Accepted Manuscript Spectroscopic (FT-IR, FT-Raman, UV and NMR) Investigation on 1-Phenyl-2Nitropropene by Quantum Computational Calculations S. Xavier, S. Periandy PII: DOI: Reference:

S1386-1425(15)00527-2 http://dx.doi.org/10.1016/j.saa.2015.04.055 SAA 13606

To appear in:

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Received Date: Revised Date: Accepted Date:

8 December 2014 25 March 2015 20 April 2015

Please cite this article as: S. Xavier, S. Periandy, Spectroscopic (FT-IR, FT-Raman, UV and NMR) Investigation on 1-Phenyl-2-Nitropropene by Quantum Computational Calculations, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (2015), doi: http://dx.doi.org/10.1016/j.saa.2015.04.055

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SPECTROSCOPIC (FT-IR, FT-Raman, UV and NMR) INVESTIGATION ON 1-PHENYL-2-NITROPROPENE BY QUANTUM COMPUTATIONAL CALCULATIONS S. Xavierab*, S. Periandyc, a

Department of Physics, St. Joseph College of Arts and Science, Cuddalore, Tamil Nadu, India. b

Research scholar, Bharathiyar University, Coimbatore,Tamil Nadu, India c

Department of Physics, Tagore Arts College,Puducherry, India.

ABSTRACT In this paper, the spectral analysis of 1-phenyl-2-nitropropene is carried out using the FTIR, FT Raman, FT NMR and UV – Vis spectra of the compound with the help of quantum mechanical computations using ab-initio and density functional theories.The FT-IR (4000 - 400 cm-1) and FT-Raman (4000-100 cm-1) spectra were recorded in solid phase, the1Hand 13C NMR spectra were recorded in CDCl3 solution phase and the UV-Vis (200-800 nm) spectrum was recordedin ethanol solution phase. The different conformers of the compound and their minimum energies are studied usingB3LYP functional with 6-311+G(d,p) basis set and two stable conformers with lowest energywere identified and the same was used for further computations. The computedwavenumbersfrom different methods are scaled so as to agree with the experimental values and the scaling factors are reported. All the modes of vibrations are assigned and the structure the molecule is analyzed interms of parameters like bond length, bond angle and dihedral angle predicted by bothB3LYP and B3PW91 methods with6-311+G(d,p) and 6311++G(d,p) basis sets.The values of dipole moment (µ), polarizability (α) and hyperpolarizability (β) of the molecule are reported, using which the non -linear property of the molecule is discussed. The HOMO-LUMO mappings are reported which reveals the different charge transfer possibilities within the molecule. The isotropic chemical shifts predicted for1Hand

13

C atoms using gauge invariant atomic orbital (GIAO) theory show good agreement

with experimental shifts. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. The local reactivity of the molecule has been studied using the Fukui function.The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated. 1

Keywords:1-phenyl-2-nitropropene,chemical shifts; NBO, HOMO-LUMO, Fukui function. *

Corresponding author E-mail address: [email protected]

Tel & Fax- +91 9443428971

1. Introduction 1-Phenyl 2-nitropropene [1P2NP]is an aromatic hydrocarbon with nitro and propenesubstitution in the phenyl ring. It is greenish-yellowsolidpowder from which certain vital drugs are synthesized.Amphetamine, one of the important derivative of 1P2NP, is a prime central nervous system stimulant, and an important member of phenyl ethylamine drug family that are used in the treatment of attention deficiency, hyperactivity disorder and narcolepsy. Amphetamine is also used as performance and cognitiveenhancer, and recreationally as aphrodisiac and euphoriant. [1] The compound 1P2NP is also known as β-methyl-β-nitrostyrene or trans-β-methyl-β-nitrostyrene. Jack DeRuiter et al have investigated the conversion of 1P2NP to amphetamine under variety of reaction conditions using gas chromatography and mass spectrometry.[2] The versatile intermediate was prepared by treating benzaldehyde with butylamine and nitroethane. Reduction of the nitropropene with a 5- molar excess of lithium aluminium hydride was found to yield 1phenyl-2- proponoxime and partial reduction with large excess of lithium aluminium hydride yielded amphetamine.1P2NP was also converted into ketone, 1 phenyl 2- propene, by partial reduction and hydrolysis. Amination of this ketone under Leuckart and reductive amination conditions provided amphetamine as the principle product.GC-MS analysis revealed that these samples also contain several other by-products. However, literature survey indicates that much works have not been carried out on these molecules, particularly on 1P2NP.Hence a thorough and systematic spectral analysis is attempted on 1P2NP with the help standard experimental and computational techniques.

2.

Experimental details 2

The compound 1-Phenyl-2-nitropropenewaspurchased in the powder form from Sigma– Aldrich Chemicals, Chennai. The FT-IR spectrum of the compound was recorded using a Bruker IFS 66V spectrometer in the range of 4000–400 cm−1. The spectral resolution is ±2 cm−1. The FT-Raman spectrum of the same compound was also recorded using the same instrument with an FRA 106 Raman module equipped with aNd:YAG laser source operating at 1.064 µm line widths with 200 mW power, in the range of 4000–100 cm−1 with a scanning speed of 30 cm−1 min−1and spectral width 2 cm−1. The frequencies of all bands are accurate to ±1 cm−1.The high resolution HNMR and CNMR spectra were recorded using 300 MHz and 75 MHz NMR spectrometer respectively.The UV-Vis spectra was recorded in liquid phase dissolved in ethanolin the range of 200 nm to 800 nm, with the scanning interval of 0.2 nm,using the UV1700 series instrument.

3.

Computational details The entire quantum chemical computations are performed using the Gaussian 09

softwareon a Pentium IV/3.02GHz personal computer

[3]

. The wave numbers and geometrical

parameters are computed using HF, B3LYP and B3PW91 methods in combination with 6311+G (d, p) and 6-311+G (d, p)basis sets. The geometry of the title molecule 1-phenyl-2nitropropeneis fully optimized usingB3LYP functional with6-311+G (d, p) basis set and the same geometry is used for the conformational analysis using semi-empirical method withPM6 basis set. The electronic properties, such as NBO and HOMO-LUMO were calculated using time-dependent TD-SCF - B3LYP methodunder the same basis set. Similarly the NMR chemical shifts are also carried out by GIAO method in combination with B3LYP/6-311G + (2d, p). In addition, Fukui function, the dipole moment, linear polarizability and the first order hyper polarizability of the title molecule are also computed using B3LYP method with the 6-311+G (d, p) basis set.

4.

