Quebra de Simetria Espontânea na Formação de Polímeros Supramoleculares: Implicações para a Origem da Homoquiralidade Biológica

sexta-feira, janeiro 25, 2019

Angewandte Chemie International Edition Volume 58, Issue 5

Communication Full Access

Spontaneous Symmetry Breaking in the Formation of Supramolecular Polymers: Implications for the Origin of Biological Homochirality

Dr. Suneesh C. Karunakaran Dr. Brian J. Cafferty Angela Weigert‐Muñoz Prof. Dr. Gary B. Schuster Prof. Dr. Nicholas V. Hud

First published: 09 December 2018


a) Chemical structures of TAP and CyCo6, the hexad structure formed by H‐bonding of three monomers of each, and an illustration of helically twisted stacked hexads. b) Circular dichroism spectra of a TAP‐CyCo6 sample (30 mm in each monomer) acquired at temperatures ranging from 5 to 40 °C. c) Circular dichroism spectra of 40 independently made samples containing TAP and CyCo6 (30 mm in each monomer) acquired at 20 °C.


Aqueous solutions of the achiral, monomeric, nucleobase mimics (2,4,6‐triaminopyrimidine, TAP, and a cyanuric acid derivative, CyCo6) spontaneously assemble into macroscopic homochiral domains of supramolecular polymers. These assemblies exhibit a high degree of chiral amplification. Addition of a small quantity of one handedness of a chiral derivative of CyCo6 generates exclusively homochiral structures. This system exhibits the highest reported degree of chiral amplification for dynamic helical polymers or supramolecular helices. Significantly, homochiral polymers comprised of hexameric rosettes with structural features that resemble nucleic acids are formed from mixtures of cyanuric acid (Cy) and ribonucleotides (l‐, d‐pTARC) that arise spontaneously from the reaction of TAP with the sugars. These findings support the hypothesis that nucleic acid homochirality was a result of symmetry breaking at the supramolecular polymer level.