Three inclusion complexes of calix arenes as dichloromethane (DCM) or chloroform solvates have been structurally authenticated, namely, the complexes of p-Bu-t-calix arene, 1, or p-H-calix arene, with DCM, 2, and a new polymorph of the complex of p-phenyl-calix arene with chloroform, 3. Complex 1 has two adjacent tbutyl groups of one calixarene embracing the analogous groups from another calixarene. Complex 2 has a slipped head-to-head arrangement of calixarenes with a DCM molecule in the cavity of each calixarene. In complex 3, the calixarenes form dimers through interdigitation, and these dimers are assembled with back-to-back arrangement of calixarenes from adjacent dimers. All solvate complexes were crystallized in the presence of p-carborane, which has complementarity of size of the cavity of the calixarenes yet is not incorporated in the structures.
Clark, T., Makha, M., Raston, C., & Sobolev, A. (2006). Varying the Interplay of Calixarenes through Chloromethane Inclusion. Crystal Growth & Design, 6(12), 2783-2787. https://doi.org/10.1021/cg0605279