Problem Set (PS) K3 – 13C-NMR Spectroscopy & Mass Spec Smith Sections A & C (15 points)
Other Problems – Gradable
Draw all possible constitutional isomers of C5H11Br and for each indicate how many different kinds of carbons (unique carbons) are present in each structure. [Hint: There should be at least 8 constitutional isomers.)
Explain in detail how you would distinguish between the following set of constitutional isomers using 13C-NMR.
Compound UWT-S (C8H16) reacts with one mole of bromine to form product C8H16Br2. Compound UWT-S has the broadband proton-decoupled 13C-NMR spectrum shown below. The number of protons attached to each carbon, as determined by DEPT, is in the boxes next to each peak. Propose a structure for UWT-S.
In the mass spectrum of 2,6-dimethyl-4-heptanol there are prominent peaks at m/z =87, 111, and 126.
a). At what m/z value would you find the molecular ion for this compound?
b) Propose reasonable structures for the fragment ions observed.