Results and discussion 3

4.1. Conformational analysis The optimized geometry of the molecule obtained using B3LYP with 6-311+G (d,p) basis set was used for conformational analysis of the molecule.Conformational analysis was performed by potential energy surface scan functionsemi-empirical method with PM6 basis set and by varying the torsion angle C18-C14-N15 in the steps of 36◦ over one complete rotation 0360◦ as recommended in the previous work on a similar molecule[4]. The graphical result, total energy verses scan coordinates, of this conformer analysis is presented in Fig. 1. The graph clearly shows that there are two conformers at minimum energy levels, one at 80◦ and the other at 220◦ with total energy 0.1636 and 0.1637 hatree respectively. The structure of the molecules at these conformation is shown in Fig.1, as conformer I and II, of which the conformer I represents the most stable conformer of this compound. Praveen [5, 6] et al. have made conformationalanalysis in the case of p-tolytrichlorosilane, which showed that the conformer with staggered structure gives lowest energy configuration whereas the conformer with eclipsed structuregives highest energy configuration. Exactly similar observation is also made in this molecule, a staggered form of C18-C14-N15 gives a most stable conformation and an eclipsed form gives the highest unstable conformer of the molecule1P2NP.

4.2.

Molecular geometry The stable configuration of the molecule obtained from the conformer analysis which has

been used for the structural analysis is shown in Fig. 2. The calculated bond length, bond angle and dihedral angle obtained using HF, B3LYP and B3PW91methods with 6-311+G(d,p) basis sets for this configuration with experimental values are presented in Table 1. The comparative bar diagram for bond lengths is presented in Fig. 3a. The CC bond lengths of the aromatic ring varies between 1.38Å to 1.39Å in all the methods, the experimental value also lie closer to these values, which signifies that the demarcation between single and double bond is not possible within the ring due to the conjugation of the electron. But in case of the propene substitution, the bond length C12C14 clearly shows that it is double bondwith value 1.32 Å in HF and 1.342 Å in B3LYP and B3PW91 methods,while the experimental value is 1.33Å. The two CC bond lengths C3-C12 and C14-C18 are longer(1.48Å) than any value inside the ring which shows only these

4

two bonds here are pure single bonded CC, which again confirms the conjugation of the electrons inside the benzene ring. In the case CH bond lengths, it is observed that all the CH bond lengths whether in phenyl ring or in the methyl group, show almost the same value 1.08Å- 1.09Å, agreeing with the experimental value which show that these bond lengths are not subjected to any external influence. Similarly in the nitro group, there are two N-O bond lengths, with computed values 1.188 Å in HF and 1.22 Å in B3LYP and B3PW91 methods, the experimental value is 1.22Å which again shows that these bonds are remain uninfluenced and the theoretical approximations are valid for these bonds. The comparative bar diagram for bond angle is presented in fig. 3b. This diagram shows that the bond angle at every carbon atom in the benzene ring is 120º in all the methods, which is slightly higher than the experimental value 119. 5 . This fact indicates that the hexagonal structure of the phenyl ring is remain undisturbed in this molecule by the substitutional group.

4.3. Vibrational assignments The vibrational frequencies for all the fundamental modes of 1-phenyl-2-nitropropene, are computed using HF, B3LYP, B3PW91 methods with 6-311+G (d,p) basis sets and the values along with the experimental values and assignments are presented in Table. 2. The molecule consists of 21 atoms and belongs toC1point group, hence the57 fundamental modes of vibrations are distributed asΓvib = 39 A′ + 18 A″.In order to fit the theoretical and experimental frequencies, suitable scaling factors are introduced. The scaling factors are 0.914, and 0.9067 for HF/6311+G (d,p) and 0.9628 and 0.959 forB3LYP/6-311+G (d,p) and B3PW91/6-311+G (d,p) respectively. The experimental and computational IR and Raman spectra of the compound are shown in Fig. 4&5 respectively.

4.3.1. AromaticC–H Vibrations TheC–H stretching vibrations of the phenyl ring are normally observed in the region 3100–3000 cm−1[10–11]which shows their uniqueness of the skeletal vibrations.In the present molecule the stretching vibrationsappear at 3090, 3080, 3070, 3060, 3010cm−1. All the five bands are well within the expected range which shows the aromatic nature of the phenyl ring is 5

not disturbed by any of the substitutional group. All these vibrations are foundactive only in IR not in Raman. Similarly, the C–H in-plane ring bending vibrations for aromatic CH occurs as strong to weak intensity bands in the region 1300–1200 cm−1[12]. In the present compound, the bandsare observed at 1350, 1330, 1320, 1300 and 1270 cm-1. The last vibration 1270 cm-1 is observed in FT-Raman with very strong intensity. Except the one vibration,others are observed in the expected region. The C–H out-of-plane bending vibrations are expected in the region 1000–800 cm−1. [13]But these vibrations are found at 860, 760, 720,700 and 680cm-1 in the present case.This shows only the out- of- plane bending vibrations are influenced by the other modes, particularly the N-O and C-C in plane bending modes which also falls in this range. This trend was also observed by H.M Badawiin 2- 4 dichlorophenoxyacetic[14].

4.3.2. Propene group vibrations The aliphatic CH stretching bands are expected between3000 and 2900 cm-1[15]. In the present compound the vibrations of the propene group are observed at 2990, 2980, 2970 and 2960 cm-1. Similarly, the in-plane and out of-plane deformationof such CH bands are expected in the regions 1200–1100 cm-1 and 900–700 cm-1. Four bands for each in-plane and out of plane are observed at1220, 1160, 1110 and 1090 cm-1and 670, 660, 580 and 570 cm−1 respectively. These observations indicate that the stretching and in-plane bending are observed within the expected region and out-of-plane vibrations are found below its expected range. This trend is exactly same as that in benzene ring CH. This shows that the CH vibrations both aromatic and aliphatic remain independent of other vibrations in the molecule except the out of plane bending vibrations where NO and CC in-plane bindings interfere.

4.3.3. TheCC vibrations The CC stretching vibrations for phenyl ring are generally observed between 1600-1400 cm

-1[16]

, in which the bands between 1600-1500 cm-1 are assigned to C=C stretching and the rest

to C-C stretching, even though no such distinction is present within the ring. In the present compound also, the bands observed at 1630, 1620, and 1580 cm-1 are assigned to C=C and the bands at 1480, 1460, 1440 to C-C in the phenyl ring. These observations for the aromatic CC are 6

in agreement with literature values, which indicate that the skeletal vibrations are not affected by the substitutional vibrations. In the case of propene group, there are two C-C and one C=C whose stretching vibrations are observed at 1680 cm-1 for C=C and at 1505 and 1490 cm-1 for C-C. The in- plane bending and out-of-plane bending vibrations for C=C are assigned at 1090 and 670 cm-1 respectively. The same thing for C-C are assigned at 970 & 950 and 570 & 540 cm-1 respectively. These observation also are in agreement with the above cited literatures[17], except the bands for out of plane bending of C-C, which is again due to the interference of NO group, whose out of plane bending vibrations also lie in this range. Hence, it may be concluded that the CC vibrations in substitutional group are also not affected by the presence of other vibrations in the molecule except the C-C out of plane bending.

