Nitroxide Biradicals

Electron–Electron Dipolar Interaction Poses a Challenge to the Radical Pair Mechanism of Magnetoreception

“…More generally, the exchange coupling J ( r ) has a complex dependence on the electronic properties of the radicals as well as their separation and relative orientation and the nature of the intervening medium. Governed by orbital symmetry, they may be small even for nearby radicals (as has been documented for nitroxide biradicals). , While this variability makes a general assessment difficult, our model is robust toward large exchange interactions and tunable for small ones, and thus, it is fully applicable to bystander radicals at close distance.…”