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Abstract  

A single crystal of sodium and potassium cinnamates was grown by slow evaporation of methanol solution at room temperature. The effect of metals sodium and potassium on the electronic structure of cinnamic acid was studied. In this research many analytical methods such as FTIR, UV, second harmonic generation (SHG) and TG–DTA were used: The spectroscopic studies lead to conclusions containing the distribution of the electronic charge in molecule, the delocalisation of π electrons and the reactivity of metal complexes. The SHG efficiency is more pronounced in the presence of sodium and potassium dopant in the growth medium. Incorporation of sodium and potassium increase the thermal stability ensuring the suitability of material for possible non-linear optical (NLO) application up to 180 °C.

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Abstract

Single crystal of tris thiourea chromium(III) sulphate was grown by slow evaporation technique at 303 K. The structural properties of the grown crystals were characterized by FTIR spectroscopy, UV spectroscopy and powder X-ray diffraction analysis. FTIR and UV spectra provide information about the presence of functional groups. Thermal analysis confirms that the crystal is thermally stable up to 163.48 °C. The TG curve presented a two-step mass loss on heating the compound at 0–1,200 °C.

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Abstract

Single crystal of bisthiourea iron(II) sulphate was grown by slow evaporation technique at 303 K. The structural properties of the grown crystals were characterized by FTIR spectroscopy, UV spectroscopy and powder X-ray diffraction. FTIR and UV spectra provide information about the presence of functional groups. Thermal analysis confirms the crystal is thermally stable up to 167.02 °C.

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Abstract

A single crystal of cinnamic acid–urea was grown by slow evaporation of methanol solution at room temperature. In this research, many analytical methods such as FTIR, second harmonic generation, NMR, and TG–DTA were used. The presence of title compound in the crystal lattice has been qualitatively determined by FTIR analysis. Thermal stability of the grown crystals was evaluated by TG-DTA. Incorporation of urea increases the thermal stability insuring the suitability of material for possible non-linear optical application up to 180 °C.

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Abstract

Mixed crystals of various proportions of urea thiourea were grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterized using thermogravimetry–differential thermal analysis (TG–DTA) and FTIR spectroscopic analyses. A fitting decomposition pattern for the title compound was formulated on the TG curve which shows a two-stage mass loss between 175 and 750 °C. In this temperature range, DTA curves show exothermic peaks supporting the formulated decomposition pattern. The FTIR spectra show the characteristic absorption, vibration frequencies due to urea thiourea. Detailed structural analysis of the compound is under progress.

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Abstract

Thiourea Urea Zinc (II) Chloride (TUZC), a new semiorganic non-linear optical material has been synthesized. The solubility studies have been carried out at room temperature. Single crystals of different proportions of TUZC have been grown by slow evaporation of saturated aqueous solution at room temperature. The FTIR and UV spectral bands have been compared with urea, thiourea and bis Thiourea Zinc Chloride (BTZC). The TG curve showed a two steps mass loss on heating the compound between 30 and 800 °C corresponding to two exothermic DTA peaks at 181–183 and 250–252 ºC.

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Journal of Thermal Analysis and Calorimetry
Authors:
S. C. Mojumdar
,
G. Madhurambal
,
M. Mariappan
, and
B. Ravindran

Abstract

The induction period of various proportion of urea–thiourea zinc chloride crystal in water has been measured experimentally using the visual observation method. The induction period, which is inversely proportional to the nucleation rate, has been used to estimate the interfacial tension between the urea–thiourea zinc chloride and water; hence, the nucleation parameters like critical radius (r∗), number of molecules in the radius (r∗) and Gibbs free energy change for the formation of a critical nucleus (ΔG∗) have been calculated.

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Journal of Thermal Analysis and Calorimetry
Authors:
B. Ravindran
,
G. Madhurambal
,
M. Mariappan
,
K. Ramamurthi
, and
S. C. Mojumdar

Abstract

Single crystals of mercury cinnamate were grown by slow evaporation of methanol solution at room temperature. The effect of mercury on the electronic structure of cinnamic acid was studied. The grown mercury cinnamate single crystals were characterized by UV, FTIR and TG-DTA. TG curve of mercury cinnamate exhibits higher thermal stability compared with cinnamic acid which was also confirmed by DTA curve. The spectroscopic studies give evidences of the distribution of the electronic charge in molecule, the delocalisation of π electrons and the reactivity of metal complexes. The Second harmonic generation efficiency is more pronounced in the presence of mercury dopant in the growth medium.

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Abstract

Single crystals of a new nonlinear optical material, bisthiourea-urea have been grown from aqueous solution by slow evaporation technique with a period of 4 weeks. The structure of the grown crystals was confirmed by X-ray diffraction (XRD). The presence of title compound in the crystal lattice has been qualitatively determined by FTIR analysis. The mechanical properties and thermal stability of the grown crystals were evaluated by Vickers microhardness test and TG and DTG, respectively.

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Abstract

The growth and characterization of a new non-linear organometallic crystal, potassium thiourea thiocyanide (PTT) is reported. The growth of single crystals was accomplished by the slow evaporation solution growth method. The grown crystals were characterized by XRD, TG–DTA, UV, and FTIR spectral analyses. PTT has good optical transmission in the entire visible region which is an essential requirement for a non-linear crystal. TG curve of PTT undergoes complete decomposition between 176 and 1,000 °C in three steps with corresponding three DTA peaks. The high thermal stability of organometallic crystals are due to strong bonding existing between the conjugation layers of thiourea molecule and the potassium ions.

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