Transcript INFRARED THEORY

BCPE03
Author
Name: Anil kumar Appapurapu
College: Bapatla college of pharmacy,
Bapatla.
Year: M. Pharmacy, 2nd year.
Profile link:
http://www.pharmainfo.net/anil-kumarappapurapu
Co-author
Name: Dr. T.E.G.K. Murthy,
M Pharm, Ph.D.
College:Bapatla College of Pharmacy
Profile link:
http://www.pharmainfo.net/tegkmurthy
1
Importance of analysis of drugs
Drug1
sources1
Natural ---animal
---- plants
----marine
Synthetic ----organic
----in-organic
Drug –receptor interaction1
Molecular basis2
Signal transduction1
Chemical / functional
Group interaction2
Analysis basis
Therapeutic effects1
The challenging scenario in the aspects of efficacy, safety, purity, and quality
determination of the drug samples became optimistic.
1.B Sue Brizuela,Ms, Judith A Hesp, MS, “Drug Information” Remington: The science and practice of pharmacy,19th edition,volume.1, Mack
publishing company Easton, Pennsylvania18042, 1995. print.
2. B.K. SHARMA," fundamental principles of spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
2
Classification of analytical techniques3
Ana lysis
Structure.
breakdown
3
ANALYSIS
1.Separation techniques
2.Spectrophotometric
chromatography
3. Electro analytical
4. Titrimetric analysis
Potential & conductometry
Titrations
1.uv-visible
2.Infra red
3.Mass
4.Neclear magnetic resonance
3. Douglas A.Skoog, F.James Holler, Timothy A.Nieman, ,”introduction to instrumental methods of analysis", principles of instrumental analysis,
5th edition, saunders Golden sunburst series. Forth worth, Philadelohia, Chicago, Sydney, Toronto. Reprint. 2005. Print.
3
Principle of spectroscopy[2,4,5]
Spectroscopy[2,4,5]
study of interaction of
electromagnetic radiation with
matter
EMR
ANALYTE
SPECTROPHOTOGRAPH
Conc. should be lower
1.UV-Visible radiations---excitation of electrons----uv-visiblespectrum
2.IR-radiations—vibration changes in electrons---IR spectrum
3.Microwave radiations---spin resonance----E.S.R spectrum
4.Radio frequency---spin rotational changes---N.M.R spectrum
2. B.K. SHARMA," fundamental principles of spectroscopy” ,spectroscopy ,20th edition, page noS-11, Goel publications, Delhi, 2007. print.
4.
www.answers.com. Web. 25 feb 2010. http://www.answers.com/topic/spectroscopy
5. www. en.wikipedia.org. Web. 25 feb 2010 < http://en.wikipedia.org/wiki/Infrared_spectroscopy>.
4
THE ELECTROMAGNETIC SPECTRUM [2,5]
nm
Characteristics of radiations
Absorbing radiations
Gamma rays
X rays
UV
EMR
Visible
Drug
substance
Λ
Energy
Kcal/mol
9.4 x
107
9.4 x103
9.4
x101
9.4 x 10-1
Frequency
0A
(Hz)
of
spectroscopy
1
1021
15 0
1017
Both E & Abs
1015
Absorption
1013
Absorption
3800
7600
Emission
Infra-Red
9.4 x 10-3
6 x 106
1011
Absorption
Micro waves
9.4 x 10-5
3 x 109
1009
Absorption
1007
NMR Abs
Radio waves 9.4 x
10-7
3x
370
Violet
430
indigo
450
Blue
490
Green
550
Yellow
590
Orange
650
Red
Type
1013
nm
Resulting spectrum
2. B.K. SHARMA," fundamental principles of spectroscopy” Spectroscopy 20th edition, page no.S-11- S-20, goel publications, Delhi, 2007.print.
5
5. www. en.wikipedia.org. Web. 25 feb 2010 < http://en.wikipedia.org/wiki/Infraredspectroscopy>.
