TG-DTA Analysis Research Articles

Advanced nano-composite coatings of ZrB₂/ZrC/SiC on carbon fibers via eco-friendly precursor synthesis

This study presents a comprehensive investigation into the synthesis and characterization of ZrB2/ZrC/SiC composite coatings on carbon fiber substrates via a solution-based process followed by high-temperature pyrolysis. The precursor solution was prepared using Gum Ghatti (GG), zirconyl chloride, tetraethyl orthosilicate, and boric acid. Optimization of precursor concentration and molar ratios was performed to achieve suitable viscosity and composition. The pyrolysis process was conducted in an argon atmosphere, resulting in the formation of well-defined ZrB2, ZrC, and SiC phases. XRD analysis confirmed the phase composition, while SEM imaging revealed spheroidal particle aggregates with a uniform distribution of composite phases. TG-DTA analysis reveals the thermal decomposition behavior, highlighting distinct stages of mass loss and phase transformations. Coated carbon fibers exhibited enhanced oxidation resistance, as evidenced by TGA analysis. SEM analysis confirmed the uniform distribution and adhesion of the composite matrix on the carbon fiber substrate. This study demonstrates the successful synthesis of ZrB2/ZrC/SiC composite coatings with promising thermal properties for advanced applications.

Synthesis, Characterization and Biological Studies of Gemifloxacin Mesylate with Nickel(II) and Copper(II)

Gemifloxacin mesylate, a fourth-generation fluoroquinolone-type antibiotic, is widely used for community treatment of acquired pneumonia and severe bacterial infections. The Cu(II) and Ni(II) complexes of gemifloxacin mesylate were synthesized by refluxing an aqueous solution of the ligand with the required amount of metal(II) salts in a round bottom flask with 2:1 (L:M) ratio in an oil bath at 90 ºC with a continuous stirring for 4 h. The mixture was kept overnight to obtain a coloured solid complex. The synthesized metal(II) complexes were characterized by physico-chemical parameters and spectral analyses, including UV-Vis, FT-IR and 1H NMR. The structures of the complexes were further confirmed by elemental (CHNS) and TG-DTA analyses. The spectral findings revealed that metal-ligand interaction has successfully occurred where the ligand acted as a bidentate chelate in the synthesized metal(II) complexes. The IR studies showed that upon complexation the characteristic carboxylic stretching frequency at 1714 cm-1 disappeared and the pyridone stretching frequency shifted to a lower frequency region. The 1H NMR data of the complexes confirm the effective interaction between the metal and the ligand via 3-carboxyl group and 4-oxo groups. The thermal and elemental analyses data were also in agreement with the proposed interaction. The ligand as well as its metal(II) complexes showed significant activity against all the studied 11 bacterial strains and one of the fungal strains, Candida sp.

Utilization of circulating fluidized bed coal ash in autoclaved aerated concrete manufacture by mineral carbonation

Using circulating fluidized bed combustion (CFBC) ash discharged from thermal power plants, we identified factors affecting mineral carbonation to sequester CO2 and produced autoclaved aerated concrete (AAC). To use CFBC ash as a raw material for AAC, free-CaO, which causes volume expansion, was replaced through hydration and carbonation. During the raw material replacement process, carbonation behavior was confirmed through pH and temperature. A Ca(OH)2 to liquid ratio similar to a fly ash to liquid ratio of 0.25 is considered to provide sufficient diffusion distance, and the reaction rate may increase due to the rise in water temperature caused by Ca2+ leaching. Additionally, the results of XRD, XRF, TG-DTA, and SEM analyses indicate that hydration and carbonation reactions were stably achieved in the materials, suggesting that CO2 sequestration allows the materials to be used as alternative raw materials. After identifying the characteristics of the CFBC ash and the substituted material, AAC was manufactured through pressurized carbonation. The weight change rate, carbonation depth, ventilation rate, pore structure, and compressive strength of the manufactured AAC were measured. As a result, the alternative raw material exhibited higher permeability and a larger pore size range in the specimens compared to the original material, indicating easier CO2 penetration into the specimens. Consequently, this experiment suggests the potential of using the material in AAC production by providing a theoretical basis for solving volume expansion issues associated with concrete admixtures and CO2 sequestration in waste materials.

