Crystal structure of the phenylacetylene-choleic acid

Deoxycholic acid (C₂₄H₄₀O₄, M_r=392.58) and phenylacetylene (C₈H₆, M_r=102.14) form a 2:1 inclusion compound which crystallizes in space groupP2₁2₁2₁ witha=25.542(6),b=13.662(5),c=7.227(2) Å,Z=4. The finalR is 0.07₁ for 2168 observed reflections withI>1.5(I). The crystal packing is characterized by an assembly of antiparallel pleated bilayers of deoxycholic acid molecules which leave empty channels running alongc. Phenylacetylene molecules are accommodated within the cavities in an ordered fashion and are very probably arranged in only one orientation, which was determined by means of Van der Waals energy calculations. Atoms of deoxycholic acid belonging to ring A and to the side-chain are engaged in binding interactions with the guest molecule. The arrangement of the guest molecules supports the experimental results of irradiation, which show a failure of the phenylacetylene molecules to undergo inclusion polymerization.Supplementary Data relevant to this paper have been deposited with the British Library Lending Division under SUP No. 82024 (13 pages).