Multidisciplinary of IR spectroscopy[2,3,6]
pharmacy
Applications[2,3,6]
uses
Genetic engineering
Engineering6
Physics3
Theory
origin of spectra
BIO-technology
IR -SPECTROSCOPY
2
Instrumentation
working
Chemistry2
Principle
observed changes
2. B.K. SHARMA," Infrared spectroscopy” Spectroscopy 20th edition, page no.S-220, goel publications, Delhi, 2007.print.
3. Douglas A.Skoog, F.James Holler, Timothy A.Nieman, ,”Infrared spectroscopy", principles of instrumental analysis, 5th edition, saunders Golden sunburst series. Forth worth, Philadelohia,
Chicago, Sydney, Toronto. Page no. 406. Print.
6
6. Hobart H. Willard, Lynne L. Merritt. Jr., John A. Dean, Frank A. Settle, Jr. “Infrared spectroscopy”, instrumental methods of analysis,7thedition page288,289,292,293, content no. 11.1 . CBS
publications, Toronto. 2005. print.
IR-REGION: 12,800 - 10 cm-1
REGION
WAVE
LENGTH
λ (μm)
WAVE NUMBER
υ (cm-1)
[3,6]
FREQUENCY
RANGE
Hz
NEAR
0.78 - 2.5
12800 - 4000
3.8x1014-1.2x1014
MIDDLE
2.5 - 50
4000 - 200
1.2x1014 - 6x112
FAR
50 - 1000
200 -10
6x1012- 30x1011
MOST USED
2.5 - 15
4000 - 670
1.2x1014-2x1013
1.Near IR----carbohydrates and proteins
2.Middle IR-----organic molecules—functional groups
3.Far IR—in-organic –co-ordination bonds& quaternary ammonium compounds
3. Douglas A.Skoog, F.James Holler, Timothy A.Nieman, ,”Infrared spectroscopy”, introduction to instrumental methods of analysis", principles of instrumental analysis, 5 th edition, saunders
Golden sunburst series. Forth worth, Philadelohia, Chicago, Sydney, Toronto. Page no. 406. Print.
7 .
6. Hobart H. Willard, Lynne L. Merritt. Jr., John A. Dean, Frank A. Settle, Jr. “Infrared spectroscopy”, instrumental methods of analysis,7thedition page288,289,292,293, content no. 11.1
CBS publications, Toronto. 2005. print.
INSTRUMENTAL AND APPLICATIONS OF VARIOUS IR REGIONS[7,8]
Detectors Source of Optical Type of
radiation system samples
Type of
analysis
measurement
NEAR
Photo
conductance
Tungsten
filament lamp
Prism
grating
Solid / liquid
Qualitative
Quantitative
Diffusive reflectance
Absorption
MIDDLE
Thermal type
Nernst
glowers/
Nichrome wire
Diffraction
grating
Liquid / gas
FAR
Golay,
pyroelectric
High pressure
mercury lamp
Double
beam
grating
Qualitative
Quantitative
Chromatographic
Diffusive reflectance
Absorption
Adsorption
Quantitative
emission
MOST
USED
Thermal type
Nernst
glowers/
Nichrome wire
Diffraction
grating
Qualitative
Quantitative
Chromatographic
Diffusive reflectance
Absorption
Adsorption
REGION
Gas
Liquid / gas
7. www. orgchem.colorado.edu. web,.25.2010. < http://orgchem.colorado.edu/hndbksupport/irtutor/tutorial.html >
8.Donald L.Pavia, Gary M.Lampman, George S. Kriz.”infrared spectroscopy "introduction to spectroscopy,3rd edition, CBSPublications Thomas books 8Australia,
U.S.print ,Canada, Mexico, 2007. print..
ORIGIN OF IR SPECTRUM
[2,3]
Due to 4 changes in energies of the molecules
1.
Electronic transitions -----E t
2.
Electronic rotations -------E r
3.
Electronic vibrations-------E v
4.
Electronic energy-----------E e
total energy of the molecule= E e + E v + E r + E t
energies required in the order ----- E e > E v> E r > E t
Various types IR –spectra
1. Rotational spectra
2. Vibrational- rotational spectra
3. Electronic band spectra
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
3. Douglas A.Skoog, F.James Holler, Timothy A.Nieman,”Infrared spectroscopy”, introduction to instrumental methods of analysis", principles of
instrumental analysis, 5th edition, saunders Golden sunburst series. Forth worth, Philadelohia, Chicago, Sydney, Toronto. Page no. 406. Print
.
