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8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
1/12
Asian Journal Of Spectroscopy (2008) , 12, 163167
ComparisonofexperimentalandabinitioHFandDFTvibrational
spectraof3'Azido 2' deoxythymidine
Y.P.SINGH*, RATNESH DASb and ARVIND SINGH TOMARc
*Department of Physics, Govt. Polytechnic College, Sagar (MP),INDIA,470001E-mail: [email protected]
bDepartment of Chemistry, Dr. H.S.Gour University, Sagar (MP), INDIA, 470001,E-mail:[email protected]
cDepartment of Physics, S.V.Polytechnic College, Bhopal (MP)
Abstract
A combined experimental andtheoretical study on molecular andvibrational structure of 3-Azido-2-deoxythymidine (Zidovudine AZT) hasbeen reported. The Fourier transforminfrared spectra of was recorded in the
solid phase, in the region of 2500400cm-1. Assuming Cs point symmetry,vibrational assignments for theobserved frequencies have beenproposed by means of quantumchemical calculations using densityfunctional theory and HartreeFockmethod with 6-311++G** basis sets. Anassignment of normal modes ofvibration to the observed andexperimental frequencies has beenbased on these calculations. Thetheoretical wavenumbers showed verygood agreement with the experimentalvalues. A detailed interpretation of theinfrared also is reported.The theoreticalFT-IR spectra of the title molecule havealso been constructed.
Keywords3'-Azido-2'-deoxythymidine,Zidovudine,FTIR Spectra, Hartree-Fock, DFT, AM1,
PM3.1.Introduction
AIDS is , not a disease but acollection of seventy or more conditions
which result from the damage done to
the immune system and other parts of
the body as a result of infection by
HIV1. There are a number of drugs that
have been considered as to be anti HIV.
The drugs like 3'-Azido-2'-
deoxythymidine (AZT), synthesized by Jerome Horowitz, and ribavirin appear
most promising because both cross the
blood-brain barrier and can be taken
orally, and in early traities they do not
cause serious side effects2-4.
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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Conformational analysis of AZT
structure and other related drugs have
been previously reported at semi
empirical and ab initiolevels of theory 5-
6. Hernndez7 at al reported an ab initio
HF and DFT study of the dipole
polarizability of AZT drug.
In the present work we have
recorded infrared spectra of AZT drug.
A quantum chemical investigation
using DFT and HF techniques with
moderately extensive basis sets havealso been performed to help in the
assignments of the observed
frequencies. The geometry of the drug
molecule is also reported.
2.Experimental
All the chemicals used to prepare
experimental sets were of Analar /BDH
grade. Zidovudine was purchased from
Cipla India Ltd. I.R. Spectrum has been
recorded using KBr disc in solid phase
in the range 400-2500cm-1 on Perkin-
Elmer spectrometer Model 397.
Preparation of KBr Pallets: A
small amount of finally grounded solid
sample was intimately mixed withabout 100 times or more than its
weight of Potassium bromide powder.
The finely ground mixture was than
pressed under very high pressure in a
press (about 10/cm2) to form a small
pallet (about 1-2 mm thick and 1cm in
diameter).
The accuracy of the
measurements was estimated to be within 3cm-1 and the resolution was
better than 2cm-1 through the entire
spectra.
3.ComputationalMethods
The AM1 and PM3 semi
empirical approaches were performed
as implemented in MOPAC program8
and the PRECISE keywords were used.
Hartree-Fock and DFT calculations
were performed using Spartan' 06
program 9 at the B3LYP 10 levels of
theory with 6-311++G** basis sets.
4. ResultsandDiscussions
MolecularGeometry
The geometry parameters
optimized at AM1, MP2 and B3LYP
levels of theory for Zidovudine are
presented in Table 1. Results indicate
that bond distances and bond angles
are very close to those reported from X
ray structure4. Our results shows that
the Azide group lies in a nonlinear
conformation, where N14N32N16 bond
angle range from 70.058 at PM3 to the
value of 69.367 at B3LYP level and is
attached in transposition to the C6C12
bond of Furancose ring.
