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THE SPECTROSCOPIC (FTIR, FT-RAMAN)

MOLECULAR ELECTROSTATIC POTENTIAL,

NBO, HOMO-LUMO AND NON-LINEAR OPTICAL

EFFECT ANALYSICS OF O-CYANOPHENYL

ACETATE BY AB INITIO AND DENSITY

FUNCTIONAL THEORY CALCULATIONS

M. Elanthiraiyana*, B. Jayasudhab

aP.G and Research Department of Physics, National College, Tiruchirappalli 620001, India

bP.G and Research Department of Physics, H. H. The Rajah’s College, Pudukkottai 622001,

India

ABSTRACT

The FT-IR and FT Raman spectra of o-cyanophenyl acetate [O-CPA] molecule have

been recorded in the region 4000-400cm-1 and 3500-50cm-1 respectively. Optimized

geometrical parameters, harmonic vibrational frequencies and depolarization ratio have

been computed by density functional theory (DFT) using B3LYP/6-31+G (d,p) and

B3LYP/6-311++G(d,p) method and basis sets. The observed FT-IR and FT-Raman

vibrational frequencies are analysed and compared with theoretically predicted vibrational

frequencies. The Mulliken charges, the values of electric dipole moment (µ) and the first-

order hyperpolarizability (β0) of the investigated molecule were computed using DFT

calculations. The calculated HOMO and LUMO energies shows that charge transfer occur

within molecule. The influences of chlorine hydrogen atoms on the geometry of benzene and

its normal modes of vibrations have also been discussed. Unambiguous vibrational

assignments of all the fundamentals was made using the total energy distribution (TED).

Keywords: o-cyanophenyl acetate, FT-IR, FT- Raman, HOMO-LUMO, DFT.

Corresponding author: mobile: +919842659208. E-mail address: [email protected]

(M.Elanthiraiyan)

1. INTRODUCTION

The importance of cyano-substituted aromatic compound in molecular electronic

devices has renewed the interest in their chemical and electronic properties. During the past

decades, organic nonlinear optical materials [1] have been attracted much attention because

of their optical nonlinearity, fast response, relatively low cost, ease of fabrication and

integration into devices. Further, they are used as a reducing agent, oxidizing agent and more

combustible. In addition to that they are used in the treatment of neuro blastoma and lung

cancer.

Journal of Information and Computational Science

Volume 9 Issue 9 - 2019

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However, the detailed HF and B3LYP/6-311++G (d,p) comparative studies on the

complete FT-IR and FT-Raman spectra of o-cyanophenyl acetate [O-CPA] have not been

reported so far. In view of these special properties and uses, the present investigation has

been undertaken to provide a satisfactorily vibrational analysis of o-cyanophenyl acetate [O-

CPA]. Therefore, a thorough Raman, IR, non-linear optical (NLO) properties and HOMO-

LUMO analyses are reported complemented by B3LYP theoretical predictions with basis

set 6-311++G(d,p) to provide novel insight on vibrational assignments and conformational

stability of O-CPA.

2. EXPERIMENTAL METHODS

The pure sample of O-CPA was obtained from Lancaster chemical company, UK and

used as such without any further purification to record FT-IR and FT-Raman spectra. The

room temperature Fourier transform IR spectrum of the title compound was measured in the

4000 – 400 cm-1 region at a resolution of ±1cm-1 using BRUKER IFS-66V Fourier transform

spectrometer equipped with an MCT detector, a KBr beam splitter and globar arc source. The

FT-Raman spectrum was recorded on a BRUKER IFS-66V model interferometer equipped

with an FRA-106 FT-Raman accessory. The FT-Raman spectrum is recorded in the 3500 –

50 cm-1 stokes region using the 1064 nm line of Nd-YAG laser for the excitation operating at

200mW power. The reported wave numbers are expected to be accurate within ± 1 cm-1.

3. COMPUTATIONAL DETAILS

The molecular structure of O-CPA in the ground state is computed using HF and

B3LYP with 6-311++G (d,p) basis set. All the computations have been done by adding

polarization function and diffuse function on heavy atoms [2], in addition to triple split

valence basis set 6-311++G(d,p), for better treatment of polar bonds of methoxy group. The

calculated frequencies are scaled by 0.890 and 0.852 for HF and for B3LYP with 6-311++G

(d,p) basis set by 0.934, 0.940, 0.982, 0.952, 0.899 and 0.969 . The theoretical results have

enabled us to make the detailed assignments of the experimental IR and Raman spectra of the

title compound. The DFT and HF calculations for O-CPA are performed using GAUSSIAN

09W program without any constraint on the geometry [3].

