Fig. 2: The self-assembly of a pair of cage enantiomers 13S6 and 13R6.
From: The sharp structural switch of covalent cages mediated by subtle variation of directing groups
(A) Structural formulae of 13S6 and 13R6 by condensing the precursor 1 and the corresponding bisamino partners namely either (S,S)-CHDA or (R,R)-CHDA. Narcissistic self-sorting occurs when 1 is combined with the racemic mixture of (S,S)-CHDA and (R,R)-CHDA. (B) Partial 1H NMR spectrum (600 MHz, CDCl3, 298 K) of 13S6. Some of the key resonances are labeled, which were assigned based on the corresponding two-dimensional NMR spectra shown in Supplementary Figs. 31 and 32. The full spectrum is also shown in Supplementary Fig. 29. (C) Solid-state structures of 13S6 obtained from single-crystal X-ray diffraction analysis. Oxygen atoms, red; nitrogen, blue; carbon, gray. Hydrogen atoms and disordered solvent molecules are omitted for clarity. We also expanded the terminal part of the cage 13S6 for the sake of clarity. It is clearly observed that all the imine protons adopt the syn conformation relative to the corresponding methine protons, as labeled with red double-head arrows. Two intramolecular hydrogen bonds between the central OH proton and the imine nitrogen on one side, and the central OH oxygen and the imine proton on the other side, are labeled with black dashed lines.
