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Mitsuo Takai - One of the best experts on this subject based on the ideXlab platform.
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complete assignment of the cp mas 13C NMR Spectrum of cellulose iiii
Macromolecules, 2003Co-Authors: Hiroyuki Kono, Tomoki Erata, Mitsuo TakaiAbstract:For the assignment of 13C resonance for C2, C3, and C5 of cellulose IIII, 13C-enriched celluloses were biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 in the culture medium containing d-(2-13C), d-(3-13C), or d-(5-13C)glucose. After the 13C-enriched celluloses and Cladophora cellulose were converted into IIII allomorph by the ethylenediamine treatment, cross-polarization/magic angle spinning (CP/MAS) 13C NMR spectra of these cellulose IIII samples were measured. By comparison of the CP/MAS 13C NMR Spectrum of Cladophora cellulose sample with those of the 13C-enriched celluloses, 13C resonance lines of the cellulose IIII were completely assigned for the first time. As a result, all carbons of cellulose IIII were shown in singlet in the CP/MAS Spectrum of cellulose IIII, which suggests that cellulose IIII is made up of one kind of glucopyranose residue.
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cp mas 13C NMR study of cellulose and cellulose derivatives 1 complete assignment of the cp mas 13C NMR Spectrum of the native cellulose
Journal of the American Chemical Society, 2002Co-Authors: Hiroyuki Kono, Tamio Shikano, Masashi Fujiwara, Tomoki Erata, Shunji Yunoki, Mitsuo TakaiAbstract:The precise assignments of cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra of cellulose Iα and Iβ were performed by using 13C labeled cellulose biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 strain from culture medium containing d-[1,3-13C]glycerol or d-[2-13C]glucose as a carbon source. On the CP/MAS 13C NMR Spectrum of cellulose from d-[1,3-13C]glycerol, the introduced 13C labeling were observed at C1, C3, C4, and C6 of the biosynthesized cellulose. In the case of cellulose biosynthesized from d-[2-13C]glucose, the transitions of 13C labeling to C1, C3, and C5 from C2 were observed. With the quantitative analysis of the 13C transition ratio and comparing the CP/MAS 13C NMR Spectrum of the Cladophora cellulose with those of the 13C labeled celluloses, the assignments of the cluster of resonances which belong to C2, C3, and C5 of cellulose, which have not been assigned before, were performed. As a result, all carbons of cellulose Iα and Iβ except for C1 and C6 of cellulose I...
Hiroyuki Kono - One of the best experts on this subject based on the ideXlab platform.
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complete assignment of the cp mas 13C NMR Spectrum of cellulose iiii
Macromolecules, 2003Co-Authors: Hiroyuki Kono, Tomoki Erata, Mitsuo TakaiAbstract:For the assignment of 13C resonance for C2, C3, and C5 of cellulose IIII, 13C-enriched celluloses were biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 in the culture medium containing d-(2-13C), d-(3-13C), or d-(5-13C)glucose. After the 13C-enriched celluloses and Cladophora cellulose were converted into IIII allomorph by the ethylenediamine treatment, cross-polarization/magic angle spinning (CP/MAS) 13C NMR spectra of these cellulose IIII samples were measured. By comparison of the CP/MAS 13C NMR Spectrum of Cladophora cellulose sample with those of the 13C-enriched celluloses, 13C resonance lines of the cellulose IIII were completely assigned for the first time. As a result, all carbons of cellulose IIII were shown in singlet in the CP/MAS Spectrum of cellulose IIII, which suggests that cellulose IIII is made up of one kind of glucopyranose residue.
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cp mas 13C NMR study of cellulose and cellulose derivatives 1 complete assignment of the cp mas 13C NMR Spectrum of the native cellulose
Journal of the American Chemical Society, 2002Co-Authors: Hiroyuki Kono, Tamio Shikano, Masashi Fujiwara, Tomoki Erata, Shunji Yunoki, Mitsuo TakaiAbstract:The precise assignments of cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra of cellulose Iα and Iβ were performed by using 13C labeled cellulose biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 strain from culture medium containing d-[1,3-13C]glycerol or d-[2-13C]glucose as a carbon source. On the CP/MAS 13C NMR Spectrum of cellulose from d-[1,3-13C]glycerol, the introduced 13C labeling were observed at C1, C3, C4, and C6 of the biosynthesized cellulose. In the case of cellulose biosynthesized from d-[2-13C]glucose, the transitions of 13C labeling to C1, C3, and C5 from C2 were observed. With the quantitative analysis of the 13C transition ratio and comparing the CP/MAS 13C NMR Spectrum of the Cladophora cellulose with those of the 13C labeled celluloses, the assignments of the cluster of resonances which belong to C2, C3, and C5 of cellulose, which have not been assigned before, were performed. As a result, all carbons of cellulose Iα and Iβ except for C1 and C6 of cellulose I...
Tomoki Erata - One of the best experts on this subject based on the ideXlab platform.
