a)
Interpretation:
The molecular formula and the structure of an unknown compound to be predicted using spectrum details.
Concept introduction:
Molecular formula:
It represents the types of atoms with their total number present in a given molecule.
Mass spectroscopy:
It is a form of spectroscopic technique which is used for the elucidation of the molecular formula and molecular weight of the compound, depending upon the mass of the molecule.
Molecular ion peak (M)+.:
It is defined as the heaviest peak in the IR spectrum of the molecule which represents the largest molecular ion in the given molecule with greater m/z value.
The (M+1)+. peak:
It denotes the peak that arises next to molecular ion peak in the mass spectrum. The peak arises due to the presence of the isotope of carbon (13C).
(M+1)+. peak in mass spectroscopy is used to explain the number of carbon atoms present in a molecule depending on the abundance of (M+1)+. peak.
1HNMR: The 1HNMR spectrum gives information on the different electronic environment of protons. The number of signal (proton types) generated in 1HNMR are predicted by performing symmetry operations (rotation or reflection symmetry).
The 13CNMR spectrum gives information on the different electronic environments of carbon. As like 1HNMR, the number of signals generated in 13CNMR are predicted by performing symmetry operations (rotation or reflection symmetry). Only chemical shift values are reported in the spectrum but not the multiplicity and integration values because the coupling between two neighboring 13C-13 C nuclei are weakly involved due to the low abundance of 13C isotopes of carbon atom.
To Identify:
The molecular formula to be identified.
b)
Interpretation:
The molecular formula and the structure of an unknown compound to be predicted using spectrum details.
Concept introduction:
Molecular formula:
It represents the types of atoms with their total number present in a given molecule.
Mass spectroscopy:
It is a form of spectroscopic technique which is used for the elucidation of the molecular formula and molecular weight of the compound, depending upon the mass of the molecule.
Molecular ion peak (M)+.:
It is defined as the heaviest peak in the IR spectrum of the molecule which represents the largest molecular ion in the given molecule with greater m/z value.
The (M+1)+. peak:
It denotes the peak that arises next to molecular ion peak in the mass spectrum. The peak arises due to the presence of the isotope of carbon (13C).
(M+1)+. peak in mass spectroscopy is used to explain the number of carbon atoms present in a molecule depending on the abundance of (M+1)+. peak.
1HNMR: The 1HNMR spectrum gives information on the different electronic environment of protons. The number of signal (proton types) generated in 1HNMR are predicted by performing symmetry operations (rotation or reflection symmetry).
The 13CNMR spectrum gives information on the different electronic environments of carbon. As like 1HNMR, the number of signals generated in 13CNMR are predicted by performing symmetry operations (rotation or reflection symmetry). Only chemical shift values are reported in the spectrum but not the multiplicity and integration values because the coupling between two neighboring 13C-13 C nuclei are weakly involved due to the low abundance of 13C isotopes of carbon atom.
To Identify:
The structure to be predicted for C5H10O.
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Chapter 13 Solutions
Organic Chemistry
- As reaction of (CH3)2CO with LIC≡CH followed by H2O affords compound D, which has a molecular ion in its mass spectrum at 84 and prominent absorptions in its IR spectrum at 3600−3200, 3303, 2938, and 2120 cm−1. D shows the following 1H NMR spectral data: 1.53 (singlet, 6 H), 2.37 (singlet, 1 H), and 2.43 (singlet, 1 H) ppm. What is the structure of D?arrow_forwardCompound I (C11H14O2) is insoluble in water, aqueous acid, and aqueous NaHCO3, but dissolves readily in 10% Na2CO3 and 10% NaOH. When these alkaline solutions are acidified with 10% HCl, compound I is recovered unchanged. Given this information and its 1H-NMR spectrum, deduce the structure of compound I.arrow_forwardNitriles, R–=C≡N, undergo a hydrolysis reaction when heated with aqueous acid. What is the structure of the compound produced by hydrolysis of propanenitrile, CH3CH2C≡N, if it has IR absorptions from 2500–3100 cm-1 and at 1710 cm-1, and has M+=74?arrow_forward
- Addition of m-xylene to the strongly acidic solvent HF/SbF5 at 45C gives a new species, which shows 1H-NMR resonances at 2.88 (3H), 3.00 (3H), 4.67 (2H), 7.93 (1H), 7.83 (1H), and 8.68 (1H). Assign a structure to the species giving this spectrum.arrow_forwardAcidcatalyzed dehydration of 3hydroxy3phenylcyclohexanone leads to an unsaturated ketone. What possible structures are there for the product? At what position in the ER spectrum would you expect each to absorb? If the actual product has an absorption at 1670 cm-1, what is its structure?arrow_forwardCompound A, MW 86, shows an IR absorption at 1730 cm-1 and a very simple 1H NMR spectrum with peaks at 9.7 (1 H, singlet) and 1.2 (9 H, singlet). Propose a structure for A.arrow_forward
Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning