Chemical shifts, multiplicities and coupling constants

Chemical Shifts, Multiplicities, and Coupling Constants of Residual Protons in Commercially Available Deuterated Solvents... [Pg.86]

Chemical shift (ppm) Number of protons Multiplicity and coupling constant (J) Assignment... [Pg.78]

Table 4 1H NMR chemical shifts (ppm), multiplicity and coupling constants (Hz) for benzotriazol-1 -yl derivatives 27-29...

The solution of a typical structural analysis problem by nmr methods utilizes at least four kinds of information obtained directly from the spectrum. They are chemical shifts (8), line intensities (signal areas), spin-spin splitting patterns (line multiplicities), and coupling constants (/). We already have shown how chemical shifts are used in the absence of spin-spin splitting. We now will illustrate how more complex spectra may be analyzed. [Pg.322]

Chemical shift assignments (Sc upright, SH italics) HH multiplicities and coupling constants (Hz) where resolved... [Pg.241]

NMR is the tool most widely used to identify the structure of triterpenes. Different one-dimension and two-dimension techniques are usually used to study the structures of new compounds. Correlation via H-H coupling with square symmetry ( H- H COSY), homonuclear Hartmann-Hahn spectroscopy (HOHAHA), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC), distortionless enhancement by polarisation transfer (DEPT), incredible natural abundance double quantum transfer experiment (INADEQUATE) and nuclear Overhauser effect spectroscopy (NOESY) allow us to examine the proton and carbon chemical shift, carbon types, coupling constants, carbon-carbon and proton-carbon connectivities, and establish the relative stereochemistry of the chiral centres. [Pg.109]

H-NMR Chemical Shifts (S in ppm and multiplicity) and Coupling Constants (J, Hz) for the Stenine Alkaloid Group. [Pg.85]

NMR spectra are basically characterized by the chemical shift and coupling constants of signals. The chemical shift for a particular atom is influenced by the 3D arrangement and bond types of the chemical environment of the atom and by its hybridization. The multiplicity of a signal depends on the coupling partners and on the bond types between atom and couphng partner. [Pg.518]

All experiments described previously deal with one-dimensional 13C NMR spectra Spectral parameters such ai chemical shifts, coupling constants and relaxation times are evaluated from spectra with one frequency axis as one dimension. A second dimension comes into the NMR experiment when two spectral parameters, such as chemical shifts and coupling constants or chemical shifts of different nuclei, are represented in an area limited by two frequency axes. These experiments are based on pulse sequences facilitating multiplicity analysis and partly involving further sensitivity enhancement of the 13C NMR experiment. [Pg.73]

Our discussions of spin-spin splitting and multiplicity have been based on first-order or weakly coupled spectra which are spin systems where Av/J > 10. The difference in chemical shift in hertz of coupled protons divided by the coupling constant is 10 or more. In such a case clean 1 1 doublets, 1 2 1 triplets, and so on, are observed and coupling constants and chemical shifts can be read directly from line positions in the spectrum. [Pg.354]

Siliconate and precursor Chemical shift (ppm) Multiplicity /(SiF) coupling constant (Hz)... [Pg.341]

Chemical shift 8[ppm] i (multiplicity)6, coupling constant J[Hz]/ concentration and solvent, pH chemical shift reference(s) remarks. [Pg.339]

C and 1H chemical shifts 8C and SH (italic) CH multiplicities, CH coupling constants (Hz), coupling protons... [Pg.205]

I3C and H chemical shifts 8e and SH (italic)------------------------CH multiplicities. CH coupling constants (Hz), coupling protons-... [Pg.207]

Multiple-step homonuclear Hartmann-Hahn transfer is not limited to highly selective transfer steps. As suggested by Glaser and Drobny (1989), several consecutive, band-selective Hartmann-Hahn mixing steps can be used to transfer coherence selectively in coupling networks with selected ranges of chemical shifts and coupling constants. [Pg.195]

Chemical shifts, multiplicity of the signals, absolute values of the coupling constants and their magnitude in the NMR spectrum as well as C NMR data indicated the p-configuration at the anomeric positions for both glucopyranosyl units a-configuration for the... [Pg.129]

Chemical Shift and Multiplicities H Chemical Shift and Coupling Constants C Chemical Shift and Multiplicities Chemical Shift and Coupling Constants... [Pg.220]