Blue phosphors of dinuclear and mononuclear copper(I) and silver(I) complexes of 3,5-bis(trifluoromethyl)pyrazolate and the related bis(pyrazolyl)borate

The synthesis, structure, and photoluminescence properties are described for the three-coordinate mononuclear and dinuclear complexes [H(2)B(3,5-(CF(3))(2)Pz)(2)]M(2,4,6-collidine), M(1)(), and [[3,5-(CF(3))(2)Pz]M(2,4,6-collidine)](2), M(2)(), respectively (M = Cu; Ag). The solids exhibit bright blue phosphorescence, at room temperature for the copper compounds and at 77 K for all compounds. Ag(1)(), Cu(1)(), and Cu(2)() exhibit blue pyrazole-based structured emissions with short phosphorescence lifetimes, 10(1)-10(2) micros, due to an internal heavy-metal effect. Meanwhile, Ag(2)() exhibits curious multiple excitation-dependent emissions.     

Metal effect on the supramolecular structure, photophysics, and acid-base character of trinuclear pyrazolato coinage metal complexes

Varying the coinage metal in cyclic trinuclear pyrazolate complexes is found to significantly affect the solid-state packing, photophysics, and acid-base properties. The three isoleptic compounds used in this study are [[3,5-(CF3)2Pz]M]3 with M = Cu, Ag, and Au (i.e., Cu3, Ag3, and Au3, respectively). They form isomorphous crystals and exist as trimers featuring nine-membered M3N6 rings with linear two-coordinate metal sites. On the basis of the M-N distances, the covalent radii of two-coordinate Cu(I), Ag(I), and Au(I) were estimated as 1.11, 1.34, and 1.25 angstroms, respectively. The cyclic [[3,5-(CF3)2Pz]M]3 complexes pack as infinite chains of trimers with a greater number of pairwise intertrimer M...M interactions upon proceeding to heavier coinage metals. However, the intertrimer distances are conspicuously short in Ag3 (3.204 angstroms) versus Au3 (3.885 angstroms) or Cu3 (3.813 angstroms) despite the significantly larger covalent radius of Ag(I). Remarkable luminescence properties are found for the three M3 complexes, as manifested by the appearance of multiple unstructured phosphorescence bands whose colors and lifetimes change qualitatively upon varying the coinage metal and temperature. The multiple emissions are assigned to different phosphorescent excimeric states that exhibit enhanced M...M bonding relative to the ground state. The startling luminescence thermochromic changes in crystals of each compound are related to relaxation between the different phosphorescent excimers. The trend in the lowest energy phosphorescence band follows the relative triplet energy of the three M(I) atomic ions. DFT calculations indicate that [[3,5-(R)2Pz]M]3 trimers with R = H or Me are bases with the relative basicity order Ag < Cu < Au while fluorination (R = CF3) renders even the Au trimer acidic. These predictions were substantiated experimentally by the isolation of the first acid-base adduct, [[Au3]2:toluene]infinity, in which a trinuclear Au(I) complex acts as an acid.     

Optical characterization of xTiO2-(60 − x)SiO2-40Na2O glasses: II. Absorption edge, Fermi level, electronic polarizability and optical basicity

In the present work different optical properties of xTiO₂-(60 − x)SiO₂-40Na₂O (wt%) optical glasses are determined. The characterization is done over a wide energy range, 0.41-6.2 eV. The refractive index and the extinction coefficient data are used to measure the absorption coefficient of the different glass compositions. Studying the UV-absorption edge, both direct and indirect allowed transitions with their optical energy gaps are carried out. In the same time, the Urbach energy is evaluated. From the extinction coefficient data, the Fermi energy of the glasses is calculated. The molar refraction, electronic polarizability and the optical basicity are obtained using the measured glass refractive indices.     

Spectrofluorometric Determination of Methocarbamol in Pharmaceutical Preparations and Human Plasma

A simple, sensitive and rapid spectrofluorometric method for determination of methocarbamol in pharmaceutical formulations and spiked human plasma has been developed. The proposed method is based on the measurement of the native fluorescence of methocarbamol in methanol at 313 nm after excitation at 277 nm. The relative fluorescence intensity-concentration plot was rectilinear over the range of 0.05–2.0 μg/mL, with good correlation (r = 0.9999), limit of detection of 0.007 μg/ mL and a lower limit of quantification of 0.022 μg/ mL. The described method was successfully applied for the determination of methocarbamol in its tablets without interference from co-formulated drugs, such as aspirin, diclofenac, paracetamol and ibuprofen, The results obtained were in good agreement with those obtained using the official method (USP 30).The high sensitivity of the method allowed the determination of the studied drug in spiked human plasma with average percentage recovery of 99.42 ± 3.84.     