9
Differences between various types of IR
Character
Electronic band
spectra a
1. IR region
Near IR
2.Energy required
Higher
3.Dipole moment
less induced
spectra2,(a,b,c)
Vibration- rotational Rotational spectra c
spectra b
Middle IR
less
Far IR
very less
Definite dipole
Intense dipole
4.Sample state
Solids
Liquids / gases
Only gases
5.Thoery supporting
Frank codon
principle
Harmonic oscillator
principle
Rigid rotor principle
6.Changes observed
Excitation,
vibration
Vibration , rotation
Only rotation
double bonds
Triple bonds
7.Highly feasible for
single bonds
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
a.S-234 to s-249 b. s-220 to s- 234
c. s-201 to s-220.
10
INFRARED THEORY
[9,10]
Matching of Frequency
Dipole moment
1. Selection rules9
Vibrational Quantum Number
Translational motion
2. Types of vibrations9
Rotational motion
3. Number of possible vibrational modes10
Vibrational motion
A. Phase and solvents used
4. Vibrational frequency[9,10]
B. Coupled interactions
5. Factors influencing vibrational
modes[9,10]
C. Hydrogen bonding
D. Fermi resonance
E. Electronic effects
9. Robert M.Silverstien Francis X.Webster ,”infrared spectroscopy”, spectroscopic identification of organic compounds, 6thedition, John Wiley, Chichester,
Singapore, Toronto, Brisbane page no. 3.5, 2005. Print.
11
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
Types of vibrations [5,11]
For stretching vibration = N -1
For bending vibration
[(3N - 6)-(N -1)]=2N -5 for non-linear
[(3N - 5)-(N -1)] =2N – 4 for linear ‘N’ is the
number of atoms in the bond.
Stretching vibrations
Bending vibrations
In-plane
Asymmetric (nu) Symmetric (nu)
2925
2850
Out -plane
In-plane
Scissoring (s) Twisting (tau) Wagging (ω) Rocking (ρ )
1465
1350
1150
Vibrational energy depends on :1. masses of the atoms
2. strength of bonds
3. arrangement of atoms within the molecule
720 cm-1
5. www. en.wikipedia.org. web.25 feb 2010. < http://en.wikipedia.org/wiki/Infrared_spectroscopy>.
11. Dudles H,Williams,Ian Fleming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
12
Singapore, Sydney, 2004. Print.
Vibrational frequency2
Ball
M1
Force constant, k M2
and spring representation of 2
atom of molecule vibrating in the
direction of bond
Factors influencing absorption frequency2
Masses of attached atoms. As masses increase, wave number decreases.
Strength of chemical bond. As bond strength
increases, wave number increases.
Hybridization. Bonds are stronger in the order
sp > sp2 > sp3.
 Resonance. Conjugation lowers the energy
to vibrate bond.
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
13
Factors influencing vibrational modes [2,10,12]
A. Phase and solvents used
Phase and solvents may bring the changes in IR in the aspects of
1.Band frequency shifts
2. Band splitting
e.g.;- the effect of phase and solvents in Acetone.
>c=o in acetone ----------1742 cm-1 in vapor state
-----------1718 cm-1 in liquid state
Acetone interactions with some solvents
Dipole-dipole lowers wave number
-----------1726 cm-1 in a solution of Hexane
-------------1713 cm-1 in chloroform
--------------1709 cm-1 in ethanol
B. Coupled interactions
Extent of coupling influenced by
1.stretching vibrations with two vibrations have common atom
2. bending vibrations with a common bond b/t vibrating groups.
3. coupled groups of identical energies.
4. groups separated by two/more bonds, little or no interaction occur.
6. vibrations of symmetrical species.
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print. 14
12.Y.R.Sharma,”infrared spectroscopy”, Elementary organic spectroscopy principles and chemical applications, first edition 1980, reprint 2007. print.
