
TY  - JOUR
A1  - Paddon-Row, Michael N. 
T1  - Superexchange-Mediated Charge Separation and Charge Recombination in Covalently Linked Donor&#8211;Bridge&#8211;Acceptor Systems
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2003
VL  - 56
IS  - 8
SP  - 729
EP  - 748
KW  - 
UR  - https://doi.org/10.1071/CH02249 
N2  - Evidence is presented in support of the concept that electron transfer (ET) between a pair of chromophores may take place efficiently over large distances (&#62;10 &#197;) by the mediation of an intervening saturated hydrocarbon medium. For example, ET is found to take place on a sub-nanosecond timescale through saturated norbornylogous bridges greater than 13 &#197; in length, by a superexchange (through-bond coupling) mechanism. The dependence of the ET dynamics on the bridge length and configuration are consistent with the operation of a superexchange mechanism. The distinction between molecular wire behaviour and superexchange-mediated ET is made. The distance dependence of ET dynamics through different types of bridges&#8212;saturated and unsaturated hydrocarbon bridges, proteins, and duplex DNA&#8212;is discussed and explained. Strategies for prolonging the lifetimes of charge-separated states are explored and discussed. In general, long-lived charge-separated species have been generated using giant multichromophoric systems in which the charges are separated by large distances, often exceeding 20 &#197;. In contrast, it is shown that very long-lived charge-separated states, possessing the triplet multiplicity, may be generated using short &#8216;dwarf&#8217; dyads, in which the charges are less than 6 &#197; apart. Charge recombination in these species is slowed by the difference in electron spin multiplicity between the charge-separated state and the ground state. 
ER  -