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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A statistical analysis shows a
mean values of 1.410 , 1.429 and
1.388 and standard deviations of
0.1472 0.03468 , 0.1487 0.03504
and 0.1314 0.03097 calculated
and experimental bond distances using
AM1, PM3 and B3LYP methods. There
is some difference due to due to
electron withdrawing property of
oxygen5 and that of nitrogen between
experimental and calculated bond
lengths in C-O of thymine and
Furancose ring and N-N of Azide ring.
Similarly, bond angles have a mean
value of 116.7 , 117.0 and 116.9 and
standard deviation of 13.603.401 ,
13.163.291 , 13.913.478 at AM1,
PM3 and B3LYP approach.4.2.Vibrationalassignments
3'-Azido-2'-deoxythymidine (AZT)
has a planar structure of Cs point
group symmetry and has 32 atoms so
that it has 90 normal modes of
fundamental vibrations which span the
irreducible representations: 60 a and
30 a. The observed FTIR frequencies
for various modes of vibrations are
presented in Table 2. Vibrational
frequencies calculated at 6311++G**
basis level were scaled by 0.96, and
those calculated at HF level were scaled
by 0.8912 .
The calculated frequencies are
slightly higher than the observed values
and this is due to the fact that the
experimental values are an anharmonic
frequencies while the calculated values
are harmonic frequencies.
4.3.CHvibrations
No peaks were observed
experimentally for the CH stretchingmodes, whereas, the calculated values
are at 3143.81 , 3142.39, 3094.79,
3072.90, 3039.39, 3020.78, 3015.48
cm-1 by DFT method and 3087.32,
3077.40, 3069.05, 2993.79, 2907.71,
2805.41, 2639.90 cm-1 by HF method.
Experimentally out-of-plane
bending vibrations are recorded at
about 1387, 1191,914 and 817 and
974 cm-1 . The corresponding scaled
frequencies are calculated at 1397.07,
1213.16, 944.84, 821.85 cm-1 (DFT )
and 1390.55, 1206.15, 981.27, 828.62
cm-1 ( HF). The changes in the
frequencies of these deformations
determined by the relative position of
the substituents and are almost
independent of their nature13.
4.4.NHvibrations
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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The calculated value NH is at3462.52 cm-1 ( DFT) and 3359 cm-1 (
HF ) shows excellent agreement with
experimentally FT-IR value 3485 cm-1
obtained by Rai14. The in-plane and
out-of-plane bending are assigned at
1448.67, 889 cm1 ( DFT ) and 1437.60,
676 cm -1 ( HF ) also agrees well with
Rai14.
4.5.OHvibrations
The OH group gives rise to three
vibrations-stretching, in-plane bending
and out-of-plane deformations. Tayyari
et al 15 observed that the frequency of
OH stretching vibration in the gas
phase is 2800 cm-1 in the case of
banzoylactone. In our case the
calculated frequencies are 3472.69 cm-1
( by DFT) and 3489.65 cm-1 ( by HF).
This deviation is due to presence of
strong intramolecular hydrogen
bonding. Krishnakumar et al16
observed the in-plane bending
vibration in substituted pyridine lies in
the region 11761243 cm1.
Experimental frequencies have not been
observed. The computed value is
1554.01 cm-1 ( DFT) and 1567.50
1554.01 cm-1 ( HF) and it coincides
with CH in-plane bending and CO
stretching. Experimental value of out-
of-plane deformation was 355 cm-1 and
it coincides with out-of-plane
deformation of NN of Azide group. The
calculated values of this vibration at
364.19 cm-1 show excellent agreement
with experimental results17.
4.6.COvibrations
CO stretching vibration has not
been shown experimentally .But
calculated frequencies are 1346.51 cm-1
(by DFT) and 1332.56 cm-1 (by HF).
