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The influence of temperature on C153 steady-state absorption and fluorescence kinetics in hydrogen bonding solvents.

Dobek K, Karolczak J - J Fluoresc (2012)

Bottom Line: It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed.Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime.We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, Adam Mickiewicz University, Poznań, Poland. dobas@amu.edu.pl

ABSTRACT
In a recent paper (J Fluoresc (2011) 21:1547-1557) a temperature induced modulation of Coumarin 153 (C153) fluorescence lifetime and quantum yield for the probe dissolved in the polar, nonspecifically interacting 1-chloropropane was reported. This modulation was also observed in temperature dependencies of the radiative and nonradiative rates. Here, we show that the modulation is also observed in another 1-chloroalkane-1-chlorohexane, as well as in hydrogen bonding propionitrile, ethanol and trifluoroethanol. Change in the equilibrium distance between S (0) an S (1) potential energies surfaces was identified as the source of this modulation. This change is driven by temperature changes. It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed. Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime. Hydrogen bonds are formed by C153 also with hydrogen accepting solvents like propionitrile. We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position. Finally, the influence of temperature on the energies of hydrogen bonds formed by C153 when acting as hydrogen donor or acceptor is reported.

No MeSH data available.


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Temperature dependence of: (a) E00, S1–S0 energy gap for C153 in ClH (filled circles) and PPN (empty circles), -full width at half-maximum in ClH (filled squares) and PPN (empty squares), -in ClH (filled triangles) and PPN (empty triangles); (b) —Huang-Rhys vibrational coupling factor in ClH (filled circles) and PPN (empty circles) as obtained from fit of C153 emission spectra in both solvents to the model given in Eqs. (4–6)
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Fig10: Temperature dependence of: (a) E00, S1–S0 energy gap for C153 in ClH (filled circles) and PPN (empty circles), -full width at half-maximum in ClH (filled squares) and PPN (empty squares), -in ClH (filled triangles) and PPN (empty triangles); (b) —Huang-Rhys vibrational coupling factor in ClH (filled circles) and PPN (empty circles) as obtained from fit of C153 emission spectra in both solvents to the model given in Eqs. (4–6)

Mentions: Similar results were obtained in both solvents, except for E00 which included a solvent induced shift, thus it was higher in ClH than in PPN (Fig. 10). There is a correlation between (T), and (T) dependencies, with significant changes in the same temperature range in which τF(T) is observed to change. At this stage it is not possible to deduce how much these correlations affect the results of the fit, thus, to what extent (T), and (T) dependencies reflects a true physical effect. These values are averages reflecting changes in different accepting modes properties [22,23]. The similarity between , and the corresponding quantities in [13] shows that the 1,150 cm−1 (in Fig. 10 ~1,250 cm−1) is the dominant mode in the emission process. However, (T) changes are hard to explain on the basis of a single mode deactivation, as they would indicate a rise and then a fall in equilibrium distance with decreasing temperature for C153 in ClH. In PPN an additional preliminary fall in this distance would be expected. However, assuming also that other accepting modes, as the 810 cm−1 and 360 cm−1 discussed in [7,13], are active in the fluorescence transition a quite simple explanation of the temperature dependence of C153 radiative deactivation can be proposed.Fig. 10


The influence of temperature on C153 steady-state absorption and fluorescence kinetics in hydrogen bonding solvents.

Dobek K, Karolczak J - J Fluoresc (2012)

Temperature dependence of: (a) E00, S1–S0 energy gap for C153 in ClH (filled circles) and PPN (empty circles), -full width at half-maximum in ClH (filled squares) and PPN (empty squares), -in ClH (filled triangles) and PPN (empty triangles); (b) —Huang-Rhys vibrational coupling factor in ClH (filled circles) and PPN (empty circles) as obtained from fit of C153 emission spectra in both solvents to the model given in Eqs. (4–6)
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3473193&req=5

Fig10: Temperature dependence of: (a) E00, S1–S0 energy gap for C153 in ClH (filled circles) and PPN (empty circles), -full width at half-maximum in ClH (filled squares) and PPN (empty squares), -in ClH (filled triangles) and PPN (empty triangles); (b) —Huang-Rhys vibrational coupling factor in ClH (filled circles) and PPN (empty circles) as obtained from fit of C153 emission spectra in both solvents to the model given in Eqs. (4–6)
Mentions: Similar results were obtained in both solvents, except for E00 which included a solvent induced shift, thus it was higher in ClH than in PPN (Fig. 10). There is a correlation between (T), and (T) dependencies, with significant changes in the same temperature range in which τF(T) is observed to change. At this stage it is not possible to deduce how much these correlations affect the results of the fit, thus, to what extent (T), and (T) dependencies reflects a true physical effect. These values are averages reflecting changes in different accepting modes properties [22,23]. The similarity between , and the corresponding quantities in [13] shows that the 1,150 cm−1 (in Fig. 10 ~1,250 cm−1) is the dominant mode in the emission process. However, (T) changes are hard to explain on the basis of a single mode deactivation, as they would indicate a rise and then a fall in equilibrium distance with decreasing temperature for C153 in ClH. In PPN an additional preliminary fall in this distance would be expected. However, assuming also that other accepting modes, as the 810 cm−1 and 360 cm−1 discussed in [7,13], are active in the fluorescence transition a quite simple explanation of the temperature dependence of C153 radiative deactivation can be proposed.Fig. 10

Bottom Line: It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed.Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime.We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, Adam Mickiewicz University, Poznań, Poland. dobas@amu.edu.pl

ABSTRACT
In a recent paper (J Fluoresc (2011) 21:1547-1557) a temperature induced modulation of Coumarin 153 (C153) fluorescence lifetime and quantum yield for the probe dissolved in the polar, nonspecifically interacting 1-chloropropane was reported. This modulation was also observed in temperature dependencies of the radiative and nonradiative rates. Here, we show that the modulation is also observed in another 1-chloroalkane-1-chlorohexane, as well as in hydrogen bonding propionitrile, ethanol and trifluoroethanol. Change in the equilibrium distance between S (0) an S (1) potential energies surfaces was identified as the source of this modulation. This change is driven by temperature changes. It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed. Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime. Hydrogen bonds are formed by C153 also with hydrogen accepting solvents like propionitrile. We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position. Finally, the influence of temperature on the energies of hydrogen bonds formed by C153 when acting as hydrogen donor or acceptor is reported.

No MeSH data available.


Related in: MedlinePlus