dr. wolf's chm 201 & 202 13- 1 chapter 13 spectroscopy infrared spectroscopy...
Post on 18-Dec-2015
219 Views
Preview:
TRANSCRIPT
Dr. Wolf's CHM 201 & 202 13- 1
Chapter 13Chapter 13
SpectroscopySpectroscopy
Infrared spectroscopyInfrared spectroscopy
Ultraviolet-Visible spectroscopyUltraviolet-Visible spectroscopy
Nuclear magnetic resonance spectroscopyNuclear magnetic resonance spectroscopy
Mass SpectrometryMass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 2
13.113.1
Principles of Molecular Principles of Molecular
Spectroscopy:Spectroscopy:
Electromagnetic RadiationElectromagnetic Radiation
Dr. Wolf's CHM 201 & 202 13- 3
is propagated at the speed of lightis propagated at the speed of light
has properties of particles and waveshas properties of particles and waves
the energy of a photon is proportional the energy of a photon is proportional to its frequencyto its frequency
Electromagnetic RadiationElectromagnetic Radiation
Dr. Wolf's CHM 201 & 202 13- 4
Figure 13.1: The Electromagnetic SpectrumFigure 13.1: The Electromagnetic Spectrum
400 nm 750 nm
Visible Light
Longer Wavelength ()Shorter Wavelength ()
Higher Frequency () Lower Frequency ()
Higher Energy (E) Lower Energy (E)
Dr. Wolf's CHM 201 & 202 13- 5
Figure 13.1: The Electromagnetic SpectrumFigure 13.1: The Electromagnetic Spectrum
UltravioletUltraviolet InfraredInfrared
Longer Wavelength (Longer Wavelength ())Shorter Wavelength (Shorter Wavelength ())
Higher Frequency (Higher Frequency ()) Lower Frequency (Lower Frequency ())
Higher Energy (E)Higher Energy (E) Lower Energy (E)Lower Energy (E)
Dr. Wolf's CHM 201 & 202 13- 6
Cosmic rays
Rays
X-rays
Ultraviolet light
Visible light
Infrared radiation
Microwaves
Radio waves
Cosmic rays
Rays
X-rays
Ultraviolet light
Visible light
Infrared radiation
Microwaves
Radio waves
Figure 13.1: The Electromagnetic SpectrumFigure 13.1: The Electromagnetic Spectrum
Energy
Dr. Wolf's CHM 201 & 202 13- 7
13.213.2Principles of Molecular Spectroscopy: Principles of Molecular Spectroscopy:
Quantized Energy StatesQuantized Energy States
Dr. Wolf's CHM 201 & 202 13- 8
Electromagnetic radiation is absorbed when theElectromagnetic radiation is absorbed when the
energy of photon corresponds to difference in energy of photon corresponds to difference in
energy between two states.energy between two states.
E = hE = h
Dr. Wolf's CHM 201 & 202 13- 9
electronicelectronic
vibrationalvibrational
rotationalrotational
nuclear spinnuclear spin
UV-VisUV-Vis
infraredinfrared
microwavemicrowave
radiofrequencyradiofrequency
What Kind of States?What Kind of States?
Dr. Wolf's CHM 201 & 202 13- 10
13.20 - 13.2213.20 - 13.22
Infrared SpectroscopyInfrared Spectroscopy
Gives information about the functional groups Gives information about the functional groups in a moleculein a molecule
Dr. Wolf's CHM 201 & 202 13- 11
region of infrared that is most useful lies betweenregion of infrared that is most useful lies between2.5-16 2.5-16 m (4000-625 cmm (4000-625 cm-1-1))
depends on transitions between vibrational depends on transitions between vibrational energy statesenergy states
stretchingstretching
bendingbending
Infrared SpectroscopyInfrared Spectroscopy
Dr. Wolf's CHM 201 & 202 13- 12
Stretching Vibrations of a CHStretching Vibrations of a CH22 Group Group
SymmetricSymmetric AntisymmetricAntisymmetric
Dr. Wolf's CHM 201 & 202 13- 13
Bending Vibrations of a CHBending Vibrations of a CH22 Group Group
In planeIn plane In planeIn plane
Dr. Wolf's CHM 201 & 202 13- 14
Bending Vibrations of a CHBending Vibrations of a CH22 Group Group
Out of planeOut of plane Out of planeOut of plane
Dr. Wolf's CHM 201 & 202 13- 15Francis A. Carey, Organic Chemistry, Fifth Edition. Copyright © 2003 The McGraw-Hill Companies, Inc. All rights reserved.