Synthesis and characterization of TiO2/ZnO/SiO2 nanocomposite using pyrrolidinium-based ionic liquids via sol–gel-hydrothermal method for photocatalytic removal of Pb (II) ions

This study aims to synthesize TiO2 with precise particle morphology, a large surface area, a stable anatase phase at high temperatures, and enhanced catalytic activity in the visible light spectrum. TiO2 was combined with ZnO and SiO2 to form a TiO2/ZnO/SiO2 composite (TZS). A TiO2/ZnO/SiO2 composite (TZS) was synthesized via sol–gel-hydrothermal method at 180 °C for 24 h employing a water-pyrrolidinium-based ionic liquid mixture. XRD analysis confirmed anatase, zincite, and amorphous silica phases post-calcination at 450 °C. Compared to water alone, TZS synthesized with the water-ILs media exhibited higher surface area and narrower band gap energy. TG-DTA analysis confirmed anatase phase stability up to 1000 °C. SEM and TEM images showed TZS particles synthesized using water as spherical, while the water-ILs mixture produced nanocoral, nanorod, and nanocubic morphologies. In photocatalysis, TZS synthesized with water-ILs removed Pb(II) ions by 99.98 %, surpassing water-synthesized TZS at 95.49 % indicating superior photocatalytic of TZS synthesized with water-ILs.

Effect of ZrO2 on Radiation Permeability Properties of Polypropylene

The study investigates the radiation permeability properties including mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), tenth value layer (TVL), half value layer (HVL), fast neutron cross section (FNRC), and mean free path (MFP) of polypropylene (PP) polymer, as well as the produced polymer matrix composites (PP+5% ZrO2, PP+10% ZrO2, PP+15% ZrO2). The studied materials were examined by considering their effect on radiation permeability against gamma and neutron radiation. Additionally, powder size, Archimedes principle (density), XRD, DSC, ATR, and DTA-TG analyses were performed. According to the radiation permeability results of the studied four materials, PP + 15% ZrO2 was found to have the highest LAC values, while PP was found to have the lowest LAC values. The FNRC values of the PP, PP+5% ZrO2, PP+10% ZrO2, and PP+15% ZrO2 materials were found to be 10.038 cm-1, 12.651 cm-1, 15.002 cm-1, and 17.091 cm-1, respectively. The most suitable material for gamma and neutron shielding was found to be 15% ZrO2 reinforced material.

Sol–Gel Synthesis and Characterizations of Spinel Nickel Chromite (NiCr2O4) Nanoparticles to Study their Photocatalytic, Antibacterial and Anticancer Activities

A facile and cost-effective sol–gel technique has been used to synthesize nickel chromite (NiCr2O4) nanoparticles (NCNPs) at 700°C to investigate their photocatalytic together with antibacterial and anticancer activities. The synthesized nanopowder was characterized by Thermogravimetric thermal analysis (TG-DTA), X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), Fourier Transform-Infrared Spectroscopy (FT-IR), X-ray Photon Electroscopy (XPS) and UV–Visible Diffuse Reflectance Spectroscopy (UV-DRS) and Photoluminescence (PL). Beyond 700°C, the thermal durability of NCNPs was confirmed by TG-DTA analysis. The synthesized NPs were cubic structured corresponding to their spinel structure, a crystallite size of 38[Formula: see text]nm and an optical bandgap of 2.7[Formula: see text]eV. The PL spectra revealed emission bands in the visible and UV regions. The surface-phase-pure elemental and electronic arrangement of the NCNPs were verified by X-ray photon spectroscopy. Photocatalytic activity of NCNPs against Methylene Blue dye revealed 89% degradation in 1[Formula: see text]h. The in vitro antibacterial and anticancer activities of NCNPs were also examined. Among the tested microbes, Staphylococcus aureus exhibited the highest level of sensitivity (9[Formula: see text]mm), while Escherichia coli had the lowest (5[Formula: see text]mm) against NCNPs. The MTT test revealed the significant cytotoxicity of NCNPs against carcinogenic HeLa and MCF-7 cells. Thus, the synthesized NCNPs could be rated as potential photocatalytic, bactericidal and anticarcinogenic agents.

