Crystallography and Spectral Analysis in structuring of 7,8-dihydroxy-4-Phenyl Coumarin Monohydrate

Vibrational assignments of 7,8-dihydroxy4-phenyl coumarin monohydrate have been made both in crystalline and gas phase. Infrared absorption and Raman spectra of 7,8-dihydroxy4-phenyl coumarin monohydrate have been interpreted and compared by electronic structure calculations at B3LYP using 6-311++G(d,p) basis set. Down-shifting of frequencies of O-H vibrations due to intra-molecular O-H…O hydrogen bonding as well as inter-molecular interactions with solvent molecule were resolved by NCA analysis. Sharpness of endothermic peak in TG/DTA shows the good degree of crystallinity and purity of the sample

Vibrational spectral investigation and natural bond orbital analysis of pharmaceutical compound 7-Amino-2,4-dimethylquinolinium formate – DFT approach

AbstractThe molecular geometry, the normal mode frequencies and corresponding vibrational assignments, natural bond orbital analysis and the HOMO–LUMO analysis of 7-Amino-2,4-dimethylquinolinium formate in the ground state were performed by B3LYP levels of theory using the 6-31G(d) basis set. The optimised bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of the title compound which is calculated by DFT method, reproduces vibrational wave numbers and intensities with an accuracy which allows reliable vibrational assignments. The possibility of N–H⋯O hydrogen bonding was identified using NBO analysis. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction

Effect of Hydrochloric Acid (HCl) on Synthesis and Anisotropic Phenomena of Triglycine Phosphate (TGP) Single Crystals

International audienceEffect of Sulphuric acid (H2SO4) addition on the growth of triglycine phosphate (TGP) crystal has been studied from the aqueous solution by slow evaporation technique. The characteristics absorption bands of pure and H2SO4 admixtured TGP crystals are confirmed by FTIR spectra. UV-visible transmittance spectra were recorded for the samples to analyze the transparency of the grown crystals. The composition of pure and doped TGP crystals have been confirmed by EDAX analysis. The dielectric constants of the crystals have been studied and result suggests that the H2SO4 is doped into TGP crystal and that the doping increases its dielectric parameters. Introduction. Investigations on semiorganic nonlinear optical (NLO) materials gain importance because of good thermal and mechanical properties with large NLO coefficients [1,2]. Among the amino acids, glycine [amino acetic acid: NH2CH2COOH] is the simplest amino acid, hence,glycine mixed semi-organic material is a fundamental building block to grow many complex crystals with improved NLO properties. Reported literature shows that glycine sodiumnitrate [3], triglycine sulphate [4] etc. crystals exhibit of some glycine based compounds like triglycine zinc chloride [5], glycine sodium nitrate [6] and triglycine selenate [7] show non-linear effects ferroelectric properties and are used as infrared detectors, transducers and piezoelectric sensors due to the large difference between the inter-molecular and intra molecular chemical bonds [5–7]. One of the hydrogen bonded ferroelectric single crystal Glycine phosphate (GPI) undergoes a continuous ferroelectric–para electric phase transition at 224.7K [8]. Subsitutional or interstitial impurities in the host lattice leads to significant changes in the properties of the pure TGS crystals [9-10]. The pyroelectric coefficient of phosphoric acid doped TGS is more than that of pure TGS and observed phase transition temperature shift [11]. Inview of this, the present investigation has been focused on the growth of semi-organic Triglycine phosphate (TGP) single crystals doped with sulphuric acid at various concentrations (0.25,0.50,0.75 and 1.0 mol %) and this doping efforts on the growth aspects, structural perfection, phase transition temperature, and optical properties were studied by conducting various characterization techniques

Дослідження електричних та структурних властивостей наночастинок діоксиду марганцю

