INCLUSION-COMPOUNDS OF (+ -)GOSSYPOL - STRUCTURE OF THE GOSSYPOL-N-VALERIC ACID(1/2) COORDINATO-CLATHRATE/

The crystal structure of the inclusion compound of gossypol with st-va leric acid as a guest molecule has been determined by X-ray structure analysis. The crystals of C30H30O8 .(C5H10O2)(2), are triclinic, space group <P(1)over bar>, a = 6.912(2), b = 14.506(3), c = 19.387(4) Angs trom, alpha = 78.85(2)degrees, beta = 83.92(3)degrees, gamma = 86.78(3 )degrees V = 1895(1) Angstrom(3), Z = 2, D-x = 1.267 g cm(-3), mu (Cu K-alpha) = 0.768 mm(-1), T = 292 K. The structure has been solved by d irect methods on intensity data collected for a twinned crystal and re fined to the final R value of 0.062 for 1606 observed reflections and 470 refined parameters. Gossypol-n-valeric acid (1/2) coordinato-clath rate is not isostructural with any of the previously investigated goss ypol inclusion compounds but shows some structural similarities to gos sypol-acetic acid (1/1). The host and one of the carboxylic acid molec ules are connected via hydrogen bonds into molecular assemblies of a c olumn type which are further bonded to centrosymmetric dimers of the s econd n-valeric acid molecule. In effect, host and guest molecules are assembled into Layer-type H-bonded aggregates. Structural features co mmon to gossypol-n-valeric acid (1/2) and other earlier reported gossy pol inclusion compounds are discussed.