FT-IR, molecular structure, first order hyperpolarizability, NBO analysis, HOMO and LUMO and MEP analysis of 1-(10H-phenothiazin-2-yl)ethanone by HF and density functional methods

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

Contents lists available at ScienceDirect

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa

FT-IR, molecular structure, first order hyperpolarizability, NBO analysis, HOMO and LUMO and MEP analysis of 1-(10H-phenothiazin-2-yl)ethanone by HF and density functional methods K.G. Vipin Das a, C. Yohannan Panicker a,⇑, B. Narayana b, Prakash S. Nayak b, B.K. Sarojini c, Abdulaziz A. Al-Saadi d a

Department of Physics, TKM College of Arts and Science, Kollam, Kerala, India Department of Studies in Chemistry, Mangalore University, Mangalagangothri, Karnataka, India c Industrial Chemistry Division, Department of Studies in Chemistry, Mangalore University, Mangalagangothri, Karnataka, India d Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia b

h i g h l i g h t s

g r a p h i c a l a b s t r a c t

 IR, XRD and NBO analysis were

reported.  The wavenumbers are calculated

theoretically using Gaussian09 software.  The wavenumbers are assigned using PED analysis.  The geometrical parameters are in agreement with XRD data.

a r t i c l e

i n f o

Article history: Received 21 April 2014 Received in revised form 15 June 2014 Accepted 29 June 2014 Available online 8 July 2014 Keywords: Phenothiazine FTIR Hyperpolarizability PED NBO MEP

a b s t r a c t FT-IR spectrum of 1-(10H-phenothiazin-2-yl)ethanone was recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational wavenumbers were investigated with the help of HF and DFT methods. The normal modes are assigned with the help of potential energy distribution analysis. The observed vibrational wavenumbers were compared with the calculated results. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The first hyperpolarizability value is also reported. Natural bond orbital analysis confirms the presence of intra-molecular charge transfer and hydrogen bonding interaction. The HOMO–LUMO gap explains the charge transfer interaction taking place within the molecule. The NAH stretching frequency is red shifted in the IR spectrum with a strong intensity from the computed frequency, which indicates weakening of the NAH bond resulting in proton transfer to the neighboring units. From the MEP analysis it is evident that the negative charge covers the carbonyl and benzene and the positive region is over the NH group. Ó 2014 Elsevier B.V. All rights reserved.

⇑ Corresponding author. Tel.: +91 9895370968. E-mail address: [email protected] (C. Yohannan Panicker). http://dx.doi.org/10.1016/j.saa.2014.06.155 1386-1425/Ó 2014 Elsevier B.V. All rights reserved.

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

163

Introduction Phenothiazine is a well known hetero-cycle and the structure occurs in many synthetic dyes and electroluminescent materials [1]. Phenothiazine derivatives have applications in medical field related to anti-tubercular [2] and antitumor activities [3]. A review of various aspects of phenothiazine has been published [4]. The crystal and molecular structure studies of phenothiazine [5], chloropromazine, thiethylperazine, thioridazine, phenothiazine, perphenazine, trifluperazine hydrochloride [6–11], N-methylphenothiazine, N-ethylphenothiazine, N-benzyl-phenylthiazine [12–14], triflupromazine, 2-methoxyphenothiazine [15] and 10-acetyl-10Hphenothaizine 5-oxide [16] are reported. Phenothiazine derivatives have applications in material science due to their high electron donating properties [17]. The ground state intra-molecular charge transfer and excited state photo-induced electron transfer properties of phenothiazine [18,19] make them serve as electro active and photoactive materials in molecular electronics. Hence they are widely used in industry as efficient non-linear optical materials [20], organic light emitting diodes [21,22], semiconductors [17], chemical sensors [23], solar cells [24], acid–base dyes and pigments [25]. Phenothiazine ring system has been chemically modified to exhibit various activities like anti-inflammatory agents, anti-bacterial, anticonvulsants [26], anti-histaminic, anthelmintics [27,28], neuroleptics, tranquilizers, anti-cholinergic, anti-allergic, anti-carcinogenic [29]. In the present study, IR spectrum of 1-(10H-Phenothiazin-2-yl)ethanone was reported both experimentally and theoretically and the theoretically obtained geometrical parameters are compared with XRD results. Another essential aim of this study is the description of the nonlinear optical properties of the compound, which will be given in addition to an NBO analysis. Experimental 1-(10H-Phenothiazin-3-yl)ethanone was obtained from Aldrich and it was crystallized from dimethylformamide solution. The single crystal XRD of the title compound is reported by Jasinski et al. [30]. The title compound crystallizes in monoclinic P21/C with a = 14.3445, b = 5.5425, c = 15.694 Å, V = 1135.4 Å3 and Z = 4. In the title compound, C14H11NOS, the thiazine ring adopts a slightly distorted boat conformation. The dihedral angle between the mean planes of the two benzene rings is 20.2°. An intermolecular NAH. . .O hydrogen bond and a weak CAH. . .p interaction occur in the crystal, creating a two dimensional network parallel to the bc plane. FT-IR spectrum (Fig. 1) was recorded using KBr pellets on a Shimadzu-FTIR infrared spectrometer. Computational details Calculations of the title compound were carried out with Gaussian09 program [31] using the HF/6-31G(d)(6D, 7F) and B3LYP/ 6-31G(d)(6D,7F) basis sets to predict the molecular structure and vibrational wavenumbers. Molecular geometry was fully optimized by Berny’s optimization algorithm using redundant internal coordinates. Harmonic vibrational wavenumbers were calculated using the analytic second derivatives to confirm the convergence to minima on the potential surface. The DFT hybrid B3LYP functional method tends to overestimate the fundamental modes; therefore scaling factor of 0.9613 has to be used for obtaining a considerably better agreement with experimental data [32]. For HF method a scaling factor of 0.8929 is used [32]. Parameters corresponding to optimized geometry (B3LYP) of the title compound with experimental data (Fig. 2) are given in Table 1. The absence of imaginary wavenumbers on the calculated vibrational spectrum

Fig. 1. FT-IR spectrum of 1-(10H-phenothiazin-3-yl)ethanone.

confirms that the structure deduced corresponds to minimum energy. The assignments of the calculated wave numbers are aided by the animation option of GAUSSVIEW program, which gives a visual presentation of the vibrational modes [33]. The potential energy distribution (PED) is calculated with the help of GAR2PED software package [34].

Results and discussion IR spectrum The observed IR bands and calculated (scaled) wavenumbers and assignments are given in Table 2. The NAH stretching vibrations generally give rise to bands [35,36] at 3500–3400 cm1. In the present study, the NAH stretching band splits into a doublet 3459, 3353 cm1 in the IR spectrum owing to Davydov coupling between neighboring units. A similar type of splitting is observed in acetanilide [37,38] and N-methylacetamide [39]. The splitting of about 106 cm1 in the IR spectrum is due to strong intermolecular hydrogen bonding. Furthermore the NAH stretching frequency is red shifted by 97 cm1 in the IR spectrum with a strong intensity from the computed frequency, which indicates weakening of the NAH bond resulting in proton transfer to the neighboring units [40]. NAH group shows bands at 1510–1500 cm1, 1235–1165 cm1 and 740–730 cm1 [41]. The CAN stretching modes are reported [42] in the range 1100–1300 cm1. In the present case the CAN stretching modes are assigned at 1148 and 1136 cm1 theoretically. According to literature if NAH is a part of a closed ring [41,43] the CANAH deformation band is absent in the region 1510–1500 cm1. For the title compound the CANAH deformation band is observed at 1321 cm1 in the IR spectrum and

