| Abstract
| - The self-inclusion behavior and induced circular dichroism (ICD) characteristics of two β-cyclodextrin(β-CD) derivatives, in which a 1-methyl-4,4‘-bipyridinium (viologen) group is connected by anoctamethylene chain to either the primary (22+) or secondary (32+) side of β-CD, and of their reducedforms, are investigated. 1H NMR studies showed that 22+ forms an intramolecular self-inclusioncomplex with Kin = 3.1 ± 0.4, whereas 32+ forms a head-to-head type of dimer with KD = 65 ± 10M-1 at 25 °C. 22+ and 32+ form [2]pseudorotaxanes with α-CD, with the secondary side of the α-CDfacing the viologen moiety. The ICD characteristics of mono-6-[4-(1-methyl-4-pyridinio)-1-pyridinio]-β-CD (12+), 22+, 32+, and methyloctyl viologen−β-CD complexes were obtained for the oxidized andreduced states of the viologen units. The results indicated dimer formation for 1°, and intramolecularcomplexation for 2•+ and 2° in which the reduced viologen units are outside the β-CD cavity. Theresults also indicated intramolecular complexation for 3•+ and 3°, but with reduced viologen unitsinside the cavity. This work provides unequivocal evidence of the preference of the secondary sideof cyclodextrins for viologen groups, regardless of their oxidation states, and the dependence ofICD of the viologen chromophores on their location with respect to the CD cavity.
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