Effects of swift heavy ion-irradiation on mica- and coal-based rocks of Lower Himalayas in Sikkim,India

Naturally occurring mica schist and coal sedimentary sequence in Sikkimese Himalaya were collected and investigated by two micro-techniques: scanning electron microscopy/energy dispersive spectrometry and Raman spectroscopy. They were applied to identify the constituents and the structure of the minerals before and after swift heavy ion irradiation. Vibrational data and the constituents of abundantly found mica schist and coal-based rock were acquired at room temperature and were compared with those reported for their analogues in the previous reports.     

Reaction of 2-silylmethylcyclopropyl ketones with in situ oxirane-derived aldehydes and formation of 2-hydroxymethyl tetrahydrofurans

The enolates formed from Lewis acid treatment of (2-trimethylsilylmethyl)cyclopropyl alkyl and aryl ketones reacted with aldehydes formed in situ from alkoxy-, aryl- and vinyl-substituted oxiranes to generate aldol products in good yields. Selected aldol products were conveniently transformed into highly substituted tetrahydrofurans under oxidative conditions.     

Synergistic use of Knudsen effusion quadrupole mass spectrometry, solid-state galvanic cell and differential scanning calorimetry for thermodynamic studies on lithium aluminates

Three ternary oxides LiAl₅O₈(s), LiAlO₂(s) and Li₅AlO₄(s) in the system Li-Al-O were prepared by solid-state reaction route and characterized by X-ray powder diffraction method. Equilibrium partial pressure of CO₂(g) over the three-phase mixtures {LiAl₅O₈(s)+Li₂CO₃(s)+5Al₂O₃(s)}, {LiAl₅O₈(s)+5LiAlO₂(s)+2Li₂CO₃(s)} and {LiAlO₂(s)+Li₅AlO₄(s)+2Li₂CO₃(s)} were measured using Knudsen effusion quadrupole mass spectrometry (KEQMS). Solid-state galvanic cell technique based on calcium fluoride electrolyte was used to determine the standard molar Gibbs energies of formations of these aluminates. The standard molar Gibbs energies of formation of these three aluminates calculated from KEQMS and galvanic cell measurements were in good agreement. Heat capacities of individual ternary oxides were measured from 127 to 868 K using differential scanning calorimetry. Thermodynamic tables representing the values of Δ_fH⁰(298.15 K), S⁰(298.15 K) S⁰(T), C_p⁰(T), H⁰(T), {H⁰(T)-H⁰(298.15 K)}, G⁰(T), Δ_fH⁰(T), Δ_fG⁰(T) and free energy function (fef) were constructed using second law analysis and FACTSAGE thermo-chemical database software.     

Synthesis and characterization of di- and triorganotin(IV) complexes of 2-tert-butyl-4-methyl phenol

The di- and trialkyltin(IV) complexes of composition R₂SnCl_2−x (OAr), and n-Bu₃Sn(OAr) (R = n-Bu and Me; x = 1 and 2; OAr = OC₆H₃Bu ^t -2-Me-4) have been synthesized by the reactions of di-n-butyl and dimethyltin dichlorides and tri-n-butyltin(IV) chloride with 2-tert-butyl-4-methylphenol and triethylamine in tetrahydrofuran. The reaction of triphenyltin chloride with trimethylsilyl-2-t-butyl-4-methylphenoxide in the same solvent however, gives a complex of composition Ph₃Sn(OAr). The complexes have been characterized by microanalyses, molar conductance measurements, molecular weight determinations and IR and ¹H, ¹³C and ¹¹⁹Sn NMR and mass spectral studies. Thermal behaviour of the complexes has been studied by TGA and DTA techniques. From the non-isothermal TG data, the kinetic and thermodynamic parameters have been calculated employing Coats-Redfern equation and the mechanism of decomposition has been computed using non-isothermal kinetic method. Thermal investigations on the blends of poly(methylmethacrylate). PMMA, with organotin(IV)-2-tert-butyl-4-methylphenoxides have shown increased thermal stability compared to pure PMMA suggesting thereby their potential as additives towards PMMA.     

