Artículo
Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques
Ragone, Fabricio; Martínez Saavedra, Héctor Hernando
; David Gara, Pedro Maximiliano; Ruiz, Gustavo Teodosio
; Wolcan, Ezequiel
Fecha de publicación:
05/2013
Editorial:
American Chemical Society
Revista:
Journal Of Physical Chemistry A
ISSN:
1089-5639
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Quantum yields and efficiencies of 1O2 (1Δg) production along with photophysical properties for a number of Re(I) complexes in acetonitrile solutions are reported. Two different classes of Re(I) complexes, LS-CO2-Re(CO)3(bpy) (LS = 2-pyrazine, 2-naphthalene, 9-anthracene, 1-pyrene, 2-anthraquinone) and XRe(CO)3L (X =CF3SO3, py; L = bpy, phen), were probed as photosensitizers for 1O2 (1Δg) production in air-saturated acetonitrile solutions. Depending on the nature of the Re(I) complex, the excited state responsible for the generation of 1O2 (1Δg) is either a metal-to-ligand charge transfer (3MLCT) or a ligand centered (3LC) state. With LS-CO2-Re(CO)3(bpy)complexes, 1O2 (1Δg) is produced by oxygen quenching of 3LC states of anthracene and pyrene with high quantum yields (ΦΔ between 0.8 and 1.0), while the complexes bearing the ligands LS = 2-anthraquinone, 2-pyrazine, and 2-naphthalene did not yield 1O2. XRe(CO)3L complexes generate 1O2 (1Δg) mainly by oxygen quenching of their 3MLCT luminescence with an efficiency of 1O2 (1Δg) formation close to unity. Bimolecular rate constants for the quenching of the XRe(CO)3L complexes? emission by molecular oxygen range between 1 × 109 and 2 × 109 M−1 s−1, and they are all ≤ 1/9kd,in good agreement with the predominance of the singlet channel in the mechanism of 1O2 (1Δg) generation using these Re(I)complexes as photosensitizers. All the experimental singlet oxygen efficiencies are consistent with calorimetric and luminescence data for the studied complexes. With LS-CO2-Re(CO)3(bpy) complexes, calorimetric experiments were utilized in the calculation of the quantum yields of triplet formation; namely ϕT = 0.76 and 0.83 for the triplet states of anthracene and pyrene, respectively.
Palabras clave:
Lioas
,
Singlet Oxygen
,
Rhenium
,
Triplet
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - LA PLATA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos(INIFTA)
Articulos de INST.DE INV.FISICOQUIMICAS TEORICAS Y APLIC.
Articulos de INST.DE INV.FISICOQUIMICAS TEORICAS Y APLIC.
Citación
Ragone, Fabricio; Martínez Saavedra, Héctor Hernando; David Gara, Pedro Maximiliano; Ruiz, Gustavo Teodosio; Wolcan, Ezequiel; Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques; American Chemical Society; Journal Of Physical Chemistry A; 117; 21; 5-2013; 4428-4435
Compartir
Altmétricas