Factors influencing vibrational modes[2,10,12]
C.. Hydrogen bonding
Strength of H-bond effected by
1. ring strain
2. molecular geometry
3. relative acidity and basicity of proton donor and acceptor
Types of hydrogen bonding :1. intermolecular hydrogen bonding
extent of bonding
depends on Temp.
2. intramolecular hydrogen bonding
D. Fermi resonance
Factors leads to Fermi resonance
a) vibrational levels are same for symmetrical compounds.
b) interacting groups located in the molecule for an appreciable mechanical coupling to
occur.
e.g.:1. co2 actual absorption frequencies at 1286,1388 cm-1 the splitting caused by coupling b/t
fundamental c=o stre. near 1340 cm-1 and 667 cm-1 -----1344 cm-1 1st overtone
2. lactones, lactims, lactums, aldehydes.
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print. 15
12.Y.R.Sharma,”infrared spectroscopy”, Elementary organic spectroscopy principles and chemical applications, first edition 1980, reprint 2007. print.
Factors influencing vibrational modes [2,10,12]
E. Electronic effects
1.Inductive effect—introduction of alkyl group
2.Mesomeric effect
HCHO----1750 cm-1
CH3CHO---1745 cm-1
3.Field effect.
length
bond strength
force constant
CH3COCH3---1715 cm-1
vibrational frequency
► Lone pair of electrons
► conjugation lowers absorption
► Mesomeric effect dominate inductive effect for some
time and vice versa
Introduction of electronegative atoms
Bond strength
Force constant
CH3COCH3---1715 cm-1
ClCH2COCH3---1725 cm-1
Vibrational frequency
Cl2CHCOCH3----1740 cm-1
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print. 16
12.Y.R.Sharma,”infrared spectroscopy”, Elementary organic spectroscopy principles and chemical applications, first edition 1980, reprint 2007. print.
INSTRUMENTATION [2,6]
1.Radiation source
2. Monochromatic light.
3.Sample handling.
4.Detectros
5.Amplifiers .
2.Sampling of substances 1.solids run in solution form
2.solid films
solids
3.mull technique
liquids
4.pressured pellet
technique.
gases .
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
6. Hobart H. Willard, Lynne L. Merritt. Jr., John A. Dean, Frank A. Settle, Jr. “Infrared spectroscopy”, instrumental methods of analysis,7thedition 17
content no. 6.18. CBS publications, Toronto. 2005. print.
INFRARED SOURCES [3,6]
S.NO
Character
Nernst
glower
Globar
Incandescent
Mercury arc
Tungsten
lamp
Co2 laser
1.
Composition
Rare earth
oxides
Silicone
carbide
Nichrome wire
High (Hg)
pressure
Tungsten –
Halogen
Tunable
Co2 laser.
2.
Operating
temp.
1200 —
2200K
1300 --1500 K
1100K
1000K
3500K
-------
3.
Radiations
produced O.P
12,8004000cm-1
5200 cm-1
10,800-8000cm-1
< 665 cm-1
10,100—4000
cm-1
1100900cm-1
4.
IR region used
Near / visible
Middle
Middle
/near
5.
Intensity of
radiation
More intense
6.
Out put
significant (λ)
7.
Used for
>2µm
Carbohydrate
, protein
Middle
As equal to
Nernst
>5µm
Simple
Functional
groups
Near
Less but
longer life.
2-4µm
complex
organic
molecules.
Far
Greater
10µm
In- organic
complexes.
Mild
More
effective
2-4µm
5 µm
Most
organic
functional
groups
NH3 C6H6,
C2H5OH
3.Douglas A.Skoog, F.James Holler, Timothy A.Nieman, ,”Infrared spectroscopy", principles of instrumental analysis, 5th edition, saunders Golden sunburst
series. Forth worth, Philadelohia, Chicago, Sydney, Toronto. Page no. 406. Print.
18
6. Hobart H. Willard, Lynne L. Merritt. Jr., John A. Dean, Frank A. Settle, Jr. “Infrared spectroscopy”, instrumental methods of analysis,7thedition
page288,289,292,293, content no. 11.1 . CBS publications, Toronto. 2005. print.
