Synthesis of tetrahalide dianions directed by crystal engineeringElectronic supplementary information (ESI) available: Synthesis, single crystal X-ray crystallographic analyses, CCDC 1409609-1409615, X-ray powder diffraction results, and Raman spectroscopy. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5ce01288k

Crystal engineering provides tools to the rational design of materials with desired structures or properties. We have exploited the analogy between hydrogen bonds and halogen bonds to trap I 2 in the channels of crystal structures, thus stabilizing the otherwise unfavourable tetrahalides via charge transfer interactions. The analogy between hydrogen bonds and halogen bonds was used to synthesize the unstable [X I-I X] 2− species by trapping I 2 in the channels of macrocyclic compounds.