Crystal Structure of β ‐Cyclodextrin‐Felbinac Inclusion Complex

The crystal structure of the inclusion complex of β ‐cyclodextrin ( β ‐CD) synthesized with felbinac (4‐biphenylacetic acid) was determined by single crystal X‐ray diffraction at 150 K. The complex contains two β ‐CDs, two felbinac molecules, twenty‐two water molecules in the asymmetric unit, and could be formulated as (C 42 H 70 O 35 ) 2 ·(C 14 H 12 O 2 ) 2 ·22(H 2 O). In the crystal lattice, the two β ‐CD moieties form a head‐to‐head dimer jointed through hydrogen bonds, and the felbinacs that interact by face‐to‐face Π‐Π stacking are included in the β ‐CD dimer cavity with their carboxyl groups protruding out from cavity opening. In crystals the dimer units of β ‐CD are stacked in an intermediate type (IM) that consists of closely packed β ‐CD dimer layers.