Study of interfacial charge transfer in nanosemiconductor–molecule composites

Interaction of sol–gel synthesized Ce–Ag‐codoped ZnO (CSZO) nanocrystals with (E)‐1‐(naphthalen‐1‐yl)‐2‐styryl‐1H‐phenanthro[9,10‐d]imidazole has been analysed. The synthesized nanocrystals and their composites with naphthyl styryl phenanthrimidazole have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X‐ray spectroscopy, X‐ray diffractometry, X‐ray photoelectron spectroscopy (XPS) lifetime and Fourier transform infrared spectroscopy and cyclic voltammetry. XPS shows doped silver and cerium in Ag⁰ and Ce⁴⁺ states, respectively_. SEM and TEM images of CSZO nanoparticles show that they appear to be 3D trapezoid and cocoon‐like shape. The selected area electron diffraction pattern supports the nanocrystalline character of the synthesized material. The percentages of doping of cerium and silver in CSZO are 0.54 (at.) and 0.34 (at.), respectively. From the energy levels of the materials used in the imidazole–CSZO composite, the dominant CT direction has been analysed. Theoretical investigation shows that the binding energy and energy gap of the imidazole composites are highly dependent on the nature of the silver oxide cluster and that charge transfer in the imidazole–Ag₄O₄ composite is faster than the same in other composites. Molecular docking technique has also been carried out to understand the imidazole–DNA interactions. Copyright © 2016 John Wiley & Sons, Ltd.     

Improved efficiencies of hybrid organic light‐emitting diodes using efficient electron injection layer

Hybrid organic‐inorganic light‐emitting diodes were developed with pristine ZnO (2.0 wt%) and Cu‐doped ZnO (2.0 wt%) as electron injection layer and iridium(III)‐bis‐2‐(4‐fluorophenyl)‐1‐(naphthalen‐1‐yl)‐1H‐phenanthro[9,10‐d]imidazole (acetylacetonate) [Ir(fpnpi)₂ (acac)] as green emissive layer (521 nm). The pristine ZnO and Cu‐doped ZnO are deposited at indium tin oxide cathode and emissive layer interface. The electroluminescent performances increased by electron injection layer–Cu‐doped ZnO compared with ZnO‐based device because Cu‐doped ZnO injects electron efficiently result in balanced h⁺ ? e^? recombination in emissive layer than ZnO‐based device. The Cu‐doped ZnO (2.0 %) device shows luminance (L) of 10 982 cd/m² at 23.0 V (ZnO, 1450 cd/m² at 23.0 V).     

119Sn Mössbauer characterization of self assembled organotin(IV) complexes with Schiff bases containing amino acetate skeletons

Several organotin(IV) compounds, viz., diorganotin(IV) compounds of the types Ph₂SnLH (monomer), ⁿBu₂SnLH·OH₂ (monomer), [Me₂SnLH·OH₂]₂ (centrosymmetric dimer), [ⁿBu₂SnLH]₃ (cyclic trinuclear), [Ph₂SnLH] _n (polymer), {[ⁿBu₂Sn(LH)]₂O}₂ (centrosymmetric tetranuclear), dinuclear di-/tri-mixed organotin(IV) compounds Ph₂SnLH·Ph₃SnCl (monomer) and triorganotin(IV) compounds of the types [Bz₃SnLH]₂ (centrosymmetric dimer) and [Me₃SnL¹H] _n (Polymer) (LH = Schiff base carboxylate) have been studied in the solid state at liquid nitrogen temperature using ¹¹⁹Sn Mössbauer spectroscopy. The tin coordination geometry of the compounds determined from crystallography was correlated with the ¹¹⁹Sn Mössbauer results.     

Elastic behavior of some manganite-based orthorhombic RMnO3 (R=Sm,Eu, Gd,Dy) multiferroics

A series of multiferroic materials with the compositional formula, RMnO₃ (where R=Sm, Eu, Gd, Dy) were prepared by the well-known citrate sol–gel technique. After characterizing the samples structurally, a systematic investigation of elastic behavior has been undertaken and it has been found that the elastic moduli are increasing continuously with decreasing ionic radii of the dopant ion. Variation of longitudinal velocity with temperature for all the samples, over a temperature range 80–300 K has also been studied and the observed experimental behavior is explained using four theoretical models. It has been concluded that Lakkad's model explains the variation of Young's modulus with temperature in a better way than the other ones.