This is in agreement with experimental
frequencies 1244 cm1 (FTIR) and 1249
cm1 (FT-Raman) as obtained by
Sundaraganesan et al18. The in-plane
bending vibration mode with the
theoretical frequency of 452 cm1
deviates positively by 200 cm1 from
experimental value obtained by
Sundaraganesan et al28. This may be
due to mixing of CO vibration with CC
in-plane bending vibration.
4.7.NNvibrationsWe hadn't observed the
asymmetric stretching vibration .But
calculated frequencies are 2612.78 cm-1
( DFT) and 2621.94 cm-1 (HF). This is
higher than the experimental
frequencies 2208 cm1 (FTIR) reported
by Jensen19, because the bond from the
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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central nitrogen atom to the attached
Furancose ring has partial double bond
character. As a consequence of the
increased delocalization, the N=N
vibration is shifted to lower wave
numbers.
Also calculated Symmetric
stretching frequencies are 1508.75 cm-1
( DFT) and 1489.23 cm1 (HF). Jensen19
reported it at 1253 cm, difference is
due to the large polarizability derivative
associated with the NN stretch.
The in-plane vibration mode with
the theoretical frequency of 430.13 cm1
( DFT) and 426.19 cm1 ( HF) deviates
very little from experimental value 451
cm1 reported by Jensen.
We observed out-of--plane-
bending at 441 cm1 and calculated
frequencies at 442.68 cm1 ( DFT) and
439.89 cm1 ( HF). Also, NN scissoring
frequency was observed at 406 cm1
and calculated frequencies were at
417.29 cm1 ( DFT) and 410.12 cm1 (
HF). This frequency is not reported by
Jensenand Zimmermann et al20.
Figure 4 and 5 shows agreement
between the experimental and
calculated wavenumbers (HF and DFT).
The graph is linear which shows that
theoretical and experimental results are
in good agreement.
5.Conclusion
Attempts have been made in thepresent work for the proper frequencyassignments for the 3'-Azido-2'-deoxythymidine from the FT-IR spectra.Any discrepancy noted between theobserved and the calculated frequenciesmay be due to the fact that thecalculations have been actually done ona single molecules in the gaseous state
contrary to the experimental valuesrecorded in the presence ofintermolecular interactions. Also,difference is attributed due to neglect ofanharmonicity and incompleteinclusion of electronic correlationeffects. Therefore, the assignmentsmade at higher levels of theory withonly reasonable deviations from theexperimental values, seem to be
correct. The B3LYP method is seen tobe better than both RHF and MP2methods for calculation of vibrationalfrequencies. For further agreementbetween computed and experimentalfrequencies, the computed frequenciesare often scaled by some specific factor.
6.Refrences
1. Dossier P, AIDS and ThirdWorld, The Panon Institute ofLondon(1988).
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
6/12
2. Yarchoan R, Mitsuya H, BroderS. AIDS therapies. Sci. Am,259(4), (1988),110
3. Alan Howie,[email protected],www.abdn.ac.uk/chemistry/rese
arch/rah/rah.hti, 2006.4. Dyer, I.D; Low,J.N; Tollin, P.T.;
Wilson, H.R; and Alan Howie;Acta Crystal, ,C44, (1988),767.
5. Baumgartner, M. T. ; Motura, M.I. ; Contreras, R. H.; Pierini, A.B. ; M. C. Brin, Nucleos.Nucleot. & Nucleic Acids, 22,(2003) 45.
6. Xinjuan, H; Mingbao,H; Dayu,Y;Sci. China Serie B: Chemistry, 45,(2002),470.
7. Hernndez,J; Soscn,H; andHinchliffe,A; Internet ElectronicJournal of Molecular Design,2,(9), (2003), 589.
8. Win MOPAC- Molecular OrbitalProgram, Fujitsu Limited, (1997).
9. Spartan' 06 for MedicinalChemistry, wave function Inc,(2006).
10.A.D.Becke, J. Chem. Phys.,98,(1993), 5648.
11.
