#antiaromatics

[materialsscienceandengineering]

Creating a nanospace like no other: Scientists build a nanocage with antiaromatic walls

Researchers at Tokyo Institute of Technology, the University of Cambridge, and the University of Copenhagen have built a self-assembled nanocage with a very unusual nanospace: Its walls are made of antiaromatic molecules, which are generally considered too unstable to work with. By overturning assumptions about the limits of nano-chemical engineering, the study creates an entirely new nanospace for scientists to explore. Nanometer-sized cavities are already finding a range of useful applications in chemistry, medicine and environmental science.

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Scientists including Masahiro Yamashina of Tokyo Institute of Technology (JSPS Overseas Research Fellow, at that time) and Jonathan R. Nitschke of the University of Cambridge, reporting their work in the journal Nature, describe the construction of a new type of nanospace inside "a self-assembled cage composed of four metal ions with six identical antiaromatic walls."

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[materialsscienceandengineering]

Nitrogen-embedded polycyclic compound with strong antiaromaticity and stability

Nitrogen-embedded polycyclic compounds with strong antiaromaticity and stability were synthesized and isolated for the first time using pyrrole as a key unit. An expedited approach toward stable antiaromatic polycyclic compounds enables not only the revealing of its fundamental properties, but also its application to organic electronic materials.

The synthesis and isolation of a nitrogen-embedded polycyclic compound with strong antiaromaticity and stability was achieved for the first time by a research group at Ehime University. This result was published on October 2, 2019 in the Journal of the American Chemical Society.

Aromaticity is one of the most important concepts in chemistry, which has the influence on fundamental properties of cyclic conjugated compounds. In general, compounds with 4n+2 π electrons in the ring are stable due to their aromatic nature, and are widely used around us: from plastics to pharmaceuticals, and from dyes to organic electronics materials. On the other hand, antiaromatic compounds with 4n π electrons in the ring lack stability, and thus research on the synthesis and characterization of such compounds remains to be elucidated. In this report, an expedited approach toward a nitrogen-embedded antiaromatic compound with strong antiaromaticity and stability is presented. The new compounds were efficiently synthesized in just three steps from commercially available reagents via a substitution reaction and successive intramolecular Schooll and Vilsmeier-type reactions. Detailed investigation revealed its strong antiaromaticity and stability even in air.

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