164

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

Fig. 2. Optimized molecular geometry (DFT) of 1-(10H-phenothiazin-3-yl)ethanone.

at 1315 cm1 theoretically. The out-of-plane NH deformation is assigned theoretically (DFT) at 704 cm1. Chandran et al. [44] are reported the NAH out-of-plane mode at 768 cm1 in the IR spectrum and at 731 cm1 theoretically. The carbonyl stretching C@O vibration [43,40] is expected in the region 1715–1680 cm1 and in the present study this mode appears at 1764 cm1 in the IR spectrum. The B3LYP calculations give this mode at 1705 cm1. The deviation of the calculated wave number for this mode can be attributed to the under estimation of the large degree of their electron delocalization due to conjugation of the molecule [45]. The intensity of the carbonyl group vibration can increase because of conjugation or formation of hydrogen bonds. The C@O in-plane deformation and the C@O out-of-plane deformation are expected in the regions 625 ± 70 and 540 ± 80 cm1 respectively [43]. The theoretically calculated values of the deformation modes of the carbonyl group are 663 and 582 cm1. Bieliauskas et al. [46] reported the C@O stretching mode 1674 cm1 for derivatives derived from phenothiazine. Kaur et al. [47] reported the C@O modes, stretching, in-plane and out-of-plane deformations at 1694, 638, 588 cm1 in the IR spectrum and at 1672, 642, 598 cm1 theoretically for a phenothiazine derivative. The stretching vibrations of CH3 are expected in the range 2900–3050 cm1 [43,48]. The first of these result from asymmetric stretching tasCH3 modes in which two CAH bonds of the methyl group are extending while the third one is contracting and the other result from symmetric stretching tsCH3 in which all three of the CAH bonds extend and contract in-phase. The asymmetric stretching modes of methyl group are calculated to be at 3047, 2994 cm1 and the symmetric mode at 2936 cm1. The bands at 3038, 2980 cm1 in the IR spectrum of the title compound are assigned as the CH3 stretching vibrations. Two bending can occur within a methyl group. The first of these, the symmetrical bending vibration, involves out-of-phase bending of the CAH bonds. The asymmetric deformations are expected in the range 1400–1485 cm1 [43]. The calculated values of dasCH3 modes are at 1450, 1449 cm1. In many molecules the symmetric deformation dsCH3 appears with an intensity varying from medium to strong and expected in the range of 1380 ± 25 cm1 [43] and the band at 1382 cm1 in the IR spectrum and at 1374 cm1 (B3LYP) are assigned as dsCH3 mode for the title compound. Esters display a methyl rock in the neighborhood of 1045 cm1 [43]. The second rock in the region 970 ± 70 cm1 [43] is more difficult to find among the CAH out-of-plane deformations. For the title compound, these modes qCH3 are calculated at 1033 and 961 cm1. The bands at 1030, 958 cm1 in the IR spectrum are assigned as qCH3 modes. For the title compound, the CAS stretching vibration [43] are assigned at 694 and 671 cm1 and only one band is observed in

the IR spectrum at 692 cm1. The CAS stretching mode is reported at about 640 cm1 for dithienothiophenes by Cravino et al. [49] and at 672 cm1 in IR, 696, 671 cm1 theoretically by Kaur et al. [47]. The CAC stretching modes are observed at 1016,826 cm1 in IR and the theoretical values are 1015 and 824 cm1 (B3LYP). In the following discussion, the di- and tri-substituted phenyl rings are designated as PhI and PhII, respectively. The phenyl CH stretching vibrations occur above 3000 cm1 and are typically exhibited as multiplicity of weak to moderate bands compared with the aliphatic CH stretching [50]. For the title compound, the DFT calculations give CH stretching vibrations of the phenyl rings at 3097, 3076, 3070, 3053 cm1 and 3093, 3079, 3078 cm1 for PhI and PhII rings, respectively. The bands observed at 3100 and 3054 cm1 in the IR spectrum are assigned as CH stretching modes of the phenyl ring. The benzene ring possesses six ring stretching modes of which the four with the highest wavenumbers occurring near 1600, 1580, 1490 and 1440 cm1 are good group vibrations [43]. With heavy substituent, the bands tend to shift to somewhat lower wavenumbers and the greater the number of substituent on the ring, the broader the absorption regions [43]. In the case of C@O substitution, the band near 1490 cm1 can be very weak [43]. The fifth ring stretching mode is active near 1315 ± 65 cm1, a region that overlaps strongly with that of the in-plane CH deformation [43]. The sixth ring stretching mode, the ring breathing vibration appears as a weak band near 1000 cm1 in mono, 1,3-di and 1,3,5-trisubstituted benzenes. In the otherwise substituted benzenes, however, this mode is substituent sensitive and difficult to distinguish from the other modes. The tPh modes are expected in the range 1260–1615 cm1 for PhI (ortho substituted) [43,51]. The DFT calculations give the Ph stretching modes at 1299, 1441, 1480, 1577, 1593 cm1 for PhI. The tPh modes are observed at 1294, 1436, 1484, 1565, 1604 cm1 in the IR spectrum. In ortho di-substitution the ring breathing mode has three frequency intervals according to whether both substituent are heavy or one of them is heavy while the other is light or both of them are light. In the first case the interval is 1100–1130 cm1, in the second case 1020–1070 cm1 while in the third case 630–790 cm1 [51]. The bands calculated at 1049 cm1 is assigned as the ring breathing mode of ortho substituted phenyl ring. Kaur et al. [47] reported the ring breathing mode of ortho substituted benzene rings at 1026 and 1023 cm1 theoretically. The in-plane CH bending modes are expected above 1000 cm1 [43] and in the present case the in-plane CH deformation bands are assigned at 1256, 1195, 1112, 1021 cm1 for PhI theoretically. Experimentally these modes are observed at 1256, 1186, 1112 cm1 in the IR spectrum. The out-of-plane CH deformation bands of the phenyl ring are assigned at 931, 907, 877,

165

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171 Table 1 Geometrical parameters of the title compound, atom labeling according to Fig. 4. Label

DFT

XRD

Label

DFT

XRD

Bond lengths (Å) C5AS1 C8AO2 C13AN3 C4AC6 C4AC11 C5AC26 C6AC10 C9AC13 C11AH12 C13AC22 C14AH16 C18AH19 C18AC24 C20AC24 C24AH25

1.7802 1.2227 1.4036 1.4019 1.4010 1.3957 1.3937 1.4057 1.0848 1.4002 1.0965 1.0863 1.3945 1.3965 1.0857

1.7606 1.2216 1.3948 1.3980 1.3946 1.3908 1.3932 1.4003 0.9300 1.3939 0.9600 0.9300 1.3840 1.3930 0.9300

C9AS1 C10AN3 N3AH28 C4AC8 C5AC10 C6AH7 C8AC14 C9AC20 C11AC26 C14AH15 C14AH17 C18AC22 C20AH21 C22AH23 C26AH27

1.7878 1.4024 1.0122 1.4974 1.4101 1.0867 1.5202 1.3950 1.3943 1.0965 1.0913 1.3944 1.0865 1.0880 1.0862

1.7664 1.3930 0.8290 1.4903 1.4026 0.9300 1.5051 1.3891 1.3868 0.9600 0.9600 1.3900 0.9300 0.9300 0.9300

