title: Supramolecular complexation of N-alkyl- and N,N'-dialkylpiperazines with cucurbit[6]uril in aqueous solution and in the solid state.
abstract: Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N'-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. It was found that the complex stability and the degree of oligomerization increase with elongating the alkyl chain attached to the piperazine core. X-ray crystallographic studies revealed a clear correlation between the structure of CB[6]-alkylpiperazine crystals obtained from aqueous solutions and the molecular weight/properties of host-guest oligomers existed in the solution as supramolecular "seeds" of crystal formation.
authors.affiliation: Entropy Control Project, ICORP, JST, 2-1 Yamada-oka, Suita, Japan.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Rekharsky
authors.forename: Hatsuo
authors.initials: H
authors.lastname: Yamamura
authors.forename: Tadashi
authors.initials: T
authors.lastname: Mori
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sato
authors.forename: Motoo
authors.initials: M
authors.lastname: Shiro
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Lindeman
authors.forename: Rajendra
authors.initials: R
authors.lastname: Rathore
authors.forename: Kouhei
authors.initials: K
authors.lastname: Shiba
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Ko
authors.forename: Narayanan
authors.initials: N
authors.lastname: Selvapalam
authors.forename: Kimoon
authors.initials: K
authors.lastname: Kim
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Inoue