Photoinduced Energy and Electron-Transfer Reactions by Polypyridine Ruthenium(II) Complexes Containing a Derivatized Perylene Diimide

Autor(es)

dos Santos, Edjane R. ; Pina, Joao ; Venancio, Tiago ; Serpa, Carlos ; Martinho, Jose M. G. ; Carlos, Rose Maria

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 120, n. 40, p. 22831-22843, OCT 13 2016.
• Citações Web of Science: 9

Resumo

The {[}Ru(II) (phen)(2)(pPDIp)](2+) complex, where pPDIp is the symmetric bridging ligand phenanthroline-perylene-phenanthroline, shows strong electronic absorption bands attributed to the pPDIp and [Ru(phen)(2)](2+) moieties in acetonitrile. The charge-separated intermediate [Ru(III) (phen)(2)(pPDIp(-center dot))] was detected by transient absorption spectroscopy upon electronic excitation in either the pPDIp or the complex moieties. The charge-separated intermediate species decays to generate the triplet state (3){*}pPDIp-Ru(II) (tau(P) = 1.8 mu s) that sensitizes the formation of singlet molecular oxygen with quantum yield phi(Delta) = 0.57. The dyad in deaerated acetonitrile solutions is reduced by triethylamine (NEt3) to the {[}Ru(II) (phen)(2)(pPDIp(center dot-))] radical anion in the dark. The electron-transfer reaction is accelerated by light absorption. By photolysis of the radical anion, a second electron transfer reaction occurs to generate the {[}Ru(II)(phen)(2)(pPDIp(center dot-))] dianion. The changes of the color of solution indicate the redox states of complexes and offer a sensitive reporter of each stage of redox reaction from start to finish. The reduced complexes can be converted to the initial complex, using methyl viologen or molecular oxygen as an electron acceptor. The accumulation of electrons in two well-separated steps opens promising opportunities such as in catalysis. (AU)

• Processo FAPESP: 13/23943-8 - Investigação dos processos de transferência de carga no estado excitado e à agregação de sistemas mono e binucleares
• Beneficiário: Edjane Rocha dos Santos
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado
• Processo FAPESP: 11/10882-5 - Desenvolvimento de sistemas binucleares artificiais que mimetizam o processo de transferência de elétrons natural presente no fotossistemaII (PSII)
• Beneficiário: Edjane Rocha dos Santos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 14/12538-8 - Desenvolvimento de complexos de Ru(II) luminescentes para reconhecer e mapear in vitro e em tempo real os processos de agregação do peptídeo b-amilóide e da proteína tau e explorar a atividade antioxidante e inibidora da enzima acetilcolinesterase
• Beneficiário: Rose Maria Carlos
• Modalidade de apoio: Auxílio à Pesquisa - Regular