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Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation

We combined femtosecond (fs) VIS pump–IR probe spectroscopy with fs VIS pump–supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br(8))(py)(2) in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a...

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Autores principales: Stensitzki, T., Yang, Y., Berg, A., Mahammed, A., Gross, Z., Heyne, K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Crystallographic Association 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866960/
https://www.ncbi.nlm.nih.gov/pubmed/27226980
http://dx.doi.org/10.1063/1.4949363
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author Stensitzki, T.
Yang, Y.
Berg, A.
Mahammed, A.
Gross, Z.
Heyne, K.
author_facet Stensitzki, T.
Yang, Y.
Berg, A.
Mahammed, A.
Gross, Z.
Heyne, K.
author_sort Stensitzki, T.
collection PubMed
description We combined femtosecond (fs) VIS pump–IR probe spectroscopy with fs VIS pump–supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br(8))(py)(2) in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a time constant of (250 ± 80) fs to the S(2) and S(1) electronic excited states. This is evident from the rise time of the stimulated emission signal in the visible spectral range. On the same time scale, narrowing of broad infrared signals in the C=C stretching region around 1500 cm(−1) is observed. Energy redistribution processes are visible in the vibrational and electronic dynamics with time constants between ∼2 ps and ∼20 ps. Triplet formation is detected with a time constant of (95 ± 3) ps. This is tracked by the complete loss of stimulated emission. Electronic transition of the emerging triplet absorption band overlaps considerably with the singlet excited state absorption. In contrast, two well separated vibrational marker bands for triplet formation were identified at 1477 cm(−1) and at 1508 cm(−1). These marker bands allow a precise identification of triplet dynamics in corrole systems.
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spelling pubmed-48669602016-05-25 Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation Stensitzki, T. Yang, Y. Berg, A. Mahammed, A. Gross, Z. Heyne, K. Struct Dyn SPECIAL TOPIC: THE HAMBURG CONFERENCE ON FEMTOCHEMISTRY (FEMTO12) We combined femtosecond (fs) VIS pump–IR probe spectroscopy with fs VIS pump–supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br(8))(py)(2) in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a time constant of (250 ± 80) fs to the S(2) and S(1) electronic excited states. This is evident from the rise time of the stimulated emission signal in the visible spectral range. On the same time scale, narrowing of broad infrared signals in the C=C stretching region around 1500 cm(−1) is observed. Energy redistribution processes are visible in the vibrational and electronic dynamics with time constants between ∼2 ps and ∼20 ps. Triplet formation is detected with a time constant of (95 ± 3) ps. This is tracked by the complete loss of stimulated emission. Electronic transition of the emerging triplet absorption band overlaps considerably with the singlet excited state absorption. In contrast, two well separated vibrational marker bands for triplet formation were identified at 1477 cm(−1) and at 1508 cm(−1). These marker bands allow a precise identification of triplet dynamics in corrole systems. American Crystallographic Association 2016-05-12 /pmc/articles/PMC4866960/ /pubmed/27226980 http://dx.doi.org/10.1063/1.4949363 Text en © 2016 Author(s). 2329-7778/2016/3(4)/043210/9 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle SPECIAL TOPIC: THE HAMBURG CONFERENCE ON FEMTOCHEMISTRY (FEMTO12)
Stensitzki, T.
Yang, Y.
Berg, A.
Mahammed, A.
Gross, Z.
Heyne, K.
Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title_full Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title_fullStr Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title_full_unstemmed Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title_short Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation
title_sort ultrafast electronic and vibrational dynamics in brominated aluminum corroles: energy relaxation and triplet formation
topic SPECIAL TOPIC: THE HAMBURG CONFERENCE ON FEMTOCHEMISTRY (FEMTO12)
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866960/
https://www.ncbi.nlm.nih.gov/pubmed/27226980
http://dx.doi.org/10.1063/1.4949363
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