Question

1a) Draw the condensed structure of isopentane. b.) Estimate what the 1H NMR spectrum of isopentane is expected to look like. c.) Clearly label each proton environments and match each to its signal. d.) Be sure to include appropriate splitting. e.) Above each signal, include the appropriate integration. 2 a.) Which of the indicated protons (Ha, Hb and Ho) is expected to be split the most, and why? b.) Provide the splitting diagrams for the two proton environments with the simplest splitting (the signals that get split into the smallest number of peaks). Use the given coupling constants to assist you with the splitting diagrams. Be sure to clearly label the two splitting diagrams so that we know which diagram is for which proton signal. Jab=13 Hz, J=7.2 Hz CI НЬ =C CH3c На

Answer 1

Solution:

1a) ​​​​​​1b)

Condensed structure of isopentane CH3 -UI _CH3 H3C " С H2

A -CH is appeared as nonane as there are total 8 protons on its adjacent carbons

2 CH3 CH3 CH2 CH unanithin 1.8 1.6 1.4 1.0 0.8 0.6 0.4 1.2 ppm

A -CH2 appeared as pentet as there are 4 protons are attached to its adjacent carbons.

There are three CH3 groups

Two are chemically equivalent and attached to the -CH thus they appeared as doublet at

The remaining CH3 is attached to the -CH2 thus it appeared as triplet.

2a) Hb proton will split more since its adjacent carbons has more number of hydrogens. Hb will show quartet since it has coupling to the four adjacent protons.

2b)

Splitting diagram of Ha and Hb Hb Ha Jab = 13Hz Jab = 13Hz |-.*121 || Jbc = 7.2 Hz Jbc = 7.2 Hz