DETECTORS or TRANSDUCERS[3,6]
Character
Thermocouple
or
Thermopile
Thermister
or
Bolometer
Pyroelectric
S.No
Golay
or
Pneumatic
1.
Principle
Pelletier effect
Whetstone bridge
Electric
polarization
Expanction of
gases
2.
Materials used
Bismuth & Antimony,
coated by metal oxides
Sintered oxides of
Mn, co, Ni
TGS, DTGS,
LiTGO3 , LiTubO3
generally CO2
3.
Material should be
Thermally active
Thermally
sensitive resistors
Non-center
symmetric crystal
Inert nature
4.
Description
Half -junction- hot
Alternate -junction -cold
--------------
------------
Metal cylinder
closed in b/t metal
plate & Ag
5.
Conversion unit
Radiant to Electric
signal ---measured
Change in
resistance - Q
Thermal alteration
to E.polarization
Expanction of gas
to pressure to
e.signal
6.
Used
Photocuastic
spectroscopy
Diffusive
reflectance
FTIR
Non –dispersive IR
7.
Response time
30 sec
4 sec
multiple scanning
0.01sec
3.Douglas A.Skoog, F.James Holler, Timothy A.Nieman, “ Infrared spectroscopy”, introduction to instrumental methods of analysis, principles of instrumental
analysis, 5th edition, saunders Golden sunburst series. Forth worth, Philadelohia, Chicago, Sydney, Toronto. Page no. 408-410. 2006 Print.
19
6. Hobart H. Willard, Lynne L. Merritt. Jr., John A. Dean, Frank A. Settle, Jr. “Infrared spectroscopy”, instrumental methods of analysis,7thedition
page288,289,292,293, content no. 11.1 . CBS publications, Toronto. 2005. print.
General guidelines for IR
[11,13]
► 3600—3000cm-1
---OH, --NH2 , >NH, C-H.
► 3200—3000cm-1
C-H, Ar— C-H.
[11,13]
Functional
group region
►3000—2500 cm-1
--C—H of methyl/methelene
asymmetric stre. --C—H, --COOH
►2300—2100 cm-1
Alkynes
2210---2100
Cyanides 2260—2200
Isocyanides 2280—2250
►1900—1650 cm-1
strong bands--- >c=o---1725—1760
anhydrides -----
1850---1740
Imides ------ two broad band at 1700
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education.
Newyork, Singapore, Sydney, page no. 45-60. 2004 . Print.
20
13.Harold F.Walton,Jorge Reyes, "infrared spectroscopy", Modern Chemical Analysis And Instrumentation,IMBD, Mumbai, Reprint 2001page no 201-203.
Print.
General guidelines for IR interpretation [11,13]
► 1650--1000cm-1
confirms --esters, alcohol, ethers. Nitro
Finger print
region[11,13]
► 1000—800 cm-1
C— Cl, C-Br
► 800—710cm-1
meta substituted benzene
► 770—730cm-1
strong mono substituted benzene.
► 710—665cm-1
ortho, Para, benzene.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education.
Newyork, Singapore, Sydney, page no. 45-60. 2004 . Print.
21
13.Harold F.Walton,Jorge Reyes, "infrared spectroscopy", Modern Chemical Analysis And Instrumentation,IMBD, Mumbai, Reprint 2001page no 201-203.
Print.
