Chemisorption and decomposition of pyrrole on Pd{111}

XPS, TPD and HREEL results indicate that molecular pyrrole is a fragile adsorbate on clean Pd{111}. At 200 K and for low coverages, the molecule remains intact and adopts an almost flat-lying geometry. With increasing coverage, pyrrole molecules tilt away from the surface and undergo N-H bond cleavage to form strongly tilted pyrrolyl (C4H4N) species. In addition, a weakly bound, strongly tilted form of molecular pyrrole is observed at coverages approaching saturation. Heating pyrrole monolayers results in desorption of similar to 15% of the overlayer as molecular pyrrole and N-a+ C4H4Na recombination with formation of hat-lying pyrrole molecules. This strongly bound species undergoes decomposition to adsorbed CN, CHx and H, leading ultimately to desorption of HCN and H-2. The implications of these results for the production of pyrrole by a heterogeneously catalysed route are discussed.

Stabilization of zinc electrodes with a conducting polymer

The reversibility of zinc anode in alkaline medium was enhanced by electrostatic deposition of a conducting polymer (polypyrrole). Electropolymerization of pyrrole onto zinc in aqueous medium using an organic acid as dopant is feasible and preferred as zinc is less corrosive in this medium. The structure of the polymer film was analyzed by FT-IR spectroscopy and scanning electron microscopy. The effect of the polypyrrole deposit on the zinc electrode was studied by cyclic voltammetry and charge–discharge cycling.

Electrochemical synthesis and characterization of conducting polymers using room temperature melt as an electrolyte

Aromatic monomers can be polymerised using the chloroaluminate room temperature melt obtained by mixing 1:2 ratio of cetyl pyridinium chloride and anhydrous aluminium chloride miscible in all proportions with organic solvents as an electrolyte. The chloroaluminate (AlCl4-) anion generated in this melt having a tetrahedral symmetry with equal bond lengths and bond angles is the dopant to stabilize macrocation generated near the vicinity of anode to yield better conducting and better ordered electronically conducting free standing polymer film. In this communication, we discuss the polymers derived from benzene and pyrrole and their characterization by various techniques.

Studies on polypyrrole film in room temperature melt

A bluish-black shining free standing polypyrrole film (PPy) of electronic conductivity 130 S cm-1 has been prepared by electrochemical oxidative polymerization of pyrrole on Pt/transparent glass conducting electrode resistance 15 O cm-1, using a room temperature melt as an electrolyte, composed of 1:3 stoichiometric ratio of cetyl pyridinium chloride and anhydrous aluminum chloride at 0.58 V versus Al wire as a reference electrode. The film possessed a charge transfer resistance of 132 O, and showed two absorption peaks at 457 and 1264 nm in the UV-vis–NIR diffused reflectance spectra. The morphology of the film was hexagonal. The potential step technique suggested a layered structure. This thin film can easily be peeled off from the electrode surface after three cycles and can be used for various applications like dissipation of electrostatic charge, battery electrode materials, solid electrolytic capacitor, electrochromic windows and displays, microactuators etc. It was also characterized by IR, thermal and SEM studies.

Discovery of substituted maleimides as liver X receptor agonists and determination of a ligand-bound crystal structure

Substituted 3-(phenylamino)-1H-pyrrole-2,5-diones were identified from a high throughput screen as inducers of human ATP binding cassette transporter A1 expression. Mechanism of action studies led to the identification of GSK3987 (4) as an LXR ligand. 4 recruits the steroid receptor coactivator-1 to human LXR alpha and LXRP with EC(50)s of 40 nM, profiles as an LXR agonist in functional assays, and activates LXR though a mechanism that is similar to first generation LXR agonists.

MIC-1 (a multifunctional modulator of dendritic cell phenotype and function) is produced by decidual stromal cells and trophoblasts

Macrophage inhibitory cytokine-1 (MIC-1) is a multifunctional cytokine produced in high amounts by placental tissue. Inhibiting trophoblast invasion and suppressing inflammation through inhibition of macrophage activation, MIC-1 is thought to provide pleiotropic functions in the establishment and maintenance of pregnancy. So far, little is known about the decidual cell subsets producing MIC-1 and the effect of this cytokine on dendritic cells (DCs), which are known to play a distinct role in the development of pro-fetal tolerance in pregnancy.