Halogen bonded supramolecular capsules: a challenging test case for quantum chemical methods.

Recently, Diederich et al. synthesized the first supramolecular capsule with a well-defined four-point halogen bonding interaction [Angew. Chem., Int. Ed., 2015, 54, 12339]. This interesting system comprising about 400 atoms represents a challenging test case for accurate quantum chemical methods. We investigate it with our new density functional based composite method for structures and noncovalent interactions (PBEh-3c) as well as our standard protocol for supramolecular thermochemistry and give predictions for chemical modifications to improve the binding strength.