Question

Unknown number: 2055 Chemistry 2540 Spectroscopy Unknown - 25 points Information: Each spectra below was obtained from a pure compound. Mass Spectrum parent peaks (M) are listed for all examples. IR peaks listed are strong (s) unless otherwise indicated for signals above 1500 cm 'H NMR Spectra, the integral is given in number of hydrogens (#H) or as a relative ratio. Important coupling constants (/-values) are listed next to the peaks for some examples. For some spectra, an inset (grey box) is also given showing a "zoom-in" on an important part of the spectrum. Mass Spectrometry (not shown): [M] = 200 (50%), [M+2) = 202 (100%), [M+4) = 204 (50%) m/z Infrared Spectroscopy (not shown): 2968, 2906 cm H Nuclear Magnetic Resonance. quin 4H 2H PŔM 13C Nuclear Magnetic Resonance. TETT 200pm 15T

Please provide possible chemical formula for this spectra!

Answer 1

The peak M, M+2 and M+4 indicates the presence of halogen atom.

4H triplet and 2H Quintet indicates the presence of following group

-CH2-CH2-CH2-

Molecular ion mass is 200 so the the possible halogen is Bromine.

Br-CH2-CH2-CH2-Br

Hence the chemical formula is C3H6Br2

3(C)+6(H)+2(Br) = 3(12)+6(1)+2(79) = 200

1H -NMR:

Br -CH2-CH2-CH2-Br

a b a

Ha : 4H triplet at 3.5 ppm

Hb : 2H Quintet at 2.2 ppm

13C -NMR:

Peak at 35 belongs to Bromine attached carbon atom and peak at 30 belongs to middle carbon atom.