Tailoring microstructure and properties of porous mullite-based ceramics via sol-gel impregnation

Nanotechnology has been introduced into the refractory industry decades ago. However, there are still some peculiarities that hinder its routine application. Poor mechanical strength is one of them. Here we present the fabrication technique for mullite porous ceramics using a calcium-free colloidal binder system followed by secondary sol-gel impregnation intended for fabrication of large up-scaled monoliths. The primary foam was prepared via direct foaming of slurry containing colloidal silica, gelling agents, surfactant, silica fume, and different types of alumina. The foam mixture was cast, de-molded and dried using a cascade drying procedure. The investigation of mullitization that occurred during the high-temperature treatment was studied by XRD and TG-DTA analysis. The optimized sintering curve was then applied to obtain the highest mechanical properties. The resulting foam (with open porosity, volume density about 900 kg/m3 and mechanical strength about 10 MPa) was further processed by the impregnation step. The applied silica or combined silica/aluminum sol and unreacted alumina underwent secondary mullitization during following high-temperature treatment, which significantly enhanced the mechanical strength (up to 18 MPa). The secondary mullitization process was also investigated by HT-XRD and TG-DTA analysis. Foam microstructure was observed by an electron scanning microscope. Thermal conductivity of as-prepared ceramics foams varied from 0.3 to 0.4 W/m·K. The foam wall porosity evolution was studied by mercury intrusion porosimeter and estimated from image analysis.

Influence of Co(II) and Cd(II) metal ions on structural, electronic and nonlinear optical properties of 4-methoxypyridine-2-carboxylic acid complexes: An experimental and computational study

Molecular engineering of metal-organic frameworks has attracted increasing attention due to their potential technological applications in the fields of optics and photonics. Therefore, a number of organometallic complexes are investigated for nonlinear optical applications. The current research aimed to synthesize and investigate spectroscopic and nonlinear optical properties of two metal-organic coordination compounds, namely Co(MeOPic)2∙(H2O)2 and Cd(MeOPic)2∙(H2O)2. The FT-IR and UV-Vis spectra for the distorted octahedral Co(II) and Cd(II) complexes were recorded. In order to provide a deep understanding about the relation between structure and nonlinear optical properties, density functional theory studies were also applied to both of the complexes by using B3LYP/6–311++G(d,p)/LanL2DZ level. TG-DTA analysis demonstrated that Cd(II) complex is approximately stable up to 134 °C, and the same complex only loss the aqua ligands between 134 and 189 °C. Therefore, the main skeleton part continues to remain stable up to 208 °C. Static NLO studies also demonstrated that both complexes have weak responses due to centrosymmetric structures, while Co(II) complex is appropriate to third-order NLO applications (γ (0;0,0,0) = 148.70×10−36 esu and γ (-2w;w,w,0)=-1521.4×10−36 esu).

Investigations on synthesis, growth and characterisations of a NLO material: L-Tryptophanium phosphite (LTP)

The nonlinear optical material L-Tryptophanium phosphite (LTP) was synthesised and grown by the process of slow evaporation solution growth. Characterisations like single crystal XRD, FT-IR, and H1 NMR spectral measurements were done to find the crystal structure and functional groups. The crystal was found to possess good transparency for the whole visible region from the UV-Vis-NIR spectral analysis. The thermal behaviour like stability and breakdown of the crystal were assessed using TG-DTA analyses. The hardness of the crystal was determined using Vickers micro hardness study. The KurtzPerry approach was used to study the nonlinear optical (NLO) characteristics of the crystal. A good value of conversion efficiency in second harmonic generation (SHG) makes the generated crystal suitable for frequency conversion.

Synthesis and characterization of alumina supported molybdosilicic acid (SiMo12/Al2O3): Efficient solid acid catalyst for the synthesis of pyranopyrazole derivatives

A series of highly reusable heterogeneous catalysts (10-40 wt.% SiMo12/Al2O3), consisting of molybdosilicic acid (SiMo12) impregnated on alumina (Al2O3) support was synthesized by the wetness impregnation method. The physicochemical properties of synthesized catalyst were studied using FT-IR, XRD, SEM, EDX, TEM, BET and TG-DTA analysis techniques. The study proves that the synthesized SiMo12 catalyst efficiently incorporated on the surface of Al2O3. The catalytic activity of prepared catalyst was investigated for the synthesis of pyranopyrazole(6-amino-4-phenyl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5carbonitrile) via cyclocondensation reaction of aldehydes, malononitrile, hydrazine hydrate and ethyl-acetoacetate under solvent-free conditions. Among different catalysts, 30% SiMo12 supported on to Al2O3 showed the highest catalytic activity. High yield, shorter reaction time, operational simplicity, solvent-free conditions and reusability of the catalyst are the distinct features of this protocol.

Synthesis, Structural Characterization, and Hirschfeld Surface Analysis of a New Cu(II) Complex and Its Role in Photocatalytic CO2 Reduction.

