Rare Case of a Triple-Stranded Molecular Braid in an Organic Cocrystal

We describe the use of two “bent” molecules, tetrabromobisphenol-S (2) and 1,3-bis(4-pyridyl)-propane (3), to build an interesting organic cocrystal [(C6H2OHBr2)2SO2]·[(C5H4N)2(CH2)3]·MeOH (4). In the molecular structure of cocrystal 4, the cocrystallizing components (coformers) 2 and 3 assemble into a 1:1 supramolecular adduct featuring unprecedented triple-stranded molecular entanglement, called a “molecular braid”, via O−H···N interactions, which is the first example of such one-dimensional entanglement in the realm of organic cocrystals.