Coupling constants magnitude

Coupling constant magnitudes (mostly reported without sign) may be read from signal splittings. This, however, is possible only if the spectrum (or subspectrum) is first order, i.e., if the ratio R of the chemical shift difference of the coupling partners X and Y (dv in Hz) and... 

Compound Nature of coupling constant Magnitude of coupling constant References ... 

These medium and temperature effects of a nonspecific nature have to be taken into account in variable temperature studies and especially in comparative studies involving small changes in chemical shifts or coupling constants. Magnitudes of... 

The radical cation of 1 (T ) is produced by a photo-induced electron transfer reaction with an excited electron acceptor, chloranil. The major product observed in the CIDNP spectrum is the regenerated electron donor, 1. The parameters for Kaptein s net effect rule in this case are that the RP is from a triplet precursor (p. is +), the recombination product is that which is under consideration (e is +) and Ag is negative. This leaves the sign of the hyperfine coupling constant as the only unknown in the expression for the polarization phase. Roth et aJ [10] used the phase and intensity of each signal to detemiine the relative signs and magnitudes of the... 

The CIDNP spectrum is shown in figure B 1.16.1 from the introduction, top trace, while a dark spectrum is shown for comparison in figure B 1.16.1 bottom trace. Because the sign and magnitude of the hyperfine coupling constant can be a measure of the spin density on a carbon, Roth et aJ [10] were able to use the... 

Figure 5, Low-eriergy vibronic spectrum in a electronic state of a linear triatomic molecule. The parameter c determines the magnitude of splitting of adiabatic bending potential curves, is the spin-orbit coupling constant, which is assumed to be positive. The zero on the...

Suppression of the tme diagonal peaks by double-quantum filtering (DQF-COSY) may resolve such problems. Finally, quantitative measurements of the magnitude of the coupling constants is possible using the Z-COSY modification, These experiments ate restricted to systems of abundant spins such as H, and which have reasonably narrow linewidths. 

Contrary to lUPAC conventions, chemical shifts 5 in this book are scaled in ppm in the spectra, thus enabling the reader to differentiate at all times between shift values (ppm) and coupling constants (Hz) ppm (parts per million) is in this case the ratio of two frequencies of different orders of magnitude, Hz / MHz =1 10 without physical dimension... 

The fact that the absolute magnitudes of these two sets of coupling constants are different is also expected on the basis of the Pople, Bothner-By treatment (48). It would clearly be of some considerable interest if a general study were to be made of the stereospecificity of this geminal dependence since this may lead to another method for determining carbohydrate conformations. 

Coupling constant, / (Section 13.11) The magnitude (expressed in hertz) of the interaction between nuclei whose spins are coupled. 

Although their chemistry is less developed than that of phosphonyl, phospho-niumyl or phosphoranyl radicals, many structural studies have been devoted to phosphinyl radicals [1]. Like their nitrogen analogs,phosphinyl radicals are 7i-type radicals (Fig. 1) and because of the very small s character of their SOMO, the magnitude of their phosphorus hyperfine coupling constants flp is below 15 mT [1]. 

In homonuclear-shift-correlated experiments, the Ft domain corresponds to the nucleus under observation in heteronuclear-shift-correlated experiments. Ft relates to the unobserved or decoupled nucleus. It is therefore necessary to set the spectral width SW, after considering the ID spectrum of the nucleus corresponding to the Ft domain. In 2D /-resolved spectra, the value of SW depends on the magnitude of the coupling constants and the type of experiment. In both homonuclear and heteronuclear experiments, the size of the largest multiplet structure, in hertz, determines... 

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