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The following exercises are designed to help you become familiar with predicting the 1H NMR spectra of simple organic molecules. For each example you should find the number of signals you expect, where they should show on the scale (chemical shift), and what shape they should be (splitting patterns).
This format shows all four pieces of data that can be inferred from a spectrum (# peaks, shift, integration, multiplicity). Then in the final column, there is a place for you to show a partial structure derived from the data presented.
Chemistry 233 Chapter 13: NMR Spectroscopy Problem Set. 1) For each compound below, identify each chemically distinct type of hydrogen. Specify the number of 1H NMR signals you would expect to see. 3) Consider the indicated protons in each of the three compounds below.
Chem 124 PAL Worksheet Proton NMR and combined practice problems Page 1 Write out the answers on separate sheets of paper. 1. 1How many signals will there be in the H NMR spectrum of each of these compounds? 2. Propose a structure that is consistent with each set of data. a. C 4 H 10 O 1H NMR spectrum singlet 1.28 (9H)
What a spectrum looks like • The data is analysed by a computer and a spectrum produced. • The spectrum contains a series of signals (or peaks) showing where the compound absorbs radiowaves. • The horizontal scale is the chemical shift (d) –this indicates how far each signal is shifted away from that for TMS (measured in parts per million).
Show all your work (= label peaks in the spectra!) Determine the degree of unsaturation for the compound. Assign the six pertinent peaks in the infrared spectrum. Suggest a structure for compound W based on the spectra given.
Numclear magnetic resonance (NMR) is particularly useful in the identification of the positions of hydrogen atoms (1H) in molecules. This is an invaluable technique in the identification of organic compounds and commonly used in analytical laboratories.
