Structure of antischistosome compounds. III. (3-Cyanopropyl)triphenylphosphonium bromide.

C22H21NP+.Br-, Mr = 410.3, monoclinic, P2(1)/c, a = 11.284 (1), b = 10.236 (1), c = 17.392 (2) A, beta = 105.33 (45) degrees, V = 1937.37 A3, Z = 4, D chi = 1.407 g cm-3, graphite-monochromatized Cu K alpha radiation, lambda = 1.5418 A, mu = 37.1 cm-1, F(000) = 840, T = 292 K. Final R = 0.044 for 3335 observed reflections. Structure solved by direct methods. The cyanopropyl moiety is in an extended conformation. However, the C-C-C-C torsion angle in this group is gauche+, which points the cyano group in a direction similar to the direction of the N-Br1 vector observed in the (2-aminoethyl)triphenylphosphonium bromide hydrobromide structure and the C-Br vector in the (3-bromopropyl)triphenylphosphonium bromide structure. This suggests a basis for the biological activities of these three compounds.