21.1 Spectroscopic Identification of Organic compounds

Part of the ¹H NMR spectrum of an organic compound is shown below:

Determine the number of unique hydrogen environments

Deduce the whole number ratio of the hydrogen environments in the spectrum.

State the splitting patterns present in the spectrum and suggest what information could be obtained from the patterns.

Assign peaks X, Y and Z to the correct location shown in the compound:

Outline what chemical information can be obtained about inorganic ionic substances and complex organic molecules from X-ray crystallography studies.

Explain why X-ray crystallography is not very useful for compounds containing hydrogen.

Suggest another limitation of X-ray crystallography for organic compounds.

An electron density map obtain from the X-ray crystallography of copper metal is shown below:

Use the diagram to estimate the radius of a copper atom. The units are nm.

An organic molecule with molecular formula C₂H₄O is analysed using MS, IR and ¹H NMR. Use section 26, 27 & 28 of the Data booklet to help you answer this question.

The MS is shown below:

Determine the relative molecular mass from the spectrum and account for the peak at m/z 29.

The IR spectrum of the same compound is shown below.

Identify the functional group responsible for the peak at X

The ¹NMR spectrum of C₂H₄O is shown below:

Account for the peaks at 2.2 ppm and 9.8 ppm and their relative areas.

Deduce the displayed structure of this compound from the spectroscopic information.

The MS of compound P is shown below. Compound P contains carbon, hydrogen and oxygen only. Use section 26, 27 & 28 of the Data booklet to help you answer this question.

Determine the relative formula mass of P and account for the peak at m/z 45.

The IR spectrum of P is shown below. 

Use the spectrum and your answer to part a) to deduce a functional group that could be present in P.

The 1H NMR spectrum of P is shown below. 

Deduce what information can be found from the spectrum.

A student suggests that P is propan-1-ol. Evaluate all the evidence from the spectra and determine whether the student is correct.