Chiral self-sorting process in the self-assembly of homochiral coordination cages from axially chiral ligands

• Published in: Communications chemistry Vol. 1; no. 1
• Main Authors: Tateishi, Tomoki, Kojima, Tatsuo, Hiraoka, Shuichi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.04.2018; Nature Publishing Group
• Subjects: 101/58; 639/638/403/935; 639/638/541/965; 639/638/541/966; Assemblies; Biomolecules; Cages; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Coordination; Ligands; Palladium; Self-assembly
• ISSN: 2399-3669; 2399-3669
• DOI: 10.1038/s42004-018-0020-4

Chiral self-sorting is a phenomenon wherein racemic components are spontaneously sorted into homo- or heterochiral molecular assemblies through chiral discrimination between the components. Chiral self-sorting may be related to biological molecular systems where chiral biomolecules are concerned, but the detail of this sorting process has been unclear. Here we show the chiral self-sorting process in the formation of a homochiral Pd 2 L 4 coordination cage from a racemic mixture of a binaphthol-based ditopic ligand by quantitative analysis of self-assembly process (QASAP). The self-assembly of the cage mainly takes place through two pathways that branch off from the intermolecular reaction of mononuclear complexes. Even though the homochiral cages are thermodynamically the most stable, heterochiral intermediates were preferentially produced at first under kinetic control, which were eventually converted into the homochiral cages. Our results reveal complicated pathways in chiral self-sorting. Chiral self-sorting is the assembly of a racemic mixture into homo- or heterochiral assemblies through chiral interactions between components. Here, the authors study chiral self-sorting in palladium cages and identify heterochiral kinetic intermediates en route to the homochiral thermodynamic end point.