Chiral Self‐sorting of Giant Cubic [8+12] Salicylimine Cage Compounds

Abstract

Chiral self-sorting is intricately connected to the complicated chiral processes observed in nature and no artificial systems of comparably complexity have been generated by chemists.H owever,o nly af ew examples of purely organic molecules have been reported so far,w here the selfsorting process could be controlled. Herein, we describe the chiral self-sorting of large cubic [8+ +12] salicylimine cage compounds based on ac hiral TBTQ precursor.O ut of 23 possible cage isomers only the enantiopure and am eso cage were observed to be formed, whichhave been unambiguously characterized by single crystal X-raydiffraction. Furthermore, by careful choice of solvent the formation of meso cage could be controlled. With internal diameters of d in = 3.3-3.5 nm these cages are among the largest organic cage compounds characterizedand show very high specific surface areas up to approx. 1500 m 2 g À1 after desolvation.

Solvent‐Controlled Quadruple Catenation of Giant Chiral [8+12] Salicylimine Cubes Driven by Weak Hydrogen Bonding

“…The positive influence of aromatic solvents on the catenation process is poorly understood and may be linked to solvation effects [34] . In dichloromethane an ( M )‐ 4 /( M )‐ 3 ratio of 12 : 88 was observed (Table 1, Entry 2), while in a previous publication we reported only the formation of single cage ( M )‐ 3 ; [23] a difference that can be explained by the fact, that the reaction conditions in this experiment were optimized for catenation (see Chapter 11 of the Supporting Information). The highest ( M )‐ 4 /( M )‐ 3 ratio of 92 : 8 was observed in toluene (Table 1, Entry 13).…”

Solvent‐Controlled Quadruple Catenation of Giant Chiral [8+12] Salicylimine Cubes Driven by Weak Hydrogen Bonding

“…We investigated the influence of a large number of aliphatic and aromatic solvents on the catenation process by MALDI‐TOF mass spectrometry and 1 H NMR spectroscopy (Scheme 1 and Table 1; for details see Chapter 12 of the Supporting Information). Since preliminary experiments had shown that an excess of the amine linker 2 favors the formation of catenane (see Chapter 11 of the Supporting Information), a small excess of amine (4 % over the stoichiometric ratio) was used in all reactions [23] . The solvents in Table 1 are listed in order of decreasing polarity according to their normalized empirical solvent polarity parameters $${{{\rm { E}}}_{{\rm { T}}}^{{\rm { N}}}}$$ [33] .…”

Chiral Self‐Sorting in Pd6L12 Metal‐Organic Cages

“…Such chiral self‐sorting has been examined through two distinct options: dynamic covalent chemistry and coordination‐driven self‐assembly. The former involves reversible bond‐forming organic reactions under thermodynamic control, wherein a significant control over the choice of chiral self‐sorting outcome has been established in higher‐order complex structures [4–7] . Differently functionalized ligands, such as bidentate catechols, [8,9] 2,2‐bipyridines [10] and imino‐2‐pyridines [11–13] with octahedral metal centers, and monodentate bis‐pyridines with square‐planar Pd(II) ions were examined with a later approach [14–19] .…”