Bimolecular photoinduced electron transfer in the Marcus inverted region involving the [Re(CO)3(4-phenylpyridine)3]+ metal-to-ligand charge transfer excited state, amines and their corresponding radical products

Ruiz, Gustavo Miguel; Rodriguez-Nieto, F.; Wolcan, Ezequiel; Feliz, Miguel

doi:10.1016/s1010-6030(97)00059-2

Cited by 29 publications

(9 citation statements)

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“…The values of k q obtained for Re-1, Re-2, and Re-3, which range between 1 × 10 9 and 2 × 10 9 M −1 s −1 , are in good agreement with k q values reported for similar Re(I) complexes with f O 2 T close to unity. 13 Because k d in acetonitrile is around 3 × 10 10 M −1 s −1 , 13,50 the values of k q obtained for Re-1, Re-2, and Re-3 are found to be ≤ 1 / 9 k d . They are in good agreement with the unity values obtained for f O 2 T and with a predominance of the singlet channel, eq 9, in the mechanism of singlet oxygen generation using these Re(I) complexes as photosensitizers.…”

Section: ■ Results and Discussionmentioning

confidence: 91%

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

et al. 2013

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Quantum yields and efficiencies of (1)O2 ((1)Δg) production along with photophysical properties for a number of Re(I) complexes in acetonitrile solutions are reported. Two different classes of Re(I) complexes, L(S)-CO2-Re(CO)3(bpy) (L(S) = 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 (1)O2 ((1)Δg) production in air-saturated acetonitrile solutions. Depending on the nature of the Re(I) complex, the excited state responsible for the generation of (1)O2 ((1)Δg) is either a metal-to-ligand charge transfer ((3)MLCT) or a ligand centered ((3)LC) state. With L(S)-CO2-Re(CO)3(bpy) complexes, (1)O2 ((1)Δg) is produced by oxygen quenching of (3)LC states of anthracene and pyrene with high quantum yields (ΦΔ between 0.8 and 1.0), while the complexes bearing the ligands L(S) = 2-anthraquinone, 2-pyrazine, and 2-naphthalene did not yield (1)O2. XRe(CO)3L complexes generate (1)O2 ((1)Δg) mainly by oxygen quenching of their (3)MLCT luminescence with an efficiency of (1)O2 ((1)Δg) formation close to unity. Bimolecular rate constants for the quenching of the XRe(CO)3L complexes' emission by molecular oxygen range between 1 × 10(9) and 2 × 10(9) M(-1) s(-1), and they are all ≤ (1/9)kd, in good agreement with the predominance of the singlet channel in the mechanism of (1)O2 ((1)Δg) 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 L(S)-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.

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Section: ■ Results and Discussionmentioning

confidence: 91%

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

et al. 2013

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“…The polymer should have a similar Δ G value. This Δ G value lies in the Marcus normal region . It is well-known that the motion of the solvent molecules in the restricted media, i.e., in micelles, is retarded by several orders of magnitude compared to that in homogeneous solvents.…”

Section: Discussionmentioning

confidence: 88%

“…Besides, in both Dexter's and Forter's theories k et α J ) . The quenching of the monomer CF 3 SO 3 [pyRe(CO) 3 bpy] luminescence by CuCl 2 follows a typical Stern−Volmer kinetics and taking into account its luminescence lifetime 28 a bimolecular rate constant k q,CuCl 2 = 2 × 10 10 M -1 s -1 can be calculated, the value of which is close to the diffusional limit in acetonitrile . A far lower bimolecular rate constant k q,Cu(CF 3 SO 3 ) 2 = 8 × 10 8 M -1 s -1 can be calculated from the quenching by Cu(CF 3 SO 3 ) 2 (Figure ).…”

Section: Discussionmentioning

confidence: 91%

“…Taking into account the oxidation redox potential of TEOA, the reduction potential of the complex pyRe(CO) 3 bpy + , and the energy of the excited state which can be estimated from the emission spectrum as E 0 - 0 ∼ 2.37 eV, we can calculate a Δ G ∼ −0.4 eV for the forward electron-transfer reaction between pyRe(CO) 3 bpy + 's MLCT excited state and TEOA. The polymer should have a similar Δ G value.…”

Section: Discussionmentioning

confidence: 99%

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On the Quenching of MLCT_Re_→_b_py Luminescence by Cu(II) Species in Re(I) Polymer Micelles

