Electron transfer in supercritical carbon dioxide: Ultraexothermic charge recombination at the end of the "inverted region"

被引：14

作者：

Serpa, Carlos ^{[1
]}

Gomes, Paulo J. S. ^{[1
]}

Arnaut, Luis G. ^{[1
]}

Formosinho, Sebastiao J. ^{[1
]}

Pina, Joao ^{[1
]}

Seixas de Melo, J. ^{[1
]}

机构：

[1] Univ Coimbra, Dept Quim, P-3004535 Coimbra, Portugal

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2006年 / 12卷 / 19期

关键词：

calorimetry; electron transfer; fluorescence; ion pairs; supercritical fluids;

D O I：

10.1002/chem.200500727

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Charge-recombination rates in contact radical-ion pairs, formed between aromatic hydrocarbons and nitriles in supercritical CO2 and heptane, decrease with the exothermicity of the reactions until they reach -70 kcal mol(-1), but from the increase is observed. The first decrease in rate is typical of the "inverted region" of electron-transfer reactions. The change to an increase in the rate for ultra-exothermic electron transfer indicates a new free-energy relationship. We show that the resulting "double-inverted region" is not due to a change in mechanism. It is an intrinsic property of electron-transfer reactions, and it is due to the increase of the reorganisation energy with the reaction exothermicity.

引用

页码：5014 / 5023

页数：10

共 68 条

[1] Absolute rate calculations for atom abstractions by radicals: Energetic, structural and electronic factors
Arnaut, LG
Pais, AACC
Formosinho, SJ
Barroso, M
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2003, 125 (17) : 5236 - 5246
[2] ARNAUT LG, 1991, J MOL STRUC-THEOCHEM, V79, P209
[3] RECENT ADVANCES IN PHOTOACOUSTIC CALORIMETRY - THEORETICAL BASIS AND IMPROVEMENTS IN EXPERIMENTAL-DESIGN
ARNAUT, LG
CALDWELL, RA
ELBERT, JE
MELTON, LA
[J]. REVIEW OF SCIENTIFIC INSTRUMENTS, 1992, 63 (11) : 5381 - 5389
[4] The intersecting-state model: a link between molecular spectroscopy and chemical reactivity
Arnaut, LG
Pais, AACC
Formosinho, SJ
[J]. JOURNAL OF MOLECULAR STRUCTURE, 2001, 563 : 1 - 17
[5] Theoretical studies of intramolecular electron transfer reactions: Distance and free energy dependences
Arnaut, LG
Formosinho, SJ
[J]. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 1996, 100 (1-3) : 15 - 34
[6] ARNAUT LG, 1994, J PHOTOCH PHOTOBIO A, V82, pR7
[7] Theory of electron transfer reactions in photosynthetic bacteria reaction centers
Arnaut, LG
Formosinho, SJ
[J]. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 1997, 111 (1-3) : 111 - 138
[8] Absolute energies of interconverting contact and solvent-separated radical-ion pairs
Arnold, BR
Farid, S
Goodman, JL
Gould, IR
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (23) : 5482 - 5483
[9] ENERGY-GAP DEPENDENCES OF CHARGE RECOMBINATION PROCESSES OF ION-PAIRS PRODUCED BY EXCITATION OF CHARGE-TRANSFER COMPLEXES - SOLVENT POLARITY EFFECTS
ASAHI, T
OHKOHCHI, M
MATAGA, N
[J]. JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (50) : 13132 - 13137
[10] CHARGE RECOMBINATION PROCESS OF ION-PAIR STATE PRODUCED BY EXCITATION OF CHARGE-TRANSFER COMPLEX IN ACETONITRILE SOLUTION - ESSENTIALLY DIFFERENT CHARACTER OF ITS ENERGY-GAP DEPENDENCE FROM THAT OF GEMINATE ION-PAIR FORMED BY ENCOUNTER BETWEEN FLUORESCER AND QUENCHER
ASAHI, T
MATAGA, N
[J]. JOURNAL OF PHYSICAL CHEMISTRY, 1989, 93 (18) : 6575 - 6578

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