Determine the structure of the following compound based IR, ^1 H &^13 C NMR info

Question

Determine the structure of the following compound based IR, ^1 H &^13 C NMR information given. the structure on the Draw bond-line structure (skeletal structure). A C_9H_18O molecule shows IR peak of about 1714 cm^-1. The proton decoupled^15 C-NMR spectrum has 9 signals. The ratio of carbon-bonded hydrogens in the^1 H-NMR spectrum is, 6:3:3:2:2: 1:1, with a corresponding signal multiplicity of d, d, t, m, t, m, m. Predict the structure and match the multiplicity of each nonequivalent set of hydrogens. (You must draw bond-line structure and match the multiplicities on the structure for full credit).

Explanation / Answer

Molecular formula is C9H18O

Degree of unsaturation = (2 C + 2 – H - X + N)/2 ; where X and N represent number of halogen and nitrogen atoms respectively.

= (2 x 9 +2 -18)/2 = 1

Indicates the presence of a double bond.

Ir absorption peak at 1714 cm-1 indicates the presence of CO group.

The proton decoupled 13CNMR spectrum shows 9 signals indicationg 9 different environment of carbon atoms.

The ratio of carbon bonded hydrogens is 6:3:3:2:2:1:1

Doublet with integration 6 corresponds to (CH3)2 close to CH group.

Doublet with integration 3 corresponds to CH3 close to CH group.

Triplet with integration 3 corresponds to CH3 close to CH2 group.

Another triplet with integration 2 corresponds to CH2 close to CH2 group.

Predicted structure is (CH3)2-CH- CH(CH3)-CO-CH2-CH2-CH3

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