Bond angles (°) C5AS1AC9 C10AN3AH28 C6AC4AC8 C8AC4AC11 S1AC5AC26 C4AC6AH7 H7AC6AC10 O2AC8AC14 S1AC9AC13 C13AC9AC20 N3AC10AC6 C4AC11AH12 H12AC11AC26 N3AC13AC22 C8AC14AH15 C8AC14AH17 H15AC14AH17 H19AC18AC22 C22AC18AC24 C9AC20AC24 C13AC22AC18 C18AC22AH23 C18AC24AH25 C5AC26AC11 C11AC26AH27

99.9 114.0 117.7 123.0 119.9 118.1 120.7 120.5 120.0 120.1 120.6 120.9 119.2 120.6 111.1 108.7 109.3 119.4 120.3 120.5 120.6 120.2 120.6 120.7 120.1

100.8 113.9 118.4 121.8 118.3 119.6 119.6 120.8 121.2 120.2 119.7 120.2 120.2 119.6 109.5 109.5 109.5 119.8 120.4 120.4 120.5 119.7 120.2 120.7 119.6

C10AN3AC13 C13AN3AH28 C6AC4AC11 S1AC5AC10 C10AC5AC26 C4AC6AC10 O2AC8AC4 C4AC8AC14 S1AC9AC20 N3AC10AC5 C5AC10AC6 C4AC11AC26 N3AC13AC9 C9AC13AC22 C8AC14AH16 H15AC14AH16 H16AC14AH17 H19AC18AC24 C9AC20AH21 H21AC20AC24 C13AC22AH23 C18AC24AC20 C20AC24AH25 C5AC26AH27

122.7 114.3 119.2 120.1 119.9 121.3 120.7 118.8 119.7 120.4 119.0 119.9 120.4 119.0 111.1 107.3 109.3 120.3 119.2 120.3 119.2 119.5 119.9 119.2

123.4 115.0 119.8 121.3 120.2 120.8 120.7 118.6 118.5 121.5 118.8 119.6 121.5 118.9 109.5 109.5 109.5 119.8 119.8 119.8 119.7 119.5 120.2 119.6

Dihedral angles (°) C9AS1AC5AC10 C5AS1AC9AC13 C13AN3AC10AC5 C10AN3AC13AC9 C8AC4AC6AC10 C6AC4AC8AO2 C11AC4AC8AO2 C6AC4AC11AC26 S1AC5AC10AN3 C26AC5AC10AN3 S1AC5AC26AC11 C4AC6AC10AN3 S1AC9AC13AN3 C20AC9AC13AN3 S1AC9AC20AC24 C4AC11AC26AC5 C9AC13AC22AC18 C22AC18AC24AC20

30.5 30.7 32.6 32.4 179.1 0.3 179.6 0.4 4.1 179.9 173.9 178.1 4.3 179.4 174.2 1.4 0.9 0.6

24.7 25.6 25.6 24.6 179.1 0.0 179.2 0.9 3.3 179.1 174.3 177.5 5.0 179.5 172.9 0.82 1.1 0.3

C9AS1AC5AC26 C5AS1AC9AC20 C13AN3AC10AC6 C10AN3AC13AC22 C11AC4AC6AC10 C6AC4AC8AC14 C11AC4AC8AC14 C8AC4AC11AC26 S1AC5AC10AC6 C26AC5AC10AC6 C10AC5AC26AC11 C4AC6AC10AC5 S1AC9AC13AC22 C20AC9AC13AC22 C13AC9AC20AC24 N3AC13AC22AC18 C24AC18AC22AC13 C9AC20AC24AC18

153.6 153.0 148.4 148.0 1.6 179.7 0.4 179.7 175.0 0.9 2.0 0.9 175.3 1.0 2.1 178.7 1.7 1.3

159.4 158.9 156.2 156.1 1.7 178.5 2.3 179.9 175.9 0.9 1.7 0.8 174.3 1.2 2.7 178.2 1.8 2.0

734 cm1 for PhI theoretically and bands are observed in the IR spectrum at 908, 868, 740 cm1. In the case of 1,2-disubstituted benzenes only one strong absorption in the region 755 ± 35 cm1 is observed and is due to cCH [43]. The strong band observed at 740 cm1 in the IR spectrum is assigned as this mode. For the title compound, the bands observed at 1548, 1430, 1352 cm1 in the IR spectrum are assigned as tPhII modes with 1582, 1555, 1422, 1351, 1265 cm1 as B3LYP values. In asymmetric tri-substituted benzene, when all the three substituent are light,

the ring breathing mode falls in the range 500–600 cm1; when all the three substituent are heavy, it appears in the range 1050– 1100 cm1 and in the case of mixed substituent, it falls in the range 600–750 cm1 [51]. For the title compound, PED analysis gives the ring breathing mode at 728 cm1 (B3LYP) and 728 cm1 in IR spectrum which is in agreement with literature [43,51]. For tri-substituted benzenes dCH modes are expected in the range 1050–1280 cm1 [43]. For the phenyl ring PhII, the bands observed at 1068 cm1 in the IR spectrum and at 1242, 1222, 1071 cm1 (B3LYP) are

166

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

Table 2 Vibrational assignments of 1-(10H-phenothiazin-3-yl)ethanone. HF/6-31G(d) (6D, 7F)

B3LYP/6-31G(d) (6D, 7F)

IR

Assignmentsa

t

IRI

t

IRI

t

–

3436 3038 3030 3030 3017 3016 3008 2993 2972 2926 2872 1775 1613 1608 1598 1574 1517 1490 1457 1451 1444 1427 1390 1369 1274 1265 1238 1231 1200 1185 1162 1115 1110 1082 1074 1055 1038 1033 1017 988 968 963 951 915 885 865 837 827 758 738 717 712 675 667 638 605 581 551 520 511 510 490 449 433 423 366 357 289 277 255 245 193 166

23.08 12.92 31.78 1.99 22.24 4.29 2.44 8.61 18.31 15.03 3.92 259.74 24.92 22.13 5.40 23.03 28.54 4.65 347.86 9.21 10.22 123.98 55.96 0.89 106.63 184.36 14.48 25.59 54.89 8.43 22.94 1.12 37.51 21.59 1.28 4.30 12.07 1.29 9.68 0.12 7.56 0.58 2.81 26.33 33.21 2.58 5.33 25.13 78.93 12.01 3.25 5.39 10.32 13.32 32.73 36.37 10.81 21.74 4.38 48.03 11.13 3.62 6.14 0.72 0.57 1.04 0.33 2.42 2.05 1.03 1.30 2.73 0.22

3450 3097 3093 3079 3078 3076 3070 3053 3047 2994 2936 1705 1593 1582 1577 1555 1502 1480 1450 1449 1441 1422 1374 1351 1315 1299 1265 1256 1242 1222 1195 1148 1136 1112 1071 1049 1033 1021 1015 961 931 907 893 890 877 838 824 791 734 728 704 694 671 663 627 604 582 543 518 511 509 485 446 426 419 366 357 281 274 254 243 192 151

15.03 9.58 25.71 16.69 6.04 3.65 0.42 9.28 14.60 9.40 2.50 182.07 47.72 6.26 6.38 25.20 40.29 7.14 347.13 9.49 17.12 132.13 47.88 15.16 56.75 102.02 52.48 175.19 10.14 2.87 115.59 0.83 4.33 17.54 16.38 4.37 14.21 31.07 1.52 17.57 0.17 0.11 4.66 34.17 18.67 2.99 2.07 19.74 25.81 46.54 5.04 0.39 9.63 8.36 18.72 23.10 7.53 42.09 16.86 8.27 13.20 0.84 4.64 1.10 0.89 0.63 0.11 1.14 1.89 1.39 0.77 3.13 0.45