2000200035003500 30003000 25002500 1000100015001500 500500
Wave number, cmWave number, cm-1-1
Figure 13.31: Infrared Spectrum of HexaneFigure 13.31: Infrared Spectrum of HexaneFigure 13.31: Infrared Spectrum of HexaneFigure 13.31: Infrared Spectrum of Hexane
CHCH33CHCH22CHCH22CHCH22CHCH22CHCH33
C—H stretching
bending bending
bending
Dr. Wolf's CHM 201 & 202 13- 16
2000200035003500 30003000 25002500 1000100015001500 500500
Wave number, cmWave number, cm-1-1
Figure 13.32: Infrared Spectrum of 1-HexeneFigure 13.32: Infrared Spectrum of 1-HexeneFigure 13.32: Infrared Spectrum of 1-HexeneFigure 13.32: Infrared Spectrum of 1-Hexene
HH22C=CHCHC=CHCH22CHCH22CHCH22CHCH33
H—CH—CC=C—HC=C—H
C=CC=C
HH22C=CC=C
Francis A. Carey, Organic Chemistry, Fifth Edition. Copyright © 2003 The McGraw-Hill Companies, Inc. All rights reserved.
Dr. Wolf's CHM 201 & 202 13- 17
Structural unitStructural unit Frequency, cmFrequency, cm-1-1
Stretching vibrations (single bonds)Stretching vibrations (single bonds)
spsp C—H C—H 3310-33203310-3320
spsp22 C—H C—H 3000-31003000-3100
spsp33 C—H C—H 2850-29502850-2950
spsp22 C—O C—O 12001200
spsp33 C—O C—O 1025-12001025-1200
Infrared Absorption FrequenciesInfrared Absorption Frequencies
Dr. Wolf's CHM 201 & 202 13- 18
Structural unitStructural unit Frequency, cmFrequency, cm-1-1
Stretching vibrations (multiple bonds)Stretching vibrations (multiple bonds)
Infrared Absorption FrequenciesInfrared Absorption Frequencies
CC CC 1620-16801620-1680
——CC NN
——CC C—C— 2100-22002100-2200
2240-22802240-2280
Dr. Wolf's CHM 201 & 202 13- 19
Structural unitStructural unit Frequency, cmFrequency, cm-1-1
Stretching vibrations (carbonyl groups)Stretching vibrations (carbonyl groups)
Aldehydes and ketonesAldehydes and ketones 1710-17501710-1750
Carboxylic acidsCarboxylic acids 1700-17251700-1725
Acid anhydridesAcid anhydrides 1800-1850 and 1740-17901800-1850 and 1740-1790
EstersEsters 1730-17501730-1750
AmidesAmides 1680-17001680-1700
Infrared Absorption FrequenciesInfrared Absorption Frequencies
CC OO
Dr. Wolf's CHM 201 & 202 13- 20
Structural unitStructural unit Frequency, cmFrequency, cm-1-1
Bending vibrations of alkenesBending vibrations of alkenes
Infrared Absorption FrequenciesInfrared Absorption Frequencies
CHCH22RCHRCH
CHCH22RR22CC
CHR'CHR'ciscis-RCH-RCH
CHR'CHR'transtrans-RCH-RCH
CHR'CHR'RR22CC
910-990910-990
890890
665-730665-730
960-980960-980
790-840790-840
Dr. Wolf's CHM 201 & 202 13- 21
Structural unitStructural unit Frequency, cmFrequency, cm-1-1
Bending vibrations of derivatives of benzeneBending vibrations of derivatives of benzene
MonosubstitutedMonosubstituted 730-770 and 690-710730-770 and 690-710
Ortho-disubstitutedOrtho-disubstituted 735-770735-770
Meta-disubstitutedMeta-disubstituted 750-810 and 680-730750-810 and 680-730
Para-disubstitutedPara-disubstituted 790-840790-840
Infrared Absorption FrequenciesInfrared Absorption Frequencies
Dr. Wolf's CHM 201 & 202 13- 22
2000200035003500 30003000 25002500 1000100015001500 500500
Wave number, cmWave number, cm-1-1
Figure 13.33: Infrared Spectrum of Figure 13.33: Infrared Spectrum of terttert-butylbenzene-butylbenzeneFigure 13.33: Infrared Spectrum of Figure 13.33: Infrared Spectrum of terttert-butylbenzene-butylbenzene
H—CH—C
Ar—HAr—H
MonsubstitutedMonsubstitutedbenzenebenzene
CC66HH55C(CHC(CH33))33
Francis A. Carey, Organic Chemistry, Fifth Edition. Copyright © 2003 The McGraw-Hill Companies, Inc. All rights reserved.
