Mössbauer studies of 151Eu in europium oxalate, europium bissalen ammonium and europium benzoate

Although a number of europium water insoluble chelates have been prepared for several decades, the covalent nature of these compounds has never been established in any quantitative fashion. Shifts in the I.R. bands and conductivity measurements of these salts were hitherto used to qualitatively compare their molecular nature. In this communique we have used temperature coefficients of ¹⁵¹Eu Mössbauer spectra to determine the Debye temperatures (θ _D) of three europium chelates: namely europium oxalate, europium bissalen ammonium (recently reported) and europium benzoate and compared their θ _D with the measured θ _D of the known ionic EuF₃. Additionally, the mean square amplitude (<x ²) of these four compounds was computed and plotted as a function of temperature giving in each case a reasonable linear plot. It was interesting to note that the θ _D of the most ionic EuF₃ was greatest (283 ± 10 K) followed by the oxalate (166 ± 15 K), then the europium bissalen ammonium (133 ± 5 K) and lastly the europium benzoate with a θ _D of (105 ± 5 K).     

Synthesis of some new fluorophenothiazines

The synthesis of various 3-substituted derivatives of 7-fluorophenothiazin-3-ol and their 5-oxides is described. The ir, uv and mass spectral data are also included.     

Hexanuclear self-assembled arene-ruthenium nano-prismatic cages: potential anticancer agents

Two novel nano-cage compounds, 8 and 9, were prepared by self-assembly of the ruthenium complexes 4 and 5, and the tripodal donor 1. The cytotoxicity of 8 was found to be considerably stronger than that of cisplatin. The complex 8 inhibited tumor cell proliferation by interfering into regulatory pathways of the cell cycle via apoptosis.     

Validated HPTLC Method for Simultaneous Analysis of Alfuzosin Hydrochloride and Dutasteride in a Pharmaceutical Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, simple, selective, precise, and accurate HPTLC method for analysis of alfuzosin hydrochloride (ALF) and dutasteride...     

Modelling of guided-wave Bragg gratings and grating sensors using the collocation method

We have used the collocation method to model the characteristics of guided-wave Bragg gratings. The collocation method being a total field method, takes into account all modes, guided as well as radiation. We have first studied the effect of the grating structural parameters such as the grating profile and the duty cycle of periodic variation and have shown that these can have significant effect on the Bragg wavelength and the reflection spectrum. We have then obtained the response characteristics of gratings for their use in strain, temperature and pressure sensing. Our results compare very well with available experimental results. Comparisons with the coupled mode theory have also been included.     

Pongamia pinnata seed extract‐mediated green synthesis of silver nanoparticles: Preparation,formulation and evaluation of bactericidal and wound healing potential

Pongamia pinnata – a plant used since olden times in Ayurvedic treatment – is reported to have diverse functions including antibacterial, antidiabetic, antineurodegenerative, antiepileptic, antiulcer, etc. In this study, our objective was to prepare silver nanoparticles (AgNPs) by green synthesis mediated by methanolic seed extract of P. pinnata and to determine their antimicrobial and antioxidant potential and wound healing activity. AgNPs were characterized for particle size and shape and for antioxidant potential. Further, the AgNPs were incorporated in a gel. The wound healing activity was investigated using an excision wound healing model in Wistar rats. The AgNP‐loaded gel was applied topically to the wounded rats daily for 30 days. The wound contraction was calculated and histopathological studies of the healed tissues were conducted. Karanjin content of the extract was found to be 349 ± 2.16 mg g^?1. Formation of AgNPs was confirmed using transmission and scanning electron microscopies and X‐ray diffraction. AgNPs showed good antioxidant potential and were active against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. Significant wound healing activity (p < 0.05) was shown by the AgNP gel as compared to 5% Betadine ointment. Thus, the prepared AgNPs have antimicrobial and wound healing effects that may be useful in treatment of topical infections especially in wounds.     

Graphene Oxide Supported Oxovanadium (IV) Complex for Catalytic Peroxidative Epoxidation of Styrene: An Eye-Catching Impact of Solvent

Graphene oxide (GO) supported transition metal complexes are apprised as sturdy and everlasting heterogeneous catalysts. GO surface was functionalized with 3-triethoxysilylpropylamine (TSPA) and this amino functionalized GO (A-f-GO) nanocomposite with vanadyl Schiff base complex (VO-f-GO) was prepared and to give credence of its potentiality, it was chosen for the selective epoxidation of styrene using environmentally benign 30% H₂O₂ to styrene oxide (SO). To evade the detrimental exposure of “inborn” water, a selective high boiling and potent hygroscopic solvent, ethylene glycol was chosen to make this transformation productively successful. With the assistance of theoretical studies, we have probed the effect of H₂O₂ on to structural properties, binding mechanism and electronic properties of the catalyst and substrate. Adsorption energy (E_ad), energy band gap (E_g) and HOMO-LUMO were also calculated. Based on DFT calculations, resonance Raman and UV/Vis studies, we confirmed the formation of metal-peroxo species and propose the plausible catalytic pathway. The influence of the diverse experimental parameters, like substrate to oxidant mole ratio, catalyst concentration, type of solvents, solvent amount, time, temperature and oxidant were tested. A clear relationship was found between different reaction parameters like solvent amount, oxidant, catalyst concentration and temperature etc. and product distribution. This heterogeneous catalyst yielded styrene oxide as nearly the sole product (selectivity = 98.7%) with a conversion value of 99.2% in the oxidation of styrene with hydrogen peroxide in ethylene glycol.     

Triplet excited states and radical intermediates formed in electron pulse radiolysis of amino-substituted fluorenones

Electron pulse radiolysis of four differently substituted amino derivatives of fluorenone, namely, 1-amino-, 2-amino- 3-amino-, and 4-aminofluorenone, has been carried out to study the effect of structure on the spectroscopic and kinetic characteristics of the triplet excited states as well as the transient free radical intermediates formed under reducing and oxidizing conditions. The triplet states of these compounds have been generated in benzene by pulse radiolysis and in other solvents by flash photolysis technique and their spectral and kinetic properties have been investigated. Hydrated electron (e_aq⁻) has been found to react with these fluorenone derivatives to form the anion radical species with a diffusion-controlled rate constant. The spectral and kinetic properties of the transient ketyl and anion radicals have been studied by generating them in aqueous solutions of suitable pH. The pK_a values of ketylanion radical equilibria are in the range of 6.8–7.7 for these derivatives. The oxidized species have been generated by reaction with the azide radical. Hydrogen atom adducts as well as the cation radicals of these derivatives have also been generated by pulse radiolysis and characterized.