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complete assignment of the cp mas 13C NMR Spectrum of cellulose iiii
Macromolecules, 2003Co-Authors: Hiroyuki Kono, Tomoki Erata, Mitsuo TakaiAbstract:For the assignment of 13C resonance for C2, C3, and C5 of cellulose IIII, 13C-enriched celluloses were biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 in the culture medium containing d-(2-13C), d-(3-13C), or d-(5-13C)glucose. After the 13C-enriched celluloses and Cladophora cellulose were converted into IIII allomorph by the ethylenediamine treatment, cross-polarization/magic angle spinning (CP/MAS) 13C NMR spectra of these cellulose IIII samples were measured. By comparison of the CP/MAS 13C NMR Spectrum of Cladophora cellulose sample with those of the 13C-enriched celluloses, 13C resonance lines of the cellulose IIII were completely assigned for the first time. As a result, all carbons of cellulose IIII were shown in singlet in the CP/MAS Spectrum of cellulose IIII, which suggests that cellulose IIII is made up of one kind of glucopyranose residue.
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cp mas 13C NMR study of cellulose and cellulose derivatives 1 complete assignment of the cp mas 13C NMR Spectrum of the native cellulose
Journal of the American Chemical Society, 2002Co-Authors: Hiroyuki Kono, Tamio Shikano, Masashi Fujiwara, Tomoki Erata, Shunji Yunoki, Mitsuo TakaiAbstract:The precise assignments of cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra of cellulose Iα and Iβ were performed by using 13C labeled cellulose biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 strain from culture medium containing d-[1,3-13C]glycerol or d-[2-13C]glucose as a carbon source. On the CP/MAS 13C NMR Spectrum of cellulose from d-[1,3-13C]glycerol, the introduced 13C labeling were observed at C1, C3, C4, and C6 of the biosynthesized cellulose. In the case of cellulose biosynthesized from d-[2-13C]glucose, the transitions of 13C labeling to C1, C3, and C5 from C2 were observed. With the quantitative analysis of the 13C transition ratio and comparing the CP/MAS 13C NMR Spectrum of the Cladophora cellulose with those of the 13C labeled celluloses, the assignments of the cluster of resonances which belong to C2, C3, and C5 of cellulose, which have not been assigned before, were performed. As a result, all carbons of cellulose Iα and Iβ except for C1 and C6 of cellulose I...
Paul Renz - One of the best experts on this subject based on the ideXlab platform.
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biosynthesis of vitamin b12 in anaerobic bacteria experiments with eubacterium limosum on the incorporation of d 1 13C erythrose and 13C formate into the 5 6 dimethylbenzimidazole moiety
FEBS Journal, 1992Co-Authors: Michael Munder, Joachim R A Vogt, Bernhard Vogler, Paul RenzAbstract:Experiments on the incorporation of erythrose and formate into the 5,6-dimethylbenzimidazole moiety of vitamin B12 are described. In one experiment, a 1:1 mixture of D-[1-13C]erythrose and D-[1-13C]threose was added to a Eubacterium limosum fermentation. The vitamin B12 formed was methylated at N3 of its 5,6-dimethylbenzimidazole part and degraded to 1,5,6-trimethylbenzimidazole. The 13C-NMR Spectrum of this compound exhibited a single prominent signal at 109.5 ppm due to 13C labeling in C7. This shows that C1 of erythrose or threose was originally incorporated exclusively into C4 of the 5,6-dimethylbenzimidazole moiety of vitamin B12. In another experiment, sodium [13C]formate was added to a culture of E. limosum. The vitamin B12 isolated was transformed into 1,5,6-trimethylbenzimidazole as before. The 13C-NMR Spectrum also showed one prominent signal at 142.8 ppm, evoked by 13C at C2. These results demonstrate that erythrose is incorporated into the base part of vitamin B12 regiospecifically and that formate is the precursor of the C2.
Malcolm H. Levitt - One of the best experts on this subject based on the ideXlab platform.
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Fine structure in the solution state 13C-NMR Spectrum of C60 and its endofullerene derivatives
Physical chemistry chemical physics : PCCP, 2020Co-Authors: George R. Bacanu, Gabriela Hoffman, Michael Amponsah, Maria Concistrè, Richard J. Whitby, Malcolm H. LevittAbstract:The 13C NMR Spectrum of fullerene C60 in solution displays two small “side peaks” on the shielding side of the main 13C peak, with integrated intensities of 1.63% and 0.81% of the main peak. The two side peaks are shifted by −12.6 ppb and −20.0 ppb with respect to the main peak. The side peaks are also observed in the 13C NMR spectra of endofullerenes, but with slightly different shifts relative to the main peak. We ascribe the small additional peaks to minor isotopomers of C60 containing two adjacent 13C nuclei. The shifts of the additional peaks are due to a secondary isotope shift of the 13C resonance caused by the substitution of a 12C neighbour by 13C. Two peaks are observed since the C60 structure contains two different classes of carbon–carbon bonds with different vibrational characteristics. The 2 : 1 ratio of the side peak intensities is consistent with the known structure of C60. The origin and intensities of the 13C side peaks are discussed, together with an analysis of the 13C solution NMR Spectrum of a 13C-enriched sample of C60, which displays a relatively broad 13C NMR peak due to a statistical distribution of 13C isotopes. The Spectrum of 13C-enriched C60 is analyzed by a Monte Carlo simulation technique, using a theorem for the second moment of the NMR Spectrum generated by J-coupled spin clusters.