Nakamura, M.; Makino, K; Sirgi,L; Aoki, T and Hatanaka, Y.Surface and Coatings, ,769,(2003), 699.
12.Altun A, Golcuk K, Kumru M, J.Mol. Struct. (Theochem.), 637,(2003),155
13.Varsanyi, G; Acta Chim. Hung,,50, (1966), 225.
14.Rai A.K, Kumar S, Rai A; Vib.Spect; ,42, (2006), 397.
15.Tayyari S F, Emampoure J S,Vakili M, Neokoei A R,
Hassanpour M; J. Mol. Struct;,794, (2006), 204.
16.Krishnakumar V andMuthundesan S; SpectrochimActa A; , 65, (2006), 818.
17.Sundaraganeshan N, Anand B, Jian F F, Zhao P,Spectrochimacta A; 65, (2006)826.
18.Sundaraganesan, N; Anand, B;and Dominic Joshua,B;
Spectrochimica ActaA,doi:10.1016/j.saa.2006.07.016,(2006).
19.Jensen, J.O; J.Mol. Structure,730, (2005), 235.
20.Zimmermann,F; Lippert,T;Beyer,C; Stebani,J; Nuyken,Oand Wokaun,A; AppliedSpectroscopy, 47(7), (1993), 986.
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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C3
C5
C7
C1
O1 9
N4 H
2 0
N2
C8
H2 2
H2 3
H2 1
C1 2
C6
O9
H2 6
H2 5
N1 4
N1 6
C1 3
H2 4
H2 7
H28
N3 2
H1 8
O1 7
H3 0 H
2 9
O15
H3 1
Fig1Structureof3'Azido2'deoxythymidineorZidovudine
Fig 2: Experimental I. R. Spectra of 3'-Azido-2'-deoxythymidine/ Zidovudine (AZT)
Fig 3: Theoretical I. R. Spectra of 3'-Azido-2'-deoxythymidine/ Zidovudine (AZT)Table1.Optimizedbonddistances(inAngstrom),bondanglesandtorsionangles
(indegrees)ofAZT.
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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Bondlength (A0 )
BondAngle (Degree)
Bond Experim
ental14
AM1 PM3 B3LYP BondAngle Experimental14
AM1 PM3 B3LYP
C1N2
N2C3
C3N4
C5N4
C5C7
C7C1
C1O17
C7C8
C8H21
N2H18
C3O19
C5H20
N4C10
C10O9
C10C6
C6C12
C12C11C11O9
C11C13
C13O15
C12N14
N14N16
N16N32
N32N14
1.384
1.368
1.372
1.386
1.332
1.197
1.503
1.201
1.463
1.391
1.535
1.529
1.414
1.515
1.405
1.467
1.231
1.100
1.391
1.391
1.391
1.391
1.391
1.391
1.107
1.542
1.694
1.095
1.095
1.095
1.456
1.401
1.598
1.581
1.9461.511
1.591
1.483
1.492
1.316
1.245
1.729
1.391
1.391
1.391
1.391
1.391
1.391
1.113
1.557
1.703
1.109
1.116
1.115
1.498
1.451
1.603
1.608
1.9931.549
1.612
1.506
1.507
1.359
1.281
1.937
1.389
1.379
1.382
1.390
1.347
1.381
1.168
1.502
1.597
1.101
1.205
1.116
1.456
1.404
1.551
1.568
1.9991.421
1.523
1.476
1.473
1.246
1.108
1.827
C1N2C3
C1N2H18
N2C1O17
N2C3O19
C3N4C5
C7C8H21
H21C8H22
C7C5H20
C5N4C10
N4C10H27
N4C10O9
H27C10C6
C11O9C10
C10C6C12
C10C6H26
O9C11C12
C11C12C6C11C13O15
C13O15H31
H30C13O15
C6C12N14
