Crystalline inclusion compounds of lower rim propyl substituted calix[4]arenes featuring different number and positions of the modifying groups

Hexameric assembly of 5,17-di-substituted calix[4]arene in the solid state

Chiral 5,17-difunctionalized-25,26,27,28-tetrapropyloxycalix[4]arene possessing (S)-mandelamide arms ((S,S)-1) afforded cocrystals (S,S)-1·(solvent) (solvent = MeOH, EtOH, 1-PrOH, 2-PrOH, and CH₃CN). Four of the five cocrystals contain unusual hexameric assembly of the calix[4]arene host.

Guest induced head-to-tail columnar assembly of 5,17-difunctionalized calix[4]arene

Calix[4]arenes often form dimeric capsules or up-down bilayer arrangements in the solid state. The head-to-tail polymeric columnar structure found in the cocrystals composed of 5,17-difunctionalized calix[4]arene 1 and organic guests represents another structural motif for calix[4]arenes.

Fine tuning of crystal architecture by intermolecular interactions: synthon engineering

The term “synthon engineering” is introduced for the directed manipulation of the molecular packing architecture including the system of secondary interactions caused by the respectively fine tuned synthons.