title: Synthesis and stacked conformations of symmetrical and unsymmetrical oligo-ureas of metaphenylenediamine.
abstract: The addition of substituted anilines to nitro-substituted isocyanates followed by reduction generates new aniline-substituted ureas, which can be further extended in a one- or two-directional iterative manner to form oligomeric ureas based on a m-phenylenediamine monomer. Oligo-ureas with up to eight urea linkages are reported. Fully N-substituted oligo-ureas are crystalline, and the X-ray crystal structures display ring-stacked conformations. 1H NMR studies indicate that the stacked conformation persists in solution.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. clayden@man.ac.uk
authors.forename: Jonathan
authors.initials: J
authors.lastname: Clayden
authors.forename: Loïc
authors.initials: L
authors.lastname: Lemiègre
authors.forename: Madeleine
authors.initials: M
authors.lastname: Helliwell
mesh_terms: D008745:Methylation; D008958:Models, Molecular; D008968:Molecular Conformation; D010655:Phenylenediamines / Q000737:chemistry*; D013237:Stereoisomerism; D014508:Urea / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D010655:Phenylenediamines; D014508:Urea