title: Exploring the ellipsoidal and core-shell geometries of copper-seamed C-alkylpyrogallol[4]arene nanocapsules in solution.
abstract: Small-angle neutron scattering (SANS) studies were used to probe the stability and geometry of copper-seamed C-alkylpyrogallol[4]arene (PgC(n)Cu; n = 11, 13, 17) hexamers in solution. Novel structural features are observed at chain lengths greater than 10 in both solid and solution phase. Scattering data for the PgC(11)Cu and PgC(13)Cu in chloroform fitted as core-shell spheres with a total spherical radius of about 22.7 and 22.9 Å respectively. On the other hand, the scattering curve for the PgC(17)Cu hexamer at both 1% and 5% mass fractions in o-xylene did not fit as a discrete sphere but rather as a uniform ellipsoid. The geometric dimensions of the ellipsoid radii are 24 Å along the minor axis and 115 Å along the major axis. It is expected that an individual hexamer with heptadecyl chains would exhibit a uniform radius of ca. 24 Å. However, an approximate ratio of 1:5 between radii lengths for the minor axis and major axis is consistent with interpenetration of the heptadceyl chains of adjacent hexamers to form a single ellipsoidal assembly.
authors.affiliation: Department of Chemistry, University of Missouri-Columbia, 601 South College Avenue, Columbia, Missouri 65211, United States.
authors.forename: Harshita
authors.initials: H
authors.lastname: Kumari
authors.forename: Steven R
authors.initials: SR
authors.lastname: Kline
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Schuster
authors.forename: Charles L
authors.initials: CL
authors.lastname: Barnes
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Atwood
mesh_terms: D047250:Calixarenes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D053769:Nanocapsules / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000737:chemistry; D012996:Solutions
chemical_list: D053769:Nanocapsules; D009942:Organometallic Compounds; D012996:Solutions; C522570:pyrogallol(4)arene; D011748:Pyrogallol; D047250:Calixarenes; D003300:Copper