The Application of Selective ROE Experiments to Study Solution Structures of Cyclomaltooligosacharide Derivatives and Complexes

Selective one-dimensional ROE experiments were applied to study the host-guest interactions of cyclomaltohexaose with p-nitrophenol and the solution structure of 3A-(4-methylamino-3-nitrobenzyl)-cyclomaltoheptaose. The line selective excitation of the aromatic signals of p-nitrophenol gave intense ROE enhancements on the cyclomaltohexaose multiplets (H3 and H5), indicating deep complexation inside the cavity. The results on 3A-(4-methylamino-3-nitrobenzyl)-cyclomaltopheptose showed that the aromatic moiety covers the wider base of the cyclomaltoheptaose cone. The rotational correlation time for this compound was calculated to be 2.9 x 10-(-10)s using carbon-13 spin-lattice relaxation data. Quantitative analysis of the measured enhancements was performed and proton-proton distances were obtained between the aromatic and cyclomaltoheptoase protons as well as interglycosidic distances inside the cyclomaltoheptaose moiety.