Banca de DEFESA: ANDRESSA VIDAL MÜLLER

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANDRESSA VIDAL MÜLLER
DATA : 10/02/2021
HORA: 14:00
LOCAL: por participação remota
TÍTULO:

Solar Energy Conversion Assisted by Ruthenium(II) and Rhenium(I) Coordination Compounds

PÁGINAS: 218
RESUMO:

Coordination compounds are useful tools to harvest, convert, and store solar energy due to their intense and tunable visible-light absorption features, associated with the possibility of modulating their redox, photophysical and photochemical properties, ground state and excited state reactivity, and to build subunits with specific functionalities by using different ligands. Ru(II) polypyridyl compounds have been extensively developed to promote solar-to-electrical energy conversion in dye-sensitized solar cells (DSSCs), and changes in the ligands directly affect the performance of the devices. Solar energy can also be converted to fuels by using Re(I) polypyridyl compounds as photocatalysts, and the molecular structure of the complexes influence the energy conversion efficiency. In this work, Ru(II) and Re(I) polypyridyl coordination compounds were prepared and characterized to be employed in the aforementioned systems for solar-to-electrical and solar-to-chemical energy conversion, respectively. The molecular engineering of the ligands allowed to fine-tune the spectroscopical, electrochemical, photophysical, and photochemical properties of the complexes. Relationships were established between molecular structure, physical-chemical properties, the kinetics and efficiency of various individual reactions and electron transfer processes that occur after light absorption by the complexes, and ultimately on the energy conversion efficiencies. The Ru(II) compounds of general formula cis-[Ru(NN)(dcbH2)(NCS)2], dcbH2 = 4,4’-dicarboxylic acid-2,2’-bipyridine and NN = 1,10-phenanthroline, 4,7-dipyrrole-1,10-phenanthroline, 4,7-diindole-1,10-phenanthroline, or 4,7-dicarbazole-1,10-phenanthroline, were employed as dye-sensitizers in DSSCs, and the photoelectrochemical characterization of the devices revealed that small, systematic changes in the number of aromatic rings of the 4,7-substituent of the ancillary phenanthroline resulted in significant changes in the performance of the DSSCs. The origins of the differences in the photoelectrochemical performance were tracked to the structure-modulated competition between the electron transfer processes that promote or inhibit solar-to-electrical energy conversion. Additionally, the Re(I) compounds of general formula fac-[Re(NN)(CO)3X], NN = 1,10-phenanthroline, 4,7-dipyrrole-1,10-phenanthroline, 4,7-diindole-1,10-phenanthroline, or 4,7-dicarbazole-1,10-phenanthroline, and X = Cl- or Br-, exhibited features that make them potential photocatalysts to promote the reduction of CO2. The presence of aromatic substituents in the polypyridyl ligand was a viable strategy to overcome the limitations presented by this class of compounds, and ultimately to modulate some reactions involved in the photocatalytic CO2 reduction cycle. Based on kinetic evidence and mechanistic approaches, some effects that drive the solar energy conversion by Ru(II) or Re(I) coordination compounds were unraveled, guiding the future design of more efficient and robust systems.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1671688 - ANDRE SARTO POLO
Membro Titular - Examinador(a) Interno ao Programa - 1544341 - WENDEL ANDRADE ALVES
Membro Titular - Examinador(a) Externo ao Programa - 1844792 - AMEDEA BAROZZI SEABRA
Membro Titular - Examinador(a) Externo à Instituição - ANTONIO OTÁVIO DE TOLEDO PATROCÍNIO - UFU
Membro Titular - Examinador(a) Externo à Instituição - ANA FLAVIA NOGUEIRA - UNICAMP
Membro Suplente - Examinador(a) Interno ao Programa - 2605463 - JOSE ANTONIO SOUZA
Membro Suplente - Examinador(a) Interno ao Programa - 1545089 - DANIEL ZANETTI DE FLORIO
Membro Suplente - Examinador(a) Externo ao Programa - 1623774 - KARINA PASSALACQUA MORELLI FRIN
Membro Suplente - Examinador(a) Externo à Instituição - SOFIA NICOLAOU