4
|
Plaza-Medina EF, Rodríguez-Córdoba W, Peon J. Role of upper triplet states on the photophysics of nitrated polyaromatic compounds: S(1) lifetimes of singly nitrated pyrenes. J Phys Chem A 2011; 115:9782-9. [PMID: 21790204 DOI: 10.1021/jp204321h] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysics of most nitrated polycyclic aromatic compounds is dominated by an ultrafast intersystem crossing channel, which makes their first singlet excited states decay with rates on the order of 10(12) to 10(13) s(-1). Some questions, however, remain about the nature of the receiver triplet states, which have been in principle assigned to specific triplets of a different electronic configuration from T(1). In particular, it could be suggested that even a small degree of n-π* character of the T(1) state may be enough to allow the S(1) state to couple to upper vibronic states of the lowest energy triplet, without the requirement for specific upper triplet states. In this report, we show that there are, in fact, nitroaromatic compounds that do not show the ultrafast intersystem crossing channel but instead have S(1) states that are two to three orders of magnitude longer lived. Our studies focused on the time resolution of the emission from singly nitrated pyrenes, which show a strong photophysical dependence on the position of the NO(2) group: Whereas S(1) in 1-nitropyrene is short-lived (up to 3 ps), in 4-nitropyrene and 2-nitropyrene this state has 0.41 and 1.2 ns lifetimes, respectively, in acetonitrile solution. Computational work at the TD-DFT level of theory indicates that such remarkable increase in the first excited singlet lifetime can indeed be explained by a loss of the energy coincidence between the S(1) state with specific upper triplet states formed from transitions that involve the nonbonding orbitals at the oxygen atoms. These results are in strong support of the previous descriptions about the requirement for intermediacy of specific triplet states in the ultrafast decay of the fluorescent state present in most nitroaromatics. The implications for the photochemistry of this group of toxic atmospheric pollutants, including the channel that redounds in the dissociation of the NO· fragment, are discussed in view of the present results.
Collapse
Affiliation(s)
- Eddy F Plaza-Medina
- Instituto de Química, Universidad Nacional Autónoma de México , Circuito Exterior, Ciudad Universitaria, México, 04510 D.F., México
| | | | | |
Collapse
|
7
|
De la Fuente JR, Aliaga C, Poblete C, Zapata G, Jullian C, Saitz C, Cañete A, Kciuk G, Sobarzo-Sanchez E, Bobrowski K. Photoreduction of Oxoisoaporphines by Amines: Laser Flash and Steady-State Photolysis, Pulse Radiolysis, and TD-DFT Studies. J Phys Chem A 2009; 113:7737-47. [DOI: 10.1021/jp901877q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Julio R. De la Fuente
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Christian Aliaga
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Cristian Poblete
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Gerald Zapata
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Carolina Jullian
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Claudio Saitz
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Alvaro Cañete
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Gabriel Kciuk
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Eduardo Sobarzo-Sanchez
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| | - Krzysztof Bobrowski
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 223, Santiago 1, Chile, Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Chile, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland, and Departamento de Química Orgánica, Facultad de Farmacia,
| |
Collapse
|
9
|
Murakami M, Ohkubo K, Mandal P, Ganguly T, Fukuzumi S. Does Bimolecular Charge Recombination in Highly Exergonic Electron Transfer Afford the Triplet Excited State or the Ground State of a Photosensitizer? J Phys Chem A 2008; 112:635-42. [DOI: 10.1021/jp0767718] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Motonobu Murakami
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan, and Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032,West Bengal, India
| | - Kei Ohkubo
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan, and Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032,West Bengal, India
| | - Paulami Mandal
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan, and Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032,West Bengal, India
| | - Tapan Ganguly
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan, and Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032,West Bengal, India
| | - Shunichi Fukuzumi
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan, and Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032,West Bengal, India
| |
Collapse
|
11
|
Mandal P, Misra T, De A, Ghosh S, Chaudhury SR, Chowdhury J, Ganguly T. Photophysical processes involved within the bichromophoric system 9-benzotriazole-1-ylmethyl-9H-carbazole and its role as an artificial photosynthetic device. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 66:534-45. [PMID: 16859957 DOI: 10.1016/j.saa.2006.03.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 02/20/2006] [Accepted: 03/28/2006] [Indexed: 05/11/2023]
Abstract
From both steady state and fluorescence lifetime measurements it reveals that due to photoexcitation of benzotriazole (BZ) part of the bichromophore, 9(1-H-benzotriazole-lylmethyl)-9H-carbazole (BHC), singlet-singlet energy transfer takes place to populate the lowest excited singlet of carbazole (CZ). CZ, thus being excited indirectly via energy transfer process, undergoes strong charge transfer (CT) reaction with the surrounding polar medium acetonitrile (ACN). On the other hand, very weak CT band was apparent when CZ part, within BHC, was directly excited. In less polar tetrahydrofuran (THF) and polar benzonitrile (BN) environment, lack of formation of CT band strongly suggests in favor of the electron-accepting behavior of ACN. Moreover, by measuring the emission spectra of BHC in microcrystals and of 30 bilayers mixed LB film at high mole fraction of BHC molecules, the possibility of excimer formation or aggregation has been ruled out. Thus, BHC, when dissolved in ACN, acts as a triad system of BZ-CZ-ACN where BZ acts as an antenna molecule and CZ as a reaction center. The possible role of the bichromophoric system BHC as an artificial photosynthetic or solar energy conversion device has been hinted.
Collapse
Affiliation(s)
- Paulami Mandal
- Department of Spectroscopy, Indian Association for the Cultivation of Science, 2A and 2B Raja S C Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | | | | | | | | | | | | |
Collapse
|