of Molecular Graphics and Modelling},

volume = {122},

pages = {108460},

abstract = {An intense absorption, phosphorescence, a long triplet excited state lifetime and singlet oxygen generation capabilities 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.},

keywords = {Benchmark, Electronic structure, Excited-states, Photophysics, Photosensitizers, Time-dependent density functional theory (TD-DFT)},

pubstate = {published},

tppubtype = {article}

}