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Optically Pure, Monodisperse cis ‐Oligodiacetylenes: Aggregation‐Induced Chirality Enhancement
Author(s) -
Chernick Erin T.,
Börzsönyi Gabor,
Steiner Christian,
Ammon Maximilian,
Gessner David,
Frühbeißer Sabine,
Gröhn Franziska,
Maier Sabine,
Tykwinski Rik R.
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201307904
Subject(s) - circular dichroism , camphor , chirality (physics) , dispersity , conjugated system , solvent , crystallography , cotton effect , chemistry , materials science , stereochemistry , polymer , organic chemistry , chiral symmetry , physics , quantum mechanics , nambu–jona lasinio model , quark
Conformational changes in the conjugated backbone of poly‐ and oligodiacetylenes (PDAs and ODAs) play an important role in determining the electronic properties of these compounds. At the same time, conformational changes can also result in a folded structure that shows helical chirality. Using D ‐camphor as a chiral building block, we have designed a high‐yielding, iterative synthesis of monodisperse, optically pure cis ‐oligodiacetylenes (ODAs). cis ‐ODAs up to the tridecamer have been formed, which is the longest monodisperse cis ‐ODA reported to date. UV/Vis spectroscopy suggests a large effective conjugation length in THF, likely the result of a linear, planar conformation in this solvent. High‐resolution STM/AFM measurements of the nonamer cast from THF onto HOPG show a linear structure. In i PrOH, circular dichroism (CD) spectra suggest the formation of chiral aggregates for ODAs with at least nine D ‐camphor units, based on a strong CD response.