4. RESULTS AND DISCUSSIONS

4.1 Structural properties

The optimization geometrical parameters of O-CPA obtained by the ab initio HF and

DFT/B3LYP methods with 6-311++G (d,p) as basis set. Comparing bond angles and bond

lengths of B3LYP method with HF method, various bond lengths are found to be almost

same at HF/6-311++G (d,p) and B3LYP/6-311++G(d,p) levels.

In O-CPA the benzene ring appears a little distorted with larger C1-C2, C3-C4 bond

length and shorter C2-C3, C5-C6 bond length and angles slightly out of the regular hexagonal

structure. These distortions are explained in terms of the change in hybridisation affected by

the substituent at the carbon site to which it is appended. The C-C bond lengths adjacent to

the C1-O7 and C2-C8 bonds are increased and the angles C1-C2-C3, C2-C3-C4 and C3-C4-

C5 are smaller than typical hexagonal angle of 120 ͦ. This is because of the effect of



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substitution of O-CH3 groups attached to the C1 and cyanogens attached to the C2 of benzene

ring. The calculated geometric parameters can be used as foundation to calculate the other

parameters for the molecule.

4.2. Vibrational spectra

The optimized molecular structure of O-CPA is shown in Fig.1. The vibrational

spectral analysis of O-CPA compound is based on FT-IR (Fig.2) and Raman (Fig.3) spectra.

The O-CPA compound consists of 19 atoms, which has 51 normal modes. The 51 normal

modes of O-CPA have been assigned according to the detailed motion of the individual atoms.

This compound belongs to C1 symmetry group. These modes are found to be IR and Raman

active suggesting that the molecules posses a non-centrosymmetric structure, which recommends

the title compound for non linear optical applications. The computed vibrational wavenumbers and

the atomic displacements corresponding to the different normal modes are used for identifying

the vibrational modes unambiguously. The calculated vibrational wavenumbers, measured

infrared and Raman band positions and their assignments are given in Table 1. Total energy

distribution (TED) is calculated by using the scaled quantum mechanical program (SQM) and

fundamental vibrational modes are characterized by their TED.

C-H vibrations

The aromatic carbon-hydrogen stretching vibrations appear in the region 3100 – 3000

cm−1, in-plane C–H bending vibrations in the range of 1000 – 1300 cm−1 [4]. These vibrations

are observed experimentally at 3096, 3081, 3041cm−1 in the FT-IR spectrum and the

corresponding Raman bands are observed at 3070 cm−1. In-plane C–H bending vibrations of

O-CPA compound are observed at 1175, 1100, 1032 cm−1 in the FT-IR spectrum and 1164 cm-1 in

FT-Raman spectrum which are mixed with other vibrations. The C-H out of plane bending

vibrations are strongly coupled vibrations and occur in the region 900-667 cm-1. The out-of-

plane C–H bending vibrations of O-CPA observed at 830, 766, 751, 714 cm-1 in IR spectrum.

CH3 vibrations

The C–H stretching vibrations of the methyl group are normally falling in the region

2840 – 2975 cm−1 [5]. There are two strong bands at 2991 cm−1 in FTIR spectrum and 2944

cm−1 in Raman spectrum are assigned to symmetric and in-plane stretching modes, respectively.

The theoretically computed values by B3LYP/6-311++G (d,p) method for CH3 stretching

approximately coincides with experimental values. The C–H in-plane and out-of-plane

bending vibrations for methyl group in the O-CPA compound are assigned at 1276 in Raman,

1042 cm−1 in IR respectively. These assignments are in line with the literature values and

coincide with the calculated frequencies by B3LYP/6-311++G (d,p). The bands obtained at

966 cm-1 in IR Spectrum and1039 cm-1 in Raman are assigned to CH3 in-plane and out-of-

plane rocking modes respectively and they show good agreement with the calculated values

[6].