Dr. Wolf's CHM 201 & 202 13- 23
Structural unitStructural unit Frequency, Frequency, cmcm-1-1
Stretching vibrations (single bonds)Stretching vibrations (single bonds)
O—H (alcohols)O—H (alcohols) 3200-36003200-3600
O—H (carboxylic acids) O—H (carboxylic acids) 3000-31003000-3100
N—HN—H 3350-35003350-3500
Infrared Absorption FrequenciesInfrared Absorption Frequencies
Dr. Wolf's CHM 201 & 202 13- 24
2000200035003500 30003000 25002500 1000100015001500 500500
Wave number, cmWave number, cm-1-1
Figure 13.34: Infrared Spectrum of 2-HexanolFigure 13.34: Infrared Spectrum of 2-HexanolFigure 13.34: Infrared Spectrum of 2-HexanolFigure 13.34: Infrared Spectrum of 2-Hexanol
H—CH—C
O—HO—H
OHOH
CHCH33CHCH22CHCH22CHCH22CHCHCHCH33
Francis A. Carey, Organic Chemistry, Fifth Edition. Copyright © 2003 The McGraw-Hill Companies, Inc. All rights reserved.
Dr. Wolf's CHM 201 & 202 13- 25
2000200035003500 30003000 25002500 1000100015001500 500500
Wave number, cmWave number, cm-1-1
Figure 13.35: Infrared Spectrum of 2-HexanoneFigure 13.35: Infrared Spectrum of 2-HexanoneFigure 13.35: Infrared Spectrum of 2-HexanoneFigure 13.35: Infrared Spectrum of 2-Hexanone
H—CH—C
C=OC=O
OO
CHCH33CHCH22CHCH22CHCH22CCHCCH33
Francis A. Carey, Organic Chemistry, Fifth Edition. Copyright © 2003 The McGraw-Hill Companies, Inc. All rights reserved.
Dr. Wolf's CHM 201 & 202 13- 26
13.2313.23
Ultraviolet-Visible (UV-VIS) Ultraviolet-Visible (UV-VIS)
SpectroscopySpectroscopy
Gives information about conjugated Gives information about conjugated electron electron systemssystems
Dr. Wolf's CHM 201 & 202 13- 27
gaps between electron energy gaps between electron energy levels are greater than thoselevels are greater than thosebetween vibrational levelsbetween vibrational levels
gap corresponds to wavelengthsgap corresponds to wavelengthsbetween 200 and 800 nmbetween 200 and 800 nm
Transitions between electron energy statesTransitions between electron energy states
EE = = hh
Dr. Wolf's CHM 201 & 202 13- 28
X-axis is wavelength in nm (high energy at left, X-axis is wavelength in nm (high energy at left, low energy at right)low energy at right)
maxmax is the wavelength of maximum absorption is the wavelength of maximum absorption
and is related to electronic makeup of molecule— and is related to electronic makeup of molecule— especially especially electron system electron system
Y axis is a measure of absorption of electromagnetic Y axis is a measure of absorption of electromagnetic radiation expressed as molar absorptivity (radiation expressed as molar absorptivity ())
Conventions in UV-VISConventions in UV-VIS
Dr. Wolf's CHM 201 & 202 13- 29
200200 220220 240240 260260 280280
10001000
20002000
Wavelength, nmWavelength, nm
maxmax 230 nm 230 nm
maxmax 2630 2630
MolarMolar
absorptivity (absorptivity ())
UV Spectrum of cis,trans-1,3-cyclooctadieneUV Spectrum of cis,trans-1,3-cyclooctadiene
Dr. Wolf's CHM 201 & 202 13- 30
Most stable Most stable -electron -electron
configurationconfiguration
-Electron -Electron configuration of configuration of
excited stateexcited state
* Transition in cis,trans-1,3-cyclooctadiene* Transition in cis,trans-1,3-cyclooctadiene
HOMOHOMO
LUMOLUMO
EE = = hh
Dr. Wolf's CHM 201 & 202 13- 31
* Transition in Alkenes* Transition in Alkenes
HOMO-LUMO energy gap is affected by HOMO-LUMO energy gap is affected by substituents on double bondsubstituents on double bond
as HOMO-LUMO energy difference as HOMO-LUMO energy difference decreases (smaller decreases (smaller EE), ), maxmax shifts to longer shifts to longer
wavelengthswavelengths
Dr. Wolf's CHM 201 & 202 13- 32
Methyl groups on double bond cause Methyl groups on double bond cause maxmax
to shift to longer wavelengthsto shift to longer wavelengths
CC CC
HH
HH
