•The present molecular complex is crystallized in the space group of P212121.•The emission peak observed at 415 nm in PL spectrum indicates blue emission.•The SHG efficiency of the present crystal is ...1.6 times higher than that of KDP.•The present crystal is thermally stable upto 224°C.•Hirshfeld surface analysis illustrates that O•••H interactions are more prominent.
The single crystal of 3-hydroxy pyridinium 2-hydroxy benzoate (3HP2HB) molecular complex was grown by solution growth method. The conformation of crystal structure was done by single crystal X-ray diffraction (SCXRD) technique and it uncovers that the title crystal belongs to orthorhombic crystal system with P212121 space group. The absorption spectrum of grown crystal was recorded using UV–Vis spectroscopy. Fluorescence emission spectrum was observed in the blue band region using spectroflurometer. 1H and 13C NMR spectral technique was used to predict the presence of hydrogen and carbon bonded network. The Fourier transform infrared spectral technique (FT-IR) was used to identify the presence of various functional groups in the crystal structure. The second order nonlinear optical property of the crystal was studied by the modify Kurtz-Perry powder SHG technique using Nd:YAG laser with wavelength 1064 nm. The thermal stability of the title crystal was carried out by TG/DTA studies. The presence of inter-molecular interactions was examined by Hirshfeld surface. The DFT method was used with B3LYP/6-311++G(d,p) basis set to compute the structural, electronic and reactivity properties of the title crystal.
Display omitted
Display omitted
•Synthesis of the charge transfer complex (CTC) using p-toulidine and 1,2,4,5-benzenetetracarboxylic acid as donor and acceptor moieties, respectively.•Characterization of CTC by ...various spectroscopic techniques like FTIR, TGA/DTA, SC-XRD, UV –VIS Spectroscopy.•Calculation of various physical parameters using Benesi-heildebrand equation.•Validation of the experimental data by the computational study using DFT / TD-DFT and Hershfeld surface analysis.•Application of the CTC as a photocatalyst for the degradation of the dye and also identifying the active species responsible for degradation by scavenging analysis.
The hydrogen bound charge transfer (CT) complex of p-toluidine (PT) and 1,2,4,5-benzenetetracarboxylic acid (BTC) was synthesized and subsequently characterized using a range of spectrum approaches such as FTIR, TGA / DTA, SC-XRD, and spectrophotometric examinations. Crystallographic evidence suggests that a strong hydrogen bond (N+____ H---O–) connects the cation and anion. This occurs when a proton is transported from the acceptor to the donor. The FTIR spectrum displays the proton transfer band, which is the region where neither the donor (PT) nor the acceptor (BTC) exhibits any absorption. A spectroscopic analysis showed that the CT complex (CTC) containing hydrogen bond has 1:1 stoichiometry. Benesi- Heildebrand equation was used for calculating the formation constant (KCT), molar extinction coefficient (ԑCT) and also to derive values for other physical parameters, such as energy of interaction (ECT), ionization potential (ID), free energy (ΔG°), resonance energy (RN) and oscillator strength (f). Thermal testing confirms that the newly synthesized CTC is stable at room temperature. DFT (Density Functional Theory) and TD-DFT (Time-Dependent Density Functional Theory) calculations at the B3LYP/6-311G++ level of theory were used to investigate the optimized geometry of the synthesized CTC and reactants (PT and BTC), with comparable theoretical data to support the experimental results. Furthermore, employing Hershfeld surfaces and the corresponding 2D fingerprint plots, the study of intermolecular interactions that maintain the crystal packing has been carried out. We also proved the CTC's efficiency as a photocatalyst for methylene blue (MB) breakdown, achieving 81 % photodegradation under UV–Vis light for 130 min. The scavenging analysis further demonstrates that holes and hydroxyl radicals are the photochemically active species responsible for dye particle disintegration.
This work investigates the swelling and mineralogical characteristics of alkali-transformed (partially and completely transformed) kaolinitic clays to bring out the subsequent effect of alkali ...contamination. One-dimensional free swell tests were conducted to determine the degree of swelling on alkali-transformed kaolinitic clays inundated with water and 4 N NaOH. Swelling increased in transformed clays with an increase in degree of transformation when inundated with water. An opposite trend was observed in the swelling patterns of alkali-transformed clays upon inundation with 4 N NaOH when compared with water i.e., swelling decreased with increase in degree of transformation upon inundation with 4 N NaOH. This was mainly attributed to mineralogical changes, which occurred in transformed clays. This was confirmed by X-ray diffraction (XRD) analysis. To further re-confirm the changes observed, Fourier transform infrared spectroscopy (FTIR), and Thermogravimetric-Differential thermal analysis (TG-DTA) techniques were carried out. Complete kaolinite mineral dissolution and neogenic formations (mainly sodalites) were the key factors for differences in swelling tendencies when inundated with water or 4 N NaOH.