3459, 3353 3100 – – – – – 3054 3038 2980 – 1764 1604 – 1565 1548 1520 1484 – – 1436 1430 1382 1352 1321 1294 – 1256 – – 1188 1155 1128 1112 1068 – 1030 – 1016 958 – 908 – 890 868 836 826 – 740 728 – 692 – – 624 597 – 539 – – – 488 447 428 – – – – – – – – –

tNH(100) tCHI(98) tCHII(97) tCHII(89) tCHII(92) tCHI(90) tCHI(94) tCHI(96) tasCH3(100) tasCH3(95) tsCH3(88) tC@O(72) tPhI(63), tPhII(16) tPhII(56), tPhI(23) tPhI(68), tPhII(12) tPhII(55), dCHI(22) tPhI(43), tPhII(40) tPhI(53), dCHII(18) dasCH3(75), dCHI(13) dasCH3(63), tPhI(22) tPhI(47), dasCH3(22) tPhII(52), dsCH3(24) dsCH3(71), tPhII(11) tPhII(48), dNH(26) dNH(51), tPhI(12), dCHII(18) tPhI(44), dCHI(22), tPhII(16) tPhII(49), dCHI(23) dCHI(55), dCHII(17) dCHII(47), dCHI(18) dCHII(61), tCN(26) dCHI(53), tCN(16) tCN(44), dCHI(22) tCN(39), dCHI(28) dCHI(55), dCHII(14) dCHII(66), tPhI(22) tPhI(53), dCH3 (17) dCH3(52), tCC(19), dCHI(14) dCHI(43), tCC(22), dCH3 (16) tCC(38), dCH3(22), cCHI(11) dCH3(58), cCHI(22) cCHI(77) cCHI(67), cCHII(12) cCHII(85) cCHII(79) cCHI(88), cCHII(10) cCHII(66), tCC(16) tCC(41), dPhI(18) dPhI(33), tCC(21), cCHI(16) cCHI(77) tPhII(55), dPhII(12) dPhII(24), cNH(35), dC@O(17) tCS(39), dC@O(12), dPhI(13) tCS(36), dPhII(19), dCC(16) dC@O(41), dCC(11), dPhI(20) dPhI(35), dPhII(25), cC@O(13) dPhII(28), cC@O(19), dCC(14) cC@O(37), dCC(22), sPhII(15) dCC(27), sPhII(22), sPhI(18) sPhII(33), sPhI(24), cCC(17) dPhI(33), cCN(22), cCS(19) dPhII(23), cCN(18), cCS(13) dPhI(34), cCN(24), cCS(21) dPhII(35), sPhI(25), sCN(14) sPhI(33), sCN(18), sCS(13) sPhII(29), sPhI(18), sCH3(24) sPhI(27), sCH3(22), sPhII(19) dPhI(26), sCC(18), sPhII(16) sPhII(22), dPhI(16), sCC(23) dCC(30), sCH3(18), sCN(11) sCH3(30), sCN(22), sCS(14) sCN(17), sPhI(19), sPhII(23) sCS(25), sPhI(22), sPhII(13) sCN(16), sPhI(22), sPhII(17)

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

167

Table 2 (continued) HF/6-31G(d) (6D, 7F)

B3LYP/6-31G(d) (6D, 7F)

IR

Assignmentsa

t

IRI

t

IRI

t

–

147 121 84 50 38

2.10 1.92 0.89 3.69 2.89

143 119 83 59 40

1.93 1.77 0.21 4.42 1.02

– – – – –

sCS(18), sCH3(22), sPhI(16) sCC(29), sPhI(21), sPhII(20) sCH3(34), sPhI(22), sPhII((19) sPhI(41), sPhII(16), sCH3(10) sPhII(23), sCH3(14), sPhI(18)

a t-stretching; d-in-plane deformation; c-out-of-plane deformation; s-torsion; PhI-di substituted phenyl ring; PhII-tri substituted phenyl ring; as-asymmetric; s-symmetric; potential energy distribution is given in brackets in the assignment column.

assigned as in-plane CH deformation modes. The out-of-plane CH modes are observed at 890, 836 cm1 in the IR spectrum and the corresponding B3LYP values are 893, 890, 838 cm1 for PhII. Most of the modes are not pure according to PED calculations, but contain significant contributions from other modes also. The substituent sensitive modes of the phenyl rings and other modes are also identified and assigned. In order to investigate the performance of vibrational wavenumbers of the title compound, the root mean square (RMS) value between the calculated and observed wavenumbers were calculated. The RMS values of wavenumbers were calculated using the following expression [52].

the reported values of similar derivatives [47,57] and which is 31.38 times that of the standard NLO material urea (0.13  1030 esu) [58]. The CAN distances in the calculated molecular structure are 1.4024 and 1.4036 which intermediate between those of a CAN single bond (1.48) and a C@N double bond (1.28). Therefore, the calculated data suggest an extended p-electron delocalization in the system which is responsible for the nonlinearity of the molecule [20]. We conclude that the title compound is an attractive object for future studies of nonlinear optical properties.

vffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi u n u 1 X 2 RMS ¼ t ðtcalc  texp i i Þ : n1 i

MEP is related to the ED and is a very useful descriptor in understanding sites for electrophilic and nucleophilic reactions as well as hydrogen bonding interactions [59,60]. The electrostatic potential V(r) is also well suited for analyzing processes based on the ‘‘recognition’’ of one molecule by another, as in drug-receptor, and enzyme-substrate interactions, because it is through their potentials that the two species first ‘‘see’’ each other [61,62]. To predict reactive sites of electrophilic and nucleophilic attacks for the investigated molecule, MEP at the B3LYP optimized geometry was calculated. The negative (red and yellow)1 regions of MEP were related to electrophilic reactivity and the positive (blue) regions to nucleophilic reactivity (Fig. 3). From the MEP it is evident that the negative charge covers the carbonyl and benzene and the positive region is over the NH group. The more electro negativity in the carbonyl and benzene rings makes it the most reactive part in the molecule.

The RMS error of the observed IR bands is found to be 28.71 for HF and 11.46 for DFT methods, respectively. The small differences between experimental and calculated vibrational modes are observed. This is due to the fact that experimental results belong to solid phase and theoretical calculations belong to gaseous phase. NLO properties Nonlinear optics deals with the interaction of applied electromagnetic fields in various materials to generate new electromagnetic fields, altered in wavenumber, phase, or other physical properties [53]. Organic molecules able to manipulate photonic signals efficiently are of importance in technologies such as optical communication, optical computing, and dynamic image processing [54,55]. In this context, the dynamic first hyperpolarizability of the title compound is also calculated in the present study. The first hyperpolarizability (b0) of this novel molecular system is calculated using SDD method, based on the finite field approach. In the presence of an applied electric field, the energy of a system is a function of the electric field. First hyperpolarizability is a third rank tensor that can be described by a 3  3  3 matrix. The 27 components of the 3D matrix can be reduced to 10 components due to the Kleinman symmetry [56]. The components of b are defined as the coefficients in the Taylor series expansion of the energy in the external electric field. When the electric field is weak and homogeneous, this expansion becomes

E ¼ E0 

X i

li F i 

1X 1X aij F i F j  b FiFjFk 2 ij 6 ijk ijk

1 X  c FiFjFkFl þ . . . 24 ijkl ijkl where E0 is the energy of the unperturbed molecule, Fi is the field at the origin, li, aij, bijk and cijkl are the components of dipole moment, polarizability, the first hyperpolarizabilities, and second hyperpolarizabilities, respectively. The calculated first hyperpolarizability of the title compound is 4.08  1030 esu, which comparable with