Кристалічний діоксид марганцю (MnO2) готували методом розчинення в мікрохвильовій печі з використанням гідроксиду натрію як агента. Електропровідність, електричний модуль та діелектричні властивості наночастинок MnO2 були проаналізовані методом імпедансної спектроскопії в діапазоні частот від 1 до 8 МГц та діапазоні температур від 273 до 423 К. Провідність MnO2 зростає зі збільшенням частоти. Було встановлено, що температурна залежність провідності наночастинок підкоряється діаграмі Арреніуса, енергія активації становить – 0,088 еВ. Максимальна провідність виявляється рівною 311,79 См/см при конкретній температурі 298 К. Відповідна не дебаєвська поведінка у матеріалах MnO2 аналізується за допомогою аналізу модулів та діелектричних спектрів. Модульний і діелектричний спектри підтвердили процес релаксації. Діелектрична константа та діелектричні втрати були виявлені діелектричним спектральним аналізом. Діелектрична константа була постійною в області високих частот і варіювалася в області низьких частот. Діелектрична константа виявилася рівною – 1211 при певній температурі 298 К в області дуже низьких частот. Діелектричні втрати також були постійними при високих частотах в будь-яких температурних умовах і змінювались в області низьких частот. Структуру наночастинок MnO2 проаналізували методом порошкової рентгенівської дифракції. Результати порошкової рентгенографії показали, що підготовлений зразок наночастинок був кристалічним з тетрагональною фазою. За формулою Шеррера середній розмір кристалітів становить близько 20 нм.Crystalline manganese dioxide (MnO2) was prepared by microwave assisted solution method using sodium hydroxide as an agent. Electric conductivity, electric modulus and dielectric properties of MnO2 nanoparticles were analyzed by AC Impedance spectroscopy in the frequency range 1 to 8 MHz and temperature range in-between 273 K to 423 K. Conductivity of MnO2 increases with increasing frequency. Temperature dependence of the nanoparticle conductivity was found to obey the Arrhenius plot, activation energy is – 0.088 eV. The maximum conductivity is found to be 311.79 S/cm at a particular temperature of 298 K. The conformed non-Debye type behavior in the MnO2 materials is analyzed through modulus analysis and dielectric spectra. The modulus and dielectric spectra confirmed the relaxation process. Dielectric constant and dielectric loss were found from the dielectric spectral analysis. The dielectric constant was constant at high frequency region and varied at low frequency region. The dielectric constant is found to be – 1211 at a particular temperature of 298 K in very low frequency region. The dielectric loss also was constant at high frequencies in all temperature conditions and varied at low frequency region. Structure of MnO2 nanoparticles has been analyzed by powder X-ray diffraction method. The powder XRD results revealed that the prepared nanoparticles sample was crystalline with a tetragonal phase. Average crystallite size is found to be around 20 nm using Scherrer formula

Structural Properties of Bioactive Molecule Naphthalene 2-Sulfonic Acid

International audienceNaphthalene 2-sulfonic acid (NSA) and its derivatives are the most important class of organic compounds and are important products of industrial chemical processes.. Bioactive molecule NSA was performed by means of Density Functional Theoretical (DFT) method using standard B3LYP/6-31G (d,p) basis set implemented with Gaussian'09 software package. NBO analysis were performed to provide valuable information about various intermolecular interactions. Optical properties of the NSA molecule were studied using UV-Vis spectral analysis. In addition, Molecular docking was performed for the different receptors for calculating binding affinities and predicting binding sites

Growth, electronic absorption and vibrational spectral analysis of semiorganic nonlinear optical material potassium acid phthalate: A scaled quantum mechanical force field study

The spectroscopic properties of the crystallized semiorganic nonlinear optical molecule Potassium Acid Phthalate (RAP) have been recorded and analyzed by FT-IR, Raman and UV techniques. The spectra were interpreted with the aid of normal coordinate analysis following structure optimizations and force field calculations based on density functional theory (DFT) at the B3LYP/6-311+G(d,p) level of theory. Normal coordinate calculations were performed using the DFT force field corrected by a recommended set of scaling factors yielding fairly good agreement between the observed and calculated wavenumbers. RAP is thermally stable up to 275.0 degrees C and optically transparent in the visible region

Growth aspects of barium oxalate monohydrate single crystals in gel medium

Single crystals of barium oxalate monohydrate (BaC2O4.H2O, BOM) were grown in pure form by controlled diffusion of Ba2+ using the gel technique at different temperatures. Starting from aqueous Ba2+ chloride (BaCl2) and acetic acid (C2H2O4) in gel, this method offers a low-cost and an easiest alternative to other preparation methods for the production of barium oxalate bulky single crystals. The optimal conditions for the growth of BOM crystals in silica gel were found by investigating different growth parameters such as gel pH, gel aging and crystallization temperature. Irrespective of all such crystallization environments, growth rate of the crystals were initially less and then exhibited supersaturation effect leading to non-linearity. Gel aging and temperature has profound effect on nucleation density that resulted less number of crystals of maximum size in the gel matrix. Perfect single crystals were grown on gels of higher pH. The macropore morphology and porosity was controlled by changing age of the gel. It has been found that temperature has a fabulous effect in controlling the nucleation density by altering the supersaturation conditions for the formation of critical nuclei. The entire growth kinetics informed that the grown crystals were derived by the one dimensional diffusion controlled process