scholarly journals Distance Dependence of Electron Transfer in DNA:  The Role of the Reorganization Energy and Free Energy

2000 ◽  
Vol 104 (48) ◽  
pp. 11541-11550 ◽  
Author(s):  
H. L. Tavernier ◽  
M. D. Fayer
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Reorganization Energy ◽  
Distance Dependence

The Role of Free Energy in Interligand Electron Transfer

1989 ◽  
pp. 253-266 ◽  
Author(s):  
L. K. Orman ◽  
D. R. Anderson ◽  
T. Yabe ◽  
J. B. Hopkins
Keyword(s):  
Electron Transfer ◽  
Free Energy

scholarly journals The photo-physical study of the interaction of riboflavin with Nicotine in bicontinuous microemulsion

2017 ◽  
Vol 6 (6) ◽  
pp. 267-275
Author(s):  
Maurice Ohaekeleihem Iwunze
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Rate Constant ◽  
Reorganization Energy ◽  
Outer Sphere ◽  
Electron Transfer Reaction ◽  
Microemulsion System ◽  
Quenching Rate ◽  
Bicontinuous Microemulsion ◽  
Bimolecular Quenching

Steady-state fluorescence spectroscopy was used to study the interaction of riboflavin with nicotine in a bicontinuous microemulsion system made up of 42.11:13.70:21.34:22.85 % w/w of water: oil: surfactant: cosurfactant. The surfactant used is cetyltrimethylammonium bromide (CTAB), the oil is tetradecane and the cosurfactant is 1-pentanol. It is observed that the interaction of riboflavin and nicotine in the prepared microemulsion lead to the quenching of riboflavin fluorescence. The bimolecular quenching rate constant, kq, of riboflavin by nicotine was observed as 4.15 x 109 M-1 s -1 with an efficiency of 56 %. The mechanism of the reaction is proposed to be diffusion limited in an activated electron transfer reaction in a solvent separated (outer-sphere) scheme. The electron transfer rate constant, kET, was calculated as 5.89 x 109 s -1 with an activation rate constant, ka, of 9.52 x 109 s -1 . The calculated solvent reorganization energy, λs, of the reaction was 1.09 eV, the free energy of interaction, ΔGo , is -2.9 eV and the free energy of activation, ΔG*, was calculated as 0.75 eV.

scholarly journals Two-Dimensional Free Energy Surfaces for Electron Transfer Reactions in Solution

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Shigeo Murata ◽  
Maged El-Kemary ◽  
M. Tachiya
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Nonpolar Solvent ◽  
Final States ◽  
Free Energies ◽  
Intermolecular Electron Transfer ◽  
Exciplex Formation ◽  
Orientational Polarization ◽  
Distance Dependence ◽  
Energy Surfaces

Change in intermolecular distance between electron donor (D) and acceptor (A) can induce intermolecular electron transfer (ET) even in nonpolar solvent, where solvent orientational polarization is absent. This was shown by making simple calculations of the energies of the initial and final states of ET. In the case of polar solvent, the free energies are functions of both D-A distance and solvent orientational polarization. On the basis of 2-dimensional free energy surfaces, the relation of Marcus ET and exciplex formation is discussed. The transient effect in fluorescence quenching was measured for several D-A pairs in a nonpolar solvent. The results were analyzed by assuming a distance dependence of the ET rate that is consistent with the above model.

scholarly journals Study of Electron Transfer between Amines and Biologically Active 4 - Aryloxymethylcoumarin

2016 ◽  
Vol 15 (1) ◽  
pp. 29-45
Author(s):  
U P Raghavendra
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Aromatic Amines ◽  
Reduction Potential ◽  
Standard Free Energy ◽  
Reorganization Energy ◽  
Biologically Active ◽  
Rate Parameter ◽  
Quenching Rate ◽  
Electron Transfer Theory

Electron transfer from aliphatic and aromatic amines to biologically    active    4-aryloxymethyl    coumarin1-(4- iodophenoxymethyl)-benzo[ f ]coumarin (1IPMBC)    has been investigated in acetonitrile solvent. The variation of quenching rate parameter with reduction potential of amines indicates the electron transfer from amines to investigated      coumarin molecule.Experimentally determined values of quenching rate parameter k q are well correlated with the standard free energy changes ( ∆G 0 ) within the framework of Marcus electron transfer theory. In the investigatedsystems,solvent reorganization energy appears to play a major role in governing electron transfer dynamics.

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