13C and 1H resonance assignment of mercerized cellulose II by two-dimensional MAS NMR spectroscopies

Through-bond C-13-C-13 and C-13-H-1 correlations in the crystal structure of cellulose II were determined by the two-dimensional (2D) refocused INADEQUATE and MAS-J-HMQC spectra of the mercerized cellulose, which was biosynthesized by Acetobacter xylinum ATCC 10245 from the uniformly labeled glucose (D-(U-C-13(6))glucose). Mercerization of the bacterial cellulose was achieved in a solution of 20% NaOH in water for 2 weeks. In the 2D INADEQUATE spectrum of cellulose II, two sets of the through-bond C-13-C-13 connectivities from C1 through C6 were clearly observed, which enabled us to completely assign the complex 1D CP/MAS C-13 spectrum of cellulose II. Following the C-13 assignment, the H-1 resonance for the proton(s) attached to each carbon of cellulose II could be assigned by use of the 2D MAS-J-HMQC spectrum of the mercerized cellulose.