A dynamically
racemic helical copolymer composed of an achiral
biphenylylacetylene (BPA) bearing methoxymethoxy groups at the 2,2′-positions
and 1 mol % of an achiral BPA carrying 2-carboxy-2′-methoxymethoxy
groups at the biphenyl pendants was found to fold into an excess one-handed
helix with significant amplification of the helicity in the presence
of a small amount of optically active amines. The induced macromolecular
helicity was retained (“memorized”) after removal of
the chiral amines. The copolymer had a significant sensitivity for
detecting the chirality of chiral amines with a sensitivity more than
10000-fold higher than that of the corresponding homopolymers with
no carboxy group, thus showing Cotton effects even in the presence
of a 0.01 equiv of an optically active amine. The effects of the substituents
at the 4′-position of the biphenyl pendants of the copolymers
and the structures of the chiral amines on the macromolecular helicity
induction were also investigated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.