Structure–aromaticity–reactivity relationship of one‐ and two‐dimensional polyaromatic hydrocarbons and polyborazines

Abstract

AbstractBoth graphene and hexagonal boron nitride (h‐BN) have found their application in catalysis and electronic devices owing to their unique π electronic nature. However, it remains unclear on how their sizes and growing modes influence their electronic properties. In order to extensively understand their structure–property relationship to stimulate and assist potential applications, in this work, the electronic structures of the polyaromatic hydrocarbons (PAHs) and polyborazines (boron nitride nanosheets, BNNSs) were analyzed by means of density functional theory calculations to investigate how the one‐ and two‐dimensional growth of their building blocks, benzene and borazine, respectively, may modulate/govern their aromaticity and reactivities. The analysis shows that the aromaticity and reactivity of PAHs exhibit significant response to their geometries, while the properties of BNNSs show strong localization nature and are nearly size‐independent. This unique nature of BNNSs is different from both the organic polyaromatic molecules and the inorganic metal/metal oxides whose reactivity may be significantly enhanced upon modulating their sizes, and offers implications in the design of new materials grafted by BNNS for manipulatable electronic properties. This study also brings caution on the application of widely used aromaticity descriptors, and shows that in general the descriptors derived from electronic structure are more reliable.