C–C vibrations

Generally the C-C stretching vibrations in aromatic compounds are seen in the region

of 1430 – 1650 cm−1 [7]. The six ring carbon atoms undergo coupled vibrations, called

skeletal vibrations and give bands in the region 1660 – 1420 cm−1. Therefore, the C-C



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stretching vibrations of O-CPA are found at 1608, 1575, 1488, 1451, 1432, 1371 cm-1 in

FTIR and 1276 cm−1 in FT-Raman spectrum and these modes are confirmed by their TED

values. In the present study the bands observed at 909, 874 cm−1 in the FTIR spectrum and

719 cm−1 in Raman spectrum have been designated to ring in-plane bending modes by careful

consideration of their quantitative descriptions. The ring out-of-plane bending modes of O-

CPA are also listed in Table 1.The reduction in the frequencies of these modes are due to the

change in force constant and the vibrations of the functional groups present in the molecule.

C≡N Vibrations

For the aromatic compound which bears a C≡N group attached to the ring, a band of

very good intensity has been observed in the region 2240–2221 cm-1 and it is being attributed

to C≡N stretching vibrations. The strong bands obtained at 2236 cm-1 in IR and 2234 cm-1

in

Raman spectrum are assigned to C≡N stretching vibration of O-CPA and the corresponding

force constant contribute 89% to the TED. The in-plane and out-of-plane bending modes of

C≡N group are strongly coupled with C–C–C bending modes. They are due to the out-of-plane

aromatic ring deformation with in-plane deformation of the C≡N vibration and in-plane

bending of the aromatic ring with the C–C≡N bending. The FT-Raman bands observed at 495

and 271 cm-1 are assigned to the individual in-plane and out-of-plane bending modes of C≡N

vibration, respectively [8].

C=O Vibrations

The carbonyl bonds are the most characteristic bands of infrared spectrum. Both the

carbon and oxygen atoms of the carbonyl group move during vibration and they have nearly

equal amplitudes. The carbonyl frequencies can be considered altered by intermolecular

hydrogen bonding. A great deal of structural information can be derived from the exact

position of the carbonyl stretching absorption peaks. Normally, carbonyl group vibrations [9]

occur in the region 1800–1700 cm-1. Accordingly, the FT-IR bands observed at 1781cm-1 is

assigned to C=O stretching vibration for O-CPA. The C=O in-plane and out-of-plane bending

vibrations of O-CPA have also been identified and listed in Table 1.

5. HOMO–LUMO ANALYSIS

The conjugated molecules are characterized by a highest occupied molecular orbital-

lowest unoccupied molecular orbital (HOMO–LUMO) separation, which is the result of a

significant degree of intermolecular charge transfer (ICT) from the end-capping electron-

donor groups to the efficient electron-acceptor groups through the conjugated path [10]. The

strong charge transfer interaction through conjugated bridge results in substantial ground

state donor–acceptor mixing and the appearance of a charge transfer band in the electronic

absorption spectrum. The atomic orbital components of the frontier molecular orbitals are shown

in Fig. 4. The HOMO–LUMO analysis for the title molecule has been carried out using

B3LYP/6-311+G (d,p) method.

EHOMO = -0.27112 a.u



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ELUMO = -0.07671a.u

Energy gap = 0.19441a.u

This low energy gap value of O-CPA is responsible for the bioactive property of the

compound. An electronic system with a larger HOMO-LUMO gap should be less reactive

than one having a smaller gap [11]. The highest occupied molecular orbitals are localized

mainly on nitro groups; the lowest unoccupied molecular orbitals are also localized on carbon

atoms.

6. MULLIKEN ATOMIC CHARGES

In order to determine the electron population of each atom of the title molecular,

Mulliken atomic charges of O-CPA calculated by DFT/B3LYP method using 6-311++G (d,p)

basis set shown in Fig.5. The charge distribution of O-CPA shows that the carbon atom

attached with hydrogen atoms is negative, whereas the remaining carbon atoms are positively

charged. The oxygen atom has more negative charges whereas all the hydrogen atoms have

positive charges. The maximum positive atomic charge is obtained for carbonyl carbon (C2)

when compared with all other atoms. The result shows that substitution of the aromatic ring

by nitriles group lead to a redistribution of electron density. The oxygen and nitrogen atoms

exhibit a negative charge, which are donor atoms. Besides, as can be seen in Table 2, all

hydrogen atoms have a net positive charge is an acceptor atom. So, this may suggest the

presence of intermolecular hydrogen bonding in the crystalline phase.

