SCHEDULED MAINTENANCE
Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties†
‡a
Duc-Truc
Pham,
b
Jonathan M.
White,
c
Stephen F.
Lincoln
b
and
Martin R.
Johnston
*a
Abstract
The effect of the degree of conformational rigidity and/or flexibility on preorganisation in artificial molecular receptors continues to be actively explored by supramolecular chemists. This work describes a bis-porphyrin architecture, linked via a rigid polycyclic backbone, in which a sterically bulky 2,3,5,6-tetramethylphenyl diimide core restricts rotation to afford two non-interconvertible tweezer conformations; syn- and anti-. After separation, the host–guest chemistry of each conformation was studied independently. The difference in host geometry allows only the syn-conformation to form a strong 1 : 1 bis-porphyrin complex with the diamino ligand 1,4-diazabicyclo[2.2.2]octane (DABCO) (K11 = 1.25 × 108 M−1), with the anti-conformation adopting a 2 : 2 sandwich complex with DABCO (K22 = 5.57 × 1017 M−3).
- This article is part of the themed collection: Supramolecular chemistry in OBC
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