Hydrogen bonding structure and stability of alpha-chitin studied by 13C solid-state NMR.
The structure and stability of hydrogen bonds in alpha-chitin were investigated by (13)C solid-state NMR measurements at different temperatures. Splitting of the carbonyl carbon signal for alpha-chitin was interpreted as two types of hydrogen bonding; the peaks at 173.5 and 175.8 ppm were assigned, respectively, to a carbonyl carbon hydrogen bonded exclusively to the NH group and a carbonyl carbon hydrogen-bonded to both NH and C(6)-OH groups. Approximately 60% of carbonyl groups exclusively contributed to the intermolecular hydrogen bonding and ca. 40% of them to the combination of intermolecular and intramolecular hydrogen bonding. Internal rotation around the C(5)-C(6) bond was detected at 55 degrees C.
Kameda
Tsunenori
T
National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634, Japan. kamedat@affrc.go.jp
Miyazawa
Mitsuhiro
M
Ono
Hiroshi
H
Yoshida
Mitsuru
M
D002236:Carbohydrate Conformation; D002247:Carbon Isotopes; D002686:Chitin / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy
D002247:Carbon Isotopes; D002686:Chitin