Synthesis,spectroscopy, magnetism and X-ray structure of μ-(bipyrimidine)-bis[aqua(bipyrimidine)(saccharinato)copper(II)] bis(saccharinate) tetrahydrate

The compound [Cu₂(bipym)₃(sac)₂(H₂O)₂](sac)₂(H₂O)₄ (bipym = 2,2-bipyrimidine and sac = saccharin) crystallizes in the space group P-1, with a = 10.710(3), b = 10.725(3), c = 13.637(5) Å, a = 70.07(3), = 80.31(2), g = 82.87(3)° and Z = 2. The geometry in the centrosymmetric dinuclear complex around each Cu^II ion is a distorted octahedron, in which the equatorial plane is formed by a nitrogen atom of a bis-didentate bridging bipym ligand, two nitrogen atoms of a didentate bipym ligand, and the nitrogen atom of a coordinating sac ligand. The axial positions in the octahedron are occupied by a second nitrogen of the bis-didentate bridging bipym ligand and a water molecule. The lattice contains two saccharinate anions and four water molecules held together in a hydrogen-bonded network. The i.r vibrations of the bipym ligand are found as a quasi-symmetric doublet at 1558 and 1580 cm^–1, while the most important i.r vibrations of the sac ligand are observed at 1629 and 1644 cm^–1 (carbonyl vibrations) and at 1285 and 1159 cm^–1 (sulfonyl vibrations). The magnetic exchange interactions between the Cu ions is very weak and is ferromagnetic (J < 0.1 cm^–1).     

Crystal structure and spectroscopy of bis-[bis(2-benzimidazolyl)propane]copper(II) bis(triflate)monohydrate, a copper complex with a geometry intermediate between tetrahedral and square planar

The structure of a mononuclear copper(II) compound with the ligand bis(2-benzimidazolyl)propane (abbreviated as tbz) is reported. The compound [Cu(tbz)₂](CF₃SO₃)₂(H₂O) crystallizes in the triclinic space group P , with a = 12.363(6), b = 13.218(9), c = 15.365(8) Å, = 82.74(5), = 68.04(4), = 65.30(5), and Z = 2. The Cu(II) atom has a geometry intermediate between tetrahedral and square planar, consisting of four nitrogen atoms of two tbz ligands. The Cu—N—Cu angles are about 135°, while the dihedral angle between them amounts to 62° (0° for square planar and 90° for a tetrahedron). Ligand field bands are observed at 10.2 × 10³, 13.8 × 10³, and 20.3 × 10³ cm^–1, while the most characteristic infrared vibrations of the triflate anion are observed at 1273, 1260, 1238, 1221, 1171, and 1157 cm^–1.     

Effect of High Pressure on Paracoccus denitrificans Growth and Polyhydroxyalkanoates Production from Glycerol

The performance of fermentation under non-conventional conditions, such as high pressure (HP), is a strategy currently tested for different fermentation processes. In the present work, the purpose was to apply HP (10–50 MPa) to fermentation by Paracoccus denitrificans, a microorganism able to produce polyhydroxyalkanoates (PHA) from glycerol. In general, cell growth and glycerol consumption were both reduced by HP application, more extensively at higher pressure levels, such as 35 or 50 MPa. PHA production and composition was highly dependent on the pressure applied. HP was found to decrease polymer titers, but increase the PHA content in cell dry mass (%), indicating higher ability to accumulate these polymers in the cells. In addition, some levels of HP affected PHA monomeric composition, with the polymer produced at 10 and 35 MPa showing considerable differences relative to the ones obtained at atmospheric pressure. Therefore, it is possible to foresee that the changes in polymer composition may also affect its physical and mechanical properties. Overall, the results of this study demonstrated that HP technology (at specific levels) can be applied to P. denitrificans fermentations without compromising the ability to produce PHA, with potentially interesting effects on polymer composition.

