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Synthesis, Characterization and DFT Calculations of
Thiosemicarbazone 4-Methoxy Benzaldehyde Zinc
Chloride
S Attralarasan, A Shiny Febena, M Victor Antony Raj, J Madhavan
To cite this version:
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.
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.
stretching vibrations normally occur at 3072cm-1 (Theory), 3081cm-1 (Experiment). 4000 3600 3200 2800 2400 2000 1600 1200 800 400 0 10 20 30 40 50 60 70 80 90 100 T ra n s m it ta n c e (% ) Wavenumber (cm-1) 3 8 5 2 3 7 4 7 3 7 2 9 3 5 0 1 3 4 3 3 3 2 8 5 3 1 8 0 3 0 8 1 3 0 2 5 3 0 0 6 2 9 7 9 29 3 6 2 8 3 7 2 8 1 7 25 6 2 2 0 2 0 1 6 0 0 1 5 5 5 15 1 3 1 4 6 3 1 3 7 7 13 1 0 1 2 5 4 1 1 1 7 1 0 5 5 1018 9 5 7 9 3 5 8 7 8 8 0 8 7 6 8 6 4 2 5 6 9521 4 9 8 4000 3500 3000 2500 2000 1500 1000 500 0 20 40 60 80 100 T ra n sm it ta n c e (% ) Wave number (cm-1 )
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
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
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
