Hexaphyrin-Cyclodextrin Hybrids: A Nest for Switchable Aromaticity, Asymmetric Confinement, and Isomorphic Fluxionality - Archive ouverte HAL Access content directly
Journal Articles Angewandte Chemie International Edition Year : 2016

Hexaphyrin-Cyclodextrin Hybrids: A Nest for Switchable Aromaticity, Asymmetric Confinement, and Isomorphic Fluxionality

Abstract

Conformational control over the highly flexible π-conjugated system of expanded porphyrins is a key step toward the fundamental understanding of aromaticity and for the development of molecular electronics. We have synthesized unprecedented hexaphyrin-cyclodextrin (HCD) capped hybrids in which the hexaphyrin part is constrained in a planar rectangular conformation in either a 26 or a 28 π-electron oxidation state ([26]/[28]HCD). These structures display strong aromaticity and antiaromaticity, respectively, exhibit markedly different chiroptical properties, and are interconvertible upon the addition of DDQ or NaBH(OAc)3 , thus affording a rare switchable aromatic-antiaromatic system with a free-base expanded porphyrin. Conformational analysis revealed discrimination of the two coordination sites of the hexaphyrin, one of which was coupled to a confined asymmetric environment, and fluxional behavior consisting of apparent rotation of the hexaphyrin cap through a shape-shifting mechanism.

Dates and versions

hal-01231166 , version 1 (19-11-2015)

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Mickaël Ménand, Matthieu Sollogoub, Bernard Boitrel, Stephane Le Gac. Hexaphyrin-Cyclodextrin Hybrids: A Nest for Switchable Aromaticity, Asymmetric Confinement, and Isomorphic Fluxionality. Angewandte Chemie International Edition, 2016, 55 (1), pp.297-301. ⟨10.1002/anie.201508009⟩. ⟨hal-01231166⟩
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