4.3.4. NO2 vibrations The characteristics group frequencies of the NO2 are usually independentof the rest of the molecule. The nitro groupvibrations are generally associated with symmetricand anti-symmetric stretching, in-plane bending vibrations which includes scissoringand rocking, and the out of plane bending which includes the wagging and twisting modes. The asymmetricstretching vibrations of the NO2 group are assigned at 1570–1485 cm-1[18]and that of symmetric vibrations at 1370-1320 cm-1. Rajamani et al

[19]

have identified the asymmetric stretching mode at 1570

cm-1 in 4-nitro phenoxyphenyl. In the present compound, two NO2 stretching vibrations have been observed at 1550 and 1520 cm-1 which shows that they are asymmetric in mode. The inplane and out-of-plane bending vibrations are found at 1010 & 980 cm-1 and 660 & 580 cm-1 respectively for NO2 group. The presence of the NO2 bands in this molecule indicates that the stretching frequencies are not influenced whereas there is some mixing of CC vibrations in bending frequencies.

4.3.5. C-N vibrations

7

The mixing of several bands causesvery difficult inthe identification ofC-N vibrations in many molecules.Silverstein et al [20] assigned the C-N stretching in the region 1382-1266 cm-1.In the present molecule, the band is observed at 1430 for C-Nstretching vibration. Frequency nearer to 1500cm-1 indicates C=N while frequency nearer 1300 cm-1 indicates the presence of C-N, in this case it lies in between these two values, which may be due to the conjugation of electrons between the two adjacent NO bonds with this CN bonds. Similarly,the in-plane and out-of-plane vibrations are assigned at900 and 520 cm-1 respectively for this C-N which again has similar deviation noticed as in stretching, which may also be due the conjugation of NO and CN bonds.

4.4. Mullikan Atomic charges Mullikan atomic charges calculation has an important role as the atomic charges cause the dipole moment, molecular polarizability, electronic structure and molecular reactivity of the system. The charges on the atoms of the present compound are calculated by Mullikan population analysis using B3LYP method with 6-311+ G (d, p) basis set, the graphical representation of the results are presented in Fig. 6. In the case of benzene ring, all the carbon atoms areexcepted to be equally negative, but in this case atom C3 is found to be highly positive which may be due to the attachment of entire nitro propene group at this atom. C4 is also found to be relatively more negative as some of the negative charge from C3 might have been repelled towards to this atom. But, all the hydrogen atoms in the benzene are found to be equally slightly positive as expected as in other molecules. In the case of propene group, there are three carbon atoms, of which one (C14) is positive and the other C12 and C18 are equally negative. The positive charge of C14 may be due to its attachment with the NO2 group and the equal negative charge of C12 and C18 may be also due to the same reason, as these carbon atoms jointly acts as a dipole. It is the charge distribution due to NO2becomes the reason for high negative charge of C3 in benzene. The C18 carbon atom is in methyl group, hence it has the chance to attract the electrons from three hydrogen atoms, which shows the delicate charge distribution among these carbon atoms C3-C12-C14-C18. The hydrogen atoms in this propene group are also equally positive, exactly similar to the hydrogen atoms in benzene group. The charge distribution in NO2 group shows that all the three atoms in this group are equally negative, which shows they have equally divided the electrons withdrawn 8

from C14.

4.5. Global softness and local region-selectivity Besides the traditional reactivity descriptors, such as HOMO & LUMO, there are certain other chemical reactivity descriptors such as global hardness (η), global softness (S) local softness (∆S), Fukui function (f) globalelectrophilicity (ω) and local electrophilicity (∆ω) [21-24] which are defined by Koopmans’s theorem [25-26] as follows. The above descriptors are calculated using the formulae cited in the previous works

[27].

All these parameters are computed

usingB3LYP method and 6-311+ G (d, p) basis set and the values are presented in Table. 5 & 6. The global hardness value (4.011eV) in comparison with benzene (3.294 eV) shows that the hardness is increased for this molecule due to the attachment of nitro propene group. This is also reflected in global softness value which gets decreased from 0.3035 eV for benzene to 0.249 eV for this molecule. The global electrophilicity value shows that it is increased from benzene (2.096eV) to 3.535eV in this molecule. This electrophilicity of this molecule is also found to increase further in gas and ethanol phase. In the case of local softness which indicate the reacting tendency of the individual atoms; the values shows that local softness is very high for C12 (0.3842) andC4 (0.2758) and minimum for C3 and C14, which shows C12 and C4 are more prone to reactions and C3 and C14 are highly inert. The electrophilicity index which shows the electron attracting ability of the individual atoms, shows that C4 and C12 are highly electrophilic and C3 and C14 are highly electrophobic which again explains the local softness and hardness of these atoms respectively.

4.6. NMR assessment The chemical shifts for H and C atoms of the compound are computed for optimized structure, supported by GIAO method using B3LYP functional with 6-311+ G (2d, p) basis set. The computed values in gas and solvent phase are presented in the Table 3 and graphical representation of the values are shown in Fig. 7&8. The aromatic carbon atoms generallyhave shifts in the range of 100-150 ppm.V. 9

Karunakaran et al.[28] have found the aromatic carbons in 4-methyl propiophenone to have chemical shift between 130- 140 ppm and around 8 ppm for methyl group carbon atom respectively. In the present compound the chemical shifts of the aromatic carbon atoms, namely C1, C2, C3, C4, C5 and C6, almost liein the same rang, from 131-138 ppm. And in the case of substitution group, the two carbon atoms C12 & C14have values of 139 & 151 ppm respectively. Among all the carbon atoms in the benzene C3 is found to have relatively larger value 138 ppm which is the carbon atom where the substitution group is attached with benzene and found to be highly positive compared to other carbon atoms. The C18 carbon atom which is present in the methyl group is found to have extreme minimum value, around 12 ppm, which shows the high shielding nature of three electrons in the methyl group. The large value of C12 and C14 indicate relatively the large magnitude of the charges associated with these atoms, though the first one is highly negative and latter is highly positive. The chemical shifts of the hydrogen atoms are found almost below 10 ppm, which show that the chemical environment of the hydrogen atoms are not affected by oxygen or any carbon atoms. Among this the methyl group proton are heavily shielded having the values below 2 ppm, this trend is in tune with the literature [28]. There is no appreciable difference observed in the chemical shifts in different solvents phases. Hence the impact of the solvents on the chemical shifts of the compound for various atoms is negligibly small.

