Synthesis, Characterization and DFT Calculations of ...efficiency was measured using the Kurtz powder technique. The efficiency was found to be higher than that of Urea crystal. Introduction

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

MMSE Journal. Open Access www.mmse.xyz

Synthesis, Characterization and DFT Calculations of Thiosemicarbazone 4- Methoxy Benzaldehyde Zinc Chloride 60

S. Attralarasan 1, A. Shiny Febena 1, M. Victor Antony Raj1, J. Madhavan1, a

1 – Department of Physics, Loyola College, Chennai, India

a – [email protected]

DOI 10.2412/mmse.98.79.782 provided by Seo4U.link

Keywords: BLZC, UV-Vis, FT-IR, DFT, HOMO-LUMO, SHG, KDP

ABSTRACT.In this work, nonlinear optical single crystal of Thiosemicarbazone 4-Methoxy Benzaldehyde Zinc Chloride (BLZC) was grown by slow evaporation technique. The grown crystal was subjected to optical characterization by UV-Vis techniques. The Fourier transform infrared (FT-IR) spectrum was recorded in the range 4000cm-1 - 500cm-1. Meanwhile, the DFT computations are performed at B3LYP/6-31G (d, p) level to derive equilibrium geometry, vibrational wavenumbers and first hyper polarizability. The nonlinear characteristic and thermal stability of the crystal were also investigated. The HOMO-LUMO energies show that charge transfer occurs within the molecule. The SHG efficiency was measured using the Kurtz powder technique. The efficiency was found to be higher than that of Urea crystal.

Introduction. Applications in NLO materials demand good quality single crystals which derives large NLO coefficient coupled with improved physical parameters [1].The synthesis of new and efficient frequency conversion materials has resulted in the development of new amino acid based NLO materials. Optical second harmonic generation (SHG) requires organic NLO crystals possessing high conversion efficiencies owing to their practical applications in the field of optoelectronics and photonics [2].Natural amino acids have a donor NH2 and COOH due to the possibility of intermolecular charge transfer which exhibits the nonlinear optical property. The donor/acceptor of benzene derivatives can produce high molecular non linearity [3]. There has been much interest in the coordination chemistry of aryl hydrazones such as semicarbazones and thiosemicarbazones due to their importance for drug design, organo catalysis and for the preparation of hetero cyclic rings. This paper is an investigationwork of Thiosemicarbazone 4-Methoxy Benzaldehyde Zinc Chloride (BLZC).

Experimental Procedure Synthesis and solubility of BLZC.The starting material was synthesized from the analytical reagent grade of thiosemicarbazide, 4-methoxy benzaldehyde and zinc chloride in 2:2:1 molar ratio using ethanol as solvent. According to the reaction scheme, the calculated amount of thiosemicarbazide, 4-methoxy benzaldehyde and zinc chloride were taken and dissolved in hot ethanol. The resulting solution was stirred well. Then the solution was filtered, kept at room temperature (30°C) and allowed to evaporate the solvents into the atmosphere. Well defined BLZC crystals with good transparency were obtained in the beaker. The purity of the synthesized material was improved by recrystallization process. The solubility curve is as shown in Fig. 1. The as grown crystal is as shown in Fig. 2.

© 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Fig. 1. Solubility curve of BLZC. Fig. 2. Photograph of BLZC crystal.

Powder X-ray diffraction analysis Powder X-ray diffraction studies was carried out for the title compound .The sample was scanned over the range 10°to 40°and it was operated in at a scan rate of 4°/min. The graph is drawn between intensity and 2θ values. From the single crystal analysis, it was observed that BLZC belongs to orthorhombic crystal system having non-centrosymmetry with Aba2 space group. The powder XRD pattern of the grown BLZC crystal is shown Fig. 3. The simulated powder XRDPattern is shown in Fig. 4.

Fig. 3. Experimentally obtained Powder XRD.

Fig. 4. Theoretically simulated Powder XRD.

Computational Details. Using the Gaussian 03 software package combined with the 6-31 G (d, p) basis set, the Quantum chemical density functional theory (DFT) calculations was performed [4], The optimized geometrical parameters and fundamental vibrational frequencies were calculated. Molecular Geometry. The numbering scheme for BLZC is shown in Fig. 5.

Fig. 5. Atomic numbering system.

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FT-IR Analysis.FT-IR spectrum of BLZC was recorded in the range 4000 cm-1 to 500 cm-1, using KBr pellet technique on BRUKKER IFS FT-IR Spectrometer. The experimental IR spectrum is compared with the results of B3LYP/6-31 G (d, p) calculation. Due to the gaseous phase of isolated molecular state some bands are not observed in theoretically obtained graph. The experimental FT-IR is shown in the Fig. 6. The theoretically simulated FT-IR spectrum is shown in Fig. 7.

C-H vibrations.Presence of band in the region 2954cm-1, 2978cm-1 (Theory) and 2936cm-1, 2979cm-

1 (Experiment) is the characteristic region of C-H stretching vibrations [5]. The C-H bending vibrations are usually occurred in the region 1288cm-1 (Theory)-1447 cm-1 (Theory) and 1310 cm-1 (Experiment), 1377cm-1 (Experiment) (Socrates 2001). In aromatic compounds, the carbon-hydrogen stretching vibrations normally occur at 3072cm-1 (Theory), 3081cm-1 (Experiment).

