Enhanced Quantum Transport in Nitrogen‐substituted Dibenzo[a,e]cyclooctatetraene

Abstract

AbstractStable [8]Annulene‐based hydrocarbons have gained significant attention recently for their potential applications in the development of responsive materials. These hydrocarbons consist of an eight‐membered carbon ring, which imparts them with exceptional stability and structural simplicity. In this study, we systematically replaced one or more carbon atoms at various positions within the dibenzo[a,e]cyclooctatetraenes (dbCOT) with nitrogen atoms and conducted a detailed theoretical investigation to comprehend their characteristics within the realm of single‐molecular electronics. Utilizing DFT, we systematically examined the structural features, energetics, and several electric and spectroscopic properties of original, reduced, and nitrogen‐substituted dbCOTs. The natural singlet dbCOT exhibits a symmetric tub‐shaped molecular structure, while the triplet configuration adopts a planar and symmetric structure, with the former demonstrating greater energetic stability. The substitutions of carbon with nitrogen atoms affect the structural symmetry in different forms, depending on the position and bonding properties of the nitrogen atoms. Most of the substituted configurations, in comparison to natural dbCOT, exhibit absorption of UV‐Vis radiation at longer wavelengths. The reduction in the HOMO‐LUMO gap results in enhanced electrical conductivity in substituted‐dbCOTs, potentially advantageous for technological applications. Notably, the spatial orientation of dbCOTs with respect to the leads exerts significant influence on the charge transfer process.