4.7. NBO, UV-Vis spectra and HOMO-LUMO analysis The electronic characteristics of the present compound 1-phenyl -2-nitropropene are studied using TD-SCF B3LYP functional with 6-311+ G (d, p) basis set. The experimental spectrum of the compound is also recorded and the same is presented along with theoretical spectrum in Fig.9. The other theoretical parameters with the possible transitions are presented in Table 4. The NBO output parameters such as occupancy, donors and acceptors, stabilization energy, polarization energy etc are presented in Table 7. The table 7 shows the various possible donors 10

and acceptors in molecule with their occupancy value in each position, similarly the various possible transitions among these donors and acceptors. The stabilization energy for these transitions give a measure of the probabilities of these transitions; which indicate the highly probable in this molecule are C1-C2 to C3- C4 (π -π*, 19.52 Kcal/mol), C1-C2 to C5- C6 (π -π*, 20.60Kcal/mol), C3-C4 to C5- C6 (π -π*, 19.82 Kcal/mol), C3-C4 to C12- C14 (π -π*, 11.78 Kcal/mol), C12-C14 to N15- O17 (π -π*, 21.04 Kcal/mol), O16 to N15-O17 (n -π*, 159.57 Kcal/mol) and O17 to N15-O16 (n -π*, 18.62 Kcal/mol). Of which the most probable transition is n -π* transition from O16 to N15-O17 (159.57 Kcal/mol), and the next probable transitions areC12-C14 to N15- O17 (π -π*, 21.04 Kcal/mol), which takes place within the substitution group and C1-C2 to C5- C6 (π -π*, 20.60Kcal/mol), inside the benzene ring. Both are π -π* transitions. Table 4 shows these three transitions in both gas and ethanol phase, with corresponding energy difference between homo and lumo and the oscillator strengths. Here, the experimental spectrum is recorded in ethanol phase which shows only two peaks, at 306 and 223nm respectively, these are corresponding to first two transitions; n -π* and π -π* transitions which have considerably high oscillator strengths(f). The Homo – Lumo contribution for the first transition is 99% which is the reason for very high stabilization energy and oscillator for this transition. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital are computed with B3LYP functional with 6-311+ G (d, p) basis set and the pictorial diagram of the HOMO-LUMO are shown in Fig. 10. And the energies of the HOMO-LUMO, energy gap and different reactivity descriptors of molecule in both optimized and electronic transition levels are presented in Table. 5. The energy gap of optimized benzene ring is 6.5886 eV, but by the addition of the substitution propene and nitro group it is widened by 8.023 eV, where the energy flow is low. On the contrary in the transition state, the gap is doubly shortened by 4.66 eV, which shows the possibility of high flow of energy from HOMO to LUMO. Similarly other descriptors of the molecule do vary from the optimized to transition state and the values are presented in Table. 5. The electronegativity, which is a measure of attraction of an atom for electrons in a covalent bond, has 3.71 eV in benzene and 5.32 & 4.86 in optimized and electronic states respectively. The chemical hardness ofbenzene is 3.29 eV and substituted 11

molecule is 4.01 & 2.33 eV in optimized and transition state respectively, which shows that the present molecule is less stable compared to the benzene ring. The electrophilicity indexis a measure of lowering of total energy due to the maximal electron flow between the donors and the acceptors. The electrophilicity indices of 1P2NP is 3.53 & 5.08 eV in optimized and transition state respectively, whereas benzene ring is 2.09 eV. This shows that the electrophilicity index, which is the measure of the lowering of total energy, is increased during transition [29]. The dipole moment in a molecule is another important electronic property. The dipole moment of the benzene ring is almost zero, whereas by addition of the propene and nitro group, dipole moment of the present molecule is increased by 5.51 & 5.52 Debye in optimized and transition state respectively, which shows the charge flow occur from negative to positive direction.

4.8. Molecular electrostatic potential (MEP) maps The molecular electrical potential surfacesfrom Fig.11illustrate the charge distributions of molecules three dimensionally. This map allows us to visualize variably charged regions of a molecule. The knowledge of the charge distributions can be used to determine how molecules interact with one another and it is also used to determine the nature of the chemical bond.Molecular electrostatic potential is calculated at the B3LYP/6-311+G (d,p) optimized geometry.[30,31]The figure shows the negative charges are more concentrated at the top of the nitro group, whereas the blue region is spread over at the top of the hydrogen atoms of the phenyl and propene hydrogen atoms and other regions are found to be neither red nor blue

[32]

,

almost neutral. The color code of these maps is in the range between −6.15a.u. (deepest red) and6.15a.u. (deepest blue) in the compound. The positive (blue) regions of MEP are related to electrophilic reactivity and the negative (green) regions to nucleophilic reactivity.

4.9. Polarizability and first order hyperpolarizability calculations In order to investigate the relationships among molecular structures and non-linear optic properties (NLO), dipole moment the polarizability and first order hyperpolarizability of the 1phenyl-2-propene compound were calculated usingB3LYP method with 6-311+G(d,p) basis set.

12

The polarizability and hyperpolarizability tensors (αxx, αxy, αyy, αxz, αyz, αzzandβxxx, βxxy, βxyy, βyyy, βxxz, βxyz, βyyz, βxzz, βyzz, βzzz) can be obtained by a frequency job output file of Gaussian. However, αandβ values of the Gaussian output are in atomic units (a.u.), so they have been converted into electronic units (esu) (α; 1 a.u. = 0.1482×10−24esu, β; 1 a.u. = 8.6393×10−33esu). The calculations of the total molecular dipole moment (µ), linearpolarizability (α) and first-order hyperpolarizability (β) from the Gaussian output have been explained in detail previously. The first hyperpolarizability (β) and the components of hyperpolarizability,βyandβz of 1P2NP along with related properties (µ0, α total, and ∆α) are reported in Table 8. The calculated value of the dipole moment is found to be 5.4317Debye. The highest value of the dipole moment is observed for component µx, which is equal to 5.3973 D and the lowest value of the dipole moment of the moleculefor the component µγis0.3513D. The calculated average polarizability and anisotropy of the polarizability is 11.13x10−24esu and 6.7194x10−24esu, respectively. The hyperpolarizabilityβ is one of the important key factors in NLO system. The B3LYP/6-311+G (d,p) calculated first hyperpolarizability value (β)is 840.373x10−33esu. From the values of dipole moment and hyper polarizability is approximately 3.955 D and 2.253 x10−33esu times higher than those of urea (µ and β of urea are 1.3732 D and 372.89 x10−33esu).[43]It is evident that the molecule constitute a better NLO material.

