Guest-dependent directional complexation based on triptycene derived oxacalixarene: formation of oriented rotaxanes

Abstract

Structural changes in the guest cause inversion of the dominant threading direction in triptycene derived oxacalixarene with different semi-cavities.

Redox‐Switchable Calix[6]arene‐Based Isomeric Rotaxanes

“…The majority of twostationm olecular shuttles reporteds of ar is based on nonsymmetricala xles, [18,24,25] but in principle the direction of motion in ar otaxanec ould be dictated by the asymmetry of the wheel component ( Figure 1). [22,[26][27][28][29][30][31] In am inimalistic design like that showni nF igure 1a,o nw eakening the interaction between the axle and the ring the formation of two orientational isomers could be envisaged. If the nonsymmetrical ring has a preferential directiono fm otion, dictated by the different natures of its two rims, then it would be possible to get selectively only one orientational isomer.I fb oth the axle andt he ring are nonsymmetrical (Figure 1b), then two orientational isomers can be synthesized, and the movement of the ring can give rise to four translational isomers( Figure 1b).…”

“…In a rotaxane‐based architecture, asymmetry can be included in both the axle and wheel components. The majority of two‐station molecular shuttles reported so far is based on nonsymmetrical axles, but in principle the direction of motion in a rotaxane could be dictated by the asymmetry of the wheel component (Figure ) . In a minimalistic design like that shown in Figure a, on weakening the interaction between the axle and the ring the formation of two orientational isomers could be envisaged.…”

Exploring and Exploiting the Symmetry-Breaking Effect of Cyclodextrins in Mechanomolecules

“…We can consider CD mechanomolecules as a case study and test bed for investigating and leveraging the effects of symmetry-breaking in other molecular systems as well. Symmetry-breaking hosts have been developed based on motifs including calix[n]arene [172][173][174][175][176][177][178][179][180][181][182], pillar[n]arene [183][184][185][186][187], cucurbit [n]uril [188], and cyanostar [189] motifs, and even transmembrane proteins [190]. These materials have much to contribute to the body of knowledge on symmetry breaking in chemical systems.…”

Directional Shuttling of a Stimuli‐Responsive Cone‐Like Macrocycle on a Single‐State Symmetric Dumbbell Axle

“…Thus, directional shuttling of a cone‐like macrocycle could be achieved on a symmetric dumbbell axle with two nonsymmetric binding stations. α‐Cyclodextrin, calix[6]arenes, and triptycene‐derived oxacalixarene are three‐dimensional cone‐like macrocycles of this type, and they have been explored for the selective construction of several oriented pseudorotaxanes and rotaxanes. However, there is only one example which demonstrates directional shuttling of α‐cyclodextrin on a symmetric and photoresponsive stilbene axle .…”