Single‐Handed Double Helix and Spiral Platelet Formed by Racemate of Dissymmetric Cages

Abstract

Spontaneous deracemization has been used to separate homochiral domains from the racemic system. However, homochirality can only be referred to when the scales of these domains and systems are specified. To clarify this, we report self‐assembly of racemates of dissymmetric cages DC‐1 with a cone‐shape propeller geometry, forming a centrosymmetric columnar crystalline phase (racemic at crystallographic level). Owing to their anisotropic geometry, the two enantiomers are packed in a frustrated fashion in this crystalline phase; single‐handed double helices are observed (single‐handedness at supramolecular level). The frustrated packing (layer continuity break‐up) in turn facilitates screw dislocation during the crystal growth, forming left‐ or right‐handed spiral platelets (symmetry‐breaking at morphological level), although each platelet is composed of DC‐1 racemates. The symmetry correlation between DC‐1 molecules, the crystalline phase and spiral platelets, all exhibit C3 symmetry.

Cofacial porphyrin organic cages. Metals regulating excitation electron transfer and CO2 reduction electrocatalytic properties

“…The great development of molecular cages, which are termed as void molecular structures with conned nano-sized cavities, has been witnessed in the eld of supramolecular chemistry, spanning from initial synthetic chemistry to interdisciplinary applications covering supramolecular chemistry and materials science. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Their categories are diversied due to the various construction processes based mainly on coordination interactions, [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] covalent bonds, [35][36][37][38][39][40][41][42][43][44][45] and hydrogen bonds. [46][47][48]…”

A Pair of Interconverting Cages Formed from Achiral Precursors Spontaneously Resolve into Homochiral Conformers

“…From achiral precursors triamino-functionalized TABPB and trialdehyde-containing TP, we synthesized a series of DC molecules with different alkyloxy groups on each terphenyl pillar (Figure 1b), except for DC-1 without lateral moiety. [30] Each DC molecule is composed of a benzene roof (in blue), a tris(N-salicylideneamine) bottom (in yellow), and three terphenyl pillars. In order to release the strain during the formation of a cage, the three pillars twist either clockwise ((P)-DC) or anti-clockwise ((M)-DC).…”

Enantioselective assembly and recognition of heterochiral porous organic cages deduced from binary chiral components

“… 10 Incorporation of chirality into artificial functional materials provides new objectives towards chiral separation, 11 stereospecific catalysis, 12 chiral recognition, 13 and unique chiroptical properties. 14 Self-assembly depending on chiral recognition and discrimination has been used to prepare chiral functional supramolecular materials through noncovalent interactions such as electrostatic interactions, 15 π–π interactions, 16 hydrogen bonding, 17 and metal-coordination bonds. 18 In quite recent years, DCC-based self-sorting of POCs has been achieved using the racemic mixtures of enantiomers as building blocks, generating a few homochiral and heterochiral cages.…”