C5C7C1
C5C7C8
C13C11O9
N4C10C6
N14N16N32
N16N32N14
N32N14N16
N2C3N4
130.4
123.1
119.1
117.9
107.8
110.2
98.8
104.7
105.6113.5
111.1
120.0
120.0
120.4
162.3
113.0
120.000
120.000
120.000
120.000
120.000
57.245
49.517
120.000
118.953
120.269
108.329
77.519
111.538
99.157
106.681
103.184
105.995114.382
141.357
29.462
113.346
121.634
119.924
120.996
160.534
47.165
59.378
73.057
110.0
120.000
120.000
120.010
120.00
120.060
58.058
40.349
121.658
119.359
121.647
109.264
76.927
112.327
100.062
106.992
104.194
104.367115.216
140.581
20.421
114.624
120.347
120.068
120.624
159.458
48.619
50.058
81.363
111.621
121.364
121.620
120.072
120.095
120.012
57.289
40.362
120.00
118.168
120.035
107.984
77.568
110.489
99.008
106.687
104.842
105.996113.859
141.887
29.564
112.549
120.006
120.068
120.001
162.547
47.245
59.367
73.380
112.895
Table 2: Experimental, Calculated Frequencies and Potential Distribution in
Zidovudine (AZT)
S.N. ExperimentalCalculatedFrequencies(incm
1)
VibrationalAssignments
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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Frequencies
(incm1)
HF DFT(B3LYP) AtomPair/Energy
Contribution(in%)a
Species a
1 3472.69 3489.65 O15 H31(99.5) s(HydroxylGroup)
2 3462.52 3359.25 N2H18(99.3) a(ThymineRing)
3 3331.98 3294.36 015H31(99.5) a(HydroxylGroup)4 3190.12 3166.24 C10H27(97.7) a(AzideRing)
5 3143.81 3087.32 C8H22(32.9)
C8H21(29.2)
C8H23(24.7)
s(ThymineRing)
6 3142.39 3077.40 C5H20(86.0) s(ThymineRing)
7 3094.79 3073.82 C11H24(54.9) s8 3084.79 3069.05 C6H26(70.1)
C6H28(28.4)
s(FurancoseRing)
9 3072.90 2993.62 C13H29(92.1) s(HydroxylGroup)
10 3055.24 2988.79 C8H22(55.8)
C8H21(39.2)
s (ThymineRing)
11 3039.39 2907.71 C8H23(66.4)
C8H21(26.5)
a (ThymineRing)
12 3020.78 2805.41 C11H24(38.8)
a (FurancoseRing)
13 3015.48 2639.90 C6H28(68.4)
C6H26(29.8)
a(FurancoseRing)
14 2612.89 2621.64 N16N32(71.7)
N14N16(28.0)
a (AzideRing)
15 2170 2162.78 2163.94 C12N14(23.6) s(FurancoseRing)
16 1887 1842.68 1949.16 C10H27(42.2)
C12N14(16.7)
C11C12(15.5)
s+ s+ s
(FurancoseRing)
17 1801 1811.70 1894.66 C5C7(21.7)
C3C5(15.7)
C3N4(10.7)
s+ s+ s
(ThymineRing)
18 1725 1728.36 1720.75 C3N4(19)C3O19(14.1)
s+ s(ThymineRing)
19 1623 1653.82 1605.83 C3N4(14.8)
C3O19(18.1)
a+ a(ThymineRing)
20 1552.48 1543.15 N4C5(24.1)
C5C7(15.6)
s+ s
(ThymineRing)
21 1554.01 1567.50 O15H31(50.3)
C13H29(11.5)
C13O15(11.1)
s+ s+ s
(HydroxylGroup)
22 1508.75 1489.23 C12N14(35.3)
