TY - JOUR
T1 - Reactive pseudorotaxanes
T2 - Inclusion complexation of reduced viologens by the hosts β-cyclodextrin and heptakis(2,6-di-O-methyl)-β-cyclodextrin
AU - Mirzoian, Armen
AU - Kaifer, Angel E.
PY - 1997/7
Y1 - 1997/7
N2 - The complexation of three guests containing 4,4'-bipyridinium redox-active residues by β-cyclodextrin (β-CD) and its heptakis-(2,6-O-dimethyl) analogue (DM-β-CD) was investigated by means of voltammetric techniques. The three 4,4'-bipyridinium (viologen) derivatives used as guests were designed to be water-soluble in all three accessible oxidation states. The N-substituents chosen to enhance aqueous solubility were: 2-(2-(2-ethoxy)ethoxy)ethanol (guest 12+), 6-hexanoate (guest 2), and 3-propanesulfonate (guest 3). Detailed analysis of the voltammetric results by digital simulation techniques revealed that the oxidized forms of the guests did not interact appreciably with either CD host; the two-electron reduced guests formed extremely stable inclusion complexes, with association constants in the range 103 - 104 M-1, while the cation radical forms exhibited intermediate binding affinities (≃102 M-1). In all cases, DM-β-CD was found to form more stable complexes than unmodified β-CD.
AB - The complexation of three guests containing 4,4'-bipyridinium redox-active residues by β-cyclodextrin (β-CD) and its heptakis-(2,6-O-dimethyl) analogue (DM-β-CD) was investigated by means of voltammetric techniques. The three 4,4'-bipyridinium (viologen) derivatives used as guests were designed to be water-soluble in all three accessible oxidation states. The N-substituents chosen to enhance aqueous solubility were: 2-(2-(2-ethoxy)ethoxy)ethanol (guest 12+), 6-hexanoate (guest 2), and 3-propanesulfonate (guest 3). Detailed analysis of the voltammetric results by digital simulation techniques revealed that the oxidized forms of the guests did not interact appreciably with either CD host; the two-electron reduced guests formed extremely stable inclusion complexes, with association constants in the range 103 - 104 M-1, while the cation radical forms exhibited intermediate binding affinities (≃102 M-1). In all cases, DM-β-CD was found to form more stable complexes than unmodified β-CD.
KW - Cyclic voltammetry
KW - Cyclodextrins
KW - Host-guest chemistry
KW - Pseudorotaxanes
KW - Viologens
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U2 - 10.1002/chem.19970030711
DO - 10.1002/chem.19970030711
M3 - Article
AN - SCOPUS:0030752366
VL - 3
SP - 1052
EP - 1058
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 7
ER -