title: Tri-substituted hexahomotrioxacalix[3]arene derivatives bearing imidazole units: synthesis and extraction properties for cations and chromate anions.
abstract: The article describes the synthesis and extraction properties of the new hexahomotrioxacalix[3]arenebased derivatives cone- and partial-cone-2 bearing 1-methyl-1H-imidazole moieties at the lower rim. It has been demonstrated that O-alkylation of the flexible macrocycle 1 with 2-(chloromethyl)-1-methyl-1Himidazole hydrochloride affords tri-O-alkylated products with a cone or partial-cone conformation. Alkali metal salts such as NaH and Cs2CO3 can play an important role in the conformer distribution via a template effect. The conformation of receptors 2 has been confirmed by X-ray crystallographic analysis. Furthermore, the complexation properties of receptors 2 toward selected alkali/transition metal cations and alkylammonium ions are reported. The new 1-methyl-1H-imidazole-substituted hexahomotrioxacalix[3] arene frameworks are also efficient extractors of HCr2O7(-)/Cr2O7(2-) anions at low pH.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi 1, Saga-shi, Saga 840-8502, Japan.
authors.forename: Xin-Long
authors.initials: XL
authors.lastname: Ni
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Jin
authors.forename: Xue-Kai
authors.initials: XK
authors.lastname: Jiang
authors.forename: Masashi
authors.initials: M
authors.lastname: Takimoto
authors.forename: Shofiur
authors.initials: S
authors.lastname: Rahman
authors.forename: Xi
authors.initials: X
authors.lastname: Zeng
authors.forename: David L
authors.initials: DL
authors.lastname: Hughes
authors.forename: Carl
authors.initials: C
authors.lastname: Redshaw
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yamato