Crystals and Aggregates of a Molecular Tetrarotor with Multiple Trityl Embraces Derived from Tetraphenyladamantane

Samples of tetrakis-1,3,5,7-(4′-(3″,3″,3″-triphenylpropynyl)-phenylene)­adamantane
and its trityl-deuterated isotopologue were synthesized and their
crystallization and packing properties were analyzed within the context
of formation of 4- or 6-fold phenyl embraces. The tetrahedral shape
of these molecules with four propeller-like triphenylmethyl moieties
generates several edge-to-face intermolecular interactions in the
solid state that result in the formation of infinite chains of molecules
that are tightly interlocked. The formation of analogous edge-to-face
intermolecular interactions leading to aggregation in solution was
also suggested by NMR experiments carried out in different solvents
as a function of concentration. The formation of interdigitated chains
was also manifested in fibrils and thin needles, which were documented
by scanning electron microscopy (SEM). Single crystal X-ray diffraction
studies revealed the presence of multiple 4-fold phenyl embraces and
edge-to-face interactions as the leading motifs behind the formation
of tightly interlocked molecular chains.