ChemInform Abstract: Conformation of 1,2-Dimethoxyethane in the Gas Phase: A Rotational Isomeric State Simulation of NMR Vicinal Coupling Constants.

ChemInform ◽  
2010 ◽  
Vol 24 (3) ◽  
pp. no-no
Author(s):  
K. INOMATA ◽  
A. ABE
Keyword(s):  
Gas Phase ◽  
Isomeric State ◽  
Coupling Constants ◽  
Rotational Isomeric State ◽  
Vicinal Coupling Constants

Conformational Studies on 1,3-Dioxepanes. Part IV. Applications of Geminal Coupling Constants to Conformational Analysis of 1,3-Dioxepanes

1974 ◽  
Vol 52 (24) ◽  
pp. 4062-4071 ◽  
Author(s):  
T. Bruce Grindley ◽  
Walter A. Szarek
Keyword(s):  
Conformational Analysis ◽  
Coupling Constants ◽  
Conformational Studies ◽  
Vicinal Coupling Constants ◽  
Geminal Coupling ◽  
Derivatives Of ◽  
Acetal Carbon

The magnitude of —OCH2O— group geminal H,H coupling contants, the size of the vicinal coupling constants, and the tenets of conformational analysis were used to establish that in solution the conformation of the 1,3-dioxepane rings in derivatives of 1,3:2,5-di-O-methylenemannitol and 2,5-O-methylenemannitol is predominantly the twist-chair in which the C2 axis passes through the acetal carbon.

scholarly journals IDENTIFICATION AND SEQUENCING BY NMR SPECTROSCOPY OF THE CARBOHYDRATE MOIETY IN A SAPONIN FROM Barringtonia asiatica

2010 ◽  
Vol 1 (3) ◽  
pp. 120-124
Author(s):  
Rymond J Rumampuk
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Coupling Constants ◽  
Carbohydrate Moiety ◽  
Glycosidic Linkage ◽  
1H And 13C Nmr ◽  
Heteronuclear Correlation ◽  
Vicinal Coupling Constants ◽  
Nmr Signals

A trisaccharide chain in a saponin from the seeds of Barringtonia asiatica has been identified and sequenced as {[b-D-galactopyranosyl(1®3)- b-D-glucopyranosyl(1®2)]-b-D-glucuronopyranosyloxy} using a combination of homonuclear and heteronuclear correlation NMR spectroscopy. The 1H and 13C NMR signals of the sugar residues can be determined and distinguished from one other by use of the HMQC-TOCSY technique. Anomeric configurations were unambiguously assigned from the vicinal coupling constants 3JH-1,H-2 of the anomeric protons. Inter-glycosidic linkage assignments were elucidated using  HMBC.   Keyword: Barringtonia asiatica, carbohydrate, saponin, NMR

Gas-phase electron paramagnetic resonance spectrum and dipole moment of NF( 1 ∆)

1973 ◽  
Vol 332 (1590) ◽  
pp. 355-363 ◽  
Keyword(s):  
Dipole Moment ◽  
Gas Phase ◽  
Resonance Spectrum ◽  
Rotational Level ◽  
Quadrupole Coupling Constant ◽  
Rotational Constant ◽  
Coupling Constants ◽  
Paramagnetic Resonance ◽  
Quadrupole Coupling ◽  
Electron Paramagnetic

The gas-phase paramagnetic resonance spectrum of NF in the J = 2 rotational level of the 1 ∆ state has been studied, and the dipole moment in this state is found to be 0.37 ± 0.60D. The rotational constant previously determined from the electronic spectrum is shown to be consistent with the electron resonance results, and the 14 N quadrupole coupling constant e 2 qQ is 4.1 ± 0.2 MHz. The hyperfine coupling constants of the 14 N and 19 F nuclei are + 109.92 ± 0.14 and +758.06 ± 0.23 MHz respectively.

scholarly journals Application of Rotational Isomeric State Theory to Ionic Polymer Stiffness Predictions

2005 ◽  
Vol 20 (9) ◽  
pp. 2443-2455 ◽  
Author(s):  
Lisa Mauck Weiland ◽  
Emily K. Lada ◽  
Ralph C. Smith ◽  
Donald J. Leo
Keyword(s):  
Isomeric State ◽  
Mechanical Response ◽  
Physical Structure ◽  
State Theory ◽  
Chain Conformation ◽  
Ionic Polymer ◽  
Polymer Morphology ◽  
Rotational Isomeric State ◽  
Material Stiffness ◽  
Chain Lengths

Presently, rotational isomeric state (RIS) theory directly addresses polymer chain conformation as it relates to mechanical response trends. The primary goal of this work is to explore the adaptation of this methodology to the prediction of material stiffness. This multiscale modeling approach relies on ionomer chain conformation and polymer morphology and thus has potential as both a predictive modeling tool and a synthesis guide. The Mark–Curro Monte Carlo methodology is applied to generate a statistically valid number of end-to-end chain lengths via RIS theory for four solvated Nafion® cases. For each case, a probability density function for chain length is estimated using various statistical techniques, including the classically applied cubic spline approach. It is found that the stiffness prediction is sensitive to the fitting strategy. The significance of various fitting strategies, as they relate to the physical structure of the polymer, are explored so that a method suitable for stiffness prediction may be identified.

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