Molecular electrostatic potential (MEP)

NBO analysis The natural bond orbital (NBO) calculations were performed using NBO 3.1 program [63] as implemented in the Gaussian09 package at the DFT/B3LYP level in order to understand various second-order interactions between the filled orbital of one subsystem and vacant orbital of another subsystem, which is a measure of the intermolecular delocalization or hyper conjugation. NBO analysis provides the most accurate possible ‘natural Lewis structure’ picture of ‘j’ because all orbital details are mathematically chosen to include the highest possible percentage of the electron density. A useful aspect of the NBO method is that it gives information about interactions of both filled and virtual orbital spaces that could enhance the analysis of intra and inter molecular interactions. The second-order Fock-matrix was carried out to evaluate the donor–acceptor interactions in the NBO basis. The interactions result in a loss of occupancy from the localized NBO of the idealized Lewis structure into an empty non-Lewis orbital. For each donor (i) and acceptor (j) the stabilization energy (E2) associated with the delocalization i ? j is determined as

1 For interpretation of color in Fig. 3, the reader is referred to the web version of this article.

168

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

Frontier molecular orbitals

Fig. 3. MEP plot of 1-(10H-phenothiazin-3-yl)ethanone.

Eð2Þ ¼ DEij ¼ qi

ðF i;j Þ2 ðEj  Ei Þ

qi ? donor orbital occupancy, Ei, Ej ? diagonal elements, Fij ? the off diagonal NBO Fock matrix element. In NBO analysis large E(2) value shows the intensive interaction between electron-donors and electron-acceptors, and greater the extent of conjugation of the whole system, the possible intensive interaction are given in NBO Table 3. The second-order perturbation theory analysis of Fock-matrix in NBO basis shows strong intermolecular hyper-conjugative interactions are formed by orbital overlap between n(S), n(O), n(N) and p*(CAC), r*(CAC), bond orbital which result in ICT causing stabilization of the system. These interactions are observed as an increase in electron density (ED) of CAC orbital that weakens the respective bonds. There occurs a strong intermolecular hyper-conjugative interaction of C5AC26 from S1 of n2(S1) ? p*(C5AC26) which increases ED (0.36642e) that weakens the respective bonds C5AC26 leading to stabilization of 16.79 kJ/ mol. There occurs a strong intermolecular hyper-conjugative interaction of C4AC8 from O2 of n2(O2) ? r*(C4AC8) which increases ED (0.05631e) that weakens the respective bonds C4AC8 leading to stabilization of 27.61 kJ/mol. A very strong intermolecular hyperconjugative interaction of C6AC10 from N3 of n1(N3) ? p*(C6AC10) which increases ED (0.32562e) that weakens the respective bonds C6AC10 leading to stabilization of 34.28 kJ/mol. The increased electron density at the oxygen atoms leads to the elongation of respective bond length and a lowering of the corresponding stretching wave number. The electron density (ED) is transferred from the n(S) to the anti-bonding p* orbital of the CAC explaining both the elongation and the red shift [64]. The hyper-conjugative interaction energy was deduced from the second-order perturbation approach. Delocalization of electron density between occupied Lewis-type (bond or lone pair) NBO orbital and formally unoccupied (anti-bond or Rydberg) non-Lewis NBO orbitals corresponds to a stabilizing donor–acceptor interaction. The NBO analysis also describes the bonding in terms of the natural hybrid orbital n2(O2), which occupy a higher energy orbital (0.44493 a.u.) with considerable p-character (99.08%) and low occupation number (1.91479) and the other n1(O2) occupy a lower energy orbital (0.91740) with p-character (46.68%) and high occupation number (1.97779). The NBO analysis also describes the bonding in terms of the natural hybrid orbital n2(S1), which occupy a higher energy orbital (0.35487 a.u.) with considerable p-character (98.49%) and low occupation number (1.88576) and the other n1(S1) occupy a lower energy orbital (0.77437) with p-character (37.65%) and high occupation number (1.98260). Thus, a very close to pure p-type lone pair orbital participates in the electron donation to the r*(C4AC8) orbital for n2(O2) ? r*(C4AC8), p*(C5AC26) orbital for n2(S1) ? p*(C5AC26) and p*(C6AC10) orbital for n1(N3) ? p*(C6AC10). The results are tabulated in Table 4.

To explain several types of reactions and for predicting the most reactive position in conjugated systems, molecular orbital and their properties such as energy are used [65]. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) are the most important orbital in a molecule. HOMO, which can be thought the outer orbital containing electrons, tends to give these electrons as an electron donor and hence the ionization potential is directly related to the energy of the HOMO. On the other hand LUMO can accept electrons and the LUMO energy is directly related to electron affinity [66]. Two important molecular orbital (MO) were examined for the title compound, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) which are given in Fig. 4. In the title compound, the HOMO of p nature is delocalized over the phenyl rings, thiazine and carbonyl groups. By contrast, the LUMO is located over the entire structure except NH group. Using HOMO and LUMO orbital energies, the ionization energy and electron affinity can be expressed as: I = EHOMO, A = ELUMO, g = (EHOMO + ELUMO)/2 and l = 1/2(EHOMO + ELUMO) [67]. Parr et al. [68] proposed the global electrophilicity power of a ligand as x = l2/2g. This index measures the stabilization in energy when the system acquires an additional electronic charge from the environment. Electrophilicity encompasses both the ability of an electrophile to acquire additional electronic charge and the resistance of the system to exchange electronic charge with the environment. It contains information about both electron transfer (chemical potential) and stability (hardness) and is a better descriptor of global chemical reactivity. The hardness g and chemical potential l are given the following relations g = (I  A)/2 and l = (I + A)/2, where I and A are the first ionization potential and electron affinity of the chemical species [69]. For the title compound, EHOMO = 7.62, ELUMO = 5.52, Energy gap = HOMO–LUMO = 2.1 eV, Ionization potential I = 7.62, Electron affinity A = 5.52, global hardness g = 1.05, chemical potential l = 6.57, global electrophilicity = l2/ 2g = 20.55 eV. It is seen that the chemical potential of the title compound is negative and it means that the compound is stable. They do not decompose spontaneously into the elements they are made up of. The hardness signifies the resistance toward the deformation of electron cloud of chemical systems under small perturbation encountered during chemical process. The principle of hardness works in Chemistry and Physics but it is not physical observable. Soft systems are large and highly polarizable, while hard systems are relatively small and much less polarizable [70]. Geometrical parameters For the title compound the CAN bond lengths C13AN3 = 1.4036 (DFT), 1.3948(XRD) and C10AN3 = 1.4024 (DFT), 1.3930 Å (XRD). Dandia et al. [71] reported corresponding bond lengths for CAN as 1.364 and 1.412 Å for similar derivative and Endredi et al. [72] reported these values as 1.408 and 1.412 Å, and Jadeja et al. [73] reported this as 1.428 Å. Tamasi et al. [74] reported this as 1.378, 1.377 and 1.397 Å. In the present case the C@O bond length is 1.2216 (XRD), 1.2227 Å (DFT). Dandia et al. [71] reported this bond length as 1.343 Å and Jadeja et al. [73] reported this as 1.252 Å. The N3AH28 bond length of the compound is 0.8290 (XRD), 1.0122 Å (DFT). Dandia et al. [71] reported this value as 0.80 Å. The C13AN3 AC10, C10AN3AH28 and C13AN3AH28 bond angle of the compound for DFT (XRD) are 122.7, (123.4), 114.0 (113.9) and 114.3° (115.0°). The asymmetry of the bond angle values is due to the interaction of NAH with hydrogen atoms H7 and H23. The C5AS1 AC9 bond angle of the title compound is 99.9 (DFT) and 100.8° (XRD). Dandia et al. [71] reported as 101.3° and Endredi et al. [72] reported this value as 96.1, 97.9, and 98.0°. The C4AC8AO2,

