Determination of surface properties and Gutmann's Lewis acidity-basicity parameters of thiourea and melamine polymerized graphitic carbon nitride sheets by inverse gas chromatography.

Melamine and thiourea-derived graphitic carbon nitrides (M-GCN/T-GCN) were synthesized and characterized. The surface properties were investigated using inverse gas chromatography (IGC) and compared. Net retention volumes of M-GCN and T-GCN were measured with n-alkanes (C5-C10) and polar probes. The London dispersive surface free energies (γsd), calculated using Schultz and Dorris-Gray methods, decreased linearly with increasing temperature. The specific components of the enthalpy and entropy of adsorption for the polar probes were obtained using the Schultz, Dong, and Sawyer-Brookman methods. The Gutmann's Lewis acid-base parameters, Ka and Kb, were determined using the surface free energy (ΔGaS) via these methods. The surface character 'S' values (Kb/Ka) of M-GCN and T-GCN using the respective methods are 4.04, 3.78, and 5.08 and 4.11, 5.27, and 2.86. Hence, the surfaces contain more basic than acidic sites and could interact strongly with acidic media. Thus, IGC elucidates the surface charges of the GCN matrix resulting from surface chemical modification.

An efficient orange-red-emitting LiNa3 P2 O7 :Sm3+ pyrophosphate: Structural and optical analysis for solid-state lighting.

A trivalent rare-earth ion (Sm3+ )-doped LiNa3 P2 O7 (LNPO) phosphor was synthesized using a conventional high-temperature solid-state reaction route. A predominant orthorhombic phase of LNPO was observed in all X-ray diffraction patterns. The surface states of the LNPO:Sm phosphor were confirmed by X-ray photoelectron spectroscopy. Under 401 nm excitation, the Sm-doped LNPO phosphors showed sharp emission peaks at 563, 600 and 647 nm that are related to the f-f transition of Sm3+ ions. The optimum concentration of Sm3+ (9 mol%) produced Commission Internationale de l'Eclairage chromaticity coordinates, color rendering index and correlated color temperature of (0.564, 0.434), 42 and 1843 K, respectively.

Toxicity and efficacy of CdO nanostructures on the MDCK and Caki-2 cells.

This article reports the toxicological effects of synthesized cadmium oxide (CdO) nanostructures via a simple green route using a Polygala tenuifolia root extract on normal and renal tumor cells. First, the formation of cadmium oxide nanostructures were confirmed structurally by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The powder was crystallized in a cubic structure with a space group of Fm-3m. The mean crystallize size was approximately 40 and 44nm from the Scherrer and size-strain plots, respectively. The surface states of the cadmium oxide nanostructure using the O 1s and Cd 3d spectra were analyzed by XPS. Transmission electron microscopy showed that the simple green route resulted in various morphologies of synthesized cadmium oxide, such as trigonal-, tetrahedron-, and sheet-like structures. Finally, the toxic effects of the cadmium oxide nanostructures on Madin-Darby canine kidney epithelial cells (MDCK cells), as well as the human renal cancer cell line (Caki-2 cells) were investigated using a SRB assay and two-color flow cytometry analysis. The cadmium oxide nanostructures showed significant cell growth inhibition in normal and also tumor cells in a dose-dependent manner. On the other hand, the inhibition was higher in the cancer cells compared to the normal cells.

Biogenic Preparation of Gold Nanostructures Reduced from Piper longum Leaf Broth and Their Electrochemical Studies.

Exploitation of green chemical procedures for the synthesis of metal nanoparticles by biological process has received great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the reduction of aqueous gold ions by the extract of Piper longum leaves leading to the formation of different morphological gold nanoparticles (AuNPs). The formation of gold nano-structures has been characterized by UV-Vis absorption spectroscopy. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns indicates the AuNPs are highly crystalline nature with the face-centered cubic (111), (200), (220) and (311) facets, respectively. The AuNPs have different sizes and morphologies that are identified by TEM studies. The involvement of water soluble bio-molecules such as carboxylic acids, flavonoids, proteins and terpenoids were identified by Fourier transform infrared (FT-IR) and Raman spectrum. The responsible mechanism of improving acidic nature and the process of encapsulation of gold nanoparticles by Piper longum extract was discussed. Additionally, we have demonstrated the modified carbon paste electrode using gold nanoparticles by means of cyclic voltammetry in a solution of 1 M KCI and 1 mM [Fe(CN)6]3-/4-. The analysis of cyclic voltammetry shows electronic transmission rate between modified Au-CPE and Bare-CPE electrode increased.

Crystal growth and characterization of γ-glycine grown from potassium fluoride for photonic applications.

Single crystals of γ-glycine, an organic nonlinear optical material have been synthesized in the presence of potassium fluoride (KF) by slow evaporation technique at ambient temperature. The size of the grown crystal is up to the dimension of 12 mm×10 mm×8 mm. The γ-phase was confirmed by single crystal X-ray diffraction, powder XRD and the FTIR analysis. Optical absorption spectrum reveals that the grown crystal has good optical transparency in the entire visible region with an energy band gap of 5.09 eV, which is an essential requirement for a nonlinear optical crystal. Thermal stability of the grown γ-glycine crystal was determined using the thermo gravimetric and differential thermal analyses. The NLO activity of γ-glycine was confirmed by the Kurtz powder technique using Nd:YAG laser and the grown crystal exhibits high relative conversion efficiency when compared to potassium dihydrogen phosphate (KDP).