Controlling the molecular arrangement of racemates through weak interactions: the synergy between π-interactions and halogen bonds.

PO⋯X and N⋯X halogen bonds in combination with π-stacking interactions lead to the sorting of π-extended R- and S-isomers. Theoretical calculations point to a positive synergistic effect between the π-interactions and the halogen bonds to be the origin of such phenomena. As a result, enantiomeric building blocks form homoleptically connected quadrangular structures. [ABSTRACT FROM AUTHOR]