169

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171 Table 3 Second order perturbation theory analysis of Fock matrix in NBO basis corresponding to the intramolecular bonds of the title compound.

a b c

Donor(i)

Type

ED/e

Acceptor(j)

Type

ED/e

E(2)a

E(j)  E(i)b

F(i,j)c

S1AC5 – – C4AC8 – – – C5AC10 – – C5AC26 – – C5AC26 – – C6AC10 – – – – – C6AC10 – C8AC14 C9AC13 – – C9AC20 – – C9AC20 – – C13AC22 – – – – C13AC22 – – LP S1 – LP S1 – – – – – LP O2 – LP O2 – LP N3 – – –

r

1.97480 – – 1.98052 – – – 1.97290 – – 1.97748 – – 1.69010 – – 1.97212 – – – – – 1.64209 – 1.99010 1.97266 – – 1.97728 – – 1.69972 – – 1.97232 – – – – 1.65193 – – 1.98260 – 1.88576 – – – – – 1.97779 – 1.91479 – 1.81959 – – –

C5AC10 C5AC26 C6AC10 C4AC6 C4AC11 C6AC10 C11AC26 N3AC10 C5AC26 C6AC10 N3AC10 C5AC10 C11AC26 S1AC9 C4AC11 C6AC10 S1AC5 N3AC10 N3AC13 C4AC6 C4AC8 C5AC10 C4AC11 C5AC26 C4AC6 N3AC13 C9AC20 C13AC22 N3AC13 C9AC13 C20AC24 S1AC5 C13AC22 C18AC24 S1AC9 N3AC10 N3AC13 C9AC13 C18AC22 N3AC10 C9AC20 C18AC24 C5AC10 C9AC13 C5AC10 C5AC26 C5AC26 C9AC13 C9AC20 C9AC20 C4AC8 C8AC14 C4AC8 C8AC14 C6AC10 C6AC10 C13AC22 C13AC22

r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* r* p* p* r* r* r* r* r* r* r* r* p* p* r* r* r* r* r* r* p* p* r* r* r* r* p* r* r* p* r* r* r* r* r* p* r* p*

0.03174 0.02020 0.02038 0.01860 0.02020 0.02038 0.01450 0.02162 0.02020 0.02038 0.02162 0.03174 0.01450 0.01942 0.02020 0.02038 0.01938 0.02162 0.02132 0.01860 0.05631 0.03174 0.37471 0.02020 0.01860 0.02132 0.02007 0.02166 0.02132 0.03104 0.01503 0.01938 0.36688 0.34137 0.01942 0.02162 0.02132 0.03104 0.01319 0.02162 0.38261 0.34137 0.03174 0.03104 0.03174 0.02020 0.36642 0.03104 0.02007 0.38261 0.05631 0.04153 0.05631 0.04153 0.02038 0.32562 0.02166 0.36688

1.23 1.24 4.45 2.66 2.93 3.13 2.54 2.02 5.55 5.44 4.53 6.27 3.81 1.25 38.03 38.50 4.16 2.16 2.58 4.25 3.19 6.30 44.99 39.56 2.67 2.07 5.76 5.44 4.57 6.54 3.74 1.38 44.61 32.98 4.29 2.63 2.10 6.39 3.62 1.18 35.45 49.21 4.55 4.41 1.20 1.69 16.79 1.22 1.68 14.68 2.42 1.80 27.61 27.18 1.54 34.28 1.53 35.19

1.66 1.69 1.70 1.73 1.74 1.74 1.74 1.67 1.82 1.83 1.68 1.79 1.83 0.77 0.51 0.52 1.38 1.66 1.67 1.81 1.64 1.78 0.49 0.48 1.71 1.67 1.82 1.81 1.67 1.79 1.82 0.76 0.51 0.52 1.37 1.66 1.66 1.78 1.81 1.04 0.48 0.50 1.61 1.62 1.19 1.22 0.52 1.20 1.22 0.52 1.62 1.57 1.14 1.09 1.29 0.60 1.28 0.59

0.040 0.041 0.078 0.061 0.064 0.066 0.059 0.052 0.090 0.089 0.078 0.095 0.075 0.030 0.126 0.127 0.068 0.054 0.059 0.078 0.065 0.095 0.134 0.123 0.061 0.053 0.092 0.089 0.078 0.097 0.074 0.031 0.137 0.118 0.069 0.059 0.053 0.095 0.072 0.034 0.118 0.140 0.077 0.076 0.034 0.042 0.089 0.035 0.041 0.084 0.056 0.048 0.160 0.156 0.042 0.133 0.041 0.135

– –

r – – –

r – –

r – –

p – –

r – – – – –

p –

r r – –

r – –

p – –

r – – – –

p – –

r –

p – – – – –

r –

p –

r – – –

E(2) means energy of hyperconjugative interactions (stabilization energy in kJ/mol). Energy difference (a.u.) between donor and acceptor i and j NBO orbitals. F(i,j) is the Fock matrix elements (a.u.) between i and j NBO orbitals.

C14AC8AO2 and C14AC8AC4 bond angle of the compound are 120.7 (DFT, XRD), 120.5 (DFT), 120.8 (XRD) and 118.8 (DFT), 118.6° (XRD). Dandia et al. [71] reported these values as 122.1, 122.3 and 115.6°. The torsion angles of the compound are C4AC6AC10AN3 = 178.1 (DFT), 177.5 (XRD); C6AC10AN3AC13 = 148.4 (DFT), 156.2 (XRD); C11AC26AC5AS1 = 173.9 (DFT), 174.3 (XRD); C26AC5AS1AC9 = 153.6 (DFT), 159.4 (XRD); C18AC22AC13AN3 = 178.7 (DFT), 178.2 (XRD); C22AC13AN3AC10 = 148.0 (DFT), 156.1 (XRD); C24AC20AC9AS1 = 174.2 (DFT), 172.9 (XRD); C20AC9AS1

AC5 = 153.0 (DFT), 158.9(XRD) and these values reveal the boat conformation for the thiazine ring with respect to the phenyl rings. The CC bond lengths in the Phenyl rings lie between 1.3937–1.44101 (B3LYP), 1.3868–1.4026 Å (XRD) for PhII and 1.3944–1.4057 (B3LYP), 1.3840–1.4003 Å (XRD) for PhI and here for the title compound, benzene ring is a regular hexagon with bond lengths somewhere in between the normal values for a single (1.54 Å) and a double (1.33 Å) bond [75]. The discrepancies between the XRD results and the calculated geometrical parameters are due

170

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171

Table 4 NBO results showing the formation of Lewis and non-Lewis orbitals. Bond(A–B)

ED/ energya

EDA%

EDB%

NBO

s%

p%

rS1AC5

1.97480 0.82490 1.98052 0.86336 1.97290 0.95076 1.97748 0.95368 1.69010 0.33445 1.97212 0.94327 1.64209 0.31852 1.99010 0.84552 1.97266 0.94842 1.97728 0.94517 1.69972 0.32990 1.97232 0.93485 1.65193 0.31632 1.98260 0.77437 1.88576 0.35487 1.97779 0.91740 1.91479 0.44493 1.81959 0.41481

