Distance, stereoelectronic effects, and the Marcus inverted region in intramolecular electron transfer in organic radical anions

1986 ◽  
Vol 90 (16) ◽  
pp. 3673-3683 ◽  
Author(s):  
G. L. Closs ◽  
L. T. Calcaterra ◽  
N. J. Green ◽  
K. W. Penfield ◽  
J. R. Miller
1983 ◽  
Vol 36 (3) ◽  
pp. 441 ◽  
Author(s):  
CM Kirk ◽  
BM Peake ◽  
BH Robinson ◽  
J Simpson

An investigation of electron attachment reactions of cluster metal carbonyls is presented. In general, alkyl and organometallic halides react rapidly with metal carbonyl cluster radical anions at ambient temperatures to give the neutral cluster molecule. Halide ion and alkyl or organometallic radicals are also produced, which indicate that these are dissociative electron attachment reactions analogous to those of organic radical anions. The rate of dissociative electron attachment in reactions of PhCCo3(CO)9- was found to depend on the R-X bond energy, the size of the alkyl group and the nature of the counter-ion. In particular, (Ph3P)2N+ retarded some electron transfer reactions to the extent that the bimolecular decay of PhCCo3(CO)9- effectively competed with the electron transfer process in determining the reaction path.


Science ◽  
2019 ◽  
Vol 364 (6439) ◽  
pp. 471-475 ◽  
Author(s):  
Giovanny A. Parada ◽  
Zachary K. Goldsmith ◽  
Scott Kolmar ◽  
Belinda Pettersson Rimgard ◽  
Brandon Q. Mercado ◽  
...  

Electron transfer reactions slow down when they become very thermodynamically favorable, a counterintuitive interplay of kinetics and thermodynamics termed the inverted region in Marcus theory. Here we report inverted region behavior for proton-coupled electron transfer (PCET). Photochemical studies of anthracene-phenol-pyridine triads give rate constants for PCET charge recombination that are slower for the more thermodynamically favorable reactions. Photoexcitation forms an anthracene excited state that undergoes PCET to create a charge-separated state. The rate constants for return charge recombination show an inverted dependence on the driving force upon changing pyridine substituents and the solvent. Calculations using vibronically nonadiabatic PCET theory yield rate constants for simultaneous tunneling of the electron and proton that account for the results.


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