Photochemical Properties of a Mononuclear Mn(I) Triscarbonyl Complex in Water: An Insight into Different Oxidation States

Autor(es)

Marchi, Rafael C. ^[1] ; Aguiar, Inara ^[1] ; Camilo, Mariana R. ^[1] ; Braga, Adriano H. ^[2] ; Do Nascimento, Eduardo S. P. ^[1] ; Santana, Vinicius T. ^[3] ; Nascimento, Otaciro R. ^[3] ; Carlos, Rose M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos UFSCar, Chem Dept, Rod Washington Luis, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Chem Engn Dept, Rod Washington Luis, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo EECC, Phys Inst, Av Trabalhador Sao Carlense, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMISTRYSELECT; v. 6, n. 33, p. 8746-8753, SEP 7 2021.
• Citações Web of Science: 0

Resumo

This study reports the photochemical behavior of fac-{[}Mn(phen)CO3(4MeImH)](+) in neutral aqueous solution. The complex presents two 4MeImH linkage isomers, adjacent (A) and remote (R), which coexist in solution although with marked stability differences. In water, the steric effect converts A into an aqua-complex while R remains stable. Photolysis of the mixture followed by UV-vis, infrared (IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and cyclic voltammetry showed changes in the coordination sphere and oxidation state of each Mn center. Upon light irradiation, the mixture behaves as an antenna system to absorb light, producing the [Mn(II)(phen(.-))](+) moieties and releasing CO, which provides open sites for water coordination. Upon successive irradiation, the EPR spectra showed an increasing signal at g=2.0 corresponding to Mn(II) centers, a phenanthroline anion (2.0046) that vanishes at longer irradiation time, and an increasing component (g(x)similar to 9.85 and g(y)similar to 3.9) corresponding to Mn(IV). This makes the spectroscopic properties, excited state character, and dynamics of fac-{[}Mn(phen)(CO)(3)(4MeImH)](+) significantly different from those of all manganese complexes studied so far. (AU)

• Processo FAPESP: 19/21143-0 - Agregados de proteínas amiloides e a relação entre a Doença de Alzheimer e Diabetes tipo 2 investigada por complexos luminescentes de Ru(II)
• Beneficiário: Rose Maria Carlos
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/06244-3 - Desenvolvimento de processos químicos seguindo os princípios adotados pela química verde: redução e conversão de CO2 usando compostos de Mn(I)
• Beneficiário: Mariana Romano Camilo Casale
• Modalidade de apoio: Bolsas no Brasil - 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