Hydrogen bonds in regioselectively substituted cellulose derivatives

Abstract

AbstractFormation of hydrogen bonds in various cellulose derivatives, 2,3‐di‐O‐ and 6‐O‐substituted cellulose ethers, were characterized by FTIR and solid‐state CP/MAS13C‐NMR. The polymers were synthesized by regioselective substitution of hydroxyl groups and had a uniform structure. Since their three hydroxyl groups (OH) are selectively blocked, the cellulose derivatives appeared to form specific inter‐ and intramolecular hydrogen bonds. The characteristic OH stretching frequencies in IR spectra and the C‐1 chemical shift in CP/MAS spectra of 6‐O‐substituted cellulose derivatives indicated existence of two equivalent intramolecular hydrogen bonds between ether oxygen and OH groups at 3‐OH‐O5′ and O6‐HO‐2′ [Figure 3(C)]. Influence of the substituents at the C‐6 position on the formation was not significant except trityl group. Behavior of the hydrogen bonds in 6‐O‐tritylcellulose were also discussed. © 1994 John Wiley & Sons, Inc.