Coulombic-enhanced hetero radical pairing interactions.

Zheng, Xujun; Zhang, Yang; Cao, Ning; Li, Xin; Zhang, Shuoqing; Du, Renfeng; Wang, Haiying; Ye, Zhenni et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

Spin-spin interactions between two identical aromatic radicals have been studied extensively and utilized to establish supramolecular recognition. Here we report that spin-pairing interactions could also take place between two different π-electron radicals, namely a bipyridinium radical cation (BPY<sup>+•</sup>) and a naphthalene-1,8:4,5-bis(dicarboximide) radical anion (NDI<sup>─•</sup>). The occurrence of this type of previously unreported hetero radical-pairing interactions is attributed to enhancement effect of Coulombic attraction between these two radicals bearing opposite charges. The Coulombic-enhanced hetero radical pairing interactions are employed to drive host-guest recognition, as well as the reversible switching of a bistable [2]rotaxane.