N14N16(29.4)
s+ s
(AzideRing)
23 1483 1479.92 1472.42 C13O15(22.6)
C11C13(18.4)
C13H29(15.5)
a+ a+ a
(HydroxylGroup)
24 1476.10 1469.10 C7C8(25.7)
C1C7(15.0)
C5C7(13.2)
s+ s+ s
(ThymineRing)
25 1460.51 1451.15 C6H26(20.1)
C6C10(16.8)
C6H28(15.8)
s+ s+ s
(FurancoseRing)
26 1452.61 1431.28 N2H18(29.2)
N2C3(10.4)
s+ s
(ThymineRing)
27 1436.61 1419.17 C11C12(21.5) s(FurancoseRing)
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
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28 1414 1412.89 1429.43 C1C7(13.1)
C8H22(10.7)
N2H18(10.6)
s+ s+ s
(ThymineRing)
29 1395.64 1382.55 C6H28(12.5)
C6H26(12.4)
s+ s
(FurancoseRing)
30 1384.84 1377.64 C11H24(17.9) s(FurancoseRing)
31 1377.14 1370.14 C11H24(14.9) a(FurancoseRing)
32 1376.39 1364.90 C8H22(34.9)
C8H23(21.5)
U(ThymineRing)
33 1346.51 1332. C3O19(11.5) s(ThymineRing)
34 1324 1320.69 1330.35 C13H29(25.1)
C11C13(13.8)
s+ s
(HydroxylGroup)
35 1318.57 1316.84 C1N2(30.0)
C1O17(13.3)
C1C7(12.6)
s+ s+ s
(ThymineRing)
36 1286.42 1280.66 C5H20(28.1)
N2C3(12.7)
N4C5(11.7)
s+ s+ s
(ThymineRing)
37 1281.31 1278.95 C13H29(17.6)
C12N14(14.2)
s(HydroxylGroup)
s(AzideRing)
38 1275.97 1269.91 C6H28(23.8)
C13H29(22.6)
s (FurancoseRing)
s(HydroxylGroup)
39 1172.30 1174.33 C13H29(19.6)
C6H28(10.0)
a (FurancoseRing)
a(HydroxylGroup)
40 1151 1171.21 1169.71 C11H24(16.9)
C11C13(14.0)
s (FurancoseRing)
s(HydroxylGroup)
41 1118.52 1112.05 C11C13(18.9)
C11H24(17.8)
a (HydroxylGroup)
a(FurancoseRing)
42 1106 1103.83 1110.50 C5H20(22.5)
C1N2(14.4)
C3N4(14.3)
s+ s+ s(ThymineRing)
43 1072.51 1062.79 C8H23(36.6)
C8H21(21.0)
C8H22(17.3)
s+ s+ s
(ThymineRing)
44 1058.95 1049.28 C8H23(11.5)
C8H21(24.7)
C8H22(26.8)
a+ a+ a
(ThymineRing)
45 1050.84 1034.86 C6C10(19.5)
C10H27(10.6)
s+ s
(FurancoseRing)
46 1013 1012.02 1006.45 C6C10(18.6)
C6H26(17.2)
C6H28(15.9)
s+ s+ s
(FurancoseRing)
47 1001 966.26 976.38 C11H24(24.1)C11C12(19.2)
s+ s(FurancoseRing)
48 927 922.03 931.15 C1C7(12.9) s (ThymineRing)
49 854.58 863.26 C5C7(13.6) a(ThymineRing)
50 694.90 715.21 C6C10(11.0) s(FurancoseRing)
51 574 574.24 562.87 C13O15(18.7)
C11C13(16.2)
rocking
(HydroxylGroup)
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52 482 490.62 450.83 C1C7(10.5) s(ThymineRing)
53 452.03 436.16 O15H31(22.4)
C11C13(18.9)
s + s
(HydroxylGroup)
54 430.13 426.19 N14N16(11.8) s(AzideGroup)
55 367.44 354.55 C3015(37.0) s(HydroxylGroup)
56 319.41 342.60 N14N16(21.9) a(AzideGroup)
