Uma hélice supramolecular que dispensa a quiralidade

quarta-feira, janeiro 06, 2016

A supramolecular helix that disregards chirality

Cécile Roche, Hao-Jan Sun, Pawaret Leowanawat, Fumito Araoka, Benjamin E. Partridge, Mihai Peterca, Daniela A. Wilson, Margaret E. Prendergast, Paul A. Heiney, Robert Graf, Hans W. Spiess, Xiangbing Zeng, Goran Ungar & Virgil Percec

Affiliations Contributions Corresponding author

Nature Chemistry 8, 80–89 (2016) doi:10.1038/nchem.2397

Received 19 April 2015 Accepted 14 October 2015 Published online 16 November 2015

Source/Fonte: Nature Chemistry

The functions of complex crystalline systems derived from supramolecular biological and non-biological assemblies typically emerge from homochiral programmed primary structures via first principles involving secondary, tertiary and quaternary structures. In contrast, heterochiral and racemic compounds yield disordered crystals, amorphous solids or liquids. Here, we report the self-assembly of perylene bisimide derivatives in a supramolecular helix that in turn self-organizes in columnar hexagonal crystalline domains regardless of the enantiomeric purity of the perylene bisimide. We show that both homochiral and racemic perylene bisimide compounds, including a mixture of 21 diastereomers that cannot be deracemized at the molecular level, self-organize to form single-handed helical assemblies with identical single-crystal-like order. We propose that this high crystalline order is generated via a cogwheel mechanism that disregards the chirality of the self-assembling building blocks. We anticipate that this mechanism will facilitate access to previously inaccessible complex crystalline systems from racemic and homochiral building blocks.

Subject terms: Organic chemistry Self-assembly




E agora José, como é que fica aquela história de homoquiralidade sendo um fenômeno especial e coisa e tal???