Supramolecular complexation of N-alkyl- and N,N'-dialkylpiperazines with cucurbit[6]uril in aqueous solution and in the solid state.
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.
Rekharsky
Mikhail V
MV
Entropy Control Project, ICORP, JST, 2-1 Yamada-oka, Suita, Japan.
Yamamura
Hatsuo
H
Mori
Tadashi
T
Sato
Akihiro
A
Shiro
Motoo
M
Lindeman
Sergey V
SV
Rathore
Rajendra
R
Shiba
Kouhei
K
Ko
Young Ho
YH
Selvapalam
Narayanan
N
Kim
Kimoon
K
Inoue
Yoshihisa
Y