Kinetics of Fluorescence Quenching by Electron and H-Atom Transfer

1970 ◽  
Vol 8 (2) ◽  
pp. 259-271 ◽  
Author(s):  
Dieter Rehm ◽  
Albert Weller
Keyword(s):  
Fluorescence Quenching ◽  
Atom Transfer ◽  
Kinetics Of

scholarly journals Experimental and Computational Investigations into Trivalent Phosphorous-Mediated Radical Thiol Desulfurization

2021 ◽  
Author(s):  
John Lopp ◽  
Valerie Schmidt
Keyword(s):  
Atom Transfer ◽  
Radical Intermediate ◽  
Thiyl Radicals ◽  
Trigonal Bipyramidal ◽  
Peptide Modification ◽  
Aliphatic Thiols ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Marked Dependence ◽  
Distorted Trigonal Bipyramidal

Radical-mediated thiol desulfurization processes using tricoordinate phosphorous reagents are used in a range of applications from small molecule synthesis to peptide modification. A combined experimental and computational examination of the mechanism and kinetics of the radical desulfurization of alkyl thiyl radicals using trivalent phosphorus reagents was performed. Primary alkyl thiols undergo desulfurization between 10^6 to 10^9 M-1s-1 depending on the phosphorus component with either an H-atom transfer step or β-fragmentation of the thiophosphoranyl intermediate may be rate-controlling. While the desulfurization of primary aliphatic thiols showed a marked dependence on the identity of phosphorous reagent used with either a rate-controlling H-atom transfer or -fragmentation, thiols yielding stabilized C-centered radicals showed much less sensitivity. Support for a stepwise S-atom transfer process progressing via a distorted trigonal bipyramidal thiophosphoranyl radical intermediate was obtained from DFT calculated energetics and hyperfine splitting values.

Transient kinetics of substrate binding to measured by fluorescence quenching

1997 ◽  
Vol 69 (2-3) ◽  
pp. 137-151 ◽  
Author(s):  
Promod R. Pratap ◽  
Edward H. Hellen ◽  
Anuradha Palit ◽  
Joseph D. Robinson
Keyword(s):  
Fluorescence Quenching ◽  
Substrate Binding ◽  
Transient Kinetics ◽  
Kinetics Of
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