Theoretical investigation of structures and electromagnetic properties of double-electron oxidized ring-expanded base pairs

Abstract

This work presents that the x-bases and xx-bases can be combined with their counterparts to form stable Watson-Crick ring-expanded base pairs. For double-electron oxidation Watson-Crick ring-expanded base pairs, they possess open-shell broken symmetry singlet states except for [xxGC]2+. Some complexes exhibit a significantly large amount of diradical character and some of diradical base pairs also possess excellent magnetic characteristics. [xGC]2+, [xAT]2+and [xxAT]2+ show more and more strong AFM with the size expansion of guanine and adenine. The magnetic interactions get relatively weaker and weaker with the size expansion of cytosine and thymin. [xxTA]2+ even manifests a weak FM character.