Chiral recognition via helical sense and phase in a crystalline supramolecular array of intermeshed triple-helices.

Hexatertiary butyl-substituted D(3)-symmetrical cage ligands composed of octahedral bidentate complexes of Ni(II) or Cu(II) ligated on either side to triskelion arrangements of three salicyl rings bound to a central nitrogen hub atom exhibit triple-helical conformations. Maximization of intermolecular aromatic-aromatic interactions between these complexes promote extended tongue and groove interleaving and affords a supramolecular array of diastereomeric intermeshed C(3)-symmetrical triple-helices perpetuating sideways throughout alternating enantiomeric layer stacks in the entire P-3 space group crystal lattice. Chiral recognition within these supramolecular ensembles is based upon the principles of helical sense and phase. A discussion of the symmetry, mechanical and chemical factors, and constraints influencing the formation of these self-assembled crystalline supramolecular ensembles will be presented.