Synthesis and Insecticidal Efficacy of Novel Bis Quinazolinone Derivatives

A novel bis benzoxazin‐4‐one derivative has been synthesized and utilized to construct a new series of bis quinazolin‐4(3H)‐one derivatives via the reactions with different nitrogen nucleophiles namely, primary amines (ammonia, ethanolamine, and 4‐aminoantipyrine), secondary amines (morpholine and piperidine), diamine (o‐phenylenediamine), hydrazine hydrate, and hydroxylamine. The insecticidal efficacy of newly synthesized compounds was also studied. The structural features of the synthesized compounds were assigned by spectral analysis.     

Spectrophotometric determination of four macrolide antibiotics in pharmaceutical formulations and biological fluids via binary complex formation with eosin [corrected

A simple, rapid, and sensitive validated spectrophotometric method was developed for the determination of certain macrolide antibiotics namely, erythromycin (I), azithromycin dihydrate (II), clarithromycin (III), and roxithromycin (IV) in bulk powders, pharmaceutical formulations, and spiked biological fluids. The proposed method is based on the formation of a binary complex between each of the studied drugs and eosin Y in aqueous buffered medium. Under the optimum conditions, the binary complexes showed absorption maxima at 542-544 nm. The absorbance of the binary complexes obeyed Beer's law over the concentration range of 1-10 micro/g/mL for II, 2-20 microg/mL for I and IV, and 3-30 microg/mL for III. The mean percentage recoveries were 100.04 +/- 0.83, 99.98 +/- 0.80, 100.17 +/- 0.91, and 99.55 +/- 0.91, with minimum detectable molarities of 2 x 10(-7) for I and II, 4 x 10(-7) for III, and 3 x 10(-7) for IV. The different experimental parameters affecting the development and stability of the colors were studied and optimized. The proposed method was successfully applied to the analysis of the cited drugs in some pharmaceutical formulations. The results obtained were in good agreement with those obtained using the reference methods. The proposed method was further applied to spiked human urine and plasma. A proposal of the reaction pathway is suggested.     

Synthesis,Anticancer Screening of Some Novel Trimethoxy Quinazolines and VEGFR2, EGFR Tyrosine Kinase Inhibitors Assay; Molecular Docking Studies

A new series of 8-methoxy-2-trimethoxyphenyl-3-substituted quinazoline-4(3)-one compounds were designed, synthesized, and screened for antitumor activity against three cell lines, namely, Hela, A549, and MDA compared to docetaxel as reference drug. The molecular docking was performed using Autodock Vina program and 20 ns molecular dynamics (MD) simulation was performed using GROMACS 2018.1 software. Compound 6 was the most potent antitumor of the new synthesized compounds and was evaluated as a VEGFR2 and EGFR inhibitor with (IC50, 98.1 and 106 nM respectively) compared to docetaxel (IC50, 89.3 and 56.1 nM respectively). Compounds 2, 6, 10, and 8 showed strong cytotoxic activities against the Hela cell line with IC50 of, 2.13, 2.8, 3.98, and 4.94 µM, respectively, relative to docetaxel (IC50, 9.65 µM). Compound 11 showed strong cytotoxic activity against A549 cell line (IC50, 4.03 µM) relative to docetaxel (IC50, 10.8 µM). Whereas compounds 6 and 9 showed strong cytotoxic activity against MDA cell line (IC50, 0.79, 3.42 µM, respectively) as compared to docetaxel (IC50, 3.98 µM).     

Synthesis and characterization of low-cost hierarchical porous silica by nanoemulsion templating: influence of nanoemulsion volume and hydrodynamic diameter

Journal of Sol-Gel Science and Technology - Silica as a stable and biocompatible material has attracted a great deal of interest, particularly concerning the synthesis of porous silica....     

Validated stability-indicating spectrofluorimetric methods for the determination of ebastine in pharmaceutical preparations

Two sensitive, selective, economic, and validated spectrofluorimetric methods were developed for the determination of ebastine (EBS) in pharmaceutical preparations depending on reaction with its tertiary amino group. Method I involves condensation of the drug with mixed anhydrides (citric and acetic anhydrides) producing a product with intense fluorescence, which was measured at 496 nm after excitation at 388 nm.