Spontaneous resolution through helical assembly of a conformationally chiral molecule with an unusual zwitterionic structure

Abstract

A conformationally chiral zwitterionic molecule forms mutually orthogonal helical superstructures in the crystal. This is achieved through a network of hydrogen bond pathways, and electrostatic interactions in crystals formed with and without water of crystallization. A systematic protocol for the computation of charge distribution on the 'molecule-in-the-crystal' is presented; the computed charges provide an insight into the origin of the intermolecular electrostatic interactions. The coexisting orthogonal helical formations lead to the homochiral assembly, and spontaneous resolution observed in the crystals. This material facilitates an appraisal of the molecular level interactions, which form the basis for the persistent spontaneous resolution of a conformationally chiral molecule in the solid state.