A tetrahedral Hg(II) diethyl dithiocarbamate (Et 2 Dt) complex containing triphenylphosphine (PPh 3 ) of the composition [HgCl(κ 2 -Et 2 Dt) 2 (PPh 3 )] (1) is prepared. Furthermore, complex (1) is used as a synthone to prepare a novel series of complexes of the following composition [Hg(Et 2 Dt)L(PPh 3 )] {L = saccharinate (2), thiosaccharinate (3), benzisothiazolinate (4), benzothiozole-2-thiolate (5), and benzooxazole-2-thiolate (6) anions}. The resulted complexes(1)-(6) are characterized by elemental analysis, molar conductivity, powder X-ray diffraction, fourier transform Infrared, and NMR ( 1 H and 31 P) spectroscopic techniques. The Et 2 Dt ligand is coordinated as bidentate chelate through the sulfur atoms, whereas the L ligands are bonded as monodentate ligands to afford a tetrahedral geometry around the Hg(II) ion. Nitrogen adsorptiondesorption isotherm for two of as-prepared complexes (2) and (3) are measured first to get their Brunauer-Emmett-Teller surface area. Moreover, the mentioned two complexes are evaluated for their ability to store hydrogen gas at 77 K. However, the results of the hydrogen storage tests proved that the selected complexes are all capable of storing hydrogen, but in varying degrees, where complex (2) exhibited a storage capacity of 4.22 wt% under 88 bar. K E Y W O R D Sbidentate chelate, complexes, diethyl dithiocarbamate, Hg(II), hydrogen storage

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Magnesium ferrite is a visible light absorber, and when combined with multiwall carbon nanotubes (MWCNTs), it can lead to low electron-hole recombination rates, thus improving its photocatalytic activity. In this work, a novel MgFe 2 O 4 /CNTs nanocomposite catalyst has been synthesized via anchoring MgFe 2 O 4 nanoparticles onto MWCNTs surface by a sol-gel and microwave-assisted route. The prepared catalyst was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, energy-dispersive x-ray analysis and vibrating scanning magnetometry. MgFe 2 O 4 nanoparticles showed a cubic inverse spinel ferrite structure, while MgFe 2 O 4 /CNTs nanohybrids showed combinations of both structures. Morphology studies including Brunauer-Emmett-Teller (BET) analysis confirmed a 40 m 2 g -1 specific surface area with narrow mesoporous size distribution for the MgFe 2 O 4 /CNTs nanocomposite. The photocatalytic performance of the new catalyst was assessed by photodegradation of methylene blue (MB). The experimental results demonstrated that MgFe 2 O 4 /CNTs exhibited strong photocatalytic activity, catalysing the photooxidation of about 98% of MB in 25 minutes under sunlight.

SUMMARYThis work reports the synthesis, structural characterisation, liquid crystallinity, luminescence and electroluminescence of novel thiophene azomethine polymers. The polymers under study were prepared via oxidative polymerisation of four novel monomers at room temperature using iron (III) chloride. The chemical structures of the prepared monomers and polymers were confirmed by infrared and 1 H and 13 C NMR spectroscopy. Molecular masses were determined for monomers and polymers by gas/liquid chromatography-mass spectrometry (GC/LC-MS) and by gel-permeation (size exclusion) chromatography (SEC), respectively. Thermal stability studies of the prepared materials were achieved by thermogravimetric analysis (TGA), and the onset of weight loss T o and the endset T max were calculated from the thermograms. Liquid crystalline mesophases and phase changes of the monomers and polymers were studied by differential scanning calorimetry (DSC) and polarised optical microscopy (POM), and the glass transition temperatures Tg of the polymers were determined from the DSC curves. The electrochemical band gaps, HOMO and LUMO energy levels were measured by cyclic voltammetry. UV-visible absorption-emission spectra (liquid and solid films) of the polymers were obtained at room temperature with different solvents. Optical band gaps were calculated from the absorption edges, and were in good agreement with those estimated from cyclic voltammetry. Mixing the polymers with lanthanide salts such as EuCl 3 and YbCl 3 gave sensitised fluorescence, and the light emitted was much more intense than that from the pure polymers. Polymer based light-emitting diodes (PLEDs) were fabricated by spin coating, and their current-voltage characteristics were measured. In preliminary work, the polymer devices were found to produce electroluminescent spectra similar to the PL spectra of the corresponding samples. Molecular modelling studies were performed on both polymer segments and monomer molecules; the absorption spectra of the prepared polymers, HOMO and LUMO energy levels were calculated with ZINDO using AMI geometry optimisation.

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