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Fig. 6. Experimental FT-IR Spectrum. Fig. 7. FT-IR Spectrum of BLZC crystal by 6-31 G (d, p) method.

NH2 vibrations The NH2 asymmetric stretching vibrations [6] give rise to a strong band in the region 3350cm-1 (Theory) and the symmetric NH2 stretching is observed as weak band in the region 3151cm-1 - 3185cm-1 (Theory) and 3180cm-1(Experiment).

C-N vibrations C-N stretching absorptions for primary aromatic amine with nitrogen directly on the ring are assigned in the region 1270cm-1 ,1382cm-1 (Theory) and 1310 cm-1, 1377cm-1 (Experiment). The frequencies are slightly up shifted from the expected value for melamine due to the substitution effect [7].

Hyperpolarizability NLO techniques are considered as one among most the structure-sensitive methods to study molecular structures and assemblies [8]. Molecularhyperpolarizability becomes one of the key factors in the second-order NLO materials design [9]. The calculated first order hyperpolarisability is 15.3863 x 10-30e.s.u.

Homo-Lumo Energy Gap In order to evaluate the energetic behavior of BLZC, the energies of HOMO and LUMO their orbital energy gaps using B3LYP/ 6-31 G (d, p) and shown in Fig 8. SHG efficiency studies.NLO efficiency of BLZC crystal was determined using Kurtz and Perry second harmonic generation (SHG) test [10]. A sample of urea was powdered to the same particle size as the experimental sample, which is used as a reference material in the present measurement. The measured amplitude of SHG for BLZC and urea were 4.51 V and 0.93 V respectively. Thus, the powder SHG efficiency obtained for BLZC is about six times that of urea crystal.

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Fig. 8. HOMO – LUMO plot.

Optical absorption spectrum. UV–vis spectral study was carried out in the range 200–1000nm by 5E UV-Vis Instrument spectrophotometer. An optically transparent crystal of BLZC was used for this measurement. The BLZC crystal has sufficient transmittance in the visible and IR regions with lower cut-off wavelength 275 nm as shown in Fig. 9 Using the Tauc relation, the plot of (αhν)2 versus hν was drawn. The direct band gap energy (Eg) of BLZC is determined as 4.7 eV from the Fig. 10.

Fig. 9. Optical absorption spectrum. Fig. 10. Optical band gap.

Summary. Optically good quality single crystals of BLZC were grown by slow solvent evaporation technique. X-ray powder diffraction analysis confirms the crystalline nature of the grown crystal. Density functional theory (DFT) computations using (B3LYP) level with 6-31 G (d, p) basis set gives optimized structure parameters of BLZC molecule. Molecular energy gap of BLZC was found as 0.175 a.u by HOMO-LUMO analysis. Optical absorption spectrum was recorded for the given crystal and it is found that it has minimum absorption between 275-1200 nm. The optical band gap of the

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material is found as 4.7 eV. SHG studies were carried out and the frequency conversion efficiency of the BLZC crystal is found to be six times that of Urea crystal.

References [1] Badan J, Hierle R., Perigaud A, American Chemical Society, Washington, 1993. [2] Ramesh Kumar G., Gokul Raj S., Mohan R, Jayavel R., (2005), Journal of Crystal Growth, Vol.283, pp. 193–197. DOI: http://dx.doi.org/10.1016/j.jcrysgro.2005.04.103 [3] Marder S R, Sohn J E and Stucky G D (1991), ‘Materials for nonlinear optics – Chemical perspectives’, American Chemical Society, Washington, DC.DOI: 10.1002/actp.1993.010440216 [4] Frisch M J, Trucks G W et al ,Gaussian 03, Revision C.02, Gaussian Inc., Wallingford CT, 2004.

[5] Ramalingam S, Periandy S, Narayanan B, Mohan S, Spectrochim. Acta A 76 (2010) 84–92.DOI: http://dx.doi.org/10.1016/j.saa.2010.02.050

[6] Roeges N G P, A Guide to the Complete Interpretation of the Infrared Spectra of Organic Structures, Wiley, NY, 1994.

[7] Marchewka M K, Pietraszko A, J. Phys. Chem. Solids 64 (2003) 2169 –2181. DOI:http://dx.doi.org/10.1016/S0022-3697 (03)00218-X

[8] Varsanyi, vols. 1 and 2 Assignments for Vibrational Spectra of Seven Hundred Benzene Derivatives, Academia kiado, Budapest, 1973.

[9] Rice J E, Handy NC, J ChemPhys, 94 (1991) 4959. DOI.org/10.1063/1.460558. [10] Li H, Han K, Shen X, Lu Z, Huang Z, Zhang W, Zhang Z, Bai L, J Mol Strut (Theochem), 767(2006)113.DOI: DOI.org/10.1016/j.theochem.2006.05.008.

Cite the paper

S. Attralarasan, A. Shiny Febena, M. Victor Antony Raj, J. Madhavan (2017). Synthesis, Characterization and DFT Calculations of Thiosemicarbazone 4-Methoxy Benzaldehyde Zinc Chloride. Mechanics, Materials

Science & Engineering, Vol 9. doi 10.2412/mmse.98.79.782

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Synthesis, Characterization and DFT Calculations of ...efficiency was measured using the Kurtz powder technique. The efficiency was found to be higher than that of Urea crystal. Introduction