Absolute Configurations of Topologically Chiral [2]Catenanes and the Acid/Base-Flippable Directions of Their Optical Rotations

Abstract

The absolute configurations of the two enantiomers of a topologically chiral [2]catenane were determined unambiguously based on HPLC resolution and X-ray crystal analysis. Although structurally dissimilar to simple amino acids, the optical rotations of these separated [2]catenanes share the Clough−Lutz−Jirgensons behavior of amino acids: the optical rotation flips direction in the presence of acid and base, the first example of such behavior for a mechanically interlocked topologically chiral catenane.

Triphasic circularly polarized luminescence switch quantum simulation of a topologically chiral catenane

“…36–38 As a consequence of the lack of the single crystal X-ray data for the catenane depicted in Fig. 1, we decided to use its precursor whose structure was deposited in CSD, 39 for our DFT benchmark (Fig. 2).…”

Multistate Circularly Polarized Luminescence Switching through Stimuli‐Induced Co‐Conformation Regulations of Pyrene‐Functionalized Topologically Chiral [2]Catenane

“…In this study, the topologically chiral [2]catenane developed by Chiu et al [11a] . was selected as both the chiral skeleton and switching platform, whose topological chirality was confirmed by its single‐crystal structure.…”

“…Starting from the topologically chiral [2]catenanes ( R mt )‐ 1 and ( S mt )‐ 1 that were synthesized through an optimized deprotection and purification procedure from the original report by Chiu et al., [11a] the corresponding pyrene‐functionalized [2]catenanes ( R mt )‐ 2 and ( S mt )‐ 2 were successfully synthesized in 25 % and 27 % yields, respectively (Scheme 1, for the details, see Supporting Information). In addition, starting from racemic [2]catenane 1 and macrocycle S5 , the racemic pyrene‐modified [2]catenane ( rac )‐ 2 and macrocycle 3 were also prepared as model compounds under similar conditions (Scheme S1).…”

Strategies for the Synthesis of Enantiopure Mechanically Chiral Molecules

“…Indeed, Leigh's co-conformationally chiral organocatalyst, 55 Hirose's mechanically planar chiral sensor for chiral guests, 30 and Goldup's mechanically planar chiral rotaxane ligand for enantioselective gold catalysis 54 remain the only direct prototypical applications to date. However, researchers have identified many properties of chiral MIMs that could lead to applications, including the ability of co-conformational stereogenic units to be biased by non-covalent interactions, which could lead to new types of sensors, 42,44 particularly when combined with the large CD response of some chiral MIMs; 22 the switchable chiroptical properties of interlocked molecules, which could be used in new materials; 23,24,52,104,105 and coming full circle, enantioselective hostguest chemistry, which might lead to new supports for CSP-HPLC. 30 Indeed, chiral MIMs have potential applications in any area where chiral covalent structures are currently used if it can be proven that a mechanical stereogenic unit can bring significant benefits.…”