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The database contains also a smaller amount of NMR data from carbohydrates, cofactors and ligands. [1] These data are crossreferenced to 3D structures in the PDB when available. The NMR data are provided in the NMR-STAR file format and a number of format conversion tools are available at the site to convert files from NMR-STAR to other formats. [1]
SDBS includes 14700 1 H NMR spectra and 13000 13 C NMR spectra as well as FT-IR, Raman, ESR, and MS data. The data are stored and displayed as an image of the processed data. Annotation is achieved by a list of the chemical shifts correlated to letters which are also used to label a molecular line drawing.
Methyl tert-butyl ether (MTBE), also known as tert-butyl methyl ether, is an organic compound with a structural formula (CH 3) 3 COCH 3. MTBE is a volatile, flammable, and colorless liquid that is sparingly soluble in water. [ 1 ]
When interpreting the COSY spectrum, diagonal peaks correspond to the 1D chemical shifts of individual nuclei, similar to the standard peaks in a 1D NMR spectrum. The key feature of a COSY spectrum is the presence of cross-peaks as shown in Figure 1, indicating coupling between pairs of nuclei.
The difference between the chemical shift of a given nucleus in a diamagnetic vs. a paramagnetic environment is called the hyperfine shift.In solution the isotropic hyperfine chemical shift for nickelocene is −255 ppm, which is the difference between the observed shift (ca. −260 ppm) and the shift observed for a diamagnetic analogue ferrocene (ca. 5 ppm).
This experiment correlates the chemical shift of amide of a residue the Cα of the same residue as well as those of the preceding residue. [2] Each strip gives two peaks, the inter and intra-residue Cα peaks. Peak from the preceding Cα may be identified from the HN(CO)CA experiment which gives only the inter-residue Cα.
Download as PDF; Printable version; ... move to sidebar hide. NMR-STAR is an extension of the STAR file format to store the results of biological NMR experiments. ...
As with NMR spectroscopy in general, good resolution requires a high signal-to-noise ratio, clear separation between peaks for each stereoisomer, and narrow line width for each peak. Chiral lanthanide shift reagents cause a clear separation of chemical shift, but they must be used in low concentrations to avoid line broadening.