Question

Question: The infrared spectrum of the compound with the mass spectrum shown below has strong absorbances at 1584, 1478, and $\mathbf{1446}\mathbf{}{\mathbf{cm}}^{\mathbf{-}\mathbf{1}}$. Propose astructure consistent with the data.

Short answer

Each compound fragments in a particular way based on the structure and two compounds do not possess identical mass spectra.The structural information regarding the molecule can be obtained by interpreting the fragmentation pattern.

Step-by-step solution

Mass spectrum

Each compound fragments in a particular way based on the structure and two compounds do not possess identical mass spectra.The structural information regarding the molecule can be obtained by interpreting the fragmentation pattern.

Infrared spectrum

The IR spectrum region from$1500$ to $400{\mathrm{cm}}^{-1}$is termed the fingerprint region. Two samples comprising identical IR spectra are identical compounds. All functional groups possess an IR absorption value that does not vary from one particular compound to another.

Proposing the structure from the data in infrared and mass spectrum

The m/z value of the compound is ${\mathrm{M}}^{+}=144$ , 112 and 77. The IR spectrum shows that the compound has an IR absorption value at 1584, 1478 and$1446{\mathrm{cm}}^{-1}$ .

The molecular weight of the given compound is which indicates that a chlorine atom is present in the molecule. Another peak is at which indicate a phenyl group.

IR absorption values at 1584, 1478 and$1446{\mathrm{cm}}^{-1}$ indicates the carbon carbon double bond in the phenyl ring.

The molecular weight of the compound matches with the expected compound. Therefore the structure of the compound is: