Kinetic Traps to Activate Stereomutation in Supramolecular Polymers

Abstract

The helical stereomutation in the kinetically controlled coassembly of the reported carbonyl-bridged triarylamines (CBTs) is described. The copolymerization of chiral CBTs (S)-1 or (R)-1 with achiral 2 in sergeants-and-soldiers (SaS) experiments results in at unable helicity conditioned by the percentage of the chiral sergeant and by the cooling rate. The dissimilar inherent chirality of the extended monomeric (M) and intramolecularly H-bonded metastable (M*) species, as well as the different stability of the kinetic trap of the chiral CBTs (S)-1/(R)-1 and the achiral CBT 2,c ondition the chirality transfer and afford J-aggregates of inverse handedness.

Revising Complex Supramolecular Polymerization under Kinetic and Thermodynamic Control

“…No thermal hysteresis, that is, discrepancy between the cooling and heating curves in a successive cycle of assembly and disassembly, could be detected for this process. Such hysteresis is a distinct characteristic of a competing species that sequesters free monomers . However, over the course of several days, the J‐aggregates transformed to H‐type fibers (step 2).…”

“…Furthermore, those species could be inactive aggregates or “dormant” monomers (e.g. through intramolecular H‐bonding). In the following, we will systematically move from purely consecutive to purely competitive systems to finally show complex systems exhibiting several of the aforementioned phenomena.…”

C3‐Symmetrical π‐Scaffolds: Useful Building Blocks to Construct Helical Supramolecular Polymers

“…The addition of achiral soldiers favours the formation of larger aggregates. At higher percentages of chiral sergeant, the kinetics of the process changes and it is possible for the metastable monomers to evolve to the thermodynamic aggregates …”

Revision komplexer supramolekularer Polymerisation unter kinetischer und thermodynamischer Kontrolle

“…Für diesen Prozess konnte keine thermische Hysterese, d. h. Diskrepanz zwischen Kühl‐ und Heizkurve in einem aufeinanderfolgenden Zyklus von Polymerisation und Depolymerisation, festgestellt werden. Solche Hysterese ist ein ausgeprägtes Merkmal für die Existenz einer kompetitiven Spezies, die freie Monomere abfängt . Dennoch verwandelten sich die J‐Aggregate im Laufe mehrerer Tage in H‐Aggregat‐Fasern (Schritt 2).…”