4.10. Thermodynamical parameters On the basis of vibrational analysis, the statically thermodynamic functions: heat capacity C entropy S and enthalpy changes ∆H for the title molecule were obtained from the theoretical harmonic frequencies and listed in Table 9. It is observed that the thermodynamic functions are increasing with temperature ranging from100 to 600 K due to the fact that the molecular vibrational intensities increase with temperature. The correlation equations between heat capacity, entropy, enthalpy, and temperatures were fitted by quadratic formulas and the corresponding fitting factors (R2) for these thermodynamic propertiesare 0.99987, 0.9973, and 0.9999 respectively. The corresponding fitting equations are as follows and the correlation graphics are shown in Fig. 12. 13

C = 1.82705+0.01195 T + 1.43685 X10-6 T2 (R2 = 0.99858) S= 0.29265+ 0.00191 T + 2.67745 X10-5 T2 (R2 = 0.9999) ∆H= 0.2117 + 0.00139 T + 1.93689X10-6 T2 (R2 = 0.9999) The conformers of this compound which was discussed in the beginning of the paper based on the total energy of the molecule, now have also been analyzed in terms of the other thermodynamical parameters, by computing these parameters with B3LYP functional and 6311++ G(d, p) basis set at room temperature. The five different conformers have been selected with scan coordinate of 0, 80°, 150° 220° and 290° , of which the conformers at 80° and 220° gave the lowest energy configuration and at 0°, 150° and 290° with highest energies. Fig.13 shows the graph drawn for the enthalpy, heat capacity and entropy for all these conformers. These graphs depict some interesting results; the enthalpy is found to be minimum only for conformer at 150° scan coordinate, which is one of the highest energy conformer. The two minimum energy conformers have intermediate enthalpy values, whereas two of the highest energy conformer retain the highest enthalpy values while third one to have the lowest enthalpy values. In the case of heat capacity, the conformer at 220° has the lowest heat capacity value while all the other four conformers have higher values. The entropy also shows the minimum value for conformer at 220°, but with small change in the pattern of variation when compared to heat capacity. All these thermodynamical parameters variation shows a delicate balance between the molecular structure and thermal properties. But the study of all these thermodynamical properties for different conformers clearly reveals that the most stable conformer among all the five is conformer at 220°.

5. Conclusion By the conformational analysis, the stable conformer with lowest energy is identified and same is used for further analysis. The study of the molecular geometry reveals that there is no appreciable change in the bond length and bond angle of the molecule by addition of the substitutional group. And most of the values are closer to the experimental values.

14

On studying the vibrations of the compound, the C-H out-of-plane vibrations are influenced by the other modes specifically N-O and C-C bending in- plane vibrations. And the CC vibrations show good agreement with expected range. In the case of NO2, stretching vibrations are not influenced and the bending vibrations are mixed with CC vibrations. Conversely, C-N inplane and out-of-plane vibrations are again influenced by NO and CC modes of vibrations. Mullikan and Fukui calculations have identified the negatively and positively charged atoms in the molecule. In NMR analysis, The chemical shifts of the aromatic carbon atoms are observed with in the expected range and substitutional carbon atom are highly deshielded, whereas the methyl group carbon atom is heavily shielded having very low chemical shifts. In NBO analysis the most probable transitions are n -π* transition from O16 to N15-O17 (159.57 Kcal/mol), the next probable transitions areC12-C14 to N15- O17 (π -π*, 21.04 Kcal/mol), which takes place within the substitution group and C1-C2 to C5- C6 (π -π*, 20.60 Kcal/mol), inside the benzene ring. The HOMO-LUMO energy gap and other reactivity descriptors of the molecule are compared with optimized state of benzene ring. The energy gap, chemical harness and electronegativity are found decreased with the addition of the substitutional group, whereas the electrophilicity index is increased. The values of the dipole moment, polarizability and hyperpolarizability reveal that the present molecule is good candidate for NLO material. The results of the thermo dynamical parameters show that the parameters: entropy, enthalpy and heat capacity increase with increase of the temperature.

Acknowledgements: We remain grateful to the Administration of St. Joseph's college of Arts and Science (Autonomous), Cuddalore for providing us the Quantum Computational Research Lab for all the computational works of the compound.

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17

Figure(s)

Table(s)

Table 1: The optimized geometrical parameters of 1-phenyl-2-nitropropene Geometrical parameter C1-C2 C1-C6 C1-H7 C2-C3 C2-H8 C3-C4 C3-C12 C4-C5 C4-H9 C5-C6 C5-H10 C6-H11 H9-H20 C12-H13 C12=C14 C14-N15 C14-C18 N15-O16 N15-O17 C18-H19 C18-H20 C18-C21 C2-C1-C6 C2-C1-H7

HF/ B3LYP/ 6-311+G(d,p) 6-311 +G (d,p) 1.3831 1.3899 1.3860 1.3946 1.0751 1.0839 1.3927 1.4067 1.0759 1.0847 1.3908 1.4057 1.4801 1.4648 1.3849 1.3912 1.0742 1.0820 1.3848 1.3944 1.0752 1.0841 1.0752 1.0840 2.4327 2.2194 1.0741 1.0851 1.3223 1.3424 1.4794 1.4911 1.4996 1.4943 1.1890 1.2261 1.1880 1.2274 1.0825 1.0904 1.0801 1.0893 1.0842 1.0942 120.0405 120.0267 119.7868 119.8109

B3PW91/ 6-311+G(d,p) 1.3878 1.3924 1.0849 1.4039 1.0857 1.4028 1.4612 1.3891 1.0834 1.3921 1.0851 1.0849 2.2340 1.0866 1.3411 1.4843 1.4885 1.2202 1.2216 1.0913 1.0901 1.0946 120.0334 119.8066

Experimental a 1.3878a 1.3940 a 1.0816 a 1.3850 a 1.3860 a 1.501 a 1.3910 a 1.3890 a

1.081b 1.336 b 1.501 b 1.214 b 1.218 b 1.09 b 119.96

C6-C1-H7 C1-C2-C3 C1-C2-H8 C3-C2-H8

120.1707 120.678 119.731 119.5889

120.1596 121.015 119.8081 119.1738

120.1572 120.9384 119.8709 119.1867

C2-C3-C4 C2-C3-C12 C4-C3-C12 C3-C4-C5 C3-C4-H9 C5-C4-H9 C4-C5-C6 C4-C5-H10 C6-C5-H10 C1-C6-C5 C1-C6-H11 C5-C6-H11 C4-H9-H20 C3-C12-H13 C3-C12-C14 H13-C12-C14 C12-C14-N15 C12=C14-C18 N15-C14-C18 C14-N15-O16 C14-N15-O17 O16-N15-O17 C14-C18-H19 C14-C18-H20 C14-C18-H21 H19-C18-H20

