Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes
An approach was developed to determine triplet quantum yields, ΦT, which overcomes most of the difficulties usually encountered in flash photolysis studies of triplet states. The combined application of near-IR emission and optoacoustics yields ΦT values which are independent of the absorption prope...
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1990
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Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223654_v94_n15_p5879_Nonell http://hdl.handle.net/20.500.12110/paper_00223654_v94_n15_p5879_Nonell |
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paper:paper_00223654_v94_n15_p5879_Nonell2023-06-08T14:50:12Z Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes Aramendía, Pedro Francisco Negri, Ricardo Martin Braslavsky, Silvia Elsa An approach was developed to determine triplet quantum yields, ΦT, which overcomes most of the difficulties usually encountered in flash photolysis studies of triplet states. The combined application of near-IR emission and optoacoustics yields ΦT values which are independent of the absorption properties of the triplets. Thus, the triplet energies derived from near-IR phosphorescence spectra together with the values of the heat stored by the triplets determined from optoacoustic experiments afforded ΦT = 0.3 ± 0.1 for porphycene (PO) and 0.4 ± 0.1 for its tetra-n-propyl derivative (TPrPO). Several calorimetric references for optoacoustic measurements in the red region were tested. The ΦT values, combined with flash photolysis data, yielded accurate triplet- minus ground-state absorption coefficients. The quantum yields for singlet molecular oxygen production determined by time-resolved phosphorescence were ΦΔ = 0.34 ± 0.05 for PO and 0.36 ± 0.03 for TPrPO which implies an efficiency near unity for O2(1Δ8) production upon collision of the triplet states of the porphycenes with ground-state O2. © 1990 American Chemical Society. Fil:Aramendía, P.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Negri, R.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Braslavsky, S.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1990 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223654_v94_n15_p5879_Nonell http://hdl.handle.net/20.500.12110/paper_00223654_v94_n15_p5879_Nonell |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
description |
An approach was developed to determine triplet quantum yields, ΦT, which overcomes most of the difficulties usually encountered in flash photolysis studies of triplet states. The combined application of near-IR emission and optoacoustics yields ΦT values which are independent of the absorption properties of the triplets. Thus, the triplet energies derived from near-IR phosphorescence spectra together with the values of the heat stored by the triplets determined from optoacoustic experiments afforded ΦT = 0.3 ± 0.1 for porphycene (PO) and 0.4 ± 0.1 for its tetra-n-propyl derivative (TPrPO). Several calorimetric references for optoacoustic measurements in the red region were tested. The ΦT values, combined with flash photolysis data, yielded accurate triplet- minus ground-state absorption coefficients. The quantum yields for singlet molecular oxygen production determined by time-resolved phosphorescence were ΦΔ = 0.34 ± 0.05 for PO and 0.36 ± 0.03 for TPrPO which implies an efficiency near unity for O2(1Δ8) production upon collision of the triplet states of the porphycenes with ground-state O2. © 1990 American Chemical Society. |
author |
Aramendía, Pedro Francisco Negri, Ricardo Martin Braslavsky, Silvia Elsa |
spellingShingle |
Aramendía, Pedro Francisco Negri, Ricardo Martin Braslavsky, Silvia Elsa Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
author_facet |
Aramendía, Pedro Francisco Negri, Ricardo Martin Braslavsky, Silvia Elsa |
author_sort |
Aramendía, Pedro Francisco |
title |
Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
title_short |
Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
title_full |
Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
title_fullStr |
Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
title_full_unstemmed |
Laser-induced optoacoustics combined with near-infrared emission. An alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
title_sort |
laser-induced optoacoustics combined with near-infrared emission. an alternative approach for the determination of intersystem crossing quantum yields applied to porphycenes |
publishDate |
1990 |
url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223654_v94_n15_p5879_Nonell http://hdl.handle.net/20.500.12110/paper_00223654_v94_n15_p5879_Nonell |
work_keys_str_mv |
AT aramendiapedrofrancisco laserinducedoptoacousticscombinedwithnearinfraredemissionanalternativeapproachforthedeterminationofintersystemcrossingquantumyieldsappliedtoporphycenes AT negriricardomartin laserinducedoptoacousticscombinedwithnearinfraredemissionanalternativeapproachforthedeterminationofintersystemcrossingquantumyieldsappliedtoporphycenes AT braslavskysilviaelsa laserinducedoptoacousticscombinedwithnearinfraredemissionanalternativeapproachforthedeterminationofintersystemcrossingquantumyieldsappliedtoporphycenes |
_version_ |
1768543168746225664 |