What do the notations in NMR spectral data mean?

[VDX]

Hello everyone. In the literature I come across spectra data as in the examples below:

English example:
1H-NMR (CDCl3) δ: 1.09 (3H, t, CH3), 3.77 (3H, s, OCH3), 3.97-4.28 (2H, m, CH2), 4.28 (1H, s, CH) 6.41 (2H, t, pyrrole-H), 6.78 (2H, t, pyrrole-H), 7.13-7.21 (5H, m, ArH), 8.53 (1H, d, J=5.2Hz, ArH), 8.69(1H, s, ArH); MS(m/z): 368(M+).

French example:
'H RMN (CDC13) 8 : 1,47 (s, 9H) ; 2,93 (dd, 1H) ; 3,07 (dd, 1H) ; 3,95 (d, 1H) ; 4,27 (ls, 1H) ; 4,34 (d, 1H) ; 5,64 (LD, 1H) ; 7,00 (M, 2H) ; 7,18 (td, 1H) ; 7,41 (d, 1H) HPLC (Chiracel OD, HEXANE/ISOPROPANOL (92 : 8), 0,5 ML/MIN) : composé (Xa-1), temps de rétention = 12,71 min ; composé (Xa-2), temps de RéTENTION = 14, 05 min ; rapport des AUC (Xa-1)/ (Xa-2) = 98 : 2.

Would someone be so kind as to point me to a reference for the above notation scheme in English (and if possible in French)?

Thanks, and great work with this forum!

 

[xanthym]

Hello everyone. In the literature I come across spectra data as in the examples below:

English example:
1H-NMR (CDCl3) δ: 1.09 (3H, t, CH3), 3.77 (3H, s, OCH3), 3.97-4.28 (2H, m, CH2), 4.28 (1H, s, CH) 6.41 (2H, t, pyrrole-H), 6.78 (2H, t, pyrrole-H), 7.13-7.21 (5H, m, ArH), 8.53 (1H, d, J=5.2Hz, ArH), 8.69(1H, s, ArH); MS(m/z): 368(M+).

French example:
'H RMN (CDC13) 8 : 1,47 (s, 9H) ; 2,93 (dd, 1H) ; 3,07 (dd, 1H) ; 3,95 (d, 1H) ; 4,27 (ls, 1H) ; 4,34 (d, 1H) ; 5,64 (LD, 1H) ; 7,00 (M, 2H) ; 7,18 (td, 1H) ; 7,41 (d, 1H) HPLC (Chiracel OD, HEXANE/ISOPROPANOL (92 : 8), 0,5 ML/MIN) : composé (Xa-1), temps de rétention = 12,71 min ; composé (Xa-2), temps de RéTENTION = 14, 05 min ; rapport des AUC (Xa-1)/ (Xa-2) = 98 : 2.

Would someone be so kind as to point me to a reference for the above notation scheme in English (and if possible in French)?

Thanks, and great work with this forum!

The above are Proton (¹H) NMR spectra, using chloroform (CDCl3) solvent, presented in standard format, indicating the Chemical Shifts (in ppm), the number of structurally equiv H atoms producing the shift ("nH"), the splitting pattern ("s"=singlet, "d"=doublet, "t"=triplet, "m"=multiplet, etc.) caused by spin coupled adjacent non-equiv H atoms, and the identified Functional Group. Examples:

"1.09 (3H, t, CH3)" ----> Chem Shift 1.09 ppm, 3 H atoms (struct equiv), triplet (3 lines) from adjacent spin-coupled H, and identified CH3 functional group.
"3.97-4.28 (2H, m, CH2)" ----> Chem Shift spread from 3.97-4.28 ppm, 2 H atoms (struct equiv), multiple lines from adjacent spin-coupled H, and identified CH2 functional group.

More info on interpreting NMR chemical shifts can be found here:
http://wwwchem.uwimona.edu.jm:1104/spectra/nmrintro.html


~~

 

[thepatientmental]

Hello! Thank you for your question. The notation used in NMR spectra is known as the chemical shift notation and it is used to describe the position of peaks in the spectrum. The chemical shift is measured in parts per million (ppm) and it indicates the relative position of the peak with respect to a reference compound, usually tetramethylsilane (TMS). The chemical shift is influenced by the electron density around the nucleus, so it can provide information about the chemical environment of a particular atom.

In the examples you provided, the first number after the chemical shift (δ) represents the position of the peak in ppm, followed by the number of hydrogens (H) contributing to the peak, the type of signal (s for singlet, d for doublet, t for triplet, dd for doublet of doublets, etc.), and any additional information such as coupling constants (J) or multiplicity (m). The letters in parentheses indicate the solvent used for the measurement.

As for the French example, it follows a similar notation, with the chemical shift (δ) expressed in a different format and the use of commas instead of parentheses. It also includes information about the peak shape (s for sharp, ls for broad), and the letters in parentheses indicate the type of experiment used (HPLC - High Performance Liquid Chromatography).

For a more detailed explanation of NMR spectra notation and nomenclature, I would recommend consulting a textbook or online resources such as the NMR Chemical Shifts Database. I hope this helps!