HH
HH
CC CC
HH
HH CHCH33
maxmax 170 nm 170 nm
CHCH33
maxmax 188 nm 188 nm
Dr. Wolf's CHM 201 & 202 13- 33
Extending conjugation has a larger effect Extending conjugation has a larger effect on on maxmax; shift is again to longer ; shift is again to longer
wavelengthswavelengths
CC CC
HH
HH
HH
HH
CC CC
HH
HH
maxmax 170 nm 170 nmmaxmax 217 nm 217 nm
HH
CC CC
HH
HHHH
Dr. Wolf's CHM 201 & 202 13- 34
maxmax 217 nm 217 nm
(conjugated (conjugated dienediene))
HH
CC CC
HH
HH CC CC
HH
HHHH
CC CC
HH CHCH33
HH
HH
CC CC
HH33CC
HH CC CC
HH
HH
maxmax 263 nm 263 nm
conjugated conjugated trienetriene plus plus two methyl groupstwo methyl groups
Dr. Wolf's CHM 201 & 202 13- 35
LycopeneLycopene
maxmax 505 nm 505 nm
orange-red pigment in tomatoesorange-red pigment in tomatoes
Dr. Wolf's CHM 201 & 202 13- 36
13.2413.24
Mass SpectrometryMass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 37
Atom or molecule is hit by high-energy electronAtom or molecule is hit by high-energy electron
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
ee––
Dr. Wolf's CHM 201 & 202 13- 38
Atom or molecule is hit by high-energy electronAtom or molecule is hit by high-energy electron
electron is deflected but transfers much of its electron is deflected but transfers much of its energy to the moleculeenergy to the molecule
ee––
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 39
Atom or molecule is hit by high-energy electronAtom or molecule is hit by high-energy electron
electron is deflected but transfers much of its electron is deflected but transfers much of its energy to the moleculeenergy to the molecule
ee––
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 40
This energy-rich species ejects an electron.This energy-rich species ejects an electron.
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 41
This energy-rich species ejects an electron.This energy-rich species ejects an electron.
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
forming a positively charged, odd-electron species forming a positively charged, odd-electron species called the called the molecular ionmolecular ion
ee––++••
Dr. Wolf's CHM 201 & 202 13- 42
Molecular ion passes between poles of a Molecular ion passes between poles of a magnet and is deflected by magnetic fieldmagnet and is deflected by magnetic field
amount of amount of deflection depends deflection depends on mass-to-charge on mass-to-charge ratioratio
highest m/z highest m/z deflected leastdeflected least
lowest m/z lowest m/z deflected mostdeflected most
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
++••
Dr. Wolf's CHM 201 & 202 13- 43
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
If the only ion that is present is the molecular ion, If the only ion that is present is the molecular ion, mass spectrometry provides a way to measure the mass spectrometry provides a way to measure the molecular weight of a compound and is often used for molecular weight of a compound and is often used for this purpose.this purpose.
However, the molecular ion often fragments to a However, the molecular ion often fragments to a mixture of species of lower m/z.mixture of species of lower m/z.
Dr. Wolf's CHM 201 & 202 13- 44
The molecular ion dissociates to a cationThe molecular ion dissociates to a cationand a radical.and a radical.
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
++••
Dr. Wolf's CHM 201 & 202 13- 45
The molecular ion dissociates to a cationThe molecular ion dissociates to a cationand a radical.and a radical.
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
++ ••
Usually several fragmentation pathways are available Usually several fragmentation pathways are available and a mixture of ions is produced.and a mixture of ions is produced.