•Kaolinitic clays were transformed at different solid:liquid ratio using 4 N NaOH.•Dissolution of kaolinite and formation of sodalites are clearly observed after the transformation phase.•Swelling characteristics of transformed kaolinitic clays is studied.•Swelling with water increased with increase in degree of transformation of clays.•Swelling with 4 N NaOH decreased with increase in degree of transformation of clays.
New efficient nonlinear optical (NLO) organic single crystals of quinoline 4-nitrophenol (QNP) were grown by slow evaporation solution technique (SEST) at room temperature using methanol as solvent. ...Primarily, the three dimensional (3D) intensity data of grown QNP crystal were collected by the single crystal X-ray diffraction (SXRD). The crystal structure was solved by the direct method using SHELXS and refined using SHELXL programs. The Hirshfeld surfaces have been investigated to define theoretical electron density (clouds) boundary surfaces for the QNP molecule and this is more useful for analyzing the intermolecular interactions of the molecular system. The crystalline planes and phase purity were analyzed by powder XRD (PXRD) measurement. Chemical environment of the present molecule and the position of carbon (C) and hydrogen (H) were analyzed by 13C and 1H NMR spectrum. Various functional groups of the QNP crystal were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical quality and related optical parameters were analyzed by UV–Vis NIR measurement. The grown crystal has good optical transparency in the visible and near IR regions. The thermal stablity of the QNP single crystal has been investigated by thermogravimetric and differential thermal analysis (TG-DTA). The laser damage threshold (LDT) energy has been measured using an Nd: YAG laser. The nonlinear refractive index (n2), absorption coefficient (β) and third-order nonlinear susceptibility (χ(3)) were studied using Z-scan technique with a continuous wave (CW) laser of 632.8 nm.
Display omitted
•New material of QNP was synthesized and it has been grown by slow evaporation solution technique.•High optical transmittance (80%) and low cut-off wavelength (415 nm).•The QNP crystal is thermally stable upto 85 °C.•Laser damage tolerance of QNP crystal is 6.25 GW/cm2.•Third order nonlinear optical susceptibility (χ(3)) of QNP is 3.52 × 10−7 esu.
Display omitted
•Role of ZrO2 polymorph and preparation conditions in MSR over Cu/ZrO2 is revealed.•Synergistic interactions of Cu and the support yield different CO2 selectivities.•Dependence on the ...synthesis conditions and the copper precursor less distinctive.•Support structure affects the catalytic performance to a higher degree.•Both t-ZrO2 and m-ZrO2 can be CO2-selective in Cu-containing catalysts or not.
We assessed the catalytic properties of the Cu/ZrO2 interface in methanol and formaldehyde steam reforming (MSR and FSR) on powder catalysts by using a comparative approach with respect to the influence of the ZrO2 polymorph support structure (monoclinic (m-)ZrO2vs. tetragonal (t-)ZrO2), its synthesis routine and the choice of the precursor material on the CO2 selectivity. Our studies reveal that ZrO2 exhibits a pronounced versatility as a support material and its catalytic properties depend most strongly on its surface properties governed by its synthesis, especially by the choice of the Zr precursor. The way of combining the support with copper introduces an additional layer of complexity, but its influence on the MSR performance is limited to a modification of the conditions provided by the ZrO2 support. Exploiting the comparative approach regarding the Cu-ZrO2 catalysts in FSR and MSR – including the pure support materials – in combination with in situ Fourier transform infrared (FT-IR) spectroscopy shows that the CO observed in MSR on Cu/m-ZrO2 can be attributed to a spillover of formaldehyde to the support. Side reactions of m-ZrO2 are suppressed at lower temperatures due to its lack of highly reactive sites, resulting in a CO2-selective MSR performance. In Cu/t-ZrO2, however, the amount of CO is higher and a combination of a formaldehyde spillover to the support and a Cu-ZrO2 phase boundary yielding CO leads to the lower CO2 selectivity of these samples. An elevated number of defects and reactive Lewis acidic and Brønsted basic centers of t-ZrO2 explains this increased activity towards side reactions in contrast to Cu/m-ZrO2 catalysts.
Thermal Study of PMMA‐LiNO3 Electrolyte Sunita, More Amit Arvind; Vithya, K.; Premalatha, M. ...
Macromolecular symposia.,
October 2019, Volume:
387, Issue:
1
Journal Article
Peer reviewed
Solid polymer electrolytes comprising PMMA doped with LiNO3 have been prepared by solution casting technique using THF as solvent. To increase the properties of SPE, dispersion of nanoparticles into ...the polymer network is a challenging and reliable one. In this work, we first report that the nanoparticle TiO2 provided substantial changes, when it is added to the complex of PMMA‐LiNO3 as supported by TG‐DTA technique. In addition, the structural disruption of PMMA‐LiNO3 dispersed with TiO2 has been analyzed by XRD technique. The significance in the present work paves the way for the design of solid electrolytes in electrochemical devices.
