Ch. 15 - Analytical Techniques: IR, NMR, Mass SpectSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Concept #1: Building Molecular Sentences

Example #1: Building a molecular sentence

Practice: Propose a structure for the following compound that fits the following 1H NMR data: 

Formula: C3H8O2                                                  1H NMR: 3.36 δ (6H, singlet) 

                                                                                         4.57 δ (2H, singlet)

Practice: Propose a structure for the following compound that fits the following 1H NMR data: 

Formula: C2H4O2                                            1H NMR: 2.1 δ (singlet, 1.2 cm) 

                                                                                   11.5 δ (0.5 cm, D2O exchange)

Practice: Propose a structure for the following compound that fits the following 1H NMR data: 

Formula: C10H14                                      1H NMR: 1.2 ppm (6H, doublet) 

                                                                             2.3 ppm (3H, singlet) 

                                                                             2.9 ppm (1H, septet) 

                                                                             7.0 ppm (4H, doublet)

Practice: Propose a structure for the following compound, C7H12O2 with the given 13C NMR spectral data: 

Broadband decoupled 13C NMR: 19.1, 28.0, 70.5, 129.0, 129.8, 165.78 δ 

DEPT-90: 28.0, 129.8 δ 

DEPT-135: 19.1 δ (↑), 28.0 (↑) , 129.8 δ (↑) , 70.5 δ (↓)&129.0δ (↓)

Practice: Propose a structure for the following compound, C5H10O with the given 13C NMR spectral data: 

Fully Broadband decoupled 13C NMR and DEPT: 206.0 δ (↑); 55.0 δ (↑); 21.0 δ (↓)& 11.0 δ (↑).

Practice: Provide the structure of the unknown compound from the given information. 

Formula: C4H10O            IR: 3200-3600 cm-1           1H NMR: 0.9 ppm (6H, doublet) 

                                                                                               1.8 ppm (1H, nonatet) 

                                                                                               2.4 ppm (1H, singlet) 

                                                                                               3.3 ppm (2H, doublet)

Practice: Provide the structure of the unknown compound from the given information. 

Formula: C4H9N              IR: 2950 cm-1, 3400 cm-1           1H NMR: 1.0 ppm (4H, triplet) 

                                                                                                         2.1 ppm (4H, triplet) 

                                                                                                         3.2 ppm (1H, singlet)