Dr. Wolf's CHM 201 & 202 13- 46
mixture of ions of mixture of ions of different mass different mass gives separate peak gives separate peak for each m/zfor each m/z
intensity of peak intensity of peak proportional to proportional to percentage of each percentage of each ion of different ion of different mass in mixturemass in mixture
separation of peaks separation of peaks depends on relative depends on relative massmass
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
++
++++
++
+
+
Dr. Wolf's CHM 201 & 202 13- 47
mixture of ions of mixture of ions of different mass different mass gives separate peak gives separate peak for each m/zfor each m/z
intensity of peak intensity of peak proportional to proportional to percentage of each percentage of each atom of different atom of different mass in mixturemass in mixture
separation of peaks separation of peaks depends on relative depends on relative massmass
++ ++ ++ ++
+ +
Principles of Electron-Impact Mass SpectrometryPrinciples of Electron-Impact Mass Spectrometry
Dr. Wolf's CHM 201 & 202 13- 48
2020 4040 6060 8080 100100 120 120
m/zm/z
m/z m/z = 78= 78
100100
8080
6060
4040
2020
00
Relative Relative intensityintensity
Some molecules undergo very little Some molecules undergo very little fragmentationfragmentation
Benzene is an example. The major peak Benzene is an example. The major peak corresponds to the molecular ion.corresponds to the molecular ion.
Dr. Wolf's CHM 201 & 202 13- 49
HH
HH HH
HHHH
HH
HH
HH HH
HHHH
HH
HH
HH HH
HHHH
HH
all H are all H are 11H and all H and all C are C are 1212CC
one C is one C is 1313CC one H is one H is 22HH
Isotopic ClustersIsotopic Clusters
7878 7979 7979
93.4%93.4% 6.5%6.5% 0.1%0.1%
Dr. Wolf's CHM 201 & 202 13- 50
2020 4040 6060 8080 100100 120 120
m/zm/z
100100
8080
6060
4040
2020
00
Relative Relative intensityintensity
112112
114114
Isotopic ClustersIsotopic Clustersin Chlorobenzenein Chlorobenzene
visible in peaks for visible in peaks for molecular ionmolecular ion
3535ClCl 3737ClCl
Dr. Wolf's CHM 201 & 202 13- 51
2020 4040 6060 8080 100100 120 120
m/zm/z
Relative Relative intensityintensity
7777
Isotopic ClustersIsotopic Clustersin Chlorobenzenein Chlorobenzene
no no mm//zz 77, 79 pair; 77, 79 pair; therefore ion therefore ion responsible forresponsible formm//zz 77 peak does 77 peak does not contain Clnot contain Cl
HH
HH
HH
HH
HH ++
100100
8080
6060
4040
2020
00
Dr. Wolf's CHM 201 & 202 13- 52
Alkanes undergo extensive fragmentationAlkanes undergo extensive fragmentation
m/zm/z
DecaneDecane
142142
4343
5757
7171
8585
9999
CHCH33—CH—CH22—CH—CH22—CH—CH22—CH—CH22—CH—CH22—CH—CH22—CH—CH22—CH—CH22—CH—CH33
Relative Relative intensityintensity
100100
8080
6060
4040
2020
00
2020 4040 6060 8080 100100 120 120
Dr. Wolf's CHM 201 & 202 13- 53
Propylbenzene fragments mostlyPropylbenzene fragments mostlyat the benzylic positionat the benzylic position
2020 4040 6060 8080 100100 120 120
m/zm/z
Relative Relative intensityintensity
120120
9191 CHCH22—CH—CH22CHCH33
100100
8080
6060
4040
2020
00
Dr. Wolf's CHM 201 & 202 13- 54
13.2513.25
Molecular FormulaMolecular Formula
as aas a
Clue to StructureClue to Structure
Dr. Wolf's CHM 201 & 202 13- 55
Molecular WeightsMolecular Weights
One of the first pieces of information we try to One of the first pieces of information we try to obtain when determining a molecular obtain when determining a molecular structure is the molecular formula.structure is the molecular formula.
However, we can gain some information even However, we can gain some information even from the molecular weight. Mass from the molecular weight. Mass spectrometry makes it relatively easy to spectrometry makes it relatively easy to determine molecular weights.determine molecular weights.
Dr. Wolf's CHM 201 & 202 13- 56
The Nitrogen RuleThe Nitrogen Rule
A molecule with an A molecule with an odd number of odd number of nitrogens has an odd nitrogens has an odd molecular weight.molecular weight.
