15. Analytical Techniques:IR, NMR, Mass Spect

Predict the splitting pattern (multiplicity) for the following molecule:

Predict the splitting pattern (multiplicity) for the following molecule:

Predict the multiplicity (the number of peaks as a result of splitting) and the chemical shift for each shaded proton in the following compounds.

(a)

(b)

Why is there no coupling between the a and c protons or between the b and c protons in the cis and trans alkenes shown in Figure 14.20?

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Predict the splitting patterns for the signals given by the compounds in Problem 4.

d.

Predict the splitting patterns for the signals given by the compounds in Problem 4.

c. CH₂=CCl₂

Label each set of chemically equivalent protons, using a for the set that will be at the lowest frequency in the ¹H NMR spectrum, b for the next lowest, and so on. Indicate the multiplicity of each signal.

c.

In Figure 15.34, H_a was assumed to be 'up.' How does the analysis change if we assume instead that H_a is down?

Though Figure 15.34 was concerned with the appearance of H_a, how would H_b appear in the spectrum?

Every number in Pascal’s triangle is the sum of the two numbers above it. Given this, fill in the missing numbers.

Indicate the number of signals and the multiplicity of each signal in the 1H NMR spectrum of each of the following compounds:

c. ClCH₂CH₂CH₂Cl 

Indicate the number of signals and the multiplicity of each signal in the 1H NMR spectrum of each of the following compounds:

a. CH₃CH₂CH₂CH₂CH₂CH₃

Predict the splitting patterns for the signals given by the compounds in Problem 4.

i.

Predict the splitting patterns for the signals given by the compounds in Problem 4.

j.

Draw all of the possible spin states to explain why a hydrogen with four neighbors appears as a quintet (quint, five peaks).