Fig. 4: The self-assembly of a series of achiral cages, including 22R2S2, 32R2S2 and 42R2S2.
From: The sharp structural switch of covalent cages mediated by subtle variation of directing groups
(A) Structural formulae of the cages 22R2S2, 32R2S2 and 42R2S2, by condensing a 2:1 mixture of racemic trans-CHDA and the corresponding tetraformyl precursor namely 2, 3 and 4, respectively. (B) Partial 1H NMR spectrum (600 MHz, CDCl3, 298 K) of 22R2S2. Some of the key resonances are labeled, which were assigned based on the corresponding two-dimensional NMR spectra shown in the Supplementary Figs. 37 and 38. The full spectrum is shown in the Supplementary Fig. 35. Solid-state structures of 22R2S2 including (C) side view) and (D) top view, as well as 32R2S2 including (E) side view) and (F) top view, which were 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.