44.22 – 52.95 – 50.01 – 51.33 – 52.80 – 48.75 – 52.80 – 48.75 – 49.92 – 51.41 – 55.36 – 51.43 – 45.62 – – – – – – – – – – –

55.78 – 47.05 – 49.99 – 48.67 – 47.20 – 51.25 – 47.20 – 51.25 – 50.08 – 48.59 – 44.64 – 48.57 – 54.38 – – – – – – – – – – –

0.6650(sp4.40)S +0.7469(sp2.81)C 0.7277(sp2.27)C +0.6859(sp1.89)C 0.7072(sp1.79)C +0.7070(sp1.85)C 0.7165(sp1.64)C +0.6976(sp1.88)C 0.7266(sp1.00)C +0.6870(sp1.00)C 0.6982(sp1.86)C +0.7159(sp1.70)C 0.7266(sp1.00)C +0.6870(sp1.00)C 0.6982(sp1.88)C +0.7159(sp2.74)C 0.7065(sp1.77)C +0.7077(sp1.83)C 0.7170(sp1.63)C +0.6971(sp1.88)C 0.7440(sp1.00)C +0.6682(sp1.00)C 0.7171(sp1.71)C +0.6969(sp1.91)C 0.6754(sp1.00)C +0.7374(sp1.00)C sp0.60 – sp65.39 – sp0.87 – sp99.99 – sp15.82 –

18.34 26.19 30.57 34.52 35.80 35.00 37.92 34.73 0.00 0.00 34.90 36.95 0.00 0.00 34.68 26.70 36.02 35.29 38.02 34.66 0.00 0.00 36.85 34.39 0.01 0.00 62.35 – 1.51 – 53.32 – 0.02 – 5.94 –

81.66 73.81 69.47 65.48 64.20 65.00 62.08 65.27 100.0 100.0 65.10 63.05 100.0 100.0 65.32 73.30 63.98 64.71 61.98 65.34 100.0 100.0 63.15 65.61 99.99 100.0 37.65 – 98.49 – 46.68 – 99.08 – 94.06 –

–

rC4AC8 –

rC5AC10 –

rC5AC26 –

pC5AC26 –

rC6AC10 –

pC6AC10 –

rC8AC14 –

rC9AC13 –

rC9AC20 –

pC9AC20 –

rC13AC22 –

pC13AC22 – n1 – n2 – n1 – n2 – n1 – a

Conclusion

S1 S1 O2 O2 N3

ED/energy expressed in a.u.

Fig. 4. HOMO and LUMO plots of 1-(10H-phenothiazin-3-yl)ethanone.

to the fact that the comparison made between the experimental data, obtained from single crystal and calculated results are for isolated molecule in the gaseous phase.

FT-IR spectrum and single crystal XRD analysis of 1-(10H-phenothiazin-3-yl)ethanone is reported in the present work. Using the Gaussian09 set of quantum chemistry codes, the vibrational wavenumbers were examined theoretically and the normal modes were assigned by potential energy distribution calculation. A computation of the first hyperpolarizability indicates that the compound may be a good candidate as a NLO material. The CAN distances in the calculated molecular structure are intermediate between those of a CAN single bond and a C@N double bond and therefore, the calculated data suggest an extended p-electron delocalization in the system which is responsible for the nonlinearity of the molecule. The geometrical parameters of the title compound are in agreement with the XRD results. Using NBO analysis the stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The HOMO is of p nature is delocalized over the phenyl rings, thiazine and carbonyl groups. By contrast, the LUMO is located over the entire structure except NH group. Acknowledgement The authors would like to thank Dr. Hema Tresa Varghese, FMN College, Kollam, Kerala, India and King Fahd University for Petroleum and Minerals (KFUPM), Saudi Arabia, for providing the computational facility. References [1] M.T. Miller, P.K. Gantzel, T.B. Karpishin, J. Am. Chem. Soc. 121 (1999) 4292– 4293. [2] J. Wang, M. Dong, J. Liang, Z. Chang, S. Feng, H. Wang, N. Ding, Chin. J. Lab. Diagn. 12 (2008) 381–382. [3] M. Lam, N.L. Oleinick, A.L. Nieminen, J. Biol. Chem. 276 (2001) 47379–47386. [4] A. Kojilo, J. Karpinska, L. Kuzmicka, W. Misiuk, H.P. Tarasiewicz, M. Tarasiewicz, J. Trace Microprobe Technol. 19 (2001) 45–70. [5] J.D. Bell, J.F. Blount, O.V. Briscoe, H.C. Freeman, Chem. Commun. (London) (1968) 1656–1657. [6] J.J.H. McDowell, Acta Cryst. B25 (1969) 2175–2181. [7] J.H. McDowell, Acta Cryst. B26 (1970) 954–964. [8] J.J.H. McDowell, Acta Cryst. B31 (1975) 2256–2264. [9] J.J.H. McDowell, Acta Cryst. B32 (1976) 5–10. [10] J.J.H. McDowell, Acta Cryst. B34 (1978) 686–689. [11] J.J.H. McDowell, Acta Cryst. B36 (1980) 2178–2181. [12] S.S. Chu, D. Vander Helm, Acta Cryst. B30 (1974) 2489–2490. [13] S.S. Chu, D. Vander Helm, Acta Cryst. B31 (1975) 1179–1183. [14] S.S. Chu, D. Vander Helm, Acta Cryst. B33 (1977) 873–876. [15] D.W. Phelps, A.W. Cordes, Acta Cryst. B30 (1974) 2812–2816. [16] Q. Wang, L. Yang, Z. Xu, Y. Sun, Acta Cryst. E65 (2009). o1978-o1978. [17] B.N. Achar, M.A. Ashok, Mater. Chem. Phys. 108 (2008) 8–15. [18] M. Sailer, M. Nonnenmacher, T. Oeser, T.J.J. Muller, Eur. J. Org. Chem. 2 (2006) 423–435. [19] M. Sailer, A.W. Franz, T.J.J. Muller, Chem. Eur. J. 14 (2008) 2602–2614. [20] C.L. Honeybourne, R.J. Ewen, K.J. Alkins, in: R.A. Hann, D. Bloor (Eds.), Inorganic Materials for Non-linear Optics, Royal Society of Chemistry, Burlington House, London, 1989. [21] G.W. Kim, M.J. Cho, Y.J. Yu, Z.H. Kim, J.K. Jin, D.Y. Kim, D.H. Choi, Chem. Mater. 19 (2007) 42–50. [22] N.S. Cho, J.H. Park, S.K. Lee, J. Lee, H.K. Shim, M.J. Park, D.H. Huang, B.J. Jung, Macromolecules 39 (2006) 177–183. [23] M. Hauck, J. Schonhaber, A.J. Zucchero, K.I. Hardcastle, T.J.J. Muller, U.H.F. Bunz, J. Org. Chem. 72 (2007) 6714–6725. [24] W.Y. Wong, W.C. Chow, K.Y. Cheung, M.K. Fung, A.B. Djurisic, W.K. Chan, J. Organomet. Chem. 694 (2009) 2717–2726. [25] C.O. Okafor, Dyes Pigments 7 (1986) 249–287. [26] M.L. Laws, R.R. Roberts, J.M. Nicholson, R. Butcher, J.P. Stables, A.M. Goodwin, C.A. Smith, K.R. Scott, Bioorg. Med. Chem. 6 (1998) 2289–2299. [27] O. Bratfos, J.O. Haug, Acta Psychiat. Scand. 60 (1979) 1–19. [28] C. Bodea, I.A. Silberg, in: A.R. Katrizky, A.J. Boulton (Eds.), Advances in Heterocyclic Chemistry, Academic Press, New York, 1968. [29] R.R. Gupta, Bioactive molecules: phenothiazine and 1,4-benzothiazines, Chemical and Biological Aspects, vol. 4, Elsevier, Amsterdam, 1988. [30] J.P. Jasinski, A.E. Pek, P.S. Nayak, B. Narayana, H.S. Yathirajan, Acta Cryst. E67 (2011) o430–o431.

