GROWTH AND CHARACTERIZATION OF L - TARTARIC ACID NICOTINAMIDE CRYSTALS (C 20 H 26 N 4 O 15 )

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1 GROWTH AND CHARACTERIZATION OF L - TARTARIC ACID NICOTINAMIDE CRYSTALS (C 20 H 26 N 4 O 15 ) S. Dheivamalar Abstract L-tartaric acid nicotinamide crystals were grown using slow evaporation method. L - tartaric acid is mixed with nicotinamide and it was observed that the nucleation density was reduced. The size of the crystals was improved to a large extent. The grown crystals were characterised by micro hardness measurement, Fourier Transform Infrared Spectroscopy (FTIR). Department of Physics,, Cauvery College for Women, Trichy 18. Counsellor, Chennai. Key Words: (LTN) ; FTIR Slow evaparation; L tartaric acid nicotinamide INTRODUCTION In recent years, more emphasis is given to semiorganic nonlinear optical (NLO) materials like L - arginine phosphate monohydrate (LAP) [1,2] L- arginine diphosphate [3] and other metal organic complex crystals, owing to their large nonlinear co - efficient, high laser damage threshold and good mechanical properties. To enable a material to potentially useful for NLO applications, the materials should be available in bulk single crystal form. It is difficult to grow large optical quality crystals of organic materials for device applications. Successful crystallization of semiorganic crystal L - tartaric acid (LTN) nicotinamide (LTN) were grown semiorganic NLO crystal with molecular formula C 20 H 26 N 4 O 15. In the present investigation, the growth aspects of LTN have been studied and bulk crystals, grown by slow evaporation technique. They are characterized by Fourier Transform Infra-Red (FTIR) DRS UV and solubility studies. The NLO property of the crystal has also been studied. EXPERIMENTAL L tartaric acid (grade AR), and nicotinamide were obtained commercially with the grade CR. Deionized water was used as solvent. In order to investigate the crystalline habit of LTN, several solvents in pure of mixture forms were tried. In general, LTN can be dissolved in most of the pure polar organic and inorganic solvents, e.g. methanol, ethanol, methanol and water, mixture of ethanol and water, and water in pure alcohol, DMF solution of mixture of alcohol and water solution. LTN were crystallized in very small size and were defective. Deionized water was suitable for crystallizing large and transparent colourless single crystals. The crystals of LTN are shown in Fig 1. Cauvery Research Journal, Volume 2, Issue 1, July

2 S. Deivamalar grown crystals by chemical etching or by X ray Lang topography and work in this direction will be reported in future publications. Fig. 1. Photograph of Crystals LTN were synthesized respectively, by dissolving L - tartaric acid (100g. 1.5 mol) in deionized water that contained nicotinamide (183 g, 1.5 mol). The mixture was heated to form saturated solution. The crystal seeds with perfect shape and transparence were formed by spontaneous nucleation in a supersaturated solution at room temperature. Seeds of about 8x4x1 mm 3 were selected. The growth of LTN crystal needed only 10 h. The single crystals of good optical quality with regular shape obtained in the size 10 x 32 x 2 mm 3 for LTN crystal were grown from seeds in solution for volume m1. In this present paper we deal with the synthesis, solubility and growth of LTN crystal from its aqueous solution by slow evaporation as well as by slow cooling method followed by characterization of the grown crystals infrared spectroscopy. At this stage it is necessary to access the quality of the CHARACTERIZATION Solubility test The solubility of LTN in water was determined by saturating the solutions at high temperature and then slowly cooling the solution in the presence of precipitated solid to maintain equilibrium and then sampling and analyzing the solution at defined temperatures. FT - IR Measurements. The infrared spectra were obtained from potassium bromide pellets on a Nicolet MAGNA IR 750 (series II) FTIR spectrometer and shown in fig. 2 and FT IR spectra of LTN recorded in the range cm. The observed wave number with relative intensities and proposed assignments are listed in Table1. The assignments are discussed in three different regions namely a high wave number region ( cm), a medium wave number region ( cm 1 ), a low wave number region (below 1000 cm 1 ), and high wave number region (below 1000 cm 1 ) and the assignments are shown in table.1. Table.1.Vibrational assignments on L-tartaric acid nicotinamide S.No Frequency in Cm -1 Nature of the Assignment of the Peak Peak Strong Presence of N-H stretching Medium Presence of N-H stretching Weak Presence of C-H stretching Cauvery Research Journal, Volume 2, Issue 1, July

3 Medium Presence of C-H stretching Weak Presence of C-H stretching Weak Presence of C-H stretching Weak Presence of amino acids Weak Presence of amino acids Strong Presence of C=O stretching Medium Presence of N-H deformation Strong Presence of O-H deformation Medium Presence of C-H deformation Weak Presence of C-N vibrations Strong Presence of C-OH stretching Variable intensity Presence of C-OH stretching Variable intensity Presence of C-H stretching Variable intensity Presence of C-H stretching Absorbance Wave number(cm -1 ) Fig. 2 FTIR Spetra of LTN Crystals The Optical absorption of LTN single crystals recorded in the region nm using Secomam Anthelic 70Mio- 291 spectrophotometer and shown in Fig. 3. The recorded spectrum show good transparency in the visible region. The increased transparency in the visible region enables the achievement of high second harmonic transmission for Nd : YAG laser (λ =1.603 a.units) Cauvery Research Journal, Volume 2, Issue 1, July

4 S. Deivamalar Absorbance Wave number(cm -1 ) Fig.3 UV Visible spectrograph of LTN The hardness of the crystal is shown in Fig 4. Single crystals was measured with miniload hardness tester (ERNST LEITAZ GMBIII WETZLAR). Vickers indentations were made for different loads and values of VHN were averaged over a large number of observations. The dwell time was 10 15s for all indentations. VHN it is shown measured at room temperature was The SHG of single crystals LTN was studied using Nd YAG laser (model continuum YG201C, (λ = 531 nm) was detected using an optical cable attached to a fluorescence instrument. The wavelength was scanned continuously with the aid of a monochromator in the spectroscope and an intensity spectrum was recorded. This shows that LTN is a nonlinear material. Indentation load in gms Fig.4.Hardness of LTN Cauvery Research Journal, Volume 2, Issue 1, July

5 CONCLUSIONS The preliminary studies show that single crystals of LTN can be grown by slow evaporation technique. The UV visible spectrograph shows good transparency in the visible rage,owing to good quality, transparency and size. LTN is a promising material for NLO applications. REFERENCE 1. Aokoi, K. Nagano, Y. litaka. Acta cryst. B.27 (1971) 2. Yakotani, T. Sasaki, K. Fujioka, S. Nakai, C. Yamanaka, J. Crystal growth. 99 (1990) A.M. Petrosynan, R.P. Sukiasyan, H.A. Karepetyan, S.S. Terzyan, R.S. Feigelson. J. cryst. Growth (2000) R.S. Krishnan, V.N. Shankaranarayanan, K. Krishnan. J. Indian. Institute of Su. 55 (1973). Cauvery Research Journal, Volume 2, Issue 1, July