118.8211 118.3896 122.7379 120.4762 120.0091 119.4972 120.237 119.6503 120.1116 119.7188 120.142 120.1357 92.5881 115.9131 127.2196 116.8571 115.8654 130.0168 114.1127 119.4448 116.2159 124.3385 110.2316 109.4078 111.6486 108.7679

118.2253 117.7923 123.9469 120.6374 120.0563 119.2626 120.3809 119.6037 120.0131 119.6756 120.1831 120.1349 101.7619 115.6874 128.8741 115.4169 115.6994 129.9644 114.3226 119.5818 116.3358 124.0808 110.2884 109.9179 111.917 108.9967

118.3341 117.9828 123.6488 120.6021 119.9436 119.4067 120.3493 119.6231 120.0251 119.7006 120.1685 120.1242 99.6507 116.1269 128.4185 115.4306 115.7076 129.8443 114.4289 119.4748 116.2352 124.2885 110.2296 109.8786 111.9238 109.0506

119.35

117 b

119 b 124.3 b

111 b 111 b

H19-C18-H21 H20-C18-H21 H9-H20-C18 C6-C1-C2-C3 C6-C1-C2-H8 H7-C1-C2-C3 H7-C1-C2-C8 C2-C1-C6-C5 C2-C1-C6-H11 H7-C1-C6-C5 H7-C1-C6-H11 C1-C2-C3-C4 C1-C2-C3-C12 H8-C2-C3-C4 H8-C2-C3-C12 C2-C3-C4-C5 C2-C3-C4-CH9 C12-C3-C4-C5 C12-C3-C4-H9 C2-C3-C12-H13 C2-C3-C12C4-C3-C12-H13 HC14 C4-C3-C12-C14 C3-C4-C5-C6 C3-C4-C5-H10 H9-C4-C5-C6 H9-C4-C5-H10 C3-C4-H9-H20 C5-C4-H9-H20 C4-C5-C6-C1 C4-C5-C6-H11 H10-C5-C6-C1 H10-C5-C6-H11 C4-H9-H20-C18

107.5173 109.2055 103.657 -1.3436 179.1928 179.1713 -0.2922 -0.1033 -179.4211 179.3797 0.0619 2.0087 179.4739 -178.527 -1.0618 -1.2533 177.2186 -178.6021 -0.1303 -40.851 137.9375 136.5087 -44.7028 -0.1638 179.4749 -178.6435 0.9952 58.9896 -122.5235 0.8528 -179.8294 -178.7843 0.5336 -121.5081

106.8174 108.8124 105.5368 -1.457 179.1941 179.1499 -0.1991 -0.2786 -179.3664 179.1124 0.0246 2.3204 -179.7601 -178.3266 -0.4071 -1.4924 176.0853 -179.2736 -1.6959 -27.6014 150.6185 150.1887 -31.5914 -0.191 179.2543 -177.7877 1.6575 56.787 -125.6021 1.097 -179.8147 -178.3459 0.7423 -115.245

106.7831 108.8877 104.984 -1.4959 179.2393 179.1057 -0.1591 -0.3056 -179.3603 179.0907 0.0361 2.4074 -179.6469 -178.3228 -0.3771 -1.5607 175.9146 -179.3814 -1.9061 -29.5104 148.6098 148.3175 -33.5624 -0.1899 179.2292 -177.6787 1.7405 58.0523 -124.4422 1.1434 -179.8016 -178.2735 0.7816 -117.0416

C3-C12-C14-N15 C3-C12-C14-C18 H13-C12-C14H13-C12-C14N15 C12-C14-N15C18 C12-C14-N15O16 C18-C14-N15O17 C18-C14-N15O16 C12-C14-C18O17 C12-C14-C18H19 C12-C14-C18H20 N15-C14-C18H21 N15-C14-C18H19 N15-C14-C18H20 C14-C18-H20H21 H19-C18-H20H9 H21-C18-H20H9 H9

177.7646 -3.1153 -3.4568 175.6633 10.3052 -169.3824 -168.9565 11.3558 -131.114 -11.5501 109.4526 48.0186 167.5824 -71.4148 60.1861 -179.3527 -62.2879

a

177.7817 -3.6536 -3.9944 174.5702 4.7168 -174.8442 -174.076 6.363 -136.8325 -16.6287 104.4019 41.7482 161.952 -77.0174 64.2493 -174.7671 -58.629

Ref [7]; b Ref [8,9]

177.9566 -3.7471 -3.9122 174.3841 3.807 -175.7782 -174.7563 5.6584 -135.5603 -15.3519 105.7516 42.7538 162.9621 -75.9344 63.8393 -175.2399 -59.0715

Table(s)

Table 2: Calculated scaled frequencies of 1-phenyl-2-nitropropene

S.No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

C1 Symmetry species A A A A A A A A A A A A A A A A A A A A A A A A A

Observed frequency FTFT-IR Raman 3090w 3080w 3060w 3070w 3010w 2990w 2980w 2970w 2960w 1680m 1630s 1620m 1580s 1550s 1520vs 1505vs 1490s 1480s 1460s 1440m 1430w 1380vs 1350m 1330vs 1320vs

HF 6-311+G (d, p) 3100 3098 3092 3081 3071 3065 3038 3005 2948 1738 1653 1643 1621 1522 1490 1479 1478 1468 1436 1417 1387 1412 1377 1357 1296

Calculated frequency B3LYP B3PW91 6-311+G 6-311+G (d, p) (d, p) 3100 3096 3098 3089 3092 3079 3081 3069 3071 3065 3065 3062 3038 3038 3005 3006 2948 2942 1738 1657 1653 1594 1643 1567 1621 1562 1522 1616 1490 1567 1479 1560 1478 1551 1468 1508 1436 1461 1417 1454 1387 1441 1412 1415 1377 1317 1357 1366 1296 1342

Vibrational assignments C-H ν C-H ν C-H ν C-H ν C-H ν C-H ν C-H ν C-H ν C-H ν C=C ν C=C ν C=C ν C=C ν N=O ν N=O ν C-C ν C-C ν C-C ν C-C ν C-C ν C-N ν C-H β C-H β C-H β C-H β

26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A

1300m 1270vs 1220m 1160m 1110w 1090m 1010w 980m 970m 950m 900w 880m 870m 860m 760s 750w 740m 720s 700w 680s 670m 660m 580s 570m 540m 520s 510m 480w 450w 440w

