The effects of insertion of nitrogen atoms on the aromatic nitrogen-containing compounds: A potential approach for designing stable radical molecular materials

摘要

The effects of insertion of nitrogen atoms on the N-H bond strength of azaphenalene and on the stability of the corresponding radicals were comprehensively investigated using density functional theory. The N-H bond dissociation enthalpy of azaphenalene is found to be strengthened in all cases, but the magnitudes are various with the replaced sites and are additive. It is correlated with the coefficient of frontier molecular orbital; that is, it is correlated with the electron density distribution of the outer electrons. The computational results explain why the product substituted with two CH groups by N atoms in the phenalenyl skeleton yielded radical easily, whereas the product replaced with six nitrogen atoms failed. In addition, the effects of insertion of nitrogen atoms in other aromatic nitrogen-containing compounds, including carbazole, indole, and pyrrole, were also studied. All the understanding about the insertion effects of nitrogen atoms would be helpful in designing novel molecules for specific applications, such as functional materials and antioxidants.