An Experimental and Quantum Chemical Investigation of CO Binding to Heme Proteins and Model Systems:  A Unified Model Based on13C,17O, and57Fe Nuclear Magnetic Resonance and57Fe Mössbauer and Infrared Spectroscopies

1998 ◽  
Vol 120 (19) ◽  
pp. 4784-4797 ◽  
Author(s):  
Michael T. McMahon ◽  
Angel C. deDios ◽  
Nathalie Godbout ◽  
Renzo Salzmann ◽  
David D. Laws ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Chemical ◽  
Heme Proteins ◽  
Unified Model ◽  
Chemical Investigation ◽  
Model Systems ◽  
Quantum Chemical Investigation ◽  
Model Based ◽  
Nuclear Magnetic

scholarly journals Improving the accuracy of model-based quantitative nuclear magnetic resonance

2020 ◽  
Vol 1 (2) ◽  
pp. 141-153
Author(s):  
Yevgen Matviychuk ◽  
Ellen Steimers ◽  
Erik von Harbou ◽  
Daniel J. Holland
Keyword(s):  
Experimental Data ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Model Fitting ◽  
Adjustment Procedure ◽  
Peak Integration ◽  
Model Based ◽  
Numerous Model ◽  
Functional Forms ◽  
Nuclear Magnetic

Abstract. Low spectral resolution and extensive peak overlap are the common challenges that preclude quantitative analysis of nuclear magnetic resonance (NMR) data with the established peak integration method. While numerous model-based approaches overcome these obstacles and enable quantification, they intrinsically rely on rigid assumptions about functional forms for peaks, which are often insufficient to account for all unforeseen imperfections in experimental data. Indeed, even in spectra with well-separated peaks whose integration is possible, model-based methods often achieve suboptimal results, which in turn raises the question of their validity for more challenging datasets. We address this problem with a simple model adjustment procedure, which draws its inspiration directly from the peak integration approach that is almost invariant to lineshape deviations. Specifically, we assume that the number of mixture components along with their ideal spectral responses are known; we then aim to recover all useful signals left in the residual after model fitting and use it to adjust the intensity estimates of modelled peaks. We propose an alternative objective function, which we found particularly effective for correcting imperfect phasing of the data – a critical step in the processing pipeline. Application of our method to the analysis of experimental data shows the accuracy improvement of 20 %–40 % compared to the simple least-squares model fitting.

Quantum chemical and nuclear magnetic resonance spectral studies on molecular properties and electronic structure of berberine and berberrubine

2007 ◽  
Vol 45 (8) ◽  
pp. 647-655 ◽  
Author(s):  
A. N. Tripathi ◽  
Lata Chauhan ◽  
P. P. Thankachan ◽  
Ritu Barthwal
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Electronic Structure ◽  
Magnetic Resonance ◽  
Quantum Chemical ◽  
Molecular Properties ◽  
Spectral Studies ◽  
Nuclear Magnetic

scholarly journals Studies on the Chemistry of Lichens, XVIII * Chemical Investigation of the Species Letharia vulpina (L .) Hue and New Derivatives of Vulpinic Acid

1978 ◽  
Vol 33 (5-6) ◽  
pp. 449-451 ◽  
Author(s):  
Yngve Solberg ◽  
Gabriele Remedios
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
Chemical Investigation ◽  
Nuclear Magnetic Resonance Spectra ◽  
Elemental Analyses ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The crystalline and amorphous constituents of Letharia vulpina collected at Flensjoen, Sor-Trendelag, Norway, have been identified as atranorin, vulpinic-, pulvinic-, usnic-, benzoic- and hydroxyfatty acids. Vulpinic acid thallate(I) and vulpinic acid isopropylether have been prepared as new derivatives. The identity of the compounds was established by consideration of elemental analyses, infrared, mass and nuclear magnetic resonance spectra, and thin layer chro­matography.

Sign in / Sign up

Export Citation Format

Share Document