H and C-13 NMR

An unknown compound containing C, H, and one kind of heteroatom only
shows a molecular ion peak at m/z 184 and a peak of almost equal
intensity at m/z 186 in the mass spectrum. The 1H and 13C NMR spectra of
the compound are given on the following page. Propose a structure for
the unknown compound and assign all peaks in the two NMR spectra.

Solution:

Molecular ion peak at 184, which is the molecular weight of the
compound. The m/z value of 186 is a parent peak.

C-13 spectra information

~18 ppm indicates alkane region. –CH3- groups

~29 ppm also indicates alkane region. CH3 groups present

~120 ppm indicates that the molecule could be aromatic with C=C bonds

~130 ppm also indicates an aromatic compound

~132 ppm –aromatic region-

small peak at ~ 143 suggest C=C bonds

H spectra information

~1.2 ppm triplet indicates two neighboring protons

~2.6 ppm quartet indicates three neighboring protons

~7.1 ppm doublet indicates one neighboring protons

~7.5 ppm doublet also indicates one neighboring proton

possible structure.