title: N,N',N''-Tris(p-methoxyphenyl)phosphoric triamide.
abstract: The title compound, C(21)H(24)N(3)O(4)P, is a self-complementary hydrogen-bond (HB) building unit, with (P=)O as the primary HB acceptor and N-H as the HB donor. Each of the four crystallographically distinct and nearly parallel molecules of the unit cell has a net dipole moment along the P=O bond direction and all of the dipoles are directed in the same general crystallographic direction. Head-to-tail N-H...O=P double-HB strands stack adjacent molecules into one-dimensional infinite polar columns. Each polar column is a 2(1) helix and all columns are essentially parallel, resulting in polar order throughout the entire crystal.
authors.affiliation: Department of Chemistry and Biochemistry, Southern Illinois University at Carbondale, Carbondale, IL 62901-4409, USA.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Li
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Dyer
authors.forename: Nigam P
authors.initials: NP
authors.lastname: Rath
authors.forename: Paul D
authors.initials: PD
authors.lastname: Robinson