Effect of water in the carbon-13 CP/MAS NMR spectrum of white spruce wood

1987 ◽  
Vol 20 (7) ◽  
pp. 1554-1556 ◽  
Author(s):  
J. M. Willis ◽  
F. G. Herring
Keyword(s):  
White Spruce ◽  
Mas Nmr ◽  
Nmr Spectrum ◽  
Effect Of Water ◽  
Spruce Wood ◽  
Cp Mas Nmr

NMR studies of 1-phenylazo-3-substituted-2-naphthols in solution and in the solid state

1990 ◽  
Vol 55 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Antonín Lyčka ◽  
Miroslav Nečas ◽  
Josef Jirman ◽  
Jaroslav Straka ◽  
Bohdan Schneider
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Nmr Spectra ◽  
Equilibrium Mixture ◽  
Mas Nmr ◽  
Nmr Studies ◽  
Nmr Spectrum ◽  
Cp Mas Nmr ◽  
Hydrazone Form

The 1H and 15Nα-enriched 1-phenylazo-3-X-2-naphthols, where X = COOH (I), X = COOCH3 (II), and X = CONHC6H5 (III), have been measured in various solvents. The values of 1J(15Nα, H) and σ(15N) indicate that in CDCl3, C6D6, CCl4, and CD3NO2 solutions the compounds I and III exist practically completely in their hydrazone forms. The hydrazone form is stabilized by the hydrogen bond of COOH or CONH protons to the C(2)=O group. The compound II represents an equilibrium mixture of azo and hydrazone forms, since it cannot form a similar hydrogen bond. Moreover, the 15N NMR spectra of compounds I-III have been measured in solid state by the CP/MAS technique. The results indicate the existence of two conformers differing by the conformation of COOCH3 group in compound II, which is supported by the 13C CP/MAS NMR spectrum of compound II.

Effects of added paramagnetic ions on the CP/MAS NMR spectrum of a de-ashed soil

Geoderma ◽  
1999 ◽  
Vol 89 (3-4) ◽  
pp. 219-248 ◽  
Author(s):  
Ronald J Smernik ◽  
J.Malcolm Oades
Keyword(s):  
Mas Nmr ◽  
Nmr Spectrum ◽  
Paramagnetic Ions ◽  
Cp Mas Nmr

Molecular Structure of Tri(2-thienyl)borane

1996 ◽  
Vol 51 (12) ◽  
pp. 1811-1814 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Wolfgang Milius ◽  
Elias Molla
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Nmr Spectra ◽  
Structural Parameters ◽  
Mas Nmr ◽  
Monoclinic Space Group ◽  
Nmr Spectrum ◽  
Π Interactions ◽  
Cp Mas Nmr ◽  
C Nmr

The molecular structure of tri(2-thienyl)borane (1) was determined [monoclinic, space group P21/ c; a = 12.216(2), b = 7.765(2), c = 12.605(2) Å, β = 93.13(2)°]; two of the three thienyl groups are disordered, as is also indicated by the solid-state 13C CP/MAS NMR spectrum of 1. The 13C NMR spectra of 1 were measured at variable tem perature in solution and the barrier to rotation about the B-C bonds was found to be <35 kJ/mol. Thus, CB(pp)π interactions must be regarded as rather weak, in spite of suggestive δ11 B. δ13C data and structural parameters.

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