Synthesis of Amphiphilic RuII Heteroleptic Complexes Based on Benzo[1,2‐b:4,5‐b′]dithiophene: Relevance of the Half‐Sandwich Complex Intermediate and Solvent Compatibility

The detailed synthesis and characterization of four ruthenium(II) complexes [RuLL′(NCS)₂] is reported, in which L represents a 2,2′‐bipyridine ligand functionalized at the 4,4′ positions with benzo[1,2‐b:4,5‐b′]dithiophene derivatives (BDT) and L′ is 2,2′‐bipyridine‐4,4′‐dicarboxylic acid unit (dcbpy) (NCS=isothiocyanate). The reaction conditions were adapted and optimized for the preparation of these amphiphilic complexes with a strong lipophilic character. The photovoltaic performances of these complexes were tested in TiO₂ dye‐sensitized solar cell (DSSC) achieving efficiencies in the range of 3–4.5 % under simulated one sun illumination (AM1.5G).     

Adsorption of sarin and chlorosarin onto the Al12N12 and Al12P12 nanoclusters: DFT and TDDFT calculations

This study provides details of the electronic and optical structures and binding energies of sarin (SF) and chlorosarin (SC) with Al–N and Al–P surfaces of Al₁₂N₁₂ and Al₁₂P₁₂ nanoclusters in the gas phase. The adsorption mechanism of SF and SC on these nanoclusters containing the Al³⁺ central cation was studied. Optimized geometries and thermodynamic parameters of SF and SC adsorption complexes were calculated. SF and SC are chemisorbed on these nanoclusters because of the formation of PO···Al bonds. The chemical bond is formed between an oxygen atom of SF and SC and an aluminum atom of fullerene-likes (chemisorption). However, the binding energies of the complexes with the Al₁₂N₁₂ nanocluster are larger than these values for the Al₁₂P₁₂ nanocluster. The interaction enthalpy and Gibbs free energy of all studied systems were found to be negative. We can conclude that SF and SC will be adsorbed preferably on Al₁₂N₁₂ nanocluster.     

The interference effect of a mixture of magnesium, aluminium, sulfate and chloride on the atomization and vaporization of manganese in graphite furnace atomic absorption spectrometry.

In this study, the interference effects of Al3+, Mg2+, Cl- and SO4(2-) ions on the determination of manganese by graphite furnace atomic absorption spectrometry (GFAAS) were investigated. At first, the interferences caused by Al2(SO4)3, AlCl3, MgCl2 and MgSO4, which are the most possible major compounds for the combinations of the ions mixed, were individually considered. Then, the effects caused by mixtures containing various amounts of MgSO4 and AlCl3 were studied. If the pyrolysis temperature is below 800 degrees C, AlCl3 changes the vaporization mechanism of manganese. These interferences disappear at higher pyrolysis temperatures. At the same time, aluminum salts may cause the formation of refractory compounds between aluminum and manganese (like spinel MnAl2O4) that shift the absorption signals of manganese to higher temperatures. Magnesium sulfate, by itself, does not cause any depression of manganese signals. In fact, it acts as a modifier, preventing volatilization losses of manganese during the pyrolysis step. A conclusion was reached that detailed investigation of the interferences in a complex media is a very difficult experimental and theoretical task. To solve practical problems, one may better follow the general notions developed in GFAAS toward complex matrices.     

Flux line lattice symmetries in the borocarbide superconductor LuNi2B2C

We compare the results of small angle neutron scattering on the flux line lattice (FLL) obtained in the borocarbide superconductor LuNi₂B₂C with the applied field along the c- and a-axes. For H‖c the temperature dependence of the FLL structural phase transition from square to hexagonal symmetry was investigated. Above 10 K the transition onset field. H ₂(T), rises sharply, bending away from H _c2(T) in contradiction to theoretical predictions of the two merging. For H‖a a first order FLL reorientation transition is observed at H _tr=3–3.5 kOe. Below H _tr the FLL nearest neighbor direction is parallel to the b-axis, and above H _tr to the c-axis. This transition cannot be explained using nonlocal corrections to the London model.     

Sonochemical decay of C.I. Acid Orange 8: Effects of CCl4 and t-butyl alcohol

Sonochemical degradation of aryl-azo-naphthol dyes represented by C.I. Acid Orange 8 was investigated at 300 kHz to assess the operational parameters and the impacts of rate enhancers (CCl₄) and rate inhibitors (t-butyl alcohol). It was found that the degradation of the dye was accelerated with increased concentrations of CCl₄ via the accumulation of reactive chlorine species and the hindrance of OH radical combination reactions with atomic hydrogen. The addition of t-butyl alcohol at all test concentrations inhibited the degradation of the dye regardless of the quantity of OH radicals (or H₂O₂) in solution. The inhibition was explained by the competition of the dye and t-butyl alcohol at the gas–liquid interface. Finally, the rate of dye degradation in the presence of both reagents at their effective concentrations was found to be considerably slower than that with CCl₄, showing that the formation of reactive chlorine species was remarkably suppressed by the rapid reaction of t-butyl alcohol at the gas–liquid interface.     

Data storage characteristics of iron doped LiNbO3 under a 90° geometry two-beam coupling configuration

A 90° geometry two-beam coupling configuration was used to investigate the storage properties of 0.03 mol% iron-doped lithium niobate. Photographs of the real image and the subsequently stored images showed partial spatial fading. The maximum diffracted light intensity against recording time rapidly increased, reaching a maximum before gradually decaying. Decay time constants against recording time, t_rec varied in the same way as the diffracted intensity. Both plots reached a maximum at the same recording time of 3 min (I≈0.8 W cm⁻²) and 12 min (I≈0.4 W cm⁻²). Erasure decay times were found to vary with recording time; the best value found in this work was 8.5 min. Erasure curves all displayed an initial oscillatory nature, which may result from oscillation of the diffraction grating via a slow damped oscillation of the constituent electrons.     

Selectivity in the aggregates of the chiral organolithium N-Boc-2-lithiopiperidine with a chiral ligand: a DFT study

In this paper the aggregates of the chiral organolithium N-Boc-2-lithiopiperidine [Boc=CO₂C(CH₃)₃], which play an important role in the formation of chiral 2-substituted piperidines found in many alkaloid structures and medicinal compounds, have been investigated within the framework of Density Functional Theory (DFT) calculations. In the complex structures, the lithium atoms are tetra-coordinated, the diaminoalkoxide ligand is tridentate to one lithium atom and forms a chelate with the substrate which is stabilized by the solvent diethyl ether. The same type of bonding was observed for all the different ligand-bound structures; for ligands 6 and 7, which have bulky substituents, selectivity was in agreement with experiment. The results shed light on the microscopic structures of these species and suggest a potential ligand, 11, to yield high enantioselectivity.