Vaishali's+Analysis+of+NMR+of+Pyridine

Vaishali Rawani

Analysis of NMR of Pyridine

[]


 * Figure 1:** HNMR Spectrum of Pyridine


 * Figure 1.2:** A zoomed view of the sets of doublet present in the NMR spectra. The doublets appear at approximately 8.355 ppm 8.375 ppm. These peaks are for each of the hydrgen atoms’ on each side of the nitrogen (attached to the benzene ring) and these hydrogens (or in other words, protons) are slightly deshieleded by the nitrogen causing a slightly higher reading. The coupling patterns here are due to meta coupling, which has a coupling constant of 2 Hz compared to the ortho couplng constant, which is equal to 8 Hz. The positioning of these peaks is consistent with the electronegative atom,nitrogen, attached to the aromatic ring present in the pyridine molecule, which increases the chemical shift from the normal aromatic ring range (7 to 8 ppm) to a little bit over 8 ppm. Additionally, coupling of adjacent protons explains the signal splitting into doublet groups.


 * Figure 1.3:** A zoomed view of the sets of triplets and a singlet present in the NMR spectra. The triplets appear at approximately 7.420 ppm, 7.380 ppm, and 7.360 ppm, and the singlet is located at approximately at 7.270 ppm. The positioning of these peaks is consistent with the aromatic ring present in the pyridine molecule, which has a chemical shift aproximately between 7 to 8 ppm. Additionally, coupling of adjacent protons explains the signal splitting into triplet groups. These peaks are for the the aromatic ring itself and corresponds to the hydrogen that is directly across from the nitrogen.


 * Figure 1.4:** A zoomed view of the multiplet present in the NMR spectra. The singlets appear at approximately 6.975 ppm and 7.015 ppm, and the triplet appears at approximately 6.995 ppm. These peaks correspnd to the hydrogens labeled “C” (sp2) in the structural diagram of pyridine underneath the first image of the compound. These protons are expected to have a chemical shift around 7.2 ppm. This coupling pattern is due to meta hydrogen coupling with three ortho couplings.


 * Figure 1.5:** A zoomed view of the singlet located at approximately 4.220 ppm. This peak corresponds to a possible impurity which has a chemical shift range value between 1 to 5 ppm.