1256 1231 1226 1178 1176 1018 1004 997 991 956 906 877 823 786 755 715 700 710 684 613 718 613 587 510 467 389 339 298 153 123

1256 1231 1226 1178 1176 1018 1004 997 991 956 906 877 823 786 755 715 700 710 684 613 718 613 587 510 467 398 339 298 153 123

1272 1251 1197 1195 1151 1143 1057 1047 1018 984 947 906 889 823 775 756 743 787 756 680 642 536 517 464 412 349 304 246 145 107

C-H β C-H β C-H β C-H β C-H β C=C β N=O β N=O β C-C β C-C β C-N β C-H δ C-H δ C-H δ C-H δ C-H δ C-H δ C-H δ C-H δ C-H δ C=C δ N=O δ N=O δ C-C δ C-C δ C-N δ CCC β CCC β CCC β CCC δ

56 57

A A

420w 100m

78 48

78 48

72 43

vs- very strong; s- strong; m- medium; w- weak; vw- very weak,

ν- stretching; β- in-plane vibrations; δ- out-of-plane vibrations

CCC δ CCC δ

Table(s)

Table. 3 : Experimental and calculated 1H and 13 C NMR chemical shifts (ppm) of 1-phenyl -2-nitropropene Atom position

Chloroform

Solvent-DMSO

TMS/B3LYP/6-311+G (2d,p) GIAO (ppm)

TMS/B3LYP/6-311+G(2d,p) GIAO (ppm)

TMS/B3LYP/6311+G(2d,p) GIAO (ppm)

2-C

131.457 132.945

131.643 133.226

131.661 133.333

3-C

138.08

137.467

137.341

4-C

130.716

131.154

131.39

5-C

131.064

131.377

131.501

6-C

131.511

132.346

132.595

12-C

139.197

141.02

141.65

14-C

151.271

152.027

152.419

18-C

12.1327

12.1353

12.1576

7-H

7.3506

7.4682

7.5114

8-H

7.2681

7.3794

7.4254

9-H

7.1849

7.3135

7.3758

10-H

7.3387

7.4645

7.5152

11-H

7.2696

7.4085

7.4595

1-C

Gas

13-H

8.18

8.2723

8.3058

19-H

1.7532

1.7432

1.7323

20-H

1.8672

1.9727

2.0112

21-H

1.9742

2.0309

2.0531

Table(s)

Table 4: Experimental and theoretical electronic absorption spectra of 1-phenyl-2-nitropropene (absorption wavelength λ (nm), excitation energies E (eV) using TD-SCF/B3LYP/6-311++G (d, p) method Experimental

Theoretical TD-SCF

λ (nm) E (eV)

Ethanol 306.5 223.5 -

Major contribution

f

λ (nm)

E (eV)

f

-

-

gas 339.27 317.86 295.99

3.6545 3.9006 4.1888

0.0053 0.2914 0.0058

-

1.238 0.892 -

349.21 327.23 321.10

3.5504 3.7889 3.8612

0.4767 0.0043 0.0065

Assig nment

Region

Bands

H-2->LUMO (91% n→π* HOMO->LUMO (95%) π →π* H-1->LUMO (93%) π →π*

Quartz UV Quartz UV Quartz UV

R-band (German, radikalartig)

n→ π* π →π* π →π*

Quartz UV Quartz UV Quartz UV

R-band (German, radikalartig)

HOMO->LUMO (99%) H-2->LUMO (64%) H-3->LUMO (24%)

Table(s)

Table 5: HOMO,LUMO, Kubo gap, global electronegativity, global hardness and softness, global Electrophilicity index of 1phenyl-2-nitropropene 1-phenyl-2-nitropropanol

Parameters

EHOMO (eV) (eV) ELUMO (eV)eV EHOMO-LUMO gap (eV) (eV) Electronegativity (χ) (eV) Chemical hardness (η) (eV) Global softness (σ) (eV) Electrophilicity index (ω) (eV) sDipole moment (μ) (Debye)

Benzene ring 7.0101 0.4215 6.5886 3.7163 3.2943 0.3035 2.0961 0.0001

Optimized state

B3LYP/ 6-311+ G (d, p) 9.338 1.314 8.023 5.326 4.011 0.249 3.535 5.513

Transition state by TD-SCF

Gas

Ethanol

7.1987 2.5358 4.6629 4.8673 2.3314 0.2144 5.0806 5.0445

7.0537 2.6634 4.3902 4.8585 2.1951 0.2277 5.3768 6.1105

Table(s)

Table 6: Fukui Function and global and local softness and Electrophilicity of 1-phenyl-2-nitropropene Atoms 1C 2 C 3 C 4 C 5 C 6 C 7 H 8 H 9 H 10 H 11 H 12 C 13 H 14 C 15 N 16 O 17 O 18 C 19 H 20 H 21 H

f+ = (q+1)-q 0.0462 0.0775 -0.1968 0.1573 0.0649 0.1234 0.0451 0.0426 0.0111 0.0438 0.0543 0.2558 0.0415 -0.1628 0.0235 0.1363 0.1138 0.0136 0.0476 0.0121 0.0485

f-=q-(q-1) -0.2318 -0.0584 1.3494 -0.9495 -0.1994 -0.1343 0.1427 0.1333 0.1850 0.1347 0.1392 -1.2857 0.1551 0.3685 -0.3746 -0.3907 -0.3052 -0.2267 0.1766 0.1689 0.2022

∆f=(f+)-(f-) 0.27811 0.13600 -1.54626 1.10684 0.26436 0.25778 -0.09753 -0.09066 -0.17387 -0.09091 -0.08488 1.5416 -0.11364 -0.53143 0.39823 0.52641 0.41904 0.24040 -0.12901 -0.15684 -0.15372

∆S =∆fσgs 0.0693 0.0338 -0.3854 0.2758 0.0658 0.0642 -0.0243 -0.0226 -0.0433 -0.0226 -0.0217 0.3842 -0.0283 -0.1324 0.0992 0.1312 0.1044 0.0599 -0.0321 -0.0390 -0.0383

∆ω=∆fωgei 0.98337 0.48088 -5.4674 3.9136 0.9347 0.9114 -0.3448 -0.3205 -0.6148 -0.3214 -0.3001 5.4510 -0.4018 -1.8791 1.4081 1.8613 1.4816 0.8500 -0.4562 -0.5545 -0.5435

∆S = local softness, σgs- global softness; -∆ω local electrophilic index, ωgei- global electrophilic index.

