4-(2,4-dihydroxyphenyl)-2,2,4-trimethylchroman: A diol counterpart of Dianin’s compound

The title resorcinol forms true clathrates analogous to those formed by Dianin’s compound itself; the ethyl acetate clathrate has space group R3, with a = 27.222(3), c = 10.727(2) å, and Z = 18 (host). One of the diol host’s OH groups participates in a hydrogen-bonded [OH]6 unit, whilst the other forms an 0H...0 (ether) hydrogen bond to an adjacent hexameric unit stacked (infinitely) along the c axis. In contrast to Dianin’s compound, sublimation in vacuo does not give the stable “empty” cage form, but leads to spontaneous resolution, the unsolvated crystal being orthorhombic, space group P212121 with a = 9.9031(15), b = 10.599(3), c= 13.501(4) Å, and Z = 4. Molecules are now linked head- to- tail by OH...0 (ether) hydrogen bonds to form infinite chains translationally propagated along a. Two such adjacent, parallel chains, related by a 21 screw axis along a, form a pair consolidated by intemwlecular hydrogen bonds of OH...O(H) type, involving both hydroxyl groups of the diol.