Dynamics of transient ion pairs and radical pairs. Solvent and salt effects by time-resolved spectroscopy

1985 ◽  
Vol 107 (14) ◽  
pp. 4356-4358 ◽  
Author(s):  
J. M. Masnovi ◽  
A. Levine ◽  
J. K. Kochi
Keyword(s):  
Ion Pairs ◽  
Radical Pairs ◽  
Salt Effects ◽  
Time Resolved ◽  
Time Resolved Spectroscopy

scholarly journals Electron and hydrogen self-exchange of free radicals of sterically hindered tertiary aliphatic amines investigated by photo-CIDNP

2013 ◽  
Vol 9 ◽  
pp. 437-446 ◽  
Author(s):  
Martin Goez ◽  
Isabell Frisch ◽  
Ingo Sartorius
Keyword(s):  
Ion Pairs ◽  
Activation Parameters ◽  
Radical Cations ◽  
Outer Sphere ◽  
Exchange Reactions ◽  
Radical Pairs ◽  
Time Resolved ◽  
Alkyl Radicals ◽  
Acid Base Equilibrium ◽  
Reorganization Energies

The photoreactions of diazabicyclo[2,2,2]octane (DABCO) and triisopropylamine (TIPA) with the sensitizers anthraquinone (AQ) and xanthone (XA) or benzophenone (BP) were investigated by time-resolved photo-CIDNP (photochemically induced dynamic nuclear polarization) experiments. By varying the radical-pair concentration, it was ensured that these measurements respond only to self-exchange reactions of the free amine-derived radicals (radical cations DH • + or α-amino alkyl radicals D • ) with the parent amine DH; the acid–base equilibrium between DH • + and D • also plays no role. Although the sensitizer does not at all participate in the observed processes, it has a pronounced influence on the CIDNP kinetics because the reaction occurs through successive radical pairs. With AQ, the polarizations stem from the initially formed radical-ion pairs, and escaping DH • + then undergoes electron self-exchange with DH. In the reaction sensitized with XA (or BP), the polarizations arise in a secondary pair of neutral radicals that is rapidly produced by in-cage proton transfer, and the CIDNP kinetics are due to hydrogen self-exchange between escaping D • and DH. For TIPA, the activation parameters of both self-exchange reactions were determined. Outer-sphere reorganization energies obtained with the Marcus theory gave very good agreement between experimental and calculated values of ∆G ‡ 298.

scholarly journals Photophysical properties and fluorosolvatochromism of D–π–A thiophene based derivatives

RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43459-43471
Author(s):  
Hussain A. Z. Sabek ◽  
Ahmed M. M. Alazaly ◽  
Dina Salah ◽  
Hesham S. Abdel-Samad ◽  
Mohamed A. Ismail ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Fluorescence Emission ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Solvation Models

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models.

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