Unusual Pyrene Excimer Formation during Sodium Deoxycholate Gelation†

Langmuir ◽  
1996 ◽  
Vol 12 (7) ◽  
pp. 1789-1793 ◽  
Author(s):  
A. Jover ◽  
F. Meijide ◽  
E. Rodríguez Núñez ◽  
J. Vázquez Tato ◽  
M. Mosquera ◽  
...  
Keyword(s):  
Sodium Deoxycholate ◽  
Excimer Formation ◽  
Pyrene Excimer Formation

scholarly journals Unfolding of Helical Poly(L-Glutamic Acid) in N,N-Dimethylformamide Probed by Pyrene Excimer Fluorescence (PEF)

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1690
Author(s):  
Weize Yuan ◽  
Remi Casier ◽  
Jean Duhamel
Keyword(s):  
Glutamic Acid ◽  
Local Density ◽  
Guanidine Hydrochloride ◽  
Racemic Mixture ◽  
Excimer Fluorescence ◽  
Excimer Formation ◽  
Blob Model ◽  
Α Helix ◽  
The Relationship ◽  
Pyrene Excimer Formation

The denaturation undergone by α–helical poly(L-glutamic acid) (PLGA) in N,N-dimethylformamide upon addition of guanidine hydrochloride (GdHCl) was characterized by comparing the fluorescence of a series of PLGA constructs randomly labeled with the dye pyrene (Py-PLGA) to that of a series of Py-PDLGA samples prepared from a racemic mixture of D,L-glutamic acid. The process of pyrene excimer formation (PEF) was taken advantage of to probe changes in the conformation of α–helical Py-PLGA. Fluorescence Blob Model (FBM) analysis of the fluorescence decays of the Py-PLGA and Py-PDLGA constructs yielded the average number (<Nblob>) of glutamic acids located inside a blob, which represented the volume probed by an excited pyrenyl label. <Nblob> remained constant for randomly coiled Py-PDLGA but decreased from ~20 to ~10 glutamic acids for the Py-PLGA samples as GdHCl was added to the solution. The decrease in <Nblob> reflected the decrease in the local density of PLGA as the α–helix unraveled in solution. The changes in <Nblob> with GdHCl concentration was used to determine the change in Gibbs energy required to denature the PLGA α–helix in DMF. The relationship between <Nblob> and the local density of macromolecules can now be applied to characterize the conformation of macromolecules in solution.

Einfluß der Deuterierung auf die Excimerenkinetik des Pyrens

1976 ◽  
Vol 31 (8) ◽  
pp. 990-994
Author(s):  
Günther Heidt
Keyword(s):  
Partition Function ◽  
Rate Constants ◽  
Formation Rate ◽  
Kinetic Constants ◽  
Theoretical Expectation ◽  
Excimer Emission ◽  
Anomalous Effect ◽  
Excimer Formation ◽  
Pyrene Excimer Formation

AbstractThe effect of deuteration on all six photophysical and kinetic constants of pyrene excimer formation is investigated. The rate constants of monomer and excimer emission and the rate of dissociation of the excimer are not affected by deuteration. The increase of the radiationless deactivation of the monomer (anomalous effect) agrees with the theoretical expectation. The radiationless deactivation of the excimer at various temperatures shows no effect and therefore does not take place via the excimer triplet. The decrease of the excimer formation rate can be explained by the effect of deuteration on the partition function and hence on the entropy.

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