Poly(triazine imide) with intercalation of Lithium and ChlorideiIons [(C3N3)2(NHxLi1−x)3⋅LiCl]: A Crystalline 2D Carbon Nitride network

Poly(triazine imide) with intercalation of lithium and chloride ions (PTI/Li+Cl−) was synthesized by temperature-induced condensation of dicyandiamide in a eutectic mixture of lithium chloride and potassium chloride as solvent. By using this ionothermal approach the well-known problem of insufficient crystallinity of carbon nitride (CN) condensation products could be overcome. The structural characterization of PTI/Li+Cl− resulted from a complementary approach using spectroscopic methods as well as different diffraction techniques. Due to the high crystallinity of PTI/Li+Cl− a structure solution from both powder X-ray and electron diffraction patterns using direct methods was possible; this yielded a triazine-based structure model, in contrast to the proposed fully condensed heptazine-based structure that has been reported recently. Further information from solid-state NMR and FTIR spectroscopy as well as high-resolution TEM investigations was used for Rietveld refinement with a goodness-of-fit (χ2) of 5.035 and wRp=0.05937. PTI/Li+Cl− (P63cm (no. 185); a=846.82(10), c=675.02(9) pm) is a 2D network composed of essentially planar layers made up from imide-bridged triazine units. Voids in these layers are stacked upon each other forming channels running parallel to [001], filled with Li+ and Cl− ions. The presence of salt ions in the nanocrystallites as well as the existence of sp2-hybridized carbon and nitrogen atoms typical of graphitic structures was confirmed by electron energy-loss spectroscopy (EELS) measurements. Solid-state NMR spectroscopy investigations using 15N-labeled PTI/Li+Cl− proved the absence of heptazine building blocks and NH2 groups and corroborated the highly condensed, triazine-based structure model.

Nanocrystalline zirconia powders synthesised by mechanochemical processing

Mechanochemical processing of zirconium and yttrium chloride precursors with lithium hydroxide has been used to synthesise ultrafine powders of yttria-stabilised zirconia. The precursors reacted during milling to form a composite consisting of nanocrystalline oxide grains embedded within a matrix of lithium chloride. The ultrafine powder was recovered subsequently by removing the lithium chloride through washing with deionised water and methanol. The powders were characterised using X-ray diffraction (XRD), transmission electron microscopy (TEM), and BET gas adsorption. The sintering behaviour of cold pressed pellets was examined by dilatometry.

Visualisation of chemical processes during corrosion of zinc using magnetic resonance imaging

Compositional and structural changes within an electrolyte solution above an electrochemically active metal surface have been visualised using magnetic resonance imaging (MRI) for the first time. In these proof-of-concept experiments, zinc metal was galvanically corroded in a saturated lithium chloride solution. Magnetic resonance relaxation maps were taken during the corrosion process and spatial variations in both T₁ and T₂ relaxation times were observed to change with time. These changes were attributed to changes in the speciation of zinc ions in the electrolyte.

Forces between mica surfaces in ethylene glycol

Measurements are presented of the force as a function of separation between two molecularly smooth mica surfaces immersed in ethylene glycol, and in solutions of lithium chloride and sulfuric acid in ethylene glycol. At surface separations greater than 3 nm the measured force is in very good agreement with double-layer theory, but at smaller separations there is an oscillatory solvation force which is superimposed on the double-layer repulsion. In contrast to the case in water, the adsorption of hydrogen ions at the mica surface does not markedly affect the short-range forces.

Homogeneous isolation of nanocelluloses by controlling the shearing force and pressure in microenvironment

Nanocelluloses were prepared from sugarcane bagasse celluloses by dynamic high pressure microfluidization (DHPM), aiming at achieving a homogeneous isolation through the controlling of shearing force and pressure within a microenvironment. In the DHPM process, the homogeneous cellulose solution passed through chambers at a higher pressure in fewer cycles, compared with the high pressure homogenization (HPH) process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) demonstrated that entangled network structures of celluloses were well dispersed in the microenvironment, which provided proper shearing forces and pressure to fracture the hydrogen bonds. Gel permeation chromatography (GPC), CP/MAS 13C NMR and Fourier transform infrared spectroscopy (FT-IR) measurements suggested that intra-molecular hydrogen bonds were maintained. These nanocelluloses of smaller particle size, good dispersion and lower thermal stability will have great potential to be applied in electronics devices, electrochemistry, medicine, and package and printing industry. © 2014 Elsevier Ltd.

Selective enumeration of dairy based strains of probiotic and lactic acid bacteria

Reliable methods for selective enumeration of probiotic and lactic acid bacteria (LAB) are required for improving the functional food quality of probiotics. Various methods were evaluated for selective enumeration of seventeen LAB and probiotic strains. Tested sugars failed to select any species however, improved recovery of total LAB count. The strains were viable and physiologically active within a range of oxygen tension levels, temperature and acidic conditions. Prior methods showed varied results such as De Man Rogosa Sharpe containing bile (MRSB), MRS containing nalidixic acid, paromomycin, neomycin sulphate and lithium chloride (MRS-NPNL), M17 and L. casei (LC) agar failed to select Lactobacillus acidophilus, Bifidobacterium, starter LAB and L. casei strains respectively. However, LC agar appears appropriate for L. paracasei and MRSB for yoghurt starter bacteria in the absence of L. reuteri and L. rhamnosus. The study suggests selective potential of culture media largely depends on target species.

The influence of water and metal ions on the transport properties of Trihexyl(tetradecyl)phosphonium chloride

A recent study indicated that the water-saturated ionic liquid (IL) trihexyl(tetradecyl)phosphonium chloride ([P_6,6,6,14][Cl]) provided a viable electrolyte for a Mg-air battery. However, there is limited literature on the properties of IL-water mixtures as battery electrolytes. The physical properties of [P_6,6,6,14][Cl] were studied with the addition of both water and metal salts (M_gCl₂ and LiCl) using conductivity and self-diffusion coefficient measurements. The conductivity of the samples at low water concentrations is surprisingly enhanced by the addition of the metal salt, contrary to lithium IL electrolytes. It was also found that the conductivity of the IL was increased by an order of magnitude by saturation with water. NMR diffusion measurements were used to probe the behaviour of both the cation and the water in the mixtures. It was found that the addition of metal salts to the water-saturated [P_6,6,6,14][Cl] did not affect the transport properties of the water or cation.

2-(2-Pyridylamino)Pyridinium2-(2-Pyridylamino)pyridinium chloride phosphorous acid: one-dimensional hydrogen-bonded and [π]-[π] stacked supramolecular chains

In the crystal structure of the title compound, C₁₀H₁₀N₃⁺·Cl-^·[P(O)(OH)₂H], the chloride ion and phosphorous acid form a one-dimensional hydrogen-bonded chain, while the 2-(2-pyridylamino)pyridinium cations form a second chain through [π]-[π] stacking. The two parallel chains are connected via a PO...H-N hydrogen bond and a weak pyridinium-to-chloride interaction.

Troubled minds: the lithium revolution

Ex-Changi prisoner of war, and psychiatrist, Dr John Cade, sought a pharmacological treatment for bipolar disorder in the 1940s ; and in so doing, marked the beginning of psychopharmacology.