There are several isomers with the molecular formula C4H12N2 - AQA - A-Level Chemistry - Question 11 - 2018 - Paper 2
Question 11
There are several isomers with the molecular formula C4H12N2.
One isomer is shown.
H3C – CH2 – N – CH2 – NH2
Give the number of peaks in the 13C NMR spectrum of th... show full transcript
Worked Solution & Example Answer:There are several isomers with the molecular formula C4H12N2 - AQA - A-Level Chemistry - Question 11 - 2018 - Paper 2
Step 1
Give the number of peaks in the 13C NMR spectrum of this isomer.
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Answer
The 13C NMR spectrum of this isomer will show 4 peaks. This is because there are four distinct carbon environments in the structure.
Step 2
State and explain the splitting pattern.
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Answer
The splitting pattern observed for the hydrogens labelled α in the 1H NMR spectrum will be a triplet. This occurs because there are two hydrogens on the adjacent carbon (the CH2 next to the carbon attached to the nitrogen).
Step 3
Explain.
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Answer
The triplet indicates that the α protons are coupled to two neighboring protons. According to the N+1 rule of splitting, where N is the number of adjacent protons, the presence of two adjacent protons results in a triplet (2 + 1 = 3).
