Symmetry-aligned supramolecular encapsulation of C-60: [C-60 subset of(L)(2)], L = p-benzylcalix[5]arene or p-benzylhexahomooxacalix[3]arene

p-Benzylcalix[5]arene (1) or p-benzylhexahomooxacalix[3]arene (2) form 2:1 complexes with C-60 in solutions of the fullerene or fullerite in toluene t o give [C-60 subset of (1)(2)].8 toluene and [C-60 subset of (2)(2)], respe ctively. In both structures the fullerene is shrouded by two staggered, tra ns-disposed, host molecules. These host calixarenes adopt a cone conformati on and the benzyl groups are either dangling ([C-60 subset of (1)(2)].8 tol uene) or they are positioned edge-on to the fullerene ([C-60 subset of (2)( 2)]). The alignment of the symmetry axis of the calixarene, C-5 or C-3, res pectively, with the same symmetry element of C-60 highlights the importance of symmetry matching in the design of host molecules for fullerenes, as it maximises the number of points of contact and the efficiency of the pi ... pi interactions. Two host-guest associations for 1 and 2 with C-60 are evi dent in solutions in toluene. The new oxacalix[3]arene 2 crystallises with chloroform as the 1:1 complex [CHCl3 subset of (2)].