An Ab Initio Study of Double-Electron Oxidized Base Pairs with Diradical Character through Ring-Expansion Modification

Publication date: Available online 20 July 2019Source: Computational and Theoretical ChemistryAuthor(s): Mei Wang, Jing Zhao, Fufang Su, Hui XuAbstractIn this work, our calculations show the Watson-Crick base pairs remain stable through ring-expansion modification. DFT calculations reveal the optimized structures and novel electromagnetic properties of the designed base pairs. It is found the optimized structures possess open-shell singlet ground states except for [yGC]2+ and [yyGC]2+. They exhibit variable degrees of magnetic exchange interaction. As the size of adenine increases, [yAT]2+ and [yyAT]2+ exhibit stronger antiferromagnetic properties. There is no significant increase in the magnetism of [yG-tC]2+ and [yyG-tC]2+, which is due to the lack of hydrogen bond in WC H-bonding zones. For the other base pairs, the magnetic interaction between the bases becomes weaker due to the increase of the size of the cytosine and thymine. The [yyTA]2+ base pair even exhibits a weak ferromagnetic property.Graphical abstract

Source: Computational and Theoretical Chemistry - July 20, 2019 Category: Chemistry Source Type: research