Theoretical Studies on the Relationship between Aromaticity and Electron Transport Properties of Analogous [10]-Annulene Derivatives.

In the overall aromaticity of a molecular system, the magnitude of σ -aromaticity influences the degree of bond length averaging in the molecular geometry, while the magnitude of π -aromaticity reflects the strength of π -electron delocalization, subsequently affecting the electronic transport properties of the entire molecular system. Simultaneously, the aromaticity type of a molecular system is primarily determined by the symmetry of the innermost π molecular orbitals. In this study, we conducted computational simulations of the aromaticity and electronic transport properties of compounds, including C8H8Cu2 with p π – d π delocalization effects and C12H8 with p π – p π delocalization effects, along with their Li derivatives. Based on calculated NICS values, ring current directions, molecular structural configurations and the symmetry of the innermost π molecular orbitals, we clarified the aromaticity types of the molecular systems. Combined with the analysis of molecular electrical conductivity properties, we gained insights into the fundamental attributes of Li-bridge bonds in Li derivatives and the factors influencing electronic transport pathways. Consequently, we established a relationship between the aromaticity of molecular systems and their electronic transport properties. To a certain extent, a novel criterion for evaluating molecular aromaticity is proposed from the perspective of single-molecule electronics. Through the analysis of molecular aromaticity and electrical conductivity, we have clarified that planar Craig-Möbius type π -aromaticity and non-planar Heilbronner-Möbius type σ -aromaticity determine the molecular electron transport capabilities. Additionally, by combining the analysis of bonding types and electron transport pathways, we explain the reason why the C 1 2 H8Li4 molecule, satisfying the 4n electron rule, exhibits Heilbronner-Möbius π -antiaromaticity, which primarily arises from the localization of electrons in its Li-bridged bonds. This research contributes to understanding the fundamental properties of molecular bonding, particularly Li-bridged bonds, and offers a new method for assessing aromaticity from the perspective of single-molecule electronics. [ABSTRACT FROM AUTHOR]