Crystal growth,characterization and Density functional theory computations of supramolecular N‐carbamothioyl acetamide

Single crystals of N‐carbamothioylacetamide (NCTA) were grown by slow evaporation technique at constant temperature. The structure is elucidated by single crystal XRD analysis. The studies reveal that the molecule is associated with accommodating weak C–O···H, N–H···O, N–H···S, C–H···N, C···C and H···H stacking interactions which are responsible for the formation and strengthening of supramolecular assembly. Inter‐ and intramolecular hydrogen bonding interactions exhibit supramolecular architecture in the crystal packing. Two different types of architecture, i.e., a column like packing, and cluster network type of infrastructure are observed. Hirshfeld surfaces and Fingerprint plots were used to locate and analyze the percentage of hydrogen bonding interactions. The various functional groups present in the molecule are confirmed by FT‐IR analysis. Density functional theory computations of the vibrational spectrum, molecular geometry, HOMO‐LUMO energy gaps, NBO and hyperpolarizability (β) were successfully evaluated. Facts concerning with the size, shape, charge density distribution and site of chemical reactivity of the molecule have been obtained by mapping electron density with electrostatic potential (ESP).     

Dye-Sensitized Solar Cell Based on a Blend of Hyperbranched Poly(aryl-ether-urethane) Electrolyte with TiO2 Nanoparticles

Hyperbranched poly(aryl-ether-urethane) is reported in this work as an efficient polymer electrolyte for photovoltaic application. Along with KI and I₂ as redox carriers in nanocrystalline dye-sensitized solar cell (DSC), this polymer yielded an overall conversion efficiency of 4.1%, upon illumination with visible light. The fabricated cell results in stable device performing under thermal stress maintaining about 70% of its initial value for 2 days in the direct atmosphere without sealing.     

Crystal growth and characterization of potassium(I)-doped tetrakis(thiourea)nickel(II) chloride

The influence of alkali metal potassium(I)-doping on the properties of tetrakis(thiourea)nickel(II) chloride crystals has been investigated. The variation in the intensity observed in powder X-ray diffraction (XRD) of doped specimen and slight shifts in vibrational frequencies confirm the lattice stress as a result of doping. Surface morphological changes due to doping of the alkali metal are observed by scanning electron microscopy. The incorporation of K(I)- into the crystal lattice was confirmed by energy dispersive X-ray spectroscopy. Lattice parameters are determined by single crystal XRD analysis. The thermogravimetric and differential thermal analysis studies reveal the purity of the materials and no decomposition is observed up to the melting point. The crystal is further characterized by UV–Vis and Kurtz powder technique.     

Synthesis, growth, structure, and characterization of a novel semiorganic crystal

Single crystals of (chloro)tris(thiourea-κS)cadmium(II) picrate have been grown by slow evaporation of a mixed solvent system water–acetone containing thiourea, cadmium chloride, and picric acid. The yellow crystals belong to triclinic system with centrosymmetric space group P-1 and the corresponding lattice parameters are a = 7.4632(3) ?, b = 7.9567(3) ?, c = 17.4885(7) ?, α = 98.990(2)°, β = 100.137(2)°, γ = 95.275(2)°, and Z = 2. The vibrational patterns of the as-grown crystals are analyzed by FT-IR and FT-Raman spectral analyses. The optical absorption study was performed to analyze the optical transparency of CTTCP and the crystals were transparent in the visible region and have a lower optical cutoff at ~507 nm with band gap energy of 2.47 eV. TG–DTA thermal analysis shows that the crystal is stable up to ~208 °C and has a good chemical stability.     

Synthesis, growth, structure and characterization of a new semiorganic crystal

A new semiorganic single crystal, tris(allylthiourea)silver(I) nitrate was grown from an aqueous solution containing silver(I) nitrate and allylthiourea by slow evaporation solution growth technique at room temperature. The crystal belongs to trigonal system with centrosymmetric space group R3 and the cell parameters are, a = 12.5090(4) Å, b = 12.5090(4) Å, c = 21.7130(8) Å, V = 3348.89 Å³, and Z = 6. The various functional groups present in the molecule are confirmed by Fourier transformed infrared spectroscopy. High transmittance is observed in the visible region and band-gap energy is calculated by Kubelka–Munk algorithm. The structure and the crystallinity of the materials were further confirmed using powder X-ray diffraction analysis. Microhardness studies were also carried out to elucidate the mechanical behavior. Thermogravimetric and differential thermal analysis reveal the purity of the sample and no decomposition is observed up to the melting point.     

