Image

Extremes of aromaticity and antiaromaticity in π-conjugated organic molecules

Abstract

p-Conjugation and aromaticity are extremely important features for the design of functional molecules and materials. But what do these terms really mean? Is benzene “more aromatic” than porphyrin, or better π-conjugated? How reliably can we measure these properties? Many of us learn about aromaticity in the early stages of our chemistry education, but we often don’t realize how hotly debated (and semi-regularly condemned!) the concept has been for the ~100 years since its introduction.

In this talk we will continue the debate. I will discuss the largest known aromatic molecules – oxidized porphyrin nanorings^1,2 – and what they can teach us about the definition and limits of aromaticity.^3,4 I will also discuss our recent experimental process towards preparing novel antiaromatic molecules, and how computational chemistry and NMR spectroscopy can be used, together and separately, to assign and quantify (anti)aromaticity and electronic delocalization.⁵

Image

1              M. D. Peeks, T. D. W. Claridge and H. L. Anderson, Nature, 2017, 541, 200–203.

2              M. Rickhaus, M. Jirasek, L. Tejerina, H. Gotfredsen, M. D. Peeks, R. Haver, H.-W. Jiang, T. D. W. Claridge and H. L. Anderson, Nat. Chem., 2020, 12, 236–241.

3              M. Jirásek, H. L. Anderson and M. D. Peeks, Acc. Chem. Res., 2021, 54, 3241–3251.

4              D. Bradley, M. Jirásek, H. L. Anderson and M. D. Peeks, Chem Sci, 2023, 14, 1762–1768.

5              D. Bradley, C. P. Branley and M. D. Peeks, Phys. Chem. Chem. Phys., 2022, 24, 11486–11490.

Biography

Dr Martin Peeks is a Scientia Senior Lecturer at UNSW. After an undergraduate degree at the University of St Andrews, he started his DPhil in 2013 at the University of Oxford, in the group of Prof Harry Anderson. He completed a postdoc at MIT as a Lindemann Trust Fellow, funded by the English-Speaking Union. In 2019 he began his independent career at UNSW as a Scientia Fellow. His research group applies experimental and computational chemistry to understand emergent properties from π-systems. He also has interests in lab sustainability.