title: Self-assembly of dendritic tris(crown ether) hexagons and their complexation with dibenzylammonium cations.
abstract: The construction of a new series of dendritic tris(crown ether) hexagons via coordination-driven self-assembly is described. Combining 120° crown ether-containing diplatinum(II) acceptors with 120° dendritic dipyridyl donors in a 1:1 ratio allows for the formation of a new family of dendritic triple crown ether derivatives with a hexagonal cavity in quantitative yields. The number and the position of these pendant groups can be precisely controlled on the hexagonal metallacycle. The structures of all dendritic multiple crown ether hexgaons are confirmed by multinuclear NMR ((1)H and (31)P), ESI-MS and ESI-TOF-MS, and elemental analysis. The complexation of these dendritic trivalent receptors with dibenzylammonium cations was investigated by (1)H NMR titration experiments. The thermodynamic binding constants between the receptors and guests were established by using the nonlinear least-squares fit method based on (1)H NMR titration experiments. It was found that the association constants of each assembly decrease correspondingly upon the increase of the generation of the dendrons from [G0] to [G3], which might be caused by the steric effect of the dendrons on host-guest complexation.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai, China, 200062.
authors.forename: Xing-Dong
authors.initials: XD
authors.lastname: Xu
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Yang
authors.forename: Yao-Rong
authors.initials: YR
authors.lastname: Zheng
authors.forename: Koushik
authors.initials: K
authors.lastname: Ghosh
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Lyndon
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stang
mesh_terms: D050339:Benzylammonium Compounds / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D050339:Benzylammonium Compounds; D043844:Crown Ethers; D050091:Dendrimers