     

Effect of high pressure on cod (Gadus morhua) desalting

The effect of high pressure on salt and water diffusion in the desalting process of cod was studied. Under pressure, up to 300 MPa, the osmotic equilibrium is reached much faster, compared to desalting at atmospheric pressure. Water (D _ew) and salt (D _es) effective diffusion coefficients reached a maximum at 200 MPa, increasing 500- and 160-fold, respectively, compared with desalting at atmospheric pressure. Increasing pressure up to 300 MPa causes a reduction in both effective diffusion coefficients, although they were still about 70-fold higher than at atmospheric pressure. Up to 200 MPa, a linear correlation was found between D _ew and D _es and pressure. However, the total diffused amounts of water and salt, when the osmotic equilibrium was reached, were lower under pressure. At atmospheric pressure cod water content increased 1.65-fold, but under pressure the increment was on average 1.25-fold, while salt content decreased to 0.51-fold the initial value at atmospheric pressure and to around 0.75-fold under pressure.     

Development of a qualitative, multiplex real-time PCR kit for screening of genetically modified organisms (GMOs)

The number of commercially available genetically modified organisms (GMOs) and therefore the diversity of possible target sequences for molecular detection techniques are constantly increasing. As a result, GMO laboratories and the food production industry currently are forced to apply many different methods to reliably test raw material and complex processed food products. Screening methods have become more and more relevant to minimize the analytical effort and to make a preselection for further analysis (e.g., specific identification or quantification of the GMO). A multiplex real-time PCR kit was developed to detect the 35S promoter of the cauliflower mosaic virus, the terminator of the nopaline synthase gene of Agrobacterium tumefaciens, the 35S promoter from the figwort mosaic virus, and the bar gene of the soil bacterium Streptomyces hygroscopicus as the most widely used sequences in GMOs. The kit contains a second assay for the detection of plant-derived DNA to control the quality of the often processed and refined sample material. Additionally, the plant-specific assay comprises a homologous internal amplification control for inhibition control. The determined limits of detection for the five assays were 10 target copies/reaction. No amplification products were observed with DNAs of 26 bacterial species, 25 yeasts, 13 molds, and 41 not genetically modified plants. The specificity of the assays was further demonstrated to be 100% by the specific amplification of DNA derived from reference material from 22 genetically modified crops. The applicability of the kit in routine laboratory use was verified by testing of 50 spiked and unspiked food products. The herein described kit represents a simple and sensitive GMO screening method for the reliable detection of multiple GMO-specific target sequences in a multiplex real-time PCR reaction.     

Organogermanium polymers prepared from s‐indacene and carbodiimide compounds

The synthesis of bis‐organogermanium compounds including s‐indacene structure was described and showed the formation of one type of trans isomer characterized by spectroscopic methods. In the same way, the digermyl‐s‐indacene dichlorides were prepared and structural characterizations confirmed the unique formation of trans isomers. These digermyl‐s‐indacene dichlorides were used as monomers in a polymerization reaction in order to prepare poly(germyl‐s‐indacenes) and poly(germyl‐s‐indacene carbodiimides). However, only the products obtained from tetraalkyl‐s‐indacene reached high molecular weight, probably due to a minor steric hindrance compared to the hexaalkyl‐s‐indacene. Thermal degradation only starts from 250°C for poly(germyl‐s‐indacene carbodiimides) and from 350°C for poly(germyl‐s‐indacenes). The structures of the first digermyl‐s‐indacene dichlorides were determined by X‐ray analysis, confirming that the chlorogermyl groups are located in trans positions. Copyright © 2012 John Wiley & Sons, Ltd.     

Spatio-temporal organization in alloy electrodeposition: a morphochemical mathematical model and its experimental validation

This paper proposes a novel mathematical model for the formation of spatio-temporal patterns in electrodeposition. At variance with classical modelling approaches that are based on systems of reaction–diffusion equations just for chemical species, this model accounts for the coupling between surface morphology and surface composition as a means of understanding the formation of morphological patterns found in electroplating. The innovative version of the model described in this work contains an original, flexible and physically straightforward electrochemical source term, able to account for charge transfer and mass transport: adsorbate-induced effects on kinetic parameters are naturally incorporated in the adopted formalism. The relevant non-linear dynamics is investigated from both the analytical and numerical points of view. Mathematical modelling work is accompanied by an extensive, critical review of the literature on spatio-temporal pattern formation in alloy electrodeposition: published morphologies have been used as a benchmark for the validation of our model. Moreover, original experimental data are presented—and simulated with our model—on the formation of broken spiral patterns in Ni–P–W–Bi electrodeposition.     

The Lower Algebraic K -theory of Γ3

We explicitly compute the lower algebraic K-theory of Γ₃ a discrete subgroup of the group of isometries of hyperbolic 3-space. An erratum to this article is available at .