A diamondoid net sustained by halogen bonds: employing a cyclobutane to generate a tetrahedral architecture

A halogen-bonded eight-fold interpenetrated diamondoid net was constructed employing a node generated in the solid state. Specifically, co-crystallization of a tetrahedral-like tecton, rctt-tetrakis(4-pyridyl)cyclobutane (4,4'-TPCB), combined with a rigid halogen-bond donor, 1,4-diiodoperchlorobenzene, achieved a diamondoid architecture. In the co-crystal, 4,4'-TPCB is found to form three types of linkages based on one cis- and two transorientations enabled by the intrinsic rctt-stereochemisty of the central cyclobutane ring. Thus, 4,4'-TPCB is able to adapt to the constraints of the diamondoid net owing to the flexibility of the pendant 4-pyridyl groups.