Additional Problems
An unknown compound has the molecular formula of C6H11O2Cl. The NMR spectrum of the compound in chloroform is presented below. The IR spectrum shows a strong peak at 1735 cm -1. What is the structure of the molecule? Draw your final solution below.
Draw the structure of the compound that produces the 1H-NMR spectrum below. The molecular formula is in the upper left of the spectrum. Make sure to put your final answer in the box provided.
Provide a structure for the compound with molecular formula C10H12O2 and with the following spectroscopic data. IR: 1680 cm–1, 2750 cm–1, 2850 cm–1 1H NMR: 1.3δ (triplet, I = 3H), 3.6δ (quartet, I = 2H), 4.5δ (singlet, I = 2H), 7.3 (doublet, I = 2H), 7.7δ (doublet, I = 2H), 9.9δ (singlet, I = 1H)
A compound with the formula C7H14O has strong IR signals near 2900 and 1720 cm –1. The 1H NMR spectrum is tabulated below. Provide an unambiuous structural formula for the compound from the data provided. 1.07 ppm (6H doublet) 2.77 ppm (1H septet)
A compound with the formula C8H10O produces six signals in its 13C NMR spectrum. The 1H NMR spectrum is tabulated below. Provide an unambiguous structural formula for the compound from the data provided.  1.19 ppm (3H triplet) 2.58 ppm (2H quartet) 4.65 ppm (1H broad singlet) 6.70 ppm (2H doublet) 7.05 ppm (2H doublet)
Determine the likely structure for a compound A (C6H10O), which is found to decolorize bromine in carbon tetrachloride. Its spectral data is as follows:
What is the structure of the compound in the following 1H-NMR spectrum with the molecular formula C6H12 ? Relative integration is shown.
A compound with the molecular formula C7H14O2 is responsible for the fragrant smell of bananas. In either acidic or basic water, it decomposes to acetic acid and an alcohol. Given the NMR spectra below, draw the structure of this compound.
Identify the following carbonyls with molecular formula C4H8O from their  1H NMR.
Given an organic molecule with the molecular formula C9H9N and the following IR and 1H NMR spectra, determine the structure of the molecule. 
Draw the molecule with a molecular formula of C 5H8O2 described by the spectra below.
A compound with a molecular formula C4H4N2 has the following 1H-NMR spectrum. Show the structure that is consistent with the spectra in the labeled box. Show work for partial credit
Deduce the structure of an unknown compound with molecular formula C5H12O using information given by its infrared spectrum. Intensity (peak):  Frequency (cm–1): m                         3300 m                         2900 m                         2800 m                         1465 m                         1450 m                         1375
Predict the structure of the compound that gives rise to the following  1H NMR spectra.    A) Molecular Formula: C4H8O
A compound with molecular formula C12H24 exhibits a 1H NMR spectrum with only one signal and a 13C NMR spectrum with two signals. Deduce the structure of this compound.    
An unknown compound, F, has the formula C3H6O2. Determine the structure of  F by using its 1H NMR spectrum, shown below. Briefly explain your reasoning. 
Which of the following structures with molecular formula C8H9Br is consistent with the the data below: 1H NMR: 1.3δ (triplet, I=3H), 2.65δ (quartet, I=2H), 7.2δ (doublet, I=2H), 7.5δ (doublet, I=2H)?  
Compound X has molecular formula C3H8O and the only significant absorption in its IR spectrum is at 2950cm-1. What is the compound?
A compound with molecular formula C3Cl4 shows a strong absorption in its IR spectrum at 1977cm-1. What is this compound?
Provide a consistent structure for a compound with a molecular formula of C9H12, and IR absorption of 2950cm-1 and no double or triple bonds.
Structure Determination with Values. MF: C6H12O2                    IR: peak at 2950 cm  -1                         1H NMR                                                peak at 1750 cm-1                           - 1.0 (doublet, I = 6H)                                                                                                         - 1.1 (triplet, I = 3H)                                                                                                         - 2.6 (septet, I = 1H)                                                                                                         - 4.2 (quartet, I = 2H)
Structure Determination with Values. Hint: No rings or triple bonds  MF: C7H12O2                IR: peak at 2950 cm  -1                            1H NMR                                             peak at 1710 cm-1                       - 1.2 (quintet, I = 1)                                                                                                  - 2.1 (singlet, I = 3)                                                                                                  - 2.3 (triplet, I = 2)
Structure Determination with Values. MF: C10H22O                       IR: peak at 2950 cm  -1                         1H NMR                                                                                               - 4.0 (singlet, I = 1.0)                                                                                               - 1.0 (singlet, I = 4.5)
Structure Determination with Values MF: C7H14O2                     IR: peak at 2950 cm  -1                             1H NMR                                                                 peak at 2500-3000cm-1                   - 1.0 (doublet, I = 6)                                                                 peak at 1750 cm-1                           - 1.1 (singlet, I = 6)                                                                                                                         - 1.4 (septet, I = 1)                                                                                                                         - 11.0 ( ------ , I = 1)
Structure Determination with Values MF: C5H10O2              IR: peak at 2950 cm  -1                    1H NMR                                           peak at 1750 cm-1                  - 1.1 (doublet, I = 6)                                                                                           - 2.4 (septet, I = 1)                                                                                           - 3.5 (singlet, I = 3)
Structure Determination with Values MF: C4H6O2                   IR: peak at 2950 cm  -1                      1H NMR                                              peak at 2700 cm-1                     - 2.2 (doublet, I = 2)                                              peak at 1710 cm-1                     - 9.4 (triplet, I = 1)