8. NON-LINEAR OPTICAL EFFECTS

Non-linear optical (NLO) effects arise from the interactions of electromagnetic fields in

various media to produce new fields altered in phase, frequency, amplitude or other

propagation characteristics from the incident fields. Organic molecules with significant non-

linear optical activity generally consist of a p electron conjugated moiety substituted by an

electron donor group on one end of the conjugated structure and an electron acceptor group

on the other end, forming a ‘push–pull’ conjugated structure [12]. The total static dipole

moment (μ) and the first hyperpolarizability (β) using the x, y, z components are defined as

[13].

µ = (µx2 + µy

2 + µz2)1/2 .

xx yy zzα +α +αα =

3

βx = βxxx + βxyy + βxzz

βy = βyyy + βxxy + βyzz

βz = βzzz + βxxz + βyyz

β0 = (βx2 + βy

2 + βz2)1/2

The calculated first hyperpolarizability and the total molecular dipole moment of o-

cyanophenyl acetate are 3.1688 × 10-30 esu and 12.3588 Debye, respectively. The total dipole

moment of title compound is approximately 10 times greater than that of urea (1.3732 debye)

and first hyperpolarizability of the title molecule is 8.5 times greater than that of urea (0.3728



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× 10-30 esu) obtained by B3LYP/6-311++G(d,p) method. These results indicate that O-CPA

is a good non-linear optical material.

10. OTHER MOLECULAR PROPERTIES

The values of some thermodynamic parameters (such as specific heat capacity, zero

point energy, entropy, thermal energy, rotational constant and dipole moment) of O-CPA by

HF and DFT with 6-311+G (d,p) basis sets are listed in Table 3. The global minimum energy

obtained by HF and DFT structure optimization using 6-311+G(d,p) basis set for the title

molecule as -518.47034128 and –522.50648429 Hartrees. Scale factors have been recommended

for an accurate prediction in determining the zero-point vibration energy (ZPVE), and the

entropy (Svib). The variation in the ZPVE seems to be insignificant. The total energy and the

change in the total entropy of the compounds at room temperature are also presented.

11. CONCLUSION

The vibrational properties of o-cyanophenyl acetate have been investegated by FTIR

and FT-Raman spectroscopy and were performed accordingly to the SQM force field method

based on the ab initio HF/6-311++G(d,p) and B3LYP/6-311++G(d,p). The role of nitro and

other groups in the vibrational frequencies of o-cyanophenyl acetate have been discussed. The

various modes of vibrations are unambiguously assigned based on the TED output. The

vibrational wave number, IR and Raman intensities were calculated and they are found in

very good agreement with experimental vibrations. The HOMO-LUMO energy gap, NLO

and other thermodynamic properties, Mullikens atomic charges, dipole moment and

optimized parameters of o-cyanophenyl acetate have been also discussed elaborately



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References

[1] P.N. Parasad, D.J. Willams, Introduction to Nonlinear optical Effects in Molecules

and polymers, John Wiley& Sons, New York, 1991.

[2] M.J.Frisch, J.A.Pople, J.S.Binkley, Journal of Chemical Physics, 80 (1984) 3265.

[3] N. Sundaraganesan, S. Ilakiamani, H. Saleem, P.M. Wojieehowski, D. Michalska,

Spectrochim. Acta A 61 (2005) 2995.

[4] G. Keresztury, Raman Spectroscopy Theory, in: J. M. Chalmers, P.R. Griffiths

(eds). Handbook of vibrational spectroscopy, Vol.1, John Wiley & sons Ltd., 2002, P.

71.

[5] M.Elanthiraiyan, B.Jayasutha, M. Arivazhagan, Spectrochim. Acta A, 134 (2015) 543

[6] M.Elanthiraiyan, B.Jayasutha,M. Arivazhagan,.J.Rec.Sce. 2 (2014) 17.

[7] M. Arivazhagan, P. Muniappan, R. Meenakshi, G. Rajavel, Spectrochim. Acta A 105

(2013) 102-108.