A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG-DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H…O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H…H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O…H/H…O, N…H/H…N and C…H/H…C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 μmol/g and a selectivity of 89.4% after three hours.

Enhanced mechanical performance and damping behavior of CFRP composites through exfoliated MWCNT functionalization

In evaluating high-performance multiwall carbon nanotube (MWCNT) based carbon fiber composites, effective chemical functionalization of fillers for sufficient exfoliation and precise interface interactions with resin matrix are challenging to attain due to significant interlayer cohesive energy and inactive surfaces of composites. Herein, we demonstrate an effective way to produce carbon fiber-reinforced polymer (CFRP) composite with amended interfacial characteristics via incorporation of MWCNT through oxidation followed by silane functionalization with their exfoliation levels (0/48/60/72 h). The surface functional elements, morphological changes, elemental groups, quantitative information, and thermal degradation of silane functionalized MWCNTs were characterized by FESEM/HR-TEM, XRD, UV, and TG-DTA analysis, respectively. The influence of silane functionalized MWCNT reinforcement on CFRP's mechanical properties were examined using tensile, flexural, ILSS, and damping behavior was analyzed through impulse excitation technique (IET). The resulting silane-modified MWCNTs with 60 h oxidation (OAC-60) infused CFRP demonstrated significant enhancement in flexural strength (73.8%), tensile strength (58.2%), interlaminar shear strength (28.5%) compared to pure-CFRP.

Synthesis, Structural Characterization, Hirschfeld Surface Analysis, Density Functional Theory, and Photocatalytic CO2 Reduction Activity of a New Ca(II) Complex with a Bis-Schiff Base Ligand.

A new bis-Schiff base (L) Ca(II) complex, CaL, was synthesized by the reaction of calcium perchlorate tetrahydrate, 1,3-diamino-2-hydroxypropane, and 2-formyl phenoxyacetic acid in an ethanol-water (v:v = 2:1) solution and characterized by IR, UV-vis, TG-DTA, and X-ray single crystal diffraction analysis. The structural analysis indicates that the Ca(II) complex crystallizes in the monoclinic system, space group P121/n1, and the Ca(II) ions are six-coordinated with four O atoms (O8, O9, O11, O12, or O1, O2, O4, O6) and two N atoms (N1, N2, or N3, N4) of one bis-Schiff base ligand. The Ca(II) complex forms a tetramer by intermolecular O-H…O hydrogen bonds. The tetramer units further form a three-dimensional network structure by π-π stacking interactions of benzene rings. The Hirschfeld surface of the Ca(II) complex shows that the H…H contacts represent the largest contribution (41.6%) to the Hirschfeld surface, followed by O…H/H…O and C…H/H…C contacts with contributions of 35.1% and 18.1%, respectively. To understand the electronic structure of the Ca(II) complex, the DFT calculations were carried out. The photocatalytic CO2 reduction test of the Ca(II) complex exhibited a yield of 47.9 μmol/g (CO) and a CO selectivity of 99.3% after six hours.

Growth and physiochemical properties of semi organic ammonium pentaborate dihydrate single crystal

Abstract The slow evaporation technique was used to produce nonlinear optical ammonium pentaborate dihydrate (APBDH) single crystals. The crystal lattice parameters and structure of APBDH crystal was determined by single crystal X-ray diffraction (S-XRD) technique with the triclinic space group. The optical band gap of the grown crystal was determined using UV–Vis spectrophotometer. There is no absorption peak was observed in the entire visible region of the spectrum. The functional groups of the APBDH crystal were identified through Fourier transforms infrared (FTIR) and Fourier transform Raman (FR-Raman) analyses. The thermal decomposition and thermal stability of the grown crystal was measured using TG-DTA analyses. The laser damage threshold (LDT) analysis was used to know the ability to withstand the influence of laser on the grown crystal. Photoconductivity of the grown crystal was studied and its photocurrent and dark current behavior was examined. The surface morphology of the APBDH crystal was evaluated using HR-SEM analysis. The APBDH crystal was exhibited second harmonic generation behavior and its efficiency was calculated with different particle sizes.

