A Triphenylene-Based Triptycene with Large Free Volume Synthesized by Zirconium-Mediated Biphenylation

Biphenylation using (Li(THF)₄)₂·Zr(biphe)₃ of hexabromotriptycenes bearing H (1-H) or Bu (1-Bu) at the bridgeheads gave triptycenes with triphenylene blades. The blades extend both perpendicular and parallel to the 3-fold axis and generate a large intramolecular free volume (IMFV) (1-H, AM1, 710 ų; cf. triptycene, AM1 71 ų). Crystals of 1-H could not be obtained. Triptycene 1-Bu, in which the Bu groups fill the voids near the bridgehead, was crystalline. X-ray diffraction analysis revealed crystal packing with alternating, interlocked corrugated and distorted hexagonal layers.