O—H
N—H
Graphical interpretation of functional groups in IR [2,10]
esters, alcohol, ethers, Nitro groups
%T
C—H
C—C
HO-C=O
C=_N
C-H, Ar— C-H
C=O C=N C=C C=S N=O S=O C—N C—O
benzene
OH, --NH2 , >NH, C-H
C—H, --COOH
2. B.K. SHARMA," Infrared spectroscopy” ,spectroscopy ,20th edition, Goel publications, Delhi, 2007. print.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
22
General guidelines for IR interpretation [10,11]
Alkanes
C–H stretch from 3000–2850 cm-1
C–H bend or scissoring from 1470-1450 cm-1
C–H rock, methyl from 1370-1350 cm-1
C–H rock, methyl, seen only in long chain alkanes, from 725-720 cm-1
90
Octane spectrum
1383
1470
2971
2963
C-H stretch
C-H rock
C-H
scissoring
728
Long chain
CH2 stretch
0
4000
2000
Wave number cm-1
1000
500
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
23
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation[1011]
Alkenes :-
C=C stretch from 1680-1640 cm-1
1- Octene spectrum
=C–H stretch from 3100-3000 cm-1
1. 3083- =C-H stretch
=C–H bend from 1000-650 cm-1
% transmittance
2. 2966- C-H stretch
3. 2863 –C-H stretch
90
4. 1644- C=C str
1
4
2
4000
5. 1455 C-H sis
5
6
3
6. 1378 C-H rock
7
2000
1000
7. 1004 =C-H bond
500
Wave number cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
24
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Alkynes :-
–C≡C– stretch from 2260-2100 cm-1
–C≡C–H: C–H stretch from 3330-3270 cm-1
–C≡C–H: C–H bend from 700-610 cm-1
1- hexyne spectrum
90
1383
2126
CC-
% transmittance
C-H rock
1470
3324
C-H scissoring 636
2679
2971
C-H stretch
C-H
scissoring
CC- H
0
4000
2000
1000
500
Wavelength cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
25
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Alkyl halides :-
C–H wag (-CH2X) from 1300-1150 cm-1
C–X stretches (general) from 850-515 cm-1
1- bromo propane spectrum
C– Cl stretch 850-550 cm-1
C–Br stretch 690-515 cm-1
90
1291
1470
2976
2940
C-H stretch
C-H wag
C-H
scissoring
651
Long chain,
C-Br stretch
0
4000
2000
1000
500
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
26
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Aromatics:-
C–H stretch from 3100-3000 cm-1
overtones, weak, from 2000-1665 cm-1
C–C stretch (in-ring) from 1600-1585 cm-1
C–C stretch (in-ring) from 1500-1400 cm-1
C–H "loop" from 900-675 cm-1
Aromatic C-H stretches are left to
3000, and aliphatic C-H stretches are
right to 3000
90
overtones
% transmittance
3099
1614
2925
3068
1465
1086
C-H stretch alkyl
1035
1505
Spectrum of Toluene
3032
0
C- H stretch In aromatic ring
738
C-H stretch aromatics
In-plane C-H bending
Wavelength cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
27
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation[10,11]
Alcohol:-
O–H stretch, hydrogen bonded 3500-3200 cm-1
C–O stretch 1260-1050 cm-1 (s)
The spectrum of ethanol is shown below. Note the very broad, strong band of the
O–H stretch (3391) and the C–O stretches (1102, 1055).
90
Spectrum of Ethanol
% transmittance
1102
2961
3391
C-H stretch
C-O stretch
1105
O-H stretch
0
Wave number cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
28
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
ketones
C=O stretch:
aliphatic ketones 1715 cm-1
α, β-unsaturated ketones 1685-1666 cm-1
The spectrum of 2-butanone is shown below. This is a saturated ketone, and the C=O band appears at 1715.
Note the C–H stretches (around 2991) of alkyl groups.
90
% transmittance
2991
2-butanone spectrum
C-H stretch
1715 C=O stretch
0
4000
3000
2000
1500
1000
500
Wave number cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
29
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Aldehydes:
H–C=O stretch 2830-2695 cm-1
C=O stretch:
aliphatic Aldehydes 1740-1720 cm-1
alpha, beta-unsaturated aldehydes 1710-1685 cm-1
The spectra of benzaldehyde and butyraldehyde are shown below. Note that the O=C stretch of the
alpha, beta-unsaturated compound -- benzaldehyde -- is at a lower wave number than that of the
saturated butyraldehyde.