Synthesis, physicochemical and quantum chemical studies of 7-azaindolinium-3,5-dinitrobenzoate single crystal for nonlinear optical applications

Abstract A novel hydrogen bonded single crystal of 7-azaindolinium-3,5-dinitrobenzoate (7AIDNB) has been grown, and the structure of the crystal was determined by single-crystal XRD analysis. The results show that the grown crystal belongs to a triclinic crystal system with centrosymmetric space group P-1 and the unit cell parameters: a = 6.998(9) Å, b = 8.498(12) Å, c = 13.103(17) Å, V = 710.78(17) Å3, Z = 2. The presence of expected discrete functional groups in 7AIDNB has been identified by an FT-IR spectroscopic study. The thermal stability and decomposition of the title crystal have been studied by TG-DTA analysis. The optical property of the grown crystal has been analyzed by UV-Vis-NIR spectroscopy analysis. The DFT with 6-311++G(d, p) basis set has been used to examine optimization of molecular geometry, Mulliken charge, and HOMO-LUMO. As the frequency of the grown crystal increases, the dielectric loss and dielectric constant decrease. The third-order NLO parameters of 7AIDNB have been examined by a Z-scan technique.

Improved photocatalytic performance of chitosan blended – Al2O3-TiO2 and garlic loaded – Al2O3-TiO2 hybrid nanocomposites

In this present study, biomaterials loaded/blended hybrid nanocomposites such as chitosan-blended Al2O3-TiO2 (CS-Al2O3-TiO2) and garlic-loaded Al2O3-TiO2 (G-Al2O3-TiO2) were synthesized by sol-gel method. They were characterized by various techniques such as XRD, UV-DRS, FTIR, FE-SEM, EDX and TG-DTA analysis. The photocatalytic activity of the CS-Al2O3-TiO2 and G-Al2O3-TiO2 was carried out using organic dyes such as Methylene blue (MB), Methyl orange (MO) and Rhodium B (Rh-B) under solar light. The antibacterial activity was done using the gram-negative bacteria Escherichia Coli (E. Coli). The comparison studies of photocatalytic and antibacterial activity between all the nanocomposites, such as TiO2, Al2O3-TiO2, CS-Al2O3-TiO2 and G-Al2O3-TiO2 were investigated. The order of photocatalytic and antibacterial activity was G-Al2O3-TiO2 > CS-Al2O3-TiO2 > Al2O3-TiO2> TiO2. The garlic loaded Al2O3-TiO2 nanocomposite shows a higher activity due to the presence of organic sulphur compounds. Followed by chitosan blended - Al2O3-TiO2 shows a remarkable activity due to the presence of an amine group present in chitosan composites.

The Effect of CuO on the Thermal Behavior and Combustion Features of Pyrotechnic Compositions with AN/MgAl

Ammonium nitrate (AN) is of considerable interest to researchers in developing new types of energetic mixtures due to the release of environmentally benign gaseous products during burning and thermal decomposition. However, poor ignition and a low burning rate require special additives to speed up this process. The advantage of this research is the use of high-energy aluminum-based alloys as fuel to compensate for the disadvantages of AN. In addition, the effect of copper oxide (CuO) on the burning kinetics and thermodynamics of the energetic mixture based on ammonium nitrate–magnesium–aluminum alloys (AN/MgAl) is investigated. Alloys based on aluminum were created through a process of high-temperature diffusion welding, conducted in an environment of argon gas. The structure and thermal characteristics of alloys are determined by X-ray diffraction, scanning electron microscopy, and DTA-TG analyses. It has been found that CuO has significant effects on the thermal decomposition of an AN/MgAl-based energetic mixture by shifting the decomposition temperature from 269.33 °C to 261.34 °C and decreasing the activation energy from 91.41 kJ mol−1 to 89.26 kJ mol−1. Adding CuO reduced the pressure deflagration limit from 2 MPa to 1 MPa, and the linear burning rate of the AN/MgAl energetic mixture increased approximately twice (rb = 6.17 mm/s vs. rb = 15.44 mm/s, at a chamber pressure of P0 = 5 MPa).

Helianthus Annuus L. Comparison Of The Properties Of Fibers Obtained From The Plant By Methods of Decortication And Retting

