The hexagonal phase of the 3:2:1 canal complex between deoxycholic acid, ethanol and water: an inclusion compound with hydrophilic channels.

The hexagonal phase of the 3:2:1 canal complex between deoxycholic acid, EtOH, and water crystd. in space group P65, with a 15.115(14) and c 18.676(15) .ANG.; Z = 6. The structure was refined to a final R of 0.08. The host mols. are arranged in spirals around the 65 axes and are held together mainly by H bonds which are also formed with the guest mols. Potential-energy calcns. detd. a satisfactory model for the EtOH mols. with their Et groups in nonequiv. crystallog. positions. The EtOH and water mols. fit into canals, parallel to c, with hydrophilic interior surfaces and are arranged according to the repeating sequence EtOH-EtOH-water. The side-chain conformation of deoxycholic acid is nearly extended. It differs from one found in the orthorhombic phase, but is similar to that presented by cholic acid in an addn. compd. with EtOH. The correlation between the side-chain and ring D conformations, found previously in some cholanic acids, is confirmed. The hexagonal phase may be used as a host lattice in which polar monomers can give rise to inclusion polymn. by, for example, .gamma.- or x-radiations