Spectroscopy CHP 12 - 13 Flashcards
What are the spin state and quantum number of 13Carbon?
quantum number (I): 1/2 spin state: 2 (+1/2 and -1/2)
What are the spin state and quantum number of 1Hydrogen?
quantum number (I): 1/2 spin state: 2 (+1/2 and -1/2)
What are the spin state and quantum number of 2Hydrogen?
quantum number (I): 1 spin state: 3
In a magnetic field, different spin states have different energies. The difference in energy between the spin states is dependent on the magnitude of the applied magnetic field. How is the spin aligned in the higher (excited) energy state?
The spin is -1/2 aligned against the applied field in the excited state
In a magnetic field, different spin states have different energies. The difference in energy between the spin states is dependent on the magnitude of the applied magnetic field. How is the spin aligned in the lower (ground) energy state?
The spin is +1/2 aligned with the applied field in the ground state
Name this Spectra
Alkane
Name this Spectra
Alkene
Name this Spectra
Alkyne
Name this Spectra
Ketone; part of the Carbonyl family
Name this Spectra
Ester; part of the Carbonyl family
Name this Spectra
Carboxylic Acid
On a spectrum, where are Aldehydes, ketones, esters, acids, and amides found?
Zone 4. Check for signals near 1700 cm-1
On a spectrum, where are OH, NH, and NH2 found?
Zone 1. Check for signals near 3400 cm-1
On a spectrum, where are alkanes, alkenes, and alkynes found?
Zone 2. Check for signals near 3000 cm-1.
Sp2 to the left and Sp3 to the right
On a spectrum, where are Alkynes and cyano groups found?
Zone 3. Check for signals near 2200 cm-1.
On a spectrum, where are alkenes found?
Zone 5. Check for signals near 1600 cm-1
How many zones is the IR spectrum divided into?
Five zones
Identify functional groups present in molecule using IR spectrum.
Coupled with other information (not given here) to get the actual structure,
The unknown compound is the ester Butyl Acetate.
An unknown has the molecular formula C10H15N.
Is the amine primary (R-NH2), secondary (R2N-H), or tertiary (R3N)?
tertiary (R3N) has 0 peaks
An unknown has the molecular formula C8H11N.
Is the amine primary (R-NH2), secondary (R2N-H), or tertiary (R3N)?
primary (R-NH2) has 2 peaks
An unknown has the molecular formula C8H11N.
Is the amine primary (R-NH2), secondary (R2N-H), or tertiary (R3N)?
secondary (R2N-H) has 1 peak
An unknown has the molecular formula C4H8O. Therefore DBE = 1.
Is it an alcohol, ketone, or ether? Is there an alkene or is it cyclic?
- No signals above 3100 cm-1. Therefore Not An Alcohol.
- No signals around 1720 cm-1. Therefore Not A Ketone.
- Strong signals around 1280 and 1100 cm-1. Therefore An Ether with Two Different C-O Bonds.
- Medium signal around 1650 cm-1. Therefore An Alkene.
An unknown has the molecular formula C7H6O3. Is it alcohol, ketone, or carboxylic acid? Is it cyclic?
- Medium signal around 3240 cm-1. Therefore free alcohol.
- Very broad signal around 3013 cm-1. Therefore carboxylic acid.
- Strong signal around 1662 cm-1. Confirms carboxylic acid.
- Medium signals around 1613 and 1484 cm-1. Therefore alkene (specifically benzene ring).
What are the steps in solving proton NMR spectroscopy?
- Find the MF
- Calculate the DBE (UN #)
- Make sure that all protons are accounted for in the H-NMR
- Read all signals on H-NMR
- Find “end pieces”, repeating units and work your way inward to solve for structure
In H-NMR, what is the structure of a doublet that integrates for 6?
isopropyl
In H-NMR, what group shows up at 5 ppm?
Alkene
In H-NMR, what group shows up at 3.5-5 ppm?
Electronegative atom (look at MF)
In H-NMR, what group shows up at 2.50 ppm?
carbonyl
What characteristics are possible with a DBE of 1?
Alkene, ring, or carbonyl
In H-NMR, what group shows up at 7 ppm?
Aromatic protons
The more electronegative the higher the
ppm and the more downfield, deshielding
What functional group corresponds to this spectra?
Amide
What functional group corresponds to this spectra?
Carbonyl?
What functional group corresponds to this spectra?
What functional group corresponds to this spectra?
Alcohol
What functional group corresponds to this spectra?
Alcohol
What functional group corresponds to this spectra?
Alkane?
In mass spec, when substituting oxygen what must be removed?
CH4 or molar mass equivalent
In mass spec, when substituting nitrogen what must be removed?
CH2 or molar mass equivalent
In mass spec, when substituting sulfur what must be removed?
C2H8 or molar mass equivalent
In mass spec, when substituting fluorine what must be removed?
CH7 or molar mass equivalent
In mass spec, when substituting chlorine what must be removed?
C2H11 or molar mass equivalent
In mass spec, when substituting bromine what must be removed?
C6H7 or molar mass equivalent
Are pairs or groups of atoms diastereotopic, enantiotropic, or homotopic when the indicated atoms are next to a chiral center?
diastereotopic
Are pairs or groups of atoms diastereotopic, enantiotropic, or homotopic when the compound is symmetrical and there is stereochemistry involved?
enantiotropic
Are pairs or groups of atoms diastereotopic, enantiotropic, or homotopic when the indicated atoms are 2 H’s with CH3?
homotopic
In mass spec, (M) represents
Nitrogens
In mass spec, (M+1) represents
Carbons
In mass spec, (M+2) represents
halides Br 1:1 ratio and Cl 1:3 ratio
Ratio of % M+2:M
What is the frequency of geminal protons?
1 Hz
What is the frequency of trans protons?
15 Hz
What is the frequency of cis protons?
10 Hz