90
Benzaldehyde spectrum
% transmittance
3073 2827 2725
C-H
C-H
aldehyde
Stretch alkyl
1696 C=O stretch
0
4000
3000 2000 1500
Wave number cm-1
1000
500
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
30
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Carboxylic acids :-
O–H stretch from 3300-2500 cm--1
C=O stretch from 1760-1690 cm-1
C–O stretch from 1320-1210 cm-1
O–H bend from 1440-1395 and 950-910 cm-1
The spectrum of hexanoic acid is shown below. Note the broad peak due to O–H stretch
superimposed on the sharp band due to C–H stretch. Note the C=O stretch (1721), C–O stretch
(1296), O–H bends (1419, 948), and C–O stretch (1296
90
% transmittance
948
O-H
2971
1419
O-H stretch and
C-H stretch
O-H
band
1721
C=O stretch
1296
C-O
stretch
0
Wave number cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. 31
Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation[10,11]
Esters :-
C=O stretch
aliphatic from 1750-1735 cm-1
α, β-unsaturated from 1730-1715 cm-1
C–O stretch from 1300-1000 cm-1
The spectra of ethyl acetate and ethyl benzoate are shown below. Note that the C=O stretch of ethyl
acetate (1752) is at a higher wavelength than that of the α, β-unsaturated ester ethyl benzoate (1726).
Also note the C–O stretches in the region 1300-1000 cm-1 .
% transmittance
Ethyl acetate
1. 2981- C-H stretch
90
2. 1752- C=O ester
stretch
3. 1250- C-O stretch
1
2
3
4. 1055- C-O stretch
4
Ethyl benzoate
90
1. 3078- C-H aromatic
stretch
1
2
3
2. 2966- C-H alkyl
stretch
4
3. 1726-C=O stretch
4000
3000
2000
1000
-1
Wave number cm
500
4. 1266, 1117- C-O
stretch
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. 32
Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
General guidelines for IR interpretation [10,11]
Amines :N–H stretch 3400-3250 cm-1
1° amine: two bands from 3400-3300 and 3330-3250 cm-1
2° amine: one band from 3350-3310 cm-1
3° amine: no bands in this region
N–H bend (primary amines only) from 1650-1580 cm-1
C–N stretch (aromatic amines) from 1335-1250 cm-1
C–N stretch (aliphatic amines) from 1250–1020 cm-1
N–H wag (primary and secondary amines only) from 910-665 cm-1
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. 33
Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
10,20,30
amine spectrums
General guidelines for IR interpretation [10,11]
90
Tri ethyl amine
1. 1241- C-N
stretching
% transmittance
1
Aniline
90
1.3442
2. 3360-
1
3. Shoulder band
3
2
4
4. 1619- N-H primary amine
5
5.1281- C-N stretch
Diethyl amine
90
1. 3288- N-H stretch Secondary
amine
1
4000
3
2
3000
2000
Wave number cm-1
1000
2.1143- C-N stretching
500
3.733- N-H waging 10 ,20.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. 34
Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
Nitro groups:-
General guidelines for IR interpretation [10,11]
N–O asymmetric stretch from 1550-1475 cm-1
N–O symmetric stretch from 1360-1290 cm-1
90
% transmittance
1573
1358
N-O stretch 1537
N-O stretch
1383
N-O stretch
0
Wave number cm-1
Nitro methane
Black spectrum
Meta nitro toluene
Blue spectrum
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
11.Dudles H,Williams,Ian Flemming ,”infrared spectroscopy”, Spectroscopy Methods In Organic Chemistry, 5thedition,Tata mecGrawHill.Education. 35
Newyork,
Singapore, Sydney, page no. 45-60. 2004 . Print.
Example for interpretation of IR for known structure[9,10,14]
A. N-H Amide----3360 cm -1 .
B. Phenolic—OH -- 3000 cm -1 --3500 cm -1
E
A
HN
G
O
C
C. C—H Stretching---3000 cm-1 .
C
C H3
D
F
H
I
OH
D. Aromatic overtone ----1840 cm-1 --1940 cm -1
E. >C=O Amide stretching -----1650 cm -1
F. Aromatic C=C stretching--- 1608 cm -1 .
G. N-H Amide bending ----1568 cm -1
B
H. Aromatic C=C stretching ----1510 cm -1 .
Acetaminophen 14
(4-acetamido-Phenol)
I. >C—H bending --------810 cm -1
9. Robert M.Silverstien Francis X.Webster ,”infrared spectroscopy”, spectroscopic identification of organic compounds, 6thedition, John Wiley, Chichester,
Singapore, Toronto, Brisbane page no. 3.5, 2005. Print.