[8] S.Ramalingam, S.Periandy, M. Karabacak, N. Karthikeyan, Spectrochim. Acta A 104

(2013) 337-351.

[9] M.Elanthiraiyan, B.Jayasutha, M.Arivazhagan, N.Saravanan, 86 (2015) 35018.

[10] M. Arivazhagan, R.Kavitha, Journal of Molecular Structure 1011 (2012) 111–120.

[12] M. Arivazhagan, R.Gayathri, Spectrochim. Acta A, 116 (2013) 170.

[13] J.S. Murray, K. Sen, Molecular Electrostatic Potentials, Concepts and 399

Applications, Elsevier, Amsterdam, 1996.



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Table 1. Vibrational assignments of fundamental modes of o-cyanophenyl acetate along with calculated IR, Raman intensities, force

comtant and normal mode description (charaxterized by TED) based on quantum mechanical force field calculations using HF

and B3LYP with 6-311++G(d,p) basis set.

Sl.

No

.

Observed

fundamentals (cm-1) Calculated frequencies (cm-1)

Vibrational

assignments

(%TED) FT-IR

FT-

Raman

HF/6-311++G(d,p) B3LYP/6-311++G(d,p)

Unscale

d

Scale

d

IR

intensity

Raman

intensit

y

Force

constan

t

Unscale

d

Scale

d

IR

intensity

Raman

intensit

y

Force

constan

t

1. 3096(w) -- 3222 3109 4.1934 6.7166 126.40 3204 3101 3.4518 6.6420 123.43 CH(99)

2. 3081(w) -- 3217 3094 2.6023 6.6717 19.09 3198 3087 2.0080 6.5960 19.99 CH(98)

3. -- 3070(s) 3208 3081 4.2928 6.6132 48.79 3190 3076 3.7302 6.5377 46.68 CH(96)

4. 3041(w) -- 3196 3049 1.3204 6.5453 26.09 3178 3045 1.1850 6.4698 24.93 CH(95)

5. 2991(w) -- 3178 3003 3.8240 6.5663 34.14 3158 2996 4.7521 6.4810 33.55 CH3 ss(91)

6. -- 2944(s) 3132 2953 1.7789 6.3642 12.83 3114 2949 1.7599 6.2831 12.33 CH3 ips(90)

7. 2880(w) -- 3065 2889 1.7645 5.7419 57.54 3052 2885 1.5110 5.6919 60.76 CH3

ops(89)



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8. 2236(vs) 2234(vs) 2338 2247 26.5418 40.8343 385.70 2335 2241 26.6855 40.7308 382.08 CN(89)

9. 1781(s) -- 1857 1790 429.437

6 24.2267 27.12 1854 1785

445.583

9 24.1910 26.45 C=O(88)

10. 1608(vs) 1606(vs) 1645 1611 27.7656 9.7844 161.96 1637 1608 27.2875 9.6637 155.99 CC(87)

11. 1575(ms

) -- 1615 1582 14.7110 9.2319 23.51 1607 1.579 13.8640 9.0893 22.54 CC(86)

12. 1488(vs) -- 1517 1471 74.4399 3.5695 17.69 1511 1481 71.5712 3.4936 16.69 CC(85)

13. 1451(vs) -- 1487 1443 14.4546 1.3677 15.63 1483 1453 13.7132 1.3592 12.90 CC(83)

14. 1432(w) -- 1480 1423 46.5243 2.8342 3.15 1476 1434 48.4099 2.7209 3.09 CC(82)

15. 1371(vs) -- 1472 1360 3.4991 1.3718 17.93 1478 1366 2.9273 1.3793 14.59 CC(81)

16. 1295(w) -- 1405 1282 38.8947 1.4853 5.40 1399 1297 35.1935 1.4604 4.82 C-O(79)

17. -- 1276(ms

) 1338 1263 0.7995 9.2283 34.26 1321 1271 0.7323 8.3820 37.51

CH3 ipb(81)

bCO(12)

18. -- 1231(s) 1296 1221 26.8691 1.5950 2.19 1296 1233 20.8692 1.6006 2.59 C-O(80)

19. 1229(w) -- 1256 1238 120.405

5 3.1457 204.16 1248 1227

100.842

1 3.1291 192.46 C-C(78)

