Sophisticated algorithm for automatic extraction and analysis of substituent-induced chemical shift differences on carbon-13 NMR spectra

1993 ◽  
Vol 33 (3) ◽  
pp. 441-446 ◽  
Author(s):  
Lingran Chen ◽  
Wolfgang Robien
Keyword(s):  
Chemical Shift ◽  
Nmr Spectra ◽  
Automatic Extraction ◽  
Sophisticated Algorithm

119Sn, 13C and 1H NMR Spectra of Tris(1-butyl)stannyl D-Glucuronate

1997 ◽  
Vol 62 (8) ◽  
pp. 1169-1176 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
David Micák
Keyword(s):  
Chemical Shift ◽  
Carbonyl Group ◽  
1H Nmr ◽  
Equatorial Plane ◽  
Title Compound ◽  
Nmr Spectra ◽  
Hydroxyl Groups ◽  
Carboxylic Group ◽  
H Nmr ◽  
Oxygen Atoms

The 119Sn, 13C and 1H NMR spectra of tris(1-butyl)stannyl D-glucuronate have been measured in hexadeuteriodimethyl sulfoxide, tetradeuteriomethanol and deuteriochloroform. The chemical shift values have been assigned unambiguously with the help of H,H-COSY, TOCSY, H,C-COSY and 1H-13C HMQC-RELAY. From the analysis of parameters of 119Sn, 13C and 1H NMR spectra of the title compound and their comparison with the corresponding spectra of tris(1-butyl)stannyl acetate and other carboxylates it follows that in solutions of non-coordinating solvents (deuteriochloroform) the title compound is present in the form of more or less isolated individual molecules with pseudotetrahedral environment around the central tin atom and with monodentately bound carboxylic group. The interaction of tin atom with oxygen atoms of carbonyl group and hydroxyl groups of the saccharide residue - if they are present at all - are very weak. In solutions in coordinating solvents (hexadeuteriodimethyl sulfoxide or tetradeuteriomethanol), the title compound forms complexes with one molecule of the solvent. Particles of these complexes have a shape of trigonal bipyramid with the 1-butyl substituents in equatorial plane and the oxygen atoms of monodentate carboxylic group and coordinating solvent in axial positions.

scholarly journals Elucidating Tricin-Lignin Structures: Assigning Correlations in HSQC Spectra of Monocot Lignins

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 916 ◽  
Author(s):  
Wu Lan ◽  
Fengxia Yue ◽  
Jorge Rencoret ◽  
José del Río ◽  
Wout Boerjan ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Nmr Spectra ◽  
Model Compounds ◽  
Heteronuclear Correlation ◽  
Nmr Methods ◽  
Nuclear Magnetic ◽  
Lignin Structure

Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one] is a flavone that has been found to be incorporated in grass lignin polymers via 4′–O–β coupling. Herein, we investigated the tricin-lignin structure using nuclear magnetic resonance (NMR) methods by comparing the 1H–13C heteronuclear correlation (HSQC) NMR spectra of the isolated lignin with a series of dimeric and trimeric tricin-4′–O–β-ether model compounds. Results showed that the tricin moiety significantly affects the chemical shift of the Cβ/Hβ of 4′–O–β unit, producing peaks at around δC/δH 82.5–83.5/4.15–4.45, that differ from the Cβ/Hβ correlations from normal 4–O–β units formed solely by monolignols, and that have to date been unassigned.

Spectroscopic Studies with N-Chloroarylsulphonamides: IR and 1H, 13C and 23Na Nmr Spectra of Sodium Salts of N-Chloro-Mono- and Di-Substituted-Benzenesulphonamides, 4-X-C6H4SO2NANCl (X = H; CH3; C2H5; F; Cl; Br; I or NO2) and i-X, j-YC6H3SO2NANCl (i-X, j-Y = 2,3-(CH3)2; 2,4-(CH3)2; 2,5-(CH3)2; 2-CH3, 4-Cl; 2-CH3, 5-Cl; 3-CH3, 4-Cl; 2,4-Cl2 or 3,4-Cl2)

2003 ◽  
Vol 58 (1) ◽  
pp. 51-56 ◽  
Author(s):  
◽  
J. D. D’Souza ◽  
B. H. Arun Kumar
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Infrared Spectra ◽  
Phenyl Ring ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spectroscopic Studies ◽  
Sodium Salts ◽  
Experimental Chemical Shift ◽  
23Na Nmr

In an effort to introduce N-chloroarylsulphonamides of different oxydising strengths, sixteen sodium salts of N-chloro-mono- and di-substituted benzenesulphonamides of the configuration, 4- X-C6H4SO2NaNCl (where X = H; CH3; C2H5; F; Cl; Br; I or NO2) and i-X, j-YC6H3SO2NaNCl (where i-X, j-Y = 2,3-(CH3)2; 2,4-(CH3)2; 2,5-(CH3)2; 2-CH3,4-Cl; 2-CH3,5-Cl; 3-CH3,4-Cl; 2,4- Cl2 or 3,4-Cl2) are prepared, characterized through their infrared spectra in the solid state and NMR spectra in solution. The υN-Cl frequencies vary in the range 950 - 927 cm−1. Effects of substitution in the benzene ring in terms of electron donating and electron withdrawing groups have been considered, and conclusions drawn. The chemical shifts of aromatic protons and carbon-13 in all the N-chloroarylsulphonamides have been calculated by adding substituent contributions to the shift of benzene. Considering the approximation employed the agreement between the calculated and experimental chemical shift values for different protons or carbon-13 is quite good. Effects of phenyl ring substitution on chemical shift values of both 1H and 13C are also graphically represented in terms of line diagrams.

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