Concept explainers
Interpretation:
The structure of compound of given molecular formula C7H12O2 to be predicted using 13CNMR spectra.
Concept introduction:
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 of given molecular formula C7H12O2.
Broadband-decoupled 13CNMR spectrum:
The spectra provide information regarding the total number of carbon environments.
DEPT (Distortionless enhancement by polarization transfer):
a) DEPT-90: The spectrum exhibits signal only from CH group and no signals from CH3, CH2, CH and quaternary carbon (carbon with no protons).
b) DEPT-135: The spectrum exhibits CH3 groups and CH groups as positive signals (pointing up); CH2 groups appear as negative signals (pointing down) and quaternary carbon does not appear.
The signals appear in each type of spectrum:
Want to see the full answer?
Check out a sample textbook solutionChapter 13 Solutions
ORGANIC CHEMISTRY-EBOOK>I<
- Following are two constitutional isomers with the molecular formula C4H8O2. (a) Predict the number of signals in the 1H-NMR spectrum of each isomer. (b) Predict the ratio of areas of the signals in each spectrum. (c) Show how you can distinguish between these isomers on the basis of chemical shift.arrow_forwardThe following 1H NMR peaks were recorded on a spectrometer operating at 200 MHz. Convert each into δ units. (a) CHCl3; 1454 Hz (b) CH3Cl; 610 Hz (c) CH3OH; 693 Hz (d) CH2Cl2; 1060 Hzarrow_forwardAssign each peak on the following spectrum.arrow_forward
- Following is the mass spectrum of an unknown compound. The two highest peaks are at m/z 120 and 122. Suggest a structure for this compound. (Data from http://webbook.nist.gov/chemistry/.)arrow_forwardWhat fragments might you expect in the mass spectra of the following compounds?arrow_forwardHow many ‘H-MNR signals are there?arrow_forward
- A mass spectrum of an unknown compound shows an [M]+ peak with an [M+2]* peak of similar height. Which statement BEST describes the reason for this observation: Bromine atom Two Chorine Atoms Three Chlorine Atoms lodine atom Chlorine atomarrow_forwardConstruct a simulated proton-decoupled 13C NMR spectrum for tert-butylamine. Drag the resonance signal to the appropriate chemical shift positions. Then label the box above each signal with the expected splitting if there were no proton decoupling. CH3 NH₂ H3C t S q ³1³ 140 200 120 220 100 80 60 40 20 0 CH3 180 160arrow_forwardIdentify the following spectra. Please find peaks are assigned on the spectrum (~5-6 peaks). Label the peaks on the spectrum and place the structure of the compound in the box on the lower left-hand corner of the spectrum (from the table below, no numbering scheme). You do not have to indicate the exact wavenumber of the peak.arrow_forward
- identify the number of signals (i.e. types of hydrogen) for each structure below. predict the approximate chemical shift, integration (i.e. number of that type of hydrogen), and splitting for each signal in each structure. bi i Brarrow_forwardPredicting the Relative Chemical Shift of Protons Rank Ha, Hb, and Hc in order of increasing chemical shift.arrow_forwardIdentify all the peaks in the H-NMR and C-NMR spectrum. Record the chemical shift, the splitting, and the number of hydrogens for each peak in the NMR table. Please fill in the data similar to the example table down below.arrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage LearningOrganic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning