Department of Science and Engineering for Materials, Tomakomai National College of Technology, Nishikioka 443, Tomakomai, Hokkaido, Japan.
Carbohydr Res. 2013 Jun 28;375:136-44. doi: 10.1016/j.carres.2013.04.019. Epub 2013 Apr 23.
(1)H and (13)C chemical shift assignment of the anhydroglucose units (AGUs) that comprise cellulose acetate with the total degree of substitution of 2.33 was performed by a combination of two-dimensional NMR spectra obtained from COSY, TOCSY, HSQC-TOCSY, and HSQC experiments. In the TOCSY spectra, there are 13 kinds of correlation networks for the H1 to H6' atoms of AGU; each (1)H resonance of the 13 AGUs was assigned from the changes in the intensities of the (1)H resonances with TOCSY spin-lock time during the TOCSY experiments. The ring (13)C resonances were assigned via analysis of HSQC spectra. Comparison of the shift data enabled the assignment of the 13 AGUs as three types of 2,3,6-tri-acetylated, one type of 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, and 3,6-di-acetylated AGU, and unsubstituted AGU, and three types of AGUs located in end units. These shift data will be useful for characterizing the molecular structures of cellulose derivatives as well as cellulose acetate (CA).
（1）H 和（13）C 化学位移赋值的脱水葡萄糖单元（AGU）组成醋酸纤维素的总取代度为 2.33 通过二维 NMR 谱的组合获得从 COSY、TOCSY、HSQC-TOCSY 和 HSQC 实验。在 TOCSY 谱中，有 13 种 AGU 的 H1 到 H6'原子的相关网络；在 TOCSY 实验中，从 TOCSY 自旋锁定时间变化时 13 个 AGU 的每个（1）H 共振的强度来分配每个（1）H 共振。通过分析 HSQC 光谱来分配环（13）C 共振。比较位移数据可以将 13 个 AGU 分配为三种 2,3,6-三乙酰化、一种 2-单、3-单、6-单、2,3-二、2,6-二和 3,6-二乙酰化 AGU，以及未取代的 AGU 和三种位于末端单元的 AGU。这些位移数据将有助于表征纤维素衍生物以及醋酸纤维素（CA）的分子结构。
