1H NMR of an organic compound recorded at 500MHz spectrometer

Chemical shifts and coupling constants of the quartet

The 1H NMR spectrum of an organic compound provides information about the hydrogen atoms present in the molecule. The spectrum is recorded using a 500MHz spectrometer, which refers to the strength of the magnetic field used in the experiment. The chemical shifts and coupling constants observed in the spectrum can provide valuable insights into the structure and environment of the compound.

Chemical shifts

Chemical shift is a measure of the resonance frequency of a hydrogen atom relative to a reference compound. It is expressed in parts per million (ppm) and is influenced by factors such as the electron density around the hydrogen atom and the presence of nearby magnetic or electron-withdrawing groups. In the given spectrum, the chemical shifts of the quartet are recorded at 1759, 1753, 1747, and 1741 Hz.

Coupling constants

Coupling constants, denoted as J values, provide information about the interaction between neighboring hydrogen atoms in a molecule. They are measured in hertz (Hz) and can reveal the number of neighboring hydrogen atoms (n+1 rule) and their relative positions. In the case of a quartet, the coupling constant is typically the distance between the central peak and the adjacent outer peaks.

Interpretation of the quartet

The quartet observed in the spectrum indicates the presence of three neighboring hydrogen atoms that interact with the hydrogen atom responsible for the quartet. The quartet signal arises due to the splitting of the peak into four smaller peaks, each corresponding to a different spin state of the neighboring hydrogens.

The coupling constant of the quartet can be determined by measuring the distance between the central peak and one of the outer peaks. In this case, the coupling constant would be the difference between 1759 Hz and 1747 Hz, which is 12 Hz.

The presence of a coupling constant indicates that the hydrogen atoms responsible for the quartet are coupled to three neighboring hydrogen atoms. The magnitude of the coupling constant provides information about the strength of the coupling interaction. A larger coupling constant suggests a stronger interaction between the hydrogen atoms.

Conclusion

In summary, the 1H NMR spectrum of the organic compound recorded at a 500MHz spectrometer shows a quartet with chemical shifts at 1759, 1753, 1747, and 1741 Hz. The quartet indicates the presence of three neighboring hydrogen atoms, and the coupling constant is determined by the difference in frequency between the central peak and one of the outer peaks. The interpretation of the spectrum provides valuable information about the structure and environment of the compound.