Table(s)

Table 7: Second order Perturbation theory of Fock matrix in NBO basis of 1- Phenyl-2-nitropropene Donor

Type of Bond

Occupancy

Acceptor

Type of Bond

Occupancy

Energy E(2) kcal/mol

C1-C2

σ σ σ σ π π σ σ σ σ σ σ σ σ σ π π π σ σ σ σ σ σ σ σ σ σ π

1.97895

C1-C6 C2-C3 C3-C12 C6-H11 C3-C4 C5-C6 C1-C2 C2-H8 C5-C6 C1-C2 C3-C4 C3-C12 C2-C3 C4-C5 C12-H13 C1-C2 C5-C6 C12-C14 C1-C2 C2-C3 C3-C4 C12-C14 C14-N15 C3-C4 C3-C12 C5-C6 C1-C6 C4-C5 C1-C2

σ* σ* σ* σ* π* π* σ* σ* σ* σ* σ* σ* σ* σ* σ* π* π* π* σ* σ* σ* σ* σ* σ* σ* σ* σ* σ* π*

0.01619 0.02307 0.02447 0.01363 0.02640 0.32763 0.01455 0.01356 0.01616 0.01455 0.02640 0.02447 0.02307 0.01513 0.01758 0.30608 0.32763 0.12312 0.01455 0.02307 0.01513 0.01975 0.11419 0.02640 0.02447 0.01616 0.01619 0.01513 0.30608

2.72 3.08 3.21 2.41 19.52 20.60 2.75 2.55 2.58 2.74 3.61 2.29 3.65 2.29 1.20 19.09 19.82 11.78 2.12 2.22 2.71 4.02 3.37 3.21 3.68 2.74 2.57 2.48 19.34

C1-C6

C2-C3

C3-C4

C3-C12

C4-C5

C5-C6

1.66287 1.97960

1.97189

1.97225

1.62699

1.97195

1.97894

1.97969 1.64254

Energy difference E(j)-E(i) a.u. 1.28 1.26 1.19 1.14 0.28 0.28 1.28 1.13 1.28 1.27 1.25 1.17 1.25 1.13 1.13 0.28 0.28 0.29 1.25 1.22 1.23 1.31 0.94 1.26 1.19 1.28 1.28 1.14 0.28

Polarized energy F(i,j) a.u. 0.053 0.056 0.055 0.047 0.067 0.068 0.029 0.048 0.051 0.053 0.060 0.046 0.060 0.045 0.033 0.067 0.067 0.056 0.046 0.047 0,051 0.065 0.052 0.057 0.059 0.053 0.051 0.053 0.067

C12-H13 C12-C14

C14-N15 N15-O17 O16

O17

π σ σ σ σ σ π π σ π π π π π σ σ π π

1.96362 1.97929

1.84794 1.98511 1.98365 1.89351

1.98149 1.90287

C3-C4 C14-N15 C14-C18 C2-C3 C3-C12 C14-C18 C3-C4 N15-O17 C3-C12 C12-C14 N15-O17 C14-N15 N15-O17 N15-O17 C14-N15 N15-O16 C14-N15 N15-O16

π* σ* σ* σ* σ* σ* π* π* σ* π* π* σ* σ* π* σ* σ* σ* σ*

0.38064 0.11419 0.01935 0.02307 0.02447 0.01935 0.38064 0.62429 0.02447 0.12312 0.62429 0.11419 0.05525 0.05525 0.11419 0.05446 0.11419 0.05446

21.46 2.43 7.72 1.47 3.37 3.40 8.24 21.04 3.12 4.42 7.16 13.09 19.01 159.57 3.97 2.24 11.92 18.62

0.28 0.78 0.93 1.32 1.25 1.18 0.32 0.16 1.26 0.48 0.32 0.55 0.72 0.14 1.06 1.23 0.55 0.73

0.070 0.040 0.076 0.039 0.058 0.057 0.048 0.060 0.056 0.042 0.051 0.076 0.106 0.138 0.059 0.047 0.073 0.105

Table(s)

Table 8: The Dipole moment (μ) (Debye), Polarizability (α) and first hyperpolarizability (β) of 1-phenyl-2-nitropropene

Parameter a.u. αxx -85.7684 αxy -0.5686 αyy -61.7938 αxz 1.7010 αyz 4.3390 αzz -77.8698 αtot 11.13x10-24esu Δα 6.7194 X10-24esu μx 5.3973 Debye μy 0.3513 Debye μz -0.4997 Debye μtot 5.4317 Debye

Parameter βxxx βxyy βxzz βyyy βyxx βyzz βzzz βyyz βxxz βtot

a.u. 98.8714 -0.7144 -0.9015 -0.2319 -1.2949 2.9415 1.6692 -1.9810 -0.9015 840.3737 X10-33esu

Table(s)

Table 9: Thermodynamic properties at different temperatures at the B3LYP/6-311+G (d,p) level of 1-phenyl-2-nitropropene

T (K) 100 200 300 400 500 600

Cm ◦

Sm◦

ΔHm◦

(cal mol−1 K−1)

(cal mol−1 K−1)

(cal mol−1 K−1)

12.380 24.097 37.514 49.639 59.410 67.064

66.543 79.919 93.033 106.109 118.723 130.622

101.868 103.666 106.747 111.123 116.595 122.934

Cm- Heat capacity; Sm- Entropy; ΔHm- Enthalpy

Table(s)

Table 10: Thermodynamic properties of different conformers at 300 k temperature the B3LYP/6-311+G (d,p) level of 1-phenyl-2-nitropropene

Conformer at ∆E(Hartree) (in degree) 0 0.1681

∆H (KCal/Mol)

Cv (cal mol-1 K-1)

S (cal mol-1 K-1)

106.747

37.514

93.033

80

0.1636

104.818

36.757

100.132

150

0.1642

104.194

34.583

91.952

220

0.1637

104.810

29.800

86.511

290

0.1643

105.877

35.327

91.389

Cv- Heat capacity; S- Entropy; ΔH- Enthalpy, ∆E- total energy

Graphical Abstract

1-phenyl- 2-nitropropene is one of the important intermediate preparation of Amphetamine, which is widely used as cognitive enhancer drug of the central nervous system. It exhibits the property of the dipole moment and hyperpolarizablity three times higher than the NLO property of the urea. There are larger charge distribution and flow of charge from electrophile to nucleophile in the molecule.

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Highlights of the paper

• • • • •

The compound 1-Phenyl- 2-nitropropene has been investigated using FT-IR, FT-Raman and NMR and UV-Vis spectroscopic tool. The chemical shift of the compounds is found and it is favorable for its change of chemical property. The charge transfer in the molecule by HOMO-LUMO is studied in relation with NBO analysis. The study of NLO property in relation with dipole moment and hyperpolarizability is done Chemical reactivity region has been found along with the Fukui function.

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