57 311 305.67 317.91 C6C10(14.5)
C6H28(21.1)
C6H26(18.9)
s+ s+ s
(FurancoseRing)
58 236.18 225.89 C6C10(24.5)
C6H28(20.1)
C6H26(19.9)
a+ a+ a
(FurancoseRing)
59 144.79 15.47 C6C10(13.4)
C10H27(13.0)
s+ s
(FurancoseRing)
60 112.24 77.84 C7C8(24.5)
C8H21(21.2)
C8H22(20.5)
a+ a
(ThymineRing)
S.N. Experimental
Frequencies
(incm1)
CalculatedFrequencies(incm1)
Vibrational
Assignments
HF DFT(B3LYP) AtomPair/Energy
Contribution(in%)
Species a
1 1387 1397.07 1390.55 C8H21(47.9)
C8H23(35.4)
s (ThymineRing)
2 1350.60 1363.73 C6H28(17.3)
C6H26(15.0)
s(FurancoseRing)
3 1246.77 1274.74 C13H29(54.1)
O15H31(12.7)
s +s(Hydroxyl
Group)
4 1191 1213.16 1206.15 C6H26(27.1)
C10H27(11.8)
C13H29(11.8)
a (FurancoseRing)
a(HydroxylGroup)
5 914 944.84 981.27 C5H20(65.0) s (ThymineGroup)
6 857.71 885.26 C6C10(11.9) s (FurancoseRing)
7 817 821.85 828.62 C10H27(24.8)
C6H26(13.9)
C6H28(13.7)
s (Furancosering)
8 741 752.51 797.30 C1C7(31.7)
C1N2(21.6)
C1O17(21.5)
s (ThymineGroup)
9 696.64 699.38 C3N4(27.3)
N2C3(21.3)
C3O19(20.8)
s (ThymineGroup)
10 689.62 676...33 N2H18(80.2) s (ThymineGroup)
11 607 624.34 647.93 C1N2(21.1)
N2C3(14.8)
C1C7(13.8)
a (ThymineGroup)
12 563.95 562.70 C3C5(14.5) Rocking(Thymine
Ring)
13 537.38 555.47 C6C10(11.6) a(FurancoseRing)
8/4/2019 Experimental Theoretical HF DFT 3'-Azido-2'-Deoxythymidine
12/12
14 486.23 489.36 C11H24(11.3) s Scissoring
(FurancoseRing)
15 461.91 453.46 C12N14(12.0)
C11C12(10.2)
aScissoring
(FurancoseRing)
16 441 442.68 439.89 N16N32(52.0)
N14N16(41.6)
s (AzideRing)
17 406 417.29 410.12 N14N16(11.8) aScissoring
(AzideRing)
18 355 364.19 389.32 O15H31(21.8)
N14N16(13.2)
s(HydroxylGroup)
s(AzideRing)
19 337.41 377.95 C7C8(20.5)
N4C5(13.0)
s(ThymineRing)
20 180.47 191.89 O9C110(12.1)
O9C11(11.4)
s(FurancoseRing)
21 167.09 183.81 C1N2(20.3)
N2C3(20.0)
N2H18(17.7)
a(ThymineRing)
22 106.61 116.5 C11C12(21.4)
C11C13(20.6)C11H24(18.8)
s(FurancoseRing)
23 81.07 71.33 C3O19(13.6) s(ThymineRing)
24 50.97 47.41 C13O15(19.0)
C11C13(16.2)
O15H31(11.9)
a(HydroxylGroup)
25 38.55 33.11 C13O15(17.5)
C11C13(12.9)
Rocking
(HydroxylGroup)
26 29.21 27.21 C7C1(19.8)
C7C5(17.3)
C7C8(12.6)
Rocking
(ThymineRing)
27 28.56 26.8 C10O9(18.6)
C10C6(16.5)
C10H27(12.9)
Rocking
(AzideRing)
28 17.86 18.42 C8H21(15.6)C8H23(14.9)
C8C7(11.60
Rocking(ThymineRing)
29 12.50 13.6 Twisting
30 10.10 10.8 Twisting
aOnlycontributions>10%arelistedb =stretching,=inplanebending, =outofplanebending,s=symmetric, a= asymmetric