K.G. Vipin Das et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 162–171 [31] Gaussian 09, Revision B.01, M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J.A. Montgomery, J.E. Peralta, F. Ogliaro, M. Bearpark, J.J. Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, T. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.M. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C.Adamo, J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth, P. Salvador, J.J. Dannenberg, S. Dapprich, A.D. Daniels, O. Farkas, J.B. Foresman, J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian Inc, Wallingford CT, 2010. [32] J.B. Foresman, in: E. Frisch (Ed.), Exploring Chemistry with Electronic Structure Methods: A Guide to Using Gaussian, Pittsburg, PA, 1996. [33] R. Dennington, T. Keith, J. Millam, Gaussview, Version 5, Semichem Inc., Shawnee Mission KS, 2009. [34] J.M.L. Martin, C. Van Alsenoy, GAR2PED, A Program to Obtain a Potential Energy Distribution from a Gaussian Archive Record, University of Antwerp, Belgium, 2007. [35] A. Spire, M. Barthes, H. Kallouai, G. DeNunzio, Physics D137 (2000) 392–396. [36] L.J. Bellami, The IR Spectra of Complex Molecules, John Wiley and Sons, New York, 1975. [37] J. Edler, R. Pfister, V. Pouthier, C. Falvo, P. Hamm, Phys. Rev. Lett. 93 (2004) 106405–106408. [38] J. Edler, P. Hamm, A.C. Scott, Phys. Rev. Lett. 88 (2002) 067403–067405. [39] J. Edler, P. Hamm, Phys. Rev. B69 (2004) 214301–214308. [40] M. Barthes, G. De Nunzio, G. Ribet, Synth. Met. 76 (1996) 337–340. [41] G. Socrates, IR Characteristic Group Frequencies, John Wiley and Sons, New York, 1981. [42] S. Kundoo, A.N. Banerjee, P. Saha, K.K. Chattophyay, Mater. Lett. 57 (2003) 2193. [43] N.P.G. Roeges, A Guide to Complete Interpretation of IR Spectra of Organic Structures, Wiles, New York, 1994. [44] A. Chandran, H.T. Varghese, Y.S. Mary, C.Y. Panicker, T.K. Manojkumar, C. Van Alsenoy, G. Rajendran, Spectrochim. Acta 92 (2012) 84–90. [45] C.Y. Panicker, H.T. Varghese, D. Philip, H.I.S. Nogueira, K. Kastkova, Spectrochim. Acta A 67 (2007) 1313–1320. [46] A. Bieliauskas, V. Martynaitis, V. Getautis, T. Malinauskas, V. Jankauskas, E. Kamarauskas, W. Holzer, A. Sackus, Tetrahedron 68 (2012) 3552–3559. [47] M. Kaur, Y.S. Mary, C.Y. Panicker, H.T. Varghese, H.S. Yathirajan, K. Byrappa, C. Van Alsenoy, Spectrochim. Acta 120 (2014) 445–455.

171

[48] N.B. Colthup, L.H. Daly, S.E. Wiberly, Introduction to Infrared and Raman Spectroscopy, Academic Press, New York, 1975. [49] A. Cravino, H. Neugebauer, S. Luzzati, M. Catellani, N.S. Sariciftci, J. Phys. Chem. B. 105 (2001) 46–52. [50] J. Coates, in: R.A. Meyers (Ed.), Interpretation of Infrared Spectra, A Practical Approach, John Wiley and Sons Inc., Chichester, 2000. [51] G. Varsanyi, Assignments of Vibrational Spectra of Seven Hundred Benzene Derivatives, Wiley, New York, 1974. [52] T. Joseph, H.T. Varghese, C.Y. Panicker, T. Thiemann, K. Viswanathan, C. Van Alsenoy, T.K. Manojkumar, Spectrochim. Acta 117 (2014) 413–421. [53] Y.R. Shen, The Principles of Nonlinear Optics, Wiley, New York, 1984. [54] P.V. Kolinsky, Opt. Eng. 31 (1992) 11676–11684. [55] D.F. Eaton, Science 25 (1991) 281–287. [56] D.A. Kleinman, Phys. Rev. 126 (1962) 1977–1979. [57] R. Minitha, Y.S. Mary, H.T. Varghese, C.Y. Panicker, R. Ravindran, K. Raju, V.M. Nair, J. Mol. Struct. 985 (2011) 316–322. [58] M. Adant, L. Dupuis, L. Bredas, Int. J. Quantum. Chem. 56 (2004) 497–507. [59] E. Scrocco, J. Tomasi, Adv. Quantum. Chem. 103 (1978) 115–121. [60] F.J. Luque, J.M. Lopez, M. Orozco, Theor. Chem. Acc. 103 (2000) 343–345. [61] E. Scrocco, J. Tomasi, Curr. Chem. 7 (1973) 95–170. [62] Y. Li, Y. Liu, H. Wang, X. Xiong, P. Wei, F. Li, Molecules 18 (2013) 877–893. [63] E.D. Glendening, A.E. Reed, J.E. Carpenter, F. Weinhold, NBO Version 3.1, Gaussian Inc., Pittsburgh, PA. [64] J. Choo, S. Kim, H. Joo, Y. Kwon, J. Mol. Struct. Theochem. 587 (2002) 1–8. [65] N. Choudhary, S. Bee, A. Gupta, P. Tandon, Comp. Theor. Chem. 1016 (2013) 8– 21. [66] B. Kosar, C. Albayrak, Spectrochim. Acta 78 (2011) 160–167. [67] T.A. Koopmans, Physica 1 (1993) 104–113. [68] R.J. Parr, L.V. Szentpaly, S. Liu, J. Am. Chem. Soc. 121 (1999) 1922–1924. [69] R.J. Parr, R.G. Pearson, J. Am. Chem. Soc. 105 (1983) 7512–7516. [70] R. Parthasarathi, V. Subramanian, D.R. Roy, P.K. Chattaraj, Bioorg. Med. Chem. 12 (2004) 5533–5543. [71] A. Dandia, P. Sarawgi, M.B. Hursthouse, A.L. Bingham, M. Elight, J.E. Drake, R. Ratnani, J. Chem. Res. (2006) 445–448. [72] C.H. Endredi, F. Billes, S. Holly, J. Mol. Struct. Theochem. 633 (2003) 73– 82. [73] R.N. Jadeja, J.R. Shah, E. Suresh, P. Paul, Polyhedron 23 (2004) 2465–2474. [74] G. Tamasi, L. Chiasserini, L. Zavini, A. Sega, R. Cini, J. Inorg. Biochem. 99 (2005) 1347–1359. [75] Y.S. Mary, K. Raju, I. Yildiz, O. Temiz-Arpaci, H.I.S. Nogueira, C.M. Granadeiro, C. Van Alsenoy, Spectrochim. Acta 96 (2012) 617–625.