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Hierarchical Superstructures with Control of Helicity from the Self‐Assembly of Chiral Bent‐Core Molecules
Author(s) -
Lin ShihChieh,
Ho RongMing,
Chang ChinYen,
Hsu ChainShu
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201200057
Subject(s) - helicity , intermolecular force , bent molecular geometry , crystallography , materials science , molecule , stereochemistry , chemistry , organic chemistry , physics , composite material , particle physics
Herein, two asymmetric chiral bent‐core molecules, 3‐[(4‐{[4‐(heptyloxy)benzoyl]oxy}benzoyl)oxy]‐phenyl‐4‐[(4‐{[(1 R )‐1‐methylheptyl]oxy}benzoyl)oxy] benzoate (BC7R) and 3‐[(4‐{[4‐(heptyloxy)benzoyl]oxy}benzoyl)oxy]‐phenyl‐4‐[(4‐{[(1 S )‐1‐methylheptyl]oxy}benzoyl)oxy] benzoate (BC7S), were synthesized to demonstrate control of the helicity of their self‐assembled hierarchical superstructures. Mirror‐imaged CD spectra showed a split‐type Cotton effect after the formation of self‐assembled aggregates of BC7R and BC7S, thereby suggesting the formation of intermolecular exciton couplets with opposite optical activities. Both twisted and helical ribbons with preferential helicity that corresponded to the twisting character of the intermolecular exciton couplet were found in the aggregates. The formation of helical ribbons was attributed to the merging of twisted ribbons through an increase in width to improve morphological stability. As a result, control of the helicity of hierarchical superstructures from the self‐assembly of bent‐core molecules could be achieved by taking advantage of the transfer of chiral information from the molecular level onto the hierarchical scale.