Aromatic compounds represented by benzene are one of the important compound groups that support today's material science.The peculiar property of benzene is called aromaticity, and it has been said that it is the (4n + 2) ring-arranged π-orbital electrons that bring about aromaticity.Recently, however, it has become clear that aromaticity is exhibited not only in the π orbital but also in the σ orbital arranged in a ring shape when (4n + 2) electrons are accommodated.
This raised the question of whether there are compounds with aromaticity consisting of π orbitals and σ orbitals at the same time (double aromatic compounds), but even if there are theoretical predictions for such compounds. It is said that experimental studies such as synthesizing and isolating as a stable compound at room temperature and elucidating its properties were extremely limited.
This time, a research group at Saitama University designed a hexaceranylbenzene dication as a π and σ double aromatic compound.This molecule also has σ-aromaticity because the central benzene ring expresses π-aromaticity and 6 electrons are contained in the σ orbital formed by the six selenium atomic functional groups present in the periphery thereof. Expected to occur.
Then, as a result of synthesizing and isolating the hexaceranylbenzene dication and investigating its electronic state from both experimental and theoretical points of view, the aromatic compound is composed of both the π orbital and the σ orbital. An element peculiar to was confirmed.That is, it was revealed that this molecule has π and σ double aromaticity.
This result, which succeeded in synthesizing a double aromatic molecule having two aromatic properties at the same time and clarified the properties of the double aromatic properties for the first time from both theoretical and experimental viewpoints, will bring about a new theory of physical chemistry. Be expected.
Paper information:[Communications Chemistry] Double aromaticity arising from σ- and π-rings