20. 1197(w) 1197(w) 1214 1182 5.3186 2.2561 49.70 1212 1194 3.1969 2.2615 144.27 C-C(77)



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21. 1175(w) -- 1191 1163 433.091

1 2.6575 0.02 1183 1171 1.9996 0.9416 07.28

bCH(75)

bCC(13)

22. -- 1164(w) 1185 1155 .3053 0.9360 36.09 1176 1163 431.078

6 2.4033 35.80

bCH(73)

bCC(14)

23. 1100(vs) -- 1124 1114 33.2201 1.5685 0.58 1123 1106 42.0783 1.5768 0.58 bCH(72)

24. 1042(w) -- 1060 1055 3.8736 1.2198 42.20 1060 1046 5.2895 1.1812 17.82 CH3

opb(74)

25. -- 1039(vs) 1057 1048 7.0000 1.3212 90.72 1055 1035 6.5814 1.3815 118.72 CH3

opr(71)

26. 1032(w) -- 1007 1044 76.1307 1.1477 9.79 1005 1028 8.2478 0.8058 1.43 bCH(70)

27. 1010(vs) -- 1004 1031 1.0093 0.7815 0.39 1002 1026 85.6918 1.1679 7.33 CH3 sb(71)

28. 966(w) -- 971 989 1.0755 0.7665 0.92 947 977 1.8240 0.7780 0.67 CH3 ipr(70)

29. 909(s) -- 922 927 62.9060 3.4687 30.41 920 919 82.5164 3.3898 32.10

30. 874(w) -- 891 861 2.2241 0.6811 1.70 891 884 4.116 0.6946 1.82 bCC (68)

bCC(22)

31. 830(s) -- 798 848 39.7650 1.1233 21.43 797 821 40.2962 1.0821 77.76 CH(59)

32. 766(ws) -- 778 743 26.4469 0.7279 4.47 777 774 25.3799 0.7604 4.54 CH(58)

Rasymd(21)



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33. 751(w) -- 761 730 11.7666 0.9854 33.46 766 764 16.4775 0.9614 20.72 CH(59)

34. -- 719(s) 719 694 5.866 1.5405 12.33 719 728 7.5357 1.4986 137.50 bCC(60)

35. 714(w) -- 642 683 1.6177 1.5310 24.81 644 701 1.5019 1.5470 23.88 CH(57)

36. 669(s) -- 585 651 0.2366 1.3641 16.68 595 662 0.1621 1.4836 16.02 bOC(60)

37. -- 662(ms) 580 648 0.6430 0.9031 19.48 582 654 0.7547 0.8870 14.71 Rtrigd(65)

38 603(w) -- 558 565 5.6159 0.4997 9.06 561 590 5.6249 0.4984 9.12 Rsymd(64)t

39. 588(s) -- 541 552 29.9150 0.6742 30.25 542 572 32.7179 0.6688 25.60 Rasymd(61)

40. 560(w) -- 517 528 1.5878 1.3683 102.68 519 542 1.0149 1.3742 104.01 CO(58)

41. -- 551(ms) 452 520 0.6194 0.4208 3.39 452 531 0.8214 0.4255 3.11 bOC(61)

42. 546(ms) -- 398 511 0.8303 0.4119 21.87 399 524 0.8038 0.4096 18.70 tRtrigd(55)

43. 541(w) -- 377 502 2.4616 0.6535 153.31 380 513 2.4718 0.6463 150.69 tRtrigd(54)

44. 495(vs) -- 365 453 1.3091 0.6755 22.60 366 475 1.2100 0.6651 24.49 bCN(59)

45. 481(w) -- 269 448 0.9007 0.1976 40.97 268 436 1.0662 0.1966 38.55 OC(58)

46. -- 451(w) 150 349 1.7320 0.1042 107.82 152 360 1.7882 0.1173 100.35

tRasymd(53

)

tRtrigd(21)

47. -- 391(w) 139 338 0.2446 0.0147 19.97 138 355 0.3606 0.0150 20.64 CC(51)



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48. -- 384(w) 132 302 3.2229 0.0364 37.15 132 312 3.0905 0.0322 35.05 CO(56)

49. -- 331(ms) 97 243 0.5080 0.0241 221.53 96 252 0.5049 0.0234 218.24 CC(50)

50. -- 271(w) 57 141 3.6354 0.0097 310.59 56 151 3.6905 0.0083 308.14 CN(52)

51. -- 166(w) 42 -- 2.6051 0.0052 662.60 40 -- 2.3905 0.0051 673.02 tOCH3(53)

Abbreviations: – stretching; ss – symmetric stretching; ass – asymmetric stretching; b – bending; - out-of-plane bending; R

– ring; trigd – trigonal deformation; symd – symmetric deformation; asymd – antisymmetric deformation; t –

torsion; s – strong; vs – very strong; ms – medium strong; w – weak; vw – very weak.