A molecule that A molecule that contains only C, H, contains only C, H, and O or which has and O or which has an even number of an even number of nitrogens has an nitrogens has an even molecular even molecular weight.weight.
NNHH22 9393
138138
NNHH22OO22NN
183183
NNHH22OO22NN
NNOO22
Dr. Wolf's CHM 201 & 202 13- 57
Exact Molecular WeightsExact Molecular Weights
CHCH33(CH(CH22))55CHCH33
HeptaneHeptane
CHCH33COCO
OO Cyclopropyl acetateCyclopropyl acetate
Molecular formulaMolecular formula
Molecular weightMolecular weight
CC77HH1616 CC55HH88OO22
100100 100100
Exact massExact mass 100.1253100.1253 100.0524100.0524
Mass spectrometry can measure exact Mass spectrometry can measure exact masses. Therefore, mass spectrometry can masses. Therefore, mass spectrometry can give molecular formulas.give molecular formulas.
Dr. Wolf's CHM 201 & 202 13- 58
Molecular FormulasMolecular Formulas
Knowing that the molecular formula of a Knowing that the molecular formula of a substance is Csubstance is C77HH1616 tells us immediately that is tells us immediately that is
an alkane because it corresponds to Can alkane because it corresponds to CnnHH22nn+2+2
CC77HH1414 lacks two hydrogens of an alkane, lacks two hydrogens of an alkane,
therefore contains either a ring or a double therefore contains either a ring or a double bond bond
Dr. Wolf's CHM 201 & 202 13- 59
Index of Hydrogen DeficiencyIndex of Hydrogen Deficiency
relates molecular formulas to multiple bonds relates molecular formulas to multiple bonds and ringsand rings
index of hydrogen deficiency = index of hydrogen deficiency =
1122
(molecular formula of alkane –(molecular formula of alkane – molecular formula of compound) molecular formula of compound)
Dr. Wolf's CHM 201 & 202 13- 60
Example 1Example 1
index of hydrogen deficiency index of hydrogen deficiency
C7H14C7H14
1122
(molecular formula of alkane –(molecular formula of alkane – molecular formula of compound) molecular formula of compound)
==
1122
(C(C77HH1616 – C – C77HH1414))==
1122
(2) = 1(2) = 1==
Therefore, one ring or one double bond.Therefore, one ring or one double bond.
Dr. Wolf's CHM 201 & 202 13- 61
Example 2Example 2
C7H12C7H12
1122
(C(C77HH1616 – C – C77HH1212))==
1122
(4) = 2(4) = 2==
Therefore, two rings, one triple bond,Therefore, two rings, one triple bond,two double bonds, or one double bond + one ring.two double bonds, or one double bond + one ring.
Dr. Wolf's CHM 201 & 202 13- 62
Oxygen has no effectOxygen has no effect
CHCH33(CH(CH22))55CHCH22OH (1-heptanol, COH (1-heptanol, C77HH1616O) has O) has
same number of H atoms as heptanesame number of H atoms as heptane
index of hydrogen deficiency = index of hydrogen deficiency =
1122
(C(C77HH1616 – C – C77HH1616O)O) = 0= 0
no rings or double bondsno rings or double bonds
Dr. Wolf's CHM 201 & 202 13- 63
Oxygen has no effectOxygen has no effect
index of hydrogen deficiency = index of hydrogen deficiency =
1122
(C(C55HH1212 – C – C55HH88OO22)) = 2= 2
one ring plus one double bondone ring plus one double bond
CHCH33COCO
OO Cyclopropyl acetateCyclopropyl acetate
Dr. Wolf's CHM 201 & 202 13- 64
If halogen is presentIf halogen is present
Treat a halogen as if it were hydrogen.Treat a halogen as if it were hydrogen.
CC CC
CHCH33
ClClHH
HH
CC33HH55ClCl
same index of hydrogensame index of hydrogendeficiency as for Cdeficiency as for C33HH66
Dr. Wolf's CHM 201 & 202 13- 65
Rings versus Multiple BondsRings versus Multiple Bonds
Index of hydrogen deficiency tells us the sum ofIndex of hydrogen deficiency tells us the sum ofrings plus multiple bonds.rings plus multiple bonds.
Catalytic hydrogenation tells us how many Catalytic hydrogenation tells us how many multiple bonds there are.multiple bonds there are.
top related