Superexchange McConnell model

The third, and possibly the most important conclusion is that the distance dependence of TB-mediated electronic coupling in 15(h) is much weaker than that predicted by the simple McConnell model. In that model, a /3el value of about 2.3 bond-1 is estimated, whereas the average /3el value of ca. 1.0 bond-1 for 15(/t) is 2.3 times smaller Thus, the attenuation in the ET rate, mediated by superexchange through a saturated hydrocarbon bridge, could be as small as ca. 2.5 bond-1, as opposed to ca. 10 bond-1, predicted from the simple McConnell model. 

The McConnell superexchange model is too simplistic for a protein intervening medium because of the complex array of bonded and nonbonded contacts between D and An important advance was made by... 

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