IR Spectroscopy (Lab E Continued) Flashcards
What is the functional group region?
4000-1400 cm^-1
What is the fingerprint region?
1400-600 cm^-1
Is lower energy associated with higher or lower wavenumber?
lower
IR spectroscopy is primarily used to detect
functional groups present
IR absorptions arise due to
stretching and bending of covalent bonds in molecules
What does 100% transmittance mean? What does 0% transmittance mean?
100% transmittance: all light shone is transmitted, none absorbed
0% transmittance: none of the light shone is transmitted, all is absorbed
The functional group(diagnostic region) determines _____________(1). The fingerprint region is used for _______________(2).
(1) the functional group present
(2) structure elucidation by special comparison
Wvaenumber is ______(1) proportional to frequency. Wavenumber is ________(2) proportional to wavelength
directly
inversely
Make a table of the four regions of the IR spectrum. Outline the fingerprint region, the region with stronger bonds and higher frequency, adn the region with lighter atoms and higher frequency
Refer to notes
what are the two peaks that indicate an anhydride C=O group?
An anhydride C=O at 1840 and 1760 cm^-1
What is the IR absorptions for amines?
N-H: broad at ~3300
1 degree = singlet, 2 degree = doublet, 3 degree = none
C-N: 1000-1250
What is the IR absorptions for ketones
C=O stretching ~1715 cm^-1
What is the IR absorptions for aldehydes?
C=O stretching ~1725 cm^-1
What is the IR absorptions for carboxylic acid?
C=O stretching ~1700 cm^-1
O-H stretching ~3000-2500 cm^-1 and broad
What is the IR absorptions for esters?
C=O stretching ~1735 cm^-1
What is the IR absorptions for amides? Draw an amide
C=O stretching 1690 cm^-1
What is the IR absorptions for acid chloride?
C=O stretching ~1800cm^-1
