title: Self-assembly, structural, and retrostructural analysis of dendritic dipeptide pores undergoing reversible circular to elliptical shape change.
abstract: The synthesis of dendritic dipeptides (4-3,4-3,5-4)12G2-CH(2)-Boc-L-Tyr-L-Ala-OMe and (4-3, 4-3,5-4)12G2-CH(2)-Boc-D-Tyr-D-Ala-OMe is described. These dendritic dipeptides self-assemble into porous elliptical and circular columns that in turn self-organize into centered rectangular columnar and hexagonal columnar periodic arrays. The transition from porous elliptical to porous circular columns is mediated in a reversible or irreversible way by the thermal history of the sample. A method to determine the dimensions of hollow elliptical and circular columns by the reconstruction of the small-angle powder X-ray diffractograms of the centered rectangular or hexagonal columnar lattices was elaborated. This technique together with wide-angle X-ray experiments performed on aligned fibers provided access to the structural and retrostructural analysis of elliptical supramolecular pores. This procedure is general and can be adapted for the determination of the dimensions of pores of any columnar shape.
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
authors.forename: Mihai
authors.initials: M
authors.lastname: Peterca
authors.forename: Virgil
authors.initials: V
authors.lastname: Percec
authors.forename: Andrés E
authors.initials: AE
authors.lastname: Dulcey
authors.forename: Sami
authors.initials: S
authors.lastname: Nummelin
authors.forename: Stephanie
authors.initials: S
authors.lastname: Korey
authors.forename: Monica
authors.initials: M
authors.lastname: Ilies
authors.forename: Paul A
authors.initials: PA
authors.lastname: Heiney
mesh_terms: D002152:Calorimetry, Differential Scanning; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D004151:Dipeptides