Prof. Rémi CHAUVIN, Laboratory of Coordination Chemistry, Paul Sabatier University, Toulouse, France

While general « Carbo-mers » are expanded versions of parent molecules defined by « dicarbon enrichment »,^[1] carbo-benzenes are benchmark representatives for benzenic parents.^[2] As benzene, C₆H₆, carbo-benzene, C₁₈H₆, satisfies the Hückel rule for aromaticity (number of π_z electron = 4n+2 for n = 1 and n=4, respectively), thus predicting augmented stability of the a priori quite reactive sp-carbon-rich empty C₁₈ macrocycle. This has been demonstrated by both computational and experimental results. In this lecture, unique structural features, synthesis methods, characterizations, and physical properties of p-difunctional carbo-benzene derivatives will be presented.^[3] Focus will be first given to selected chromophoric properties, such as porphyrin-like one-photon absorption ability,^[4] dichromism in solution,^[5] and two-photon absorption.^[6]  Further emphasis will be then given to strategies devised to address the recurring issue of the poor solubility of carbo-benzenes. Their supra-molecular interactions in the crystal, liquid crystal, and solution states will be addressed from several examples.^[7]

References

[1] R. Chauvin, Tetrahedron Lett. 1995, 37, 397.

[2] (a) Y. Kuwatani, N. Watanabe, I. Ueda, Tetrahedron Lett. 1995, 36, 119 ; (b) R. Chauvin, Tetrahedron Lett. 1995, 37, 401 ; (c) K. Cocq, C. Lepetit, V. Maraval, R. Chauvin, Chem. Soc. Rev. 2015, 44, 6535-6559.

[3] (a) Z. Li, M. Smeu, A. Rives, V. Maraval, R. Chauvin, M. A. Ratner, E.  Borguet, Nature Commun. 2015, 6:6321 ; (b) K. Cocq, N. Saffon-Merceron, Y. Coppel, C. Poidevin, V. Maraval, R.  Chauvin, Angew. Chem. Int. Ed. 2016, 55, 15133. (c) K. Cocq, C. Barthes, A. Rives, V. Maraval, R. Chauvin, Synlett 2019, 30, 30.

[4] D. Listunov, C. Duhayon, A. Poater, S. Mazères, A. Saquet, V. Maraval, R. Chauvin, Chem. Eur. J. 2018, 24, 10699, and references therein.

[5] L. Leroyer, C. Lepetit, A. Rives, V. Maraval, N. Saffon-Merceron, D. Kandaskalov, D. Kieffer, R. Chauvin, Chem. Eur. J. 2012, 18, 3226-3240

[6] I. Baglai, M. de Anda-Villa, R. M. Barba-Barba, C. Poidevin, G. Ramos-Ortíz, V. Maraval, C. Lepetit, N. Saffon-Merceron, J. L. Maldonado, R. Chauvin, Chem. Eur. J. 2015, 21, 14186.

[7] (a) C C. Zhu, T.-H. Wang, C.-J. Su, S.-L. Lee, A. Rives, C. Duhayon, B. Kauffmann, V. Maraval, C.-h. Chen, H.-F. Hsu, R. Chauvin, Chem. Commun. 2017, 53, 5902. (b) Zhu, A. Poater, C. Duhayon, B. Kauffmann, A. Saquet, V. Maraval, R. Chauvin, Angew. Chem. Int. Ed.  2018, 57, 5640.