Steps in Spectral Identification
For your report, the following items must be completed: the point-breakdown for each item is also indicated.
¨ Use molecular formula to determine degrees of unsaturation: 2 points
IHD = # of (rings + p bonds)
¨ Identify major peaks in IR spectrum, if any: 4 points
Use the IR data tables in your lab manual and organic textbook to
determine if there are characteristic signals corresponding to the
various functional groups.
e.g.,
OâH OH single bond stretch
NâH or NâH2 NH single bond stretch
CºCâH terminal alkyne, CH stretch
CºC, CºN triple bond stretch
HâC=O aldehyde CH stretch
C=O CO double bond stretch
CâO CO single bond stretch
Other�
q Speculate on possible functional groups that might be present.
- Deduce structural fragments for each of the 1H NMR spectral signals.
Usually working upfield (from high to low chemical shift) is
most efficient.
o Explain your reasoning
- Assemble the fragments to construct the molecule.
¨ Give the structure of the compound. 2 points
¨ Assign the signals in the 1H NMR spectra to specific protons. 6 points
¨ Assign carbons to the peaks in the 13C NMR spectrum 6 points
Unknown 014 MF C4H80 Mw 72 %C 66.6 %H 11.2 8 Mass Spec. D relativ m/z abund. 3124 2 2 se- Freknwh 40- 72 36 1000 25aa 3see