Calcium silicate amorphous materials of general formula
x
CaO·(1–
x
)SiO
2
, being 0.3 ≤
x
≤ 0.6, and pure silica (SiO
2
) have been prepared by the sol–gel method and characterized by X-ray ...diffraction. Freshly prepared glassy samples of these materials were reduced to fine powders by gentle grinding in an agate mortar. Subsequently, a simultaneous thermogravimetry (TG) and differential thermal analysis equipment was used to study their thermal behavior under a stream of argon in the temperature range from room temperature to 1200 °C. All samples undergo dehydration up to 250 °C followed by a second process with a slight mass loss in the range 350–500 °C due to the thermal degradation of the residual nitrate, followed by a third endothermic process ascribed to dehydroxylation, due to evolution of water by condensation of the OH– surface groups, took place between 500 and 600 °C. At high temperatures, around 900 °C, all gel-glasses undergo an exothermic process without mass changes ascribed to crystallization. A reliable isoconversional procedure was applied to investigate the conversion dependency of activation energy for the thermally activated release of water molecules physically or chemically bound to the structure of the materials as well as that to dehydroxylation. The results obtained were discussed in terms of the different water absorption capabilities related to their different molar ratio Ca/Si and, depending on the amount of Ca, to the formation of one or more calcium silicate phases that crystallize at high temperature.
•A new organic–inorganic hybrid nitrate was synthesized at room temperature.•The atomic arrangement shows three-dimensional network.•Quantum mechanical calculations were performed using the DFT ...method and topological analyzes.•IR spectroscopy, thermal and electrical measurement was investigated.•The biological activity was performed via molecular docking analysis.
1,3-Benzenedimethanaminium bis(trioxonitrate), denoted by BD(NO3)2 was prepared and its structure determined by X-ray crystallography. This compound solidifies into the triclinic system and the P21/c space group with the lattice parameters a = 21.4308 (7) Å, b = 5.7255 (2) Å, c = 20.4476 (5) Å, β = 108.502 (1) °, V = 2379.28 (13) Å3, Z = 8, R = 0.047 and Rw = 0.129. In the crystal, the ions are allied by a huge number of NH···O hydrogen bonds, creating layers parallel to (100). These layers are associated by hydrogen bonding type CH···O, endorsing consequently a 3D arrangement. B3LYP/6–311++G**calculations were carried out to analyze the structure and properties of BD(NO3)2. Intermolecular contacts involved in the selection and packaging of the crystalline structure of BD(NO3)2 were investigated using fingerprint traces of the Hirshfeld surface. HOMO and LUMO analyses explain the charge transfers within the molecule. Topological analysis, RDG, molecular electrostatic potential (MEP) have been processed to calculate the intermolecular H-bonds interactions in detail. Thermal fusion and decomposition were investigated using TG, DTA and DSC measurements. Ionic conduction (H+) has been intentional in the temperature range 323 to 393 K, indicating semiconductor behavior of the material produced. Complete assignments of bands observed in the FTIR spectrum were reported together with the main force constants. The presence of dimeric species is important to explain why the intense bands predicted for the monomer due to NH···ON interactions are not observed in the experimental IR spectrum. The biological activity of BD(NO3)2 was accomplished in silico to investigate their antibacterial activity.
Display omitted
•A high-quality transparent crystal was harvested by a slow evaporation technique.•A molecular structure was confirmed using NMR spectra.•Homo and LUMO molecules have highly effective electrical ...activities.•DFT/B3LYP method used to determine the nonlinear optical properties.•The grown crystal is suitable materials for an NLO applications.
Here we report, the formation of an optically active single crystal of D-2-aminobutyric acid L-Norvaline (ABANV) by the slow evaporation technique by co-crystallization of amino acids D-2-aminobutyric acid (ABA) and L-Norvaline together in water. An X-ray diffraction technique has been used to determine the dimensions of the single crystal unit cells. The functional group of ABANV crystal was studied using FTIR spectroscopy in order to determine its chemical structure. The FT NMR spectrum was conducted to analyze the carbon and hydrogen environments of the grown crystal. In optical absorption studies, the crystal was shown to be transparent in the visible region with a lower cut off wavelength of 236 nm, which led to an optical band gap energy Eg of 5.25 eV. In addition, using TG/DSC techniques, we have investigated the thermal stability of the grown ABANV single crystal as well as their accurate melting point. A HOMO and LUMO analysis were performed to determine the electronic charge distribution and reactivity of the molecules within the crystal. First-order molecular hyperpolarizality (β) properties of the grown crystal have been determined using the B3LYP method. The scatter graph provides an explanation of the chemical bonding of ELF and LOL, as well as the inter and intra fragment interactions.
PDF
