Do we need to rethink collaborative trials?

The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would be more informative.

A note on Michael Weisberg’s: challenges to the structural conception of chemical bonding

Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is in trouble. This note casts doubts on that claim.

Chemistry, commentary, and community: discussion of “an examination of the vaporization enthalpies and vapor pressures of pyrazine, pyrimidine, pyridazine, and 1,3,5-triazine” by Lipkind and Chickos

Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation techniques. It is suggested that pyridazine shows enigmatic behavior.

A novel Ce<Superscript>III</Superscript>-cyclam type complex and its redox chemistry in aqueous solutions

A new Ce^III complex was synthesized by mixing the ligand “dioxocyclam” with Ce^III ions at pH 8.0 and its redox properties were investigated.

Operating ‘cost’ characteristics in sampling by variable and attribute

A discussion in economic terms of common rules in conformity assessment based on measurement is given. The present work extends tools of sampling when using inspection by variable and attribute, such as the setting of acceptance quality limits (AQL) and limiting quality limits (LQL), by including an economic decision theory approach, leading, amongst other things, to a new ‘cost’ curve as a complement to the traditional operating characteristic curves of statistical significance testing. The methodology is of general applicability but is illustrated in the present work in the simple case of homogeneously pre-packaged goods priced linearly with the amount of content. The relation to the optimised uncertainty methodology is explained. Optimum strategies for the supplier are illustrated in terms of minimising production and testing costs, while at the same time maintaining satisfactory levels of customer satisfaction.

Encapsulating of single quantum dots into polymer particles

Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μm by an emulsion polymerization procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation, as demonstrated by fluorescence confocal microscopy.

The meaning of ‘concentration’

Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings of “concentration” are explored to present a systematic nomenclature, including a concept diagram.

Food anaphylaxis

    Figure Avoidance is the primary measure in food allergy confirmed

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Electrochemical studies of bi- and polymetallic complexes featuring acetylide based bridging ligands

Acetylide-based bridging ligands have been widely used in the preparation of complexes that display a degree of electronic interaction between metal-based redox groups located at the ligand termini. The electrochemical response of these systems has been selectively reviewed, with a focus on the variation in properties that accompany changes in the structure of the bridging ligand and the nature of the metal groups.

Paneth, Kant, and the philosophy of chemistry

Immanuel Kant has built up a dualistic epistemology that seems to fit to the peculiarities of chemistry quite well. Friedrich Paneth used Kant’s concept and characterised simple and basic substances which refer to the empirical and to the transcendental world, respectively. This paper takes account of the Kantian influences in Paneth’s philosophy of chemistry, and discusses pertinent topics, like observables, atomism and realism.

Core-shell structured electrode materials for lithium ion batteries

Recent progress in studies of several types of core-shell structured electrode materials, including TiO₂/C, Si/C, Si/SiO _x , LiCoO₂/C, and LiFePO₄/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.

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Kinetics of substitution at [tris(3,5-dimethylpyrazolyl)-hydroborato]molybdenum nitrosyl dihalides by alcohols and by aniline

The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure are reported and interpreted in terms of an associative mechanism.

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Hydrogen evolution and oxidation—a prototype for an electrocatalytic reaction

Due to progress in the theory of electrocatalysis and in quantum chemistry, it has become possible to investigate the hydrogen reaction and perform quantitative calculations for the reaction rate. First, we demonstrate this with model calculations for the adsorption of hydrogen on Pt(111). In accordance with experimental data, we find hydrogen adsorption at a potential above the equilibrium potential and with an almost vanishing energy of activation. As a second example, we explain trends in the catalytic activity of palladium overlayers and clusters on Au(111) electrodes. Dedicated to J.O’M. Bockris on the occasion of his 85th birthday and in recognition of his contributions to electrochemistry.

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Preparation, structural, and optical features of two-dimensional cross-linked DNA/gold-nanoparticle conjugates

The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.

Core-shell effects of functionalized oxide nanoparticles inside long-range meso-ordered spray-dried silica spheres

Core-shell and homogeneous distributions of functionalized cerium oxide nanoparticles within spray-dried mesostructured silica spheres are achieved by modification of synthesis parameters such as the templating agent and nanoparticle capping functions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Modeling of solvent viscosity effects on the electroreduction of Pt(II) aquachlorocomplexes

Solvent dynamics effects on the electroreduction of [PtCl₃(H₂O)]⁻ at a mercury electrode are explored in the framework of Sumi–Marcus model using an efficient computational scheme. According to results of density functional calculations, the second electron transfer step may be regarded as rate controlling. The nonmonotonous influence of solvent viscosity on the reaction rate is predicted and explained in terms of the saddle point avoidance. The results of model calculations are employed to interpret experimental data reported earlier in the literature.

Stress generation and fracture in lithium insertion materials

A mathematical model that calculates volume expansion and contraction and concentration and stress profiles during lithium insertion into and extraction from a spherical particle of electrode material has been developed. The maximum stress in the particle has been determined as a function of dimensionless current, which includes the charge rate, particle size, and diffusion coefficient. The effects of pressure-driven diffusion and nonideal interactions between the lithium and host material have also been described. The model predicts that carbonaceous particles will fracture in high-power applications such as hybrid-electric vehicle batteries.

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NMR and HPLC study of chiral selectors with naphthyl unit

Doubling of resonances in NMR spectra of chiral selectors with naphthyl group attached to the tertiary amide nitrogen atom has been noticed what revealed the presence of two isomers. To test the enantiorecognition ability of these chiral selectors they are covalently bonded to the HPLC silica gel. Those kind of chiral stationary phases were compared with analogous commercial leucine chiral stationary phase. They exhibit the better enantioseparation results which indicate that the existence of cis/trans isomers does not have the negative influence on their enantioselective ability.

Chemistry,commentary and community: Discussion of “The NaDyBr<Subscript>4</Subscript> complex: its molecular structure and thermodynamic properties” by Varga and Hargittai

The molecular geometries, relative stabilities, binding energies, and dissociation energies of NaDyBr₄ and its molecular ion are discussed. Both the bidentate and tridentate isomers are stable for the neutral species, while only the bidentate form is stable for NaDyBr₄ ⁺.

Vocabulary of terms in protometrology

Protometrology is a new term recently proposed to designate the science of observation. As any field of knowledge needs a terminological system, in this article a system of terms and definitions on protometrology, with examples belonging to clinical laboratory sciences, is presented. This terminological system starts with the definitions of the two primitive concepts “object” and “property”.