Polyethylene Glycol as String for the Simultaneous Complexation of α-Cyclodextrin and Cucurbit[6]uril

α-Cyclodextrin and cucurbit[6]uril are macrocyclic ligands with nearly identical molecular properties. Both ligands possess nonpolar cavities with similar dimensions. They are able to include nonpolar molecules within their cavities. The main difference between both ligands is their solubility in water. An acceptable solubility for cucurbit[6]uril is only given in the presence of acids or salts. Due to the similarity of both ligands, the formation of mixed polyrotaxanes seems to be possible. The synthesis of statistically threaded α-cyclodextrin and cucurbit[6]uril on polyethylene glycol 2000 is verified using elemental analysis, ¹H-NMR spectroscopy and differential scanning calorimetry. Under the experimental conditions used the number of threaded α-cyclodextrin molecules is higher compared with cucurbit[6]uril. However it is shown that the formation of mixed complexes is possible.     

Disilberoxotellurat(VI), Ag2TeO4

Disilver Oxotellurate(VI), Ag₂TeO₄ Ag₂TeO₄ was synthesised by reaction of Ag₂O and TeO₂ applying an elevated oxygen pressure. According to a single crystal structure determination (C2/c, a = 9.0588(9), b = 9.2456(8), c = 13.623(1) Å, β = 91.758(8)°, Z = 12, 1289 independent reflections, R1 = 2.32 %, wR2 = 5.51 %), Ag₂TeO₄ contains a novel chain‐like polyanion with tellurium in an octahedral coordination. The TeO₆ octahedra are connected via common edges and vertices in a way that the resulting polyanion represents a section of the rutile structure type. Ag₂TeO₄ shows diamagnetic and insulating behaviour, it decomposes at 560 °C into Ag₂TeO₃ and oxygen.     

On the evaluation of spin–orbit coupling matrix elements in a spin‐adapted basis

In the present article, we outline a simple scheme for generating configuration interaction matrix elements for spin–orbit interactions in molecules. The procedure leads to a close parallelism with spin‐free permutation‐group approaches. Unitary shift operators were successfully used on the orbital space to generate the matching permutations necessary to evaluate the required matrix elements. The procedure is adequately illustrated using examples. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 23–27, 1999     

Natriumtrithiophosphat(V): Kristallstruktur und Natriumionenleitfähigkeit

Sodium Trithiophosphate(V): Crystal Structure and Sodium Ionic Conductivity Na₃POS₃ was synthesized from the corresponding hydrate by freeze‐drying. The crystal structure of Na₃POS₃ was determined using X‐ray and neutron powder data, and refined applying simultaneous Rietveld refinements of the neutron and X‐ray data (Cmc2₁, a = 9.5105(1), b = 11.5463(1), c = 5.9323(1)Å, R_p = 5.37 %, R_wp = 4.47 %). The barycenters of the POS₃ tetrahedra are arranged in the sense of a hexagonal close packing. The P—O bonds are oriented in a polar manner parallel to the c‐axis, and with the PS₃‐groups in an eclipsed mutual orientation. The structure of Na₃POS₃ is closely related (maximal subgroup) to the one of Ca₃CrN₃. Above 250 °C, Na₃POS₃ can be considered as a fast ionic conductor due to its throughout high conductivity.     

Convergence of multipole expanded intermolecular interaction energies for Gaussian-type-function and Slater-type-function basis sets

 It is shown that the multipole expansion of each order of the polarization series converges for large enough intermolecular distances when finite basis sets of Gaussian or Slater-type functions are used to approximate molecular response properties. Convergence of the multipole expansion for each order of the polarization series does not imply convergence of the polarization series itself. A corresponding convergence condition is extracted from the general perturbation theory in a finite-dimensional space and is applied to the H + H⁺ problem. Received: 29 September 1999 / Accepted: 22 May 2000 / Published online: 18 August 2000     

Controlled way to prepare quasi-1D nanostructures with complex chemical composition in porous anodic alumina

Herein we propose a novel approach to the preparation of quasi-1D nanostructures with various chemical compositions based on infiltration of colloidal solution into the asymmetric anodic alumina membrane. The proposed technique was successfully applied for the preparation of ordered arrays of the magnetically hard anisotropic hexaferrite nanostructures.     

Proton transport in a binary biomimetic solution revealed by molecular dynamics simulation

We report the simulation results of the proton transport in a binary mixture of amphiphilic tetramethylurea (TMU) molecules and water. We identify different mechanisms that either facilitate or retard the proton transport. The efficiency of these mechanisms depends on the TMU concentration. The overall picture is more complicated than a recent suggestion that the presence of amphiphilic molecules suppresses the proton mobility by slowing down the reorientation of the surrounding water molecules. It has also been suggested that the hydronium ion induces local water orientational order, which results in an ordered region that has to move along with the proton potentially slowing down the proton transport as suggested by experiment. We find that water-wire like structures formed at low amphiphile concentrations facilitate proton transfer, and reduction of the hydrogen bond connectivity induced at high concentrations retards it.     

New CO-CO interaction potential tested by rovibrational calculations

A four-dimensional potential energy surface (PES) for the CO dimer consisting of rigid molecules has been calculated, using a scheme that combines density functional theory to describe the monomers and symmetry adapted perturbation theory for the interaction energy (DFT-SAPT). The potential is fitted in terms of analytic functions, and the fitted potential is used to compute the lowest rovibrational states of the dimer. The quality of the PES is comparable to that of a previously published surface, which was calculated with the coupled cluster single double and perturbative triples [CCSD(T)] method. It is shown that a weighted average of the DFT-SAPT and the CCSD(T) potential gives results that are in very good agreement with experimental data, for both ((12)CO)(2) and ((13)CO)(2). The relative weight was determined by adjusting the energy gap between the origins of the lowest two stacks of rotational levels of ((12)CO)(2) to the measured value.     

Development and in-house validation of allergen-specific ELISA tests for the quantification of Dau c 1.01, Dau c 1.02 and Dau c 4 in carrot extracts (<Emphasis Type="Italic">Daucus carota</Emphasis>)

Even though carrot allergy is common in Europe, the amount of different allergens in carrots is still unknown due to a lack of methods for quantitative allergen measurements. The current study aimed at the development of quantitative ELISA tests for the known carrot allergens, namely Dau c 1.01, Dau c 1.02, and Dau c 4 in pure carrot extracts. Monoclonal antibodies targeting the major carrot allergen isoforms Dau c 1.01 and Dau c 1.02 were generated and combined in sandwich ELISA with rabbit antisera against Api g 1, the celery homologue of Dau c 1. A competitive ELISA for the carrot profilin Dau c 4 was based on a polyclonal rabbit antiserum. The three ELISA tests were allergen-specific and displayed detection limits between 0.4 and 6 ng allergen/ml of carrot extract. The mean coefficient of variation (CV) as a means of intraassay variability of the Dau c 1.01, Dau c 1.02 and Dau c 4 ELISA tests was 8.1%, 6.9%, and 11.9%, and the mean interassay CV 13.3%, 37.1% and 15.6%, respectively. Target recovery ranged between 93 and 113%. In conclusion, the specific, accurate and reproducible quantification of three important carrot allergens may help to identify less allergenic carrot varieties, as well as to standardize the amount of allergens in extracts used for carrot allergy diagnosis.