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From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers
Author(s) -
Cobos Katherine,
Rodríguez Rafael,
Quiñoá Emilio,
Riguera Ricardo,
Freire Félix
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202009215
Subject(s) - copolymer , chirality (physics) , conformational isomerism , diastereomer , chemistry , monomer , polymer , helix (gastropod) , composition (language) , stereochemistry , conformational change , chloroform , crystallography , molecule , organic chemistry , chiral symmetry , physics , philosophy , ecology , linguistics , quantum mechanics , snail , nambu–jona lasinio model , biology , quark
Different communication mechanisms can be switched within a copolymer by acting on the conformational composition of the components and their chirality. Thus, a sergeant and soldiers effect is produced in two diastereomeric copolymer series, poly[(S)‐ 1 r ‐co‐(S)‐ 2 (1−r) ] and poly[(R)‐ 1 r ‐co‐(S)‐ 2 (1−r) ], owing to the presence in chloroform of a preferred conformation in (S)‐ 2 , and a conformational equilibrium in 1 , where a P helix is induced independently of the absolute configuration of the soldier. In THF, the presence of a conformational equilibrium at the pendants of the two components produces a reciprocal chiral enhancement effect by copolymerization of the two monomers, while in DMF, a third chiral to chiral communication switch is produced due to the presence of a single conformer at the pendant group of the two components. In such a case, a chiral conflict or chiral accord effect is produced depending if the two components induce the same or the opposite helical sense.