Nuclear Overhauser effect spectroscopy (NOESY) detection of the specific interaction between substituents in cellulose and amylose triacetates.

Nuclear Overhauser effect spectroscopy measurements on cellulose triacetate and on amylose triacetate with a mixing time of 500 ms, on the order of T1 of acetyl protons, were performed to detect the specific through-space interaction between acetyl groups arising from their helix structures in solution. For cellulose triacetate, cross peaks were detected in CDCl3 between acetyl proton signals at 3 and 6 positions on an anhydroglucose unit. In DMSO-d6, on the other hand, correlation peaks were observed not only between the 3 and 6 positions but also the 2 and 6 positions. For amylose triacetate, cross peaks were detected in CDCl3 between the acetyl proton signals at the 2 and 6 positions. The through-space interaction of acetyl groups in cellulose triacetate and in amylose triacetate in solution was then interpreted based on their three-dimensional structures in solid state determined by x-ray crystallography.