Growth and characterization of Fe3+-doped bis(thiourea)zinc(II) chloride crystals

Fe3+-doping at ～10 mol% in aqueous medium during crystal growth by slow evaporation solution method in bis(thiourea)zinc(II) chloride (BTZC) leads to form a new compound C2H8Cl2N4S2Zn0.93Fe0.07 (BTZCF) which crystallizes in orthorhombic structure with centrosymmetric space group Pnma though the parent compound BTZC crystallizes in noncentrosymmetric structure with space group Pn2(1)a. The interesting feature observed in this new crystal is that though it crystallizes in centrosymmetric structure, it exhibits positive SHG result (weak signal), quite likely due to possible surface effects or internal stress. The calculated first-order hyperpolarizability is 1.457×10(-30) esu which is ～5.5 times that of urea. Fe3+-doping enhances the transmittance to a significant extent. Comparison of the thermal analysis results by DSC reveals the incorporation of dopant into the crystalline matrix. The high resolution XRD studies reveal that the crystalline quality is improved considerably when the doping level is reached to ～10 mol%.     

Gold nanoparticles induced apoptosis via oxidative stress and mitochondrial dysfunctions in MCF‐7 breast cancer cells

Green synthesis of functionalized gold nanoparticles has been considered to be more biocompatible and has gained much attention in recent years. The eco‐friendly synthesis, long half‐life of drugs, low cost, and nontoxicity make them an appealing potential option for the biomedical field. The leaf aqueous extract of 10 different plants, namely, Araucaria heterophylla (Ah), Lagerstroemia indica (Li), Combretum indicum (Ci), Melia azedarach (Ma), Muntingia calabura (Mc), Hygrophila auriculata (Ha), Rivina humilis (Rh), Callistemon lanceolatus (Cl), Pterygota alata (Pa), and Vateria indica (Vi) was used for the synthesis of gold nanoparticles (AuNPs). Among them, six plants supported the synthesis of stable AuNPs. The generation of ruby red from pale yellow color proved AuNPs synthesis and which was further confirmed by the absorption peak in UV–Vis spectroscopy. Enhanced antioxidant activity was found with Pa–AuNPs compared with other phytosynthesized AuNPs. Pa–AuNPs were thus characterized by HR‐TEM, EDX, XRD, and FTIR. Pa–AuNPs exhibited potent dose‐dependent anticancer efficacy and an effective dose of IC₅₀ mediated apoptosis and necrosis in MCF‐7 breast cancer cells. Pa–AuNPs significantly enhanced the generation of ROS, in effect inducing mitochondrial membrane sensitization to trigger the cascade of apoptosis. The research highlights the effectiveness of AuNPs on cancer cells in vitro and, in turn, a progressive step toward novel biomedical applications. These findings indicate that phytosynthesized AuNPs may be an enticing anti‐cancer strategy for breast cancer without eliciting toxicity to normal cells.     

Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

Nanosized platinum particles loaded on the TiO₂ nanoparticles were prepared to assess its photocatalytic activity in simple one-pot synthesis of quinaldines from anilines in ethanol using UV light. The catalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy, X-ray photoelectron spectra (XPS), Brunauer?CEmmer?CTeller surface area, atomic force microscope and diffuse reflectance spectra. XRD patterns revealed that the crystal structure of Pt?CTiO₂ resembled anatase phase of TiO₂. The UV?CVis spectra indicated an increase in absorption of visible light when compared to TiO₂. XPS analysis reveals that platinum particles are present mainly in metallic form. Furthermore, TEM analysis showed non-spherical-shaped Pt?CTiO₂ nanoparticles of the diameter 10?C30?nm. Upon irradiation in the presence of Pt?CTiO₂, aniline and oxidation products derived from ethanol undergo condensation?Ccyclization to afford quinaldines. Higher efficiency of Pt?CTiO₂ than Au?CTiO₂ in the conversion of aniline to quinaldines is due to the higher work function of Pt.     

Kinetics and mechanism of the reaction of α‐phenoxypropanoic acids with sodium salt of N‐Chlorobenzene‐sulphonamide: EDTA catalysis

EDTA smoothly catalyses the oxidation cum chlorination of some 17 α‐phenoxypropanoic acids with sodium salt of N‐chlorobenzenesulphonamide in acidic solution. A ternary intermediate can be envisaged for describing the enhanced reactivity. Imperfections are observed in the linear Hammett relationship in the case of ? NO₂ substituents, irrespective of the position. The susceptibility constant, ρ(≈ + 1) indicates the development of an electron‐rich transition state. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 27–33, 2002