Molecular and supramolecular chirality: From local to long-range dissymmetry

CHED 1522

Roberto Purrello, rpurrello@unict.it, Department of Chemistry, University of Catania, Viale Andrea Doria, 6, 95125 Catania, Italy
Supramolecular chemistry has been defined as the “chemistry beyond the molecule”. This scale expansion also holds for chirality. Molecular chirality is, in fact, confined to a single center (e.g. an asymmetric carbon or a metal center) while supramolecular chirality extends over a longer range (e.g. left and right handed helix).

A supramolecular assembly can be chiral either (a) because one component is chiral, or (b) if the interaction between achiral components and their organization in a supramolecular structure leads to dissymetrization and therefore to a supramolecular chiral structure (as observed for example in crystal, e.g. sodium chlorate). This kind of process (“generation” of chirality) has intriguing implications on the bias of chirality in nature, but it also opens interesting perspectives for possible technological applications.

Different examples of these topics (both from natural and “synthetic” systems) will be discussed during my talk.