A large amount of sunflower production is carried out in our country. The 2,500,000 tons of sunflower stalks that appeared after production pose a problem for our farmer. In order to clean up this environmental problem from the field, sunflower stalks are destroyed by burning to warm up in winter, broken down and mixed into the soil, or burned after harvesting. It is thought that by obtaining qualified, ecological and naturally decomposing sunflower fiber from the stem of the sunflower plant, which is an agricultural waste, it can increase the added value of agricultural products and contribute to the protection of the environment. In this study, the anatomical characteristics of the stem of the sunflower plant were determined, and natural lignocellulosic fibers were obtained from the sunflower stem by retting and decortication methods (fresh stem, dried stem). Various physical, chemical and mechanical properties of these fibers have been measured. For this purpose, FTIR (Fourier Transform Infrared Spectroscopy) analysis, XRD (X-Ray Diffractometer) analysis and SEM (Scanning Electron Microscope) analysis were applied to the fibers obtained by different methods. Thermal analyses were performed by TG-DTA (Thermogravimetric) analysis. In addition, fiber strength, fiber fineness, fiber length and color measurements were made. The chemical content of the obtained fibers (pectin, lignin, cellulose, hemicellulose) was determined. The properties of the fibers were compared using the obtained data. As a result of the study, it has been seen that the characteristic properties of the sunflower fibers obtained by the retting method are better. It has been determined that the elemental, thermal and crystal structures of the fibers obtained by different methods are similar. It was concluded that sunflower fiber will not be spun as a yarn, but can be used as a natural polymeric composite reinforcement material.

Crystallographic, Electric and Optical Analysis of Cs1+ Doped H3PW12O40 Nanocrystalline Thin Films Deposited by Microwave Assisted Chemical Bath Deposition Method

AbstractThe polyoxometalates like phosphotungstic acid (PTA) (H3PW12O40) and Cesium (Cs+) doped phosphotungstic acid (Cs‐PTA) (Cs3‐PW12O40) nanocrystalline thin films were effectively deposited by microwave assisted chemical bath deposition (MA‐CBD) technique. The structural characterization of microwave aided H3PW12O40 and Cs3‐PW12O40 thin films were done by Thermo gravimetric (TG) and Differential thermal analysis (DTA) techniques, X‐ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X‐ray analysis (EDAX). The TGDTA analysis revealed that the complete decomposition process of Cs‐PTA compound is carried out at 600 °C and which is comparatively lower than that of other chemical method. The X‐ray diffractogram confirms the polycrystalline nature of the synthesized H3PW12O40 and Cs3‐PW12O40 thin films having spinel cubic crystal structure. The lattice parameter of H3PW12O40 and Cs3‐PW12O40 compound found to be in the range of 11.34 Å to 11.46 Å. The main absorption peaks observed nearly 800, 1000 and 1100 cm−1 confirms the formation of H3PW12O40 and Cs3‐PW12O40 materials. The porous structure of nanocrystalline spherical grains morphology of H3PW12O40 and Cs3‐PW12O40 films were confirmed from SEM analysis. An appropriate peaks of metal ions like P, W, O and Cs observed in EDAX spectra shows the stoichiometric formation of H3PW12O40 and Cs3‐PW12O40 thin films.

Crystal growth, structural, vibrational, spectroscopic studies of novelly synthesized NLO active melaminium sulfamate single crystal: Experimental and theoretical approach

Semi-organic nonlinear optical (NLO) melaminium sulfamate (MASA) single crystals were synthesized by slow evaporation method and analyzed by using X-ray diffraction, UV–vis, FT-IR and FT-Raman experiments. Single crystal X-ray diffraction (SXRD) analysis confirms that MASA crystal belongs to triclinic system with centrosymmetric space group P-1. The quantum chemical calculation were carried out using density functional theory (DFT) with B3LYP/6-31+G(d) basis set. The intermolecular interactions were deeply analyzed by NBO analysis. The molecule with intermolecular N-H⋯N and N-H⋯O hydrogen bonds show notable vibrational effect. The optical property of MASA was evaluated by UV–vis optical transmittance spectrum. Thermal stability of the grown crystal was performed by using TG-DTA analysis. The frontier molecular orbital analysis illustrates the charge transferred from sulfamate anion to melaminium cation. Hirshfeld and 2D fingerprint plot reveals the intermolecular N-H⋯O and N-H⋯N contacts of MASA molecule. The existence of various functional groups and vibrational modes are affirmed by Fourier transform infrared (FT-IR) and FT-Raman spectral analysis. Additionally, the molecular electrostatic potential (MESP) and topological analysis such as electron localization function (ELF), reduced density gradient(RDG), localized orbital locator(LOL) and atoms in molecule(AIM) have been used to predict the intermolecular interaction, especially the hydrogen bonds. The hydrogen atom from sulphamic acid was transferred to the melamine molecule giving the singly protonated melaminium cation. The outcome of SXRD, UV–visible, TG/DTA, HOMO–LUMO, NLO and Z-Scan values were compared with earlier reported compounds and amongst the analyzed compound MASA shows good NLO activity. The NLO activity of MASA was analyzed theoretically and experimentally by DFT and Z-scan method.