Control of supramolecular chirality in co-crystals of achiral moleculesviastacking interactions and hydrogen bonding

Abstract

An approach is proposed to obtain non-centrosymmetric crystal structures using co crystallization of specific achiral molecules. The co-formers, donors and acceptors of electron density, are selected in such a way...

What are the prospects of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides, 1,5-dioxides and their nitro derivatives as high-energy-density materials? Synthesis, experimental and predicted crystal structures, and calculated explosive properties

“…Although the selection and the order of the motifs used above in a “bottom-up construction” analysis of the crystal packing is undoubtedly arbitrary, such an analysis can be very useful for comparing different crystal structures and for revealing of specific features responsible for a particular crystal packing formation. 38 For example, it is interesting to note that some motifs found in a real crystal of cinnoline 1 are also present in the predicted ten lowest-energy structures. Namely, the ribbons with a head-to-tail orientation of the adjacent molecules related by translation are found in seven structures.…”

Supramolecular axial chirality in [N–I–N]+-type halogen bonded dimers

“…8,9 However, it is still limited to specic packings, such as the Sohncke space groups. 10 It is hard to rationally describe supramolecular chirality in most cases. At the molecular level, axial chirality is generated when two pairs of substitutes are within a nonpolar orientation around an aryl-aryl bond, which limits the free rotation by the steric hindrance.…”