10. Jag Mohan ,”infrared spectroscopy”, Organic Spectroscopy, Principles And Applications, 2ndedition,Narosa,Newdelhi, Chennai 2005. Print.
14.David watson,”infrared spectroscopy”, pharmaceutical Analysis, A test book for pharmacy students & pharmaceutical chemists, 2nd edition, Elsevier36
churchil,livingston. Edinburgh,london,newyork,oxford,sydney, and Toronto. Print
Examples for interpretation of IR for known structure15
15
15
O
C
H3C
15
15
O
O
OH
C
O
C
HO
O
CH3
C
HO
15.www.cem.msu.edu. Web feb 25 2010. < http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/irspec1.htm#ir1 >
37
Tips for interpretation of IR for unknown structure 14

Always place relines to negative information evidence i.e., absence of band at
1900 cm-1---1600 cm-1----absence of >C=O, >CHO

Always starts from higher frequency end of the spectrum.

Absence of band at 880 cm-1—650 cm-1 indicates absence of aromatic ring.

For easy identification go for fingerprint and functional group region.

Finger print region range is 1400 cm-1--900 cm-1. In this region if absorbance band is present the
groups esters, alcohols, ethers, nitro are Confirmed.

Functional region range is 4000 cm-1---1400 cm-1.amines, alcohols, aromatic rings, carboxylic acids,
alkynes, alkanes, alkenes, anhydrides, imides, etc, may be confirmed.

Stretching vibrations at 4000 cm-1----600 cm-1.

Bending vibrations at 1500 cm-1-----500 cm-1.
14.David watson,”infrared spectroscopy”, pharmaceutical Analysis, A test book for pharmacy students & pharmaceutical chemists, 2nd edition, Elsevier
churchil,livingston. Edinburgh,london,newyork,oxford,sydney, and Toronto. Print
38
Example for interpretation of IR for unknown structure[14,15]
Unsat’d
90
Aromatic
P- Disubst
Sat’d
% transmittance
CH2 CH3
Aromatic
P- Disubst
NH2
C=0
C=C
0
4000
3000
2000 1500
Wave number cm-1
1000
500
Carbonyl Group
Carbon Oxygen Group
Primary Amine Group
Saturated Alkane
Unsaturated Alkene / Aromatic
Methyl Group
14.David watson,”infrared spectroscopy”, pharmaceutical Analysis, A test book for pharmacy students & pharmaceutical chemists, 2nd edition, Elsevier
churchil,livingston. Edinburgh,london,newyork,oxford,sydney, and Toronto. Print
39
15.www.cem.msu.edu. Web feb 25 2010. < http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/irspec1.htm#ir1 >
Example for interpretation of IR for unknown structure15
Peak status
POSITION
Reason
REDUCED
MASS
BOND
STRENGTH
(STIFFNESS)
3350 -- OH stetching vibrational frequency
2950 -- CH aliphatic asymmetrical stretching
vibrational band. The less intense band at 2860 –
is the symmetrical stretching vibrational band.
1425 -- CH2 characteristic absorption
1065 -- CO absorption
inference
LIGHT ATOMS
HIGH
FREQUENCY
STRONG
BONDS HIGH
FREQUENCY
STRENGTH
CHANGE IN
‘POLARITY’
STRONGLY
POLAR BONDS
GIVE INTENSE
BANDS
WIDTH
HYDROGEN
BONDING
STRONG
HYDROGEN
BONDING
GIVES BROAD
BANDS
15.www.cem.msu.edu. Web feb 25 2010. < http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/irspec1.htm#ir1 >
40
Conclusion
Drug
discovery
IR
spectroscopy
Drug
incompatibility
Drug
Quality control
On considering the all above aspects of “INFRA RED SPECTROSCOPY”. It
is concluded that IR technique is “ an unbound spectroscopic technique for
quality optimization from drug discovery to drug quality control parameters”.
41
NOTE:
This presentation does not include
plagiarized material.
THANK YOU
42