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Application of the multi-standard methodology for calculating 1H NMR chemical shifts
(American Chemical Society, 2012-07)
Gauge including atomic orbitals (GIAO)1H NMR chemical shift calculations have been performed for 66 organic compounds at 72 di fferent levels of theory using the multi-standard approach (MSTD) previously developed for 13C ...
A Multi-standard Approach for GIAO 13C NMR Calculations
(American Chemical Society, 2009-12)
The influence of the reference standard employed in the calculation of 13C NMR chemical shifts was investigated over a large variety of known organic compounds, using different quantum chemistrymethods and basis sets. After ...
Consecutive Queries to Assess Biological Correlation in NMR Metabolomics: Performance of Comprehensive Search of Multiplets over Typical 1D 1H NMR Database Search
(American Chemical Society, 2020-05-25)
NMR-based metabolomics requires proper identification of metabolites to draw conclusions from the system under study. Normally, multivariate data analysis is performed using 1D 1H NMR spectra, and identification of peaks ...
Indirect nuclear spin-spin coupling constants and chemical shifts in norbornene- derivatives bearing boronic acid pinacol ester group
(Research Trends, 2021-11-02)
We have simulated the nuclear magnetic resonance (NMR) parameters of ten norbornene-derivativesbearing a boronic acid pinacol ester group. In particular, we have calculated the 13C and 1H chemicalshifts and proton-proton ...
Covalence and π-electron delocalization influence on hydrogen bonds in proton transfer process of o-hydroxy aryl Schiff bases: A combined NMR and QTAIM analysis
(American Institute of Physics, 2021-08)
Within the framework of the density functional theory approach, we studied the relationship between the chemical nature of intramolecular hydrogen bonds (HBs) and nuclear magnetic resonance (NMR) parameters, J-couplings ...
Phytochemical study of Senecio volckmannii assisted by CASE-3D with residual Dipolar Couplings and Isotropic 1H/13C NMR Chemical Shifts
(American Chemical Society, 2018-11)
Nine new eremophilanolides, with seven known sesquiterpenoids, and 4-hydroxyacetophenone were isolated from the aerial parts of Senecio volckmannii var. volckmannii. The structures of these compounds were fully characterized ...
Factors affecting the use of 13Cα chemical shifts to determine, refine, and validate protein structures
(Veterinary and Human Toxicology, 2008-05)
Interest centers here on the analysis of two different, but related, phenomena that affect side-chain conformations and consequently 13Cα chemical shifts and their applications to determine, refine, and validate protein ...
Substituent effects on NMR spectroscopy of 2,2-dimethylchroman-4-one derivatives: Experimental and theoretical studies
(Molecular Diversity Preservation International, 2020-04)
The attribution of 1H and 13C NMR signals of a library of 5-, 6- and 7-substituted 2,2-dimethylchroman-4-one derivatives is reported. Substituent effects were interpreted in terms of the Hammett equation, showing a good ...
Insight into the conformational space of n-benzyl-n-(furan-2-ylmethyl) acetamide by NMR spectroscopy and DFT calculations
(Sociedade Brasileira de Química, 2020-09-21)
In this study, the conformational behavior of N-benzyl-N-(furan-2-ylmethyl) acetamide in chloroform was addressed by using a combined experimental/theoretical strategy using NMR spectroscopy and quantum chemical calculations. ...
Unblocked statistical-coil tetrapeptides and pentapeptides in aqueous solution: a theoretical study
(Springer, 2002-03)
NMR studies of the molecular conformations of peptides and proteins rely on a comparison of the relevant spectral parameters with the corresponding values for so-called statistical-coilpolypeptides. For this reason, it is ...