Helical Diastereomerism in Self-organization of Molecular Strands

Abstract

The polyheterocyclic molecule 2 reported in this paper is a helically-wrapped molecular strand presenting two helical substrands of same helicity separated in space thus forming P-P and M-M helical enantiomers. It represents the case of a molecule presenting two chiral centers of helical type. The dimerization process of the compound described in this paper appears to give rise to heterodimeric and homodimeric species. At high and room temperature the formation of dimeric species is accompanied by folding-unfolding interconversion of single molecular strands. Sliding of the monomers along one another without dissociation at low temperature allows each of two helical partners to associate in dimers stabilized by pronounced p�p stacking interactions between the internal heterocycles of the strands.