3.Conference Paper (10)

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Author: search.filters.author.Shanmuga Sundari, SStart date: 2019

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    OPTICAL AND BIOLOGICAL CHARACTERISTICS OF NOVEL ORGANIC SINGLE CRYSTAL 4-CHLORO N-METHYL 4-STILBAZOLIUM TOSYLATE
    (Elsevier, 2019) Arunadevi, N; Kanchana, P; Mehala, M; Shanmuga Sundari, S
    When compared with inorganic materials, the molecular organic materials acquire significant interest because of their considerable nonlinear optical properties, virtual unlimited design possibilities and extremely fast response times. Amongst them, organic crystals which are based on the charged chromophores and substantial Coulomb interaction have a number of benefits over non-ionic species, like first-order hyperpolarizability or greater molecular nonlinearity, durable stability and having a larger capability to override the dipole–dipole interactions and therefore it forms a non-centro symmetric macroscopic packing. For instance, DAST (4-N, N-dimethylamino-4′-N′-methyl-stilbazolium tosylate), the organic salt crystal, is one of the finest nonlinear optical materials having larger second-order nonlinear optical susceptibilities. Even though benchmark stilbazolium crystals display a great macroscopic nonlinearity and noble crystal characteristics, improving these physical properties comprising the environmental stability is a provocative topic. Based on this, the present paper discusses the growth of cationic substituted DAST namely 4-chloro -N-methyl 4-stilbazolium tosylate (CMST). Knoevenagel reaction method was used to synthesis CMST salt using Dean-Stark apparatus. The synthesized salt of CMST was dried at 100 °C for 24 h. The dried CMST salt was used to grow the crystals after three recrystallization process. Based on the solubility curve new solvent, mixture of methanol and acetonitrile was used to grow the crystals at room temperature by slope nucleation method. Structure of the grown crystals was characterized using single crystal XRD and FTIR. The compositional analysis was carried out using NMR and CHN analysis. Luminescence characteristics was studied using photoluminescence spectrum. The dielectric characteristics ware carried out from room temperature to 250 °C. Invitro analysis was carried out in the cancer cell line to study it’s anti-cancer activity.
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    GROWTH, STRUCTURAL, DIELECTRIC AND OPTICAL CHARACTERISTICS OF GLYCINE PHOSPHITE SINGLE CRYSTALS
    (Elsevier, 2019) Shanmuga Sundari, S; Kanchana, P; Arunadevi, N; Shobana, C
    Interesting compounds are formed when glycine reacts with inorganic materials. These compounds exhibit phase transitions with exciting dielectric and elastic properties. In this aspect, glycine with orthophosphorus acid forms glycine phosphite (GPI) single crystals. Good quality, optical transparent glycine phosphite (GPI) single crystals are grown from aqueous solution. GPI crystals have a wide range of nonlinear optical applications. The present work focuses on the growth of GPI from its aqueous solution by slow evaporation method. The PXRD (powder XRD) pattern recorded at ambient temperature shows the single phase nature of the grown GPI crystals and it exists in the monoclinic system with space group P21/a. Etching studies were carried out to know more about the growth morphology and FTIR spectra shows the presence of a variety of normal mode vibration of GPI crystals. Dielectric studies were carried out from 100 K to 383 K. the ferroelectric to para electric transition was observed at 201 K. The dielectric relaxation of the grown crystals was studied using Debye fitting. The activation energy associated with the transition was also calculated. As the GPI crystals are paraelectric at room temperature, no second order non linearity was observed.