118093-22-4Relevant articles and documents
Synthesis and structural characterization of N,N'-diarylpiperazine N,N'-dioxide tetrahydrates (aryl=o-tolyl, p-tolyl, p-chlorophenyl)
Kwok, Chun-Kiu,Mak, Thomas C. W.
, p. 1836 - 1847 (2007/10/02)
The synthesis and X-ray structure determination of N,N'-di(o-tolyl)piperazine N,N'-dioxide tetrahydrate, I, N,N'-di(p-tolyl)piperazine N,N'-dioxide tetrahydrate, II, and N,N'-di(p-chlorophenyl)piperazine N,N'-doxide tetrahydrate, III, are described.Compound I crystallizes in space group P1 with a=7.778(1), b=7.915(2), c=8.919(2) A, α=106.25(2), β=99.56(1), γ=108.80(2) deg, and Z=1.Compound II crystallizes in space group P1 with a=6.558(1), b=7.134(2), c=11.610(3) A; α=73.23(2), β=78.08(2), γ=72.67(2) deg., and Z=1.Compound III crystallizes in space group P21/c with a=9.159(3), b=12.390(4), c=8.339(4) A, β=97.38(3) deg., and Z=2.The structures of I-III were solved by the direct method and refined to R=0.049 (1749 observed MoKα reflections), 0.055 (2651 observed reflections), and 0.035 (1827 observed reflections), respectively.In each case, the N,N'-dioxide molecule occupies a site of symmetry 1.The piperazine ring takes the chair form, with two N-O bonds oriented axially in a trans configuration.The structures are characterized by strong hydrogen bonding between the water molecules, as well as between the N-oxide groups and water molecules, giving rise to puckered layers composed of various combinations of edge-sharing four-membered, six-membered, ten-membered, and twelve-membered rings.The aryl rings, which protrude on both sides of each puckered layer, constitute hydrophobic regions separating the hydrophylic layers in the crystal packing.
