From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers

Abstract

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.