2005

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Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies on acetonitrile solutions of the polymer {[(vpy)2-vpyRe(CO)3bpy] CF3SO3}200 demonstrated that the Re(I) polymer molecules aggregate to form spherical micelles of radius R = 156 nm. Coordination of Cu(II) species to the Re (I) polymer causes a decrease in the micelle radius and a distortion from the spherical shape. Besides, the coordination of Cu(II) species to the {[(vpy)2-vpyRe(CO)3bpy] CF3SO3}200 polymer produces the quenching of the metal to ligand charge transfer (MLCT) excited state by energy transfer processes that are more efficient than those in the quenching of the monomer pyRe(CO)3bpy+ luminescence by Cu(II). Moreover, the kinetics of the quenching by Cu(II) do not follow a Stern-Volmer behavior. Conversely, the quenching of the MLCT luminescence of the Re(I) polymer by the sacrificial electron donor 2,2',2' '-nitrilotriethanol, TEOA, follows a Stern-Volmer kinetics. A comparison is made between the quenching by CuX2 (X = Cl or CF3SO3) and TEOA.

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“…En los estudios con 'kexcñ =400 nm, los resultados obtenidos son similares. M'^s^ en CH3CN [47] Por otro lado, se investigó la dependencia del tiempo de vida con la temperatura, hallándose cambios significativos, para el decaimiento más lento, cuando se varía la temperatura entre 290 y 330 K y se irradian las soluciones del Ferroceno -CO2-Re(CO)3(1,10-fenantrolina) con pulsos de luz de 337 nm. A continuación se muestra la dependencia del logaritmo de i con la inversa de la temperatura.…”

Section: Ferroceno-c02re(c0)3(22'-bipírídina)unclassified

Transferencia de carga fotoinducida en complejos de Re(I) mono y binucleares

Juliarena¹

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El objetivo de este trabajo de tesis es aportar información sobre las propiedades fotoquímicas y fotofísicas de nuevos complejos de Re(I) mono y binucleares que contienen ligandos piridínicos bidentados. Particularmente, contribuir a elucidación del mecanismo de transferencia de carga intramolecular analizando el efecto del puente que une la parte donora con la aceptara en Ia molécula del complejo. En la Parte I se describe la estructura general de un complejo d6 en un entorno octahédrico, orbitales del ligando y configuración electrónica y la generalidad de los procesos fotofísicos y fotoquímicos. Luego, de manera específica, se describen los orbitales moleculares de los complejos de Renio estudiados, así como también los procesos primarios del estado excitado de los complejos tricarbonílicos de Re(I). A continuación, se detallan las técnicas y equipamiento utilizado para el estudio y monitoreo de los estados excitados. En la Parte II se presentan los estudios sobre las propiedades de los estados excitado de los complejos R-C02-Re(C0)3(2,2'-bipiridina), donde R-C02= naftaleno-2-carboxilato, antraceno-9-carboxilato, pireno-1-carboxilato y acetato. Además, del papel de los estados excitados emisores en la fotofísica de estos complejos se analizó el rol del puente carboxilato en la conexión entre el areno y el Re(CO)3(2-2'bipiridina). En la parte III se describe la obtención y caracterización de un grupo de complejos binucleares que contienen al complejo Ferroceno unido al Re(CO)3L2, con L2= 2,2'-bipiridina, 1,10-fenantrolina y (4-fenilpiridina)2. Se realizó además un estudio detallado de los estados excitados de esos compuestos. Por último se describen la síntesis y propiedades fotoquímicas del complejo (CH3)2N(C6H4)-C02-Re(C0)3(1,10-fenantrolina), ideado para comparar sus propiedades con las de los compuestos binucleares estudiados.

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Bimolecular photoinduced electron transfer in the Marcus inverted region involving the [Re(CO)3(4-phenylpyridine)3]+ metal-to-ligand charge transfer excited state, amines and their corresponding radical products

Cited by 29 publications

References 53 publications

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

On the Quenching of MLCT_Re_→_b_py Luminescence by Cu(II) Species in Re(I) Polymer Micelles

Transferencia de carga fotoinducida en complejos de Re(I) mono y binucleares

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Bimolecular photoinduced electron transfer in the Marcus inverted region involving the [Re(CO)3(4-phenylpyridine)3]+ metal-to-ligand charge transfer excited state, amines and their corresponding radical products

Cited by 29 publications

References 53 publications

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

Photosensitized Generation of Singlet Oxygen from Re(I) Complexes: A Photophysical Study Using LIOAS and Luminescence Techniques

On the Quenching of MLCTRe→bpy Luminescence by Cu(II) Species in Re(I) Polymer Micelles

Transferencia de carga fotoinducida en complejos de Re(I) mono y binucleares

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On the Quenching of MLCT_Re_→_b_py Luminescence by Cu(II) Species in Re(I) Polymer Micelles