Self-Assembly of beta-Cyclodextrin in Water. 2. Electron Spin Resonance

The interaction of amphipilic spin labels with β-cyclodextrin was investigated using conventional ESR (ESR) spectroscopy to explore the aggregation of cyclodextrins in water. Me 5-doxylstearate (5-DMS) and stearic acid spin probes (n-DSA), which contain a cyclic nitroxide moiety with unpaired electrons covalently linked to the aliph. chain carbon in positions 5, 7, 12, and 16, show that different dynamic domains coexist in β-CD water solns. above 3 mM. The results are consistent with the formation of β-CD self-assembled structures in water above a crit. aggregation concn. and confirm the previous findings that were reported in the part 1 article of this series.