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Table 2. The charge distribution calculated by the Mulliken method for o-

cyanophenyl acetate.

Atoms

Method / Basis set

HF/6-311++G(d,p) B3LYP/6-31H++(d,p)

C1 -0.611 -1.426

C2 1.732 2.640

C3 -0.093 0.106

C4 -0.347 -0.214

C5 -0.164 -0.199

C6 0.003 -0.506

O7 -0.066 -0.048

C8 -1.063 -1.095

H9 0.211 0.192

H10 0.178 0.173

H11 0.178 0.175

H12 0.206 0.282

N13 -0.185 -0.217

C14 0.143 0.109

C15 -0.436 -0.392

H16 0.197 0.194



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H17 0.162 0.182

H18 0.188 0.151

O19 -0.245 -0.036



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Table 3. The thermodynamical parameters o-cyanophenyl acetate calculated at the

HF/B3LYP methods and basis set.

Parameter

Methods/Basis set

HF/6-31++G(d,p) B3LYP/6-

31++G(d,p)

Total energy (thermal), E total (k cal mol-1) 95.432 89.493

Heat capacity cv. (k cal mol-1) 0.0413 0.0301

Entropy.S (k cal mol-1K-1)

Total 0.0943 0.928

Translational 0.0456 0.0394

Rotantional 0.0285 0.0291

Vibrational 0.0204 0.0197

Vibrational energy, E vib (k cal mol-1) 81.734 68.501

Zero point vibrational energy, (k cal mol-1) 101.732 97.473

Rational constants(GHz)

A 2.9931 3.123

B 1.5921 1.601

C 0.9432 0.9982

Dipole moment (Debye)

x -1.6732 -2.0012

s -4.432 -5.0021

z -0.0021 0.0010

total 5.0123 5.9231



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Fig. 1.



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Fig. 3.

Ram

an

In

ten

sit

y (

Arb

.

un

its)

(a)

(b)

(c)



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Fig. 2.

4000 3500 3000 2500 2000 1500 1000 400

Tra

ns

mit

tan

ce

(%

)

(a)

(b)

(c)



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(First Excited State)

ELUMO = -0.07671 a.u

-1.5

-1

-0.5

0

0.5

1

1.5

2

C1

C2

C3

C4

C5

C6

O7

C8

H9

H1

0

H1

1

H1

2

N1

3

C1

4

C1

5

H1

6

H1

7

H1

8

O1

9

ATOMS

CH

AR

GES

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

C1

C2

C3

C4

C5

C6

O7

C8

H9

H1

0

H1

1

H1

2

N1

3

C1

4

C1

5

H1

6

H1

7

H1

8

O1

9

ATOMS

CH

AR

GES

Fig. 5.



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LUMO

HOMO

Fig.4.



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Fig.6.



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Figure caption

Fig. 1: The optimized structure of o-cyanophenyl acetate

Fig. 2: Comparison of observed and calculated IR spectra of o-cyanophenyl acetate.

(a) observed, (b) calculated with B3LYP/6-311++G(d,p) and (c) calculated

With HF/6-311++G (d,p).

Fig. 3: Comparison of observed and calculated IR spectra of o-cyanophenyl acetate.

(a) observed (b) calculated with B3LYP/6-311++G(d,p) and (c) calculated

With HF/6-311++G (d,p)

Fig. 4 the atomic orbital compositions of frontier molecular orbital for o-

cyanophenyl acetate.:

Fig. 5: Plot of Mulliken’s charges obtained by HF, B3LYP/6-311++G (d,p) method.

Fig. 6: Molecular electrostatic potential map calculated at B3LYP/6-311++G (d,p)

Level for o-cyanophenyl acetate.



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