Interaction of cyclodextrins with pyrene-modified polyacrylamide in a mixed solvent of water and dimethyl sulfoxide as studied by steady-state fluorescence

• Akihito Hashidzume,
• Yongtai Zheng and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1312–1317, doi:10.3762/bjoc.8.150

• fluorescence; water/DMSO mixed solvent; Introduction Cyclodextrins (CDs) are cyclic oligomers composed of glucopyranose units linked through α-1,4-glycoside bonding. They bear a tapered structure with a narrower rim of primary hydroxy groups and a wider rim of secondary hydroxy groups. CDs of 6, 7, and 8

• β-CD and γ-CD with Py-modified polyacrylamide (pAAmPy, Scheme 1) was investigated in the water/DMSO mixed solvent of varying composition by steady-state fluorescence to elucidate the mechanism of the selectivity switching. Results Figure 1a demonstrates the steady-state fluorescence spectra measured

• for 0.04 g L−1 pAAmPy (5 μM in Py residue) at varying volume fractions of DMSO (xDMSO) in the water/DMSO mixed solvent in the absence of CD. At xDMSO = 0 (i.e., in water), the spectrum exhibits not only emission bands ascribable to monomeric Py in the region of 370–430 nm, but also a broad band