Abstract
5α,14α-Androstane (C19H32) crystallizes in two different polymorphic forms in the same vapor diffusion experiment. The major form (Form I) crystallizes as thin plates in the space group P21, with Z = 4. These plates are twinned along a long c axis of length 43 Å and readily suffer from radiation damage when diffracted. The minor form (Form II) crystallizes as fine needles in the space group P212121, Z = 3. In the minor form, 5α,14α-androstane cocrystallizes with 5α,14α-androstan-17-one, an oxidation product of 5α,14α-androstane. The presence of 5α,14α-androstan-17-one in the minor form of the crystals was confirmed by HR-MS. Form II can be crystallized as a pure form without the ketone impurity using a different solvent system. High level density functional theory (DFT) lattice free energy calculations were performed and show that both pure forms are isoergic within the estimated error of the calculations.
Publisher
International Union of Crystallography (IUCr)
Subject
Materials Chemistry,Inorganic Chemistry,Physical and Theoretical Chemistry,Condensed Matter Physics