Mössbauer studies of Ni70Fe10Si8B12 metglass: Reentrant properties

Amorphous metal Fe₁₀Ni₇₀Si₈B₁₂ has been studied by Mössbauer spectroscopy without and with an weak applied field in the plane of ribbons. Reentrant properties have been confirmed with the existence of a canted state at low temperature. Studies with different values of the applied field have shown that a field near 50 0e is sufficient to saturate the average direction of the ferromagnetism.     

Synthesis and surface chemistry of nano silver particles

In this report, we present a simple wet chemical route to synthesize nano-sized silver particles, and their surface properties are discussed in detail. Silver nano particles of the size 40–80 nm are formed in the process of oxidation of glucose to gluconic acid by amine in the presence of silver nitrate, and the gluconic acid caps the nano silver particle. The presence of gluconic acid on the surface of nano silver particles was confirmed by XPS and FTIR studies. As the nano silver particle is encapsulated by gluconic acid, there was no surface oxidation, as confirmed by XPS studies. The nano silver particles have also been studied for their formation, structure, morphology and size using UV–Visible spectroscopy, XRD and SEM. Further, the antibacterial properties of these nano particles show promising results for E. Coli. The influence of the alkaline medium towards the particle size and yield was also studied by measuring the pH of the reaction for DEA, NaOH and Na₂CO₃.     

Synthesis and characterization of benzo[c]thiophene analogs tethered with dibenzo-heterocycles as potential OLEDs

Synthesis of mixed heterocyclic system containing benzo[c]thiophene, dibenzo-heterocycles, and thiophene unit is described.     

Click chemistry‐assisted triazole‐substituted azobenzene and fulgimide units in the pendant‐based copoly(decyloxymethacrylate)s for dual‐mode optical switches

Copolymer containing new thermally reversible click chemistry‐assisted triazole‐substituted azobenzene and fulgimide units in the pendant F‐co‐A was prepared by free‐radical solution addition polymerization technique. The F and A were also prepared for comparison. The DSC analysis of F indicates that the polymer possessing the C‐form of fulgimide unit exhibited higher T_m than that of E‐form of the same polymer and revealed that the C‐form of fulgimide unit in F is highly ordered. The cis‐trans back isomerization behavior of the click chemistry‐assisted triazole‐substituted azobenzene unit in film A has thermal irreversibility, while in F‐co‐A it exhibited thermal reversibility. The UV‐exposed film of F‐co‐A heated around T_g leads to cis‐trans back isomerization of azobenzene unit and thermally stable C‐form of fulgimide which retains its conjugated structure where both the photochromic units are converted into planar conformations and exhibit high fluorescence properties. The fluorescence maxima of C‐form in F‐co‐A red shifted compared with F , because the substituted triazole ring in the azobenzene unit stabilized the C‐form of fulgimide unit. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7843–7860, 2008     

Heterogeneous catalysis by new bead‐shaped polymer‐supported multisite phase transfer catalysts

Three different new insoluble bead‐shaped polymer‐supported multisite phase transfer catalysts containing two, four and six active sites have been prepared and characterized by FTIR, TGA, [chloride ion] and SEM analyses. The presence of number of active sites in each catalyst and their corresponding catalytic ability were studied by determining pseudo‐first order rate constants for C‐alkylation of phenylacetonitrile (PAN) and four different substituted PAN as the substrate using a low concentration of NaOH (25% w/w) at 50 °C. The observed rate constants were compared with rate constants of same reactions catalyzed by single‐site catalyst under identical reaction conditions. From comparative study, the efficiency of catalysts were found to be in the order six‐site>four‐site>two‐site>single‐site thus confirming number of active sites in each catalyst. Further, the detailed kinetic profile of C‐alkylation of PAN has been investigated using the superior six‐site catalyst by varying stirring speed, [substrate], [catalyst], [NaOH], and temperature. Based on the observed kinetic and activation parameters, an interfacial mechanism was proposed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 771–785, 2009