Evolution of a Constitutional Dynamic Library Driven by Self-Organisation of a Helically Folded Molecular Strand

✍ Scribed by Luciana Lisa Lao; Jean-Louis Schmitt; Jean-Marie Lehn

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 328 KB
• Volume: 16
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200903437

✦ Synopsis

Abstract

Conversion of macrocyclic imine entities into helical strands was achieved through three‐ and four‐component exchange reactions within constitutionally dynamic libraries. The generation of sequences of the intrinsic helicity codon, based on the hydrazone–pyrimidine fragment obtained by condensation of pyrimidine dialdehyde A with pyrimidine bis‐hydrazine B, shifted the equilibrium between all the possible macrocycles and strands towards the full expression (>98%) of helical product [A/B]. Furthermore, it was shown that chain folding accelerated the dynamic exchange reactions among the library members. Lastly, in four‐component experiments (involving A, B, E and either C or D), even though the macrocyclic entities ([A/C], [B/E]; [A/D], [B/E]) were the kinetically preferred products, over time dialdehyde A relinquished its initial diamine partners C or D to opt for bis‐hydrazine B, which allowed the preferential formation of the helically folded strand. The present results indicate that self‐organisation pressure was able to drive the dynamic system towards the selective generation of the strand undergoing helical folding.