A century on from Dmitrii Mendeleev: tables and spirals,noble gases and Nobel prizes

Mendeleev’s failure to represent the periodic system as a continuum may have hidden from him the space for the noble gases. A spiral format might have revealed the significance of the wide gaps in atomic mass between his rows. Tables overemphasize the division of the sequence into ‘periods’ and blocks. Not only do spirals express the continuity; in addition they are more attractive visually. They also facilitate a new placing for hydrogen and the introduction of an ‘element of atomic number zero’.

Hermann Jahn and Rudolf Renner of the Jahn–Teller and Renner–Teller effects

Vibronic interactions have received increasing attention in modern structural chemistry. Edward Teller played a pioneering role in understanding and describing them during the “molecular physics” period of his scientific career. Very little is known about the two scientists who contributed significantly to our knowledge about these effects and whose names have become associated with Teller’s. This Editorial is devoted to Hermann Jahn and Rudolf Renner and attempts to lift them out of oblivion by paying them tribute for their contributions.

Metrology and protometrology: the ordinal question

Laboratory medicine provides results for quantities as well as for properties having no magnitude. The terminology of the latter is less well established and sources are contradictory. Two recent papers on “protometrology” published in this journal offer an opportunity to discuss the necessary concept systems. The delineations of “metrology” versus “protometrology”, “observation” versus “measurement”, and the generic division of “property” are examined with emphasis on avoiding conflict with the International Vocabulary of Metrology. It is suggested that having “examination” as a top generic concept coupled with systematic modifiers for division, especially ‘nominal’ and ‘ordinal’, is a preferable terminological solution.

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.

Interaction force diagrams: new insight into ligand-receptor binding

A method is described to calculate and visualize the interaction forces of ligand-receptor complexes. Starting from an X-ray crystallographic structure, a “thawing” procedure results in a force-field energy-minimized geometry which is close to the crystallographic starting point. By subtracting non-bonded interactions of the ligand with each amino acid residue and using the resulting force vectors to describe the slope of the remaining potential, two types of interaction force diagrams are created; the first shows the direction of the force vectors in 3D and the second shows the magnitude of the force vectors. The latter representation leads to definition of an ‘Interaction Force Fingerprint’ (IFFP) which is characteristic of the ligand-receptor binding. IFFPs are used to discuss ligand binding in the human estrogen receptors ERα and ERβ, and provide new insight into ligand selectivity between receptor isoforms. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Wilhelm Ostwald’s energetics 3: energetic theory and applications,part II

This is the third of a series of essays on the development and reception of Wilhelm Ostwald’s energetics. The first essay described the chemical origins of Ostwald’s interest in the energy concept and his motivations for seeking a comprehensive science of energy. The second essay and the present one discuss his various attempts, beginning in 1891 and extending over almost 3 years, to develop a consistent and coherent energetic theory. A final essay will consider reactions to this work and Ostwald’s replies, and will also seek to evaluate his program of research. Ostwald’s project—to reconstruct physics and chemistry “as a pure energetics”—is worth attending to for several reasons: first, because Ostwald did ground-breaking work in chemistry (he was awarded a Nobel Prize in 1909 for his studies in catalysis and rates of reaction); second, because an important school of physical chemistry formed around him at Leipzig, a school that promoted his ideas; and, finally, because he was a prominent and vigorous participant in debates at the end of the nineteenth century concerning the proper course of physical theory.

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.

In defence of the correlation coefficient

The relationship between calibrated range, residual standard deviation and correlation coefficient r is discussed. It is shown that in typical chemical calibration applications with appropriately distributed calibration points (particularly, with range comparable to mean and with approximately even or with ‘successive dilution’ spacing), the linear correlation coefficient has valid application as a routine criterion for acceptable fit if used with due care.

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.

The advent of chemical symbolism in the art of Sonya Rapoport

This paper explores the use of chemical symbolism in works by the new media artist Sonya Rapoport, with a focus on the pivotal Cobalt series from the late 1970s. These works, drawings on computer printouts generated by research at the Lawrence Berkeley Laboratory, respond to experiments in nuclear chemistry. They mark the beginning of three productive decades in which Rapoport produced a variety of images related to chemistry in her work. She states, “I looked for authentic research projects that were interesting to me, preferably with captivating pictorial subject matter. Then came the creative chaotic process of resolving a cohesive product that combined scientific research with art concept.” Rapoport had an unusual degree of access to scientific materials through her husband, organic chemist Henry Rapoport, a faculty member at the University of California, Berkeley. At the time of production, these works were outside mainstream art world interests and they have received little critical attention. This paper examines the development of Rapoport’s images and places her use of chemical references in context in her lifetime of work.

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”.

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 chemist’s concept of molecular structure

The concept of molecular structure is fundamental to the practice and understanding of chemistry, but the meaning of this term has evolved and is still evolving. The Born–Oppenheimer separation of electronic and nuclear motions lies at the heart of most modern quantum chemical models of molecular structure. While this separation introduces a great computational and practical simplification, it is neither essential to the conceptual formulation of molecular structure nor universally valid. Going beyond the Born–Oppenheimer approximation introduces new paradigms, bringing fresh insight into the chemistry of fluxional molecules, proteins, superconductors and macroscopic dielectrics, thus opening up new avenues for exploration. But it requires that our ideas of molecular structure need to evolve beyond simple ball-and-stick-type models.

Electron free energy levels in oxidic solutions: relating oxidation potentials in aqueous and non-aqueous systems

We provide background to the problem of describing the state of redox couples in different types of solvent media ranging from acidic aqueous solutions to high temperature molten silicates, pointing out the essential similarity between these solvent media in Lewis acid–base terms. We review the adaptation of the Gurney proton energy level diagram approach to the case of electron transfer processes. Using data from various spectroscopic and analytical chemistry sources, we review the construction of electron free energy level diagrams for redox couples in aqueous and non-aqueous systems using, as a common reference, the potential of the oxygen gas (1 atm)/oxide ion couple in the solution of interest. We emphasize the anomalous effect of “oxide ion activity” (mean ionic activity of alkali oxide) on the state of equilibrium and interpret this in terms of oxide ion transfers that accompany electron transfers. After showing the essential agreement between recent direct electrochemical assessments of the energy levels and those deduced in our original analysis of oxidic melts of different glass formers, we provide an interpretation of the apparent “oxide ion transfer” in terms of the differential medium polarization by the two redox species involved in the equilibrium. We anticipate the extension of these ideas to redox chemistry in the currently burgeoning field of “ionic liquids” in its recent ambient temperature liquid incarnation. Dedicated to the 85th birthday of John O’M. Bockris.

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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.

Atom and aether in nineteenth-century physical science

This paper suggests that the cases made for atoms and the aether in nineteenth-century physical science were analogous, with the implication that the case for the atom was less than compelling, since there is no aether. It is argued that atoms did not play a productive role in nineteenth-century chemistry any more than the aether did in physics. Atoms and molecules did eventually find an indispensable home in chemistry but by the time that they did so they were different kinds of entities to those figuring in the speculations of those natural philosophers who were atomists. Advances in nineteenth-century chemistry were a precondition for rather than the result of the productive introduction of atoms into chemistry.

Electrochemical studies and semiempirical calculations on π-conjugated dienones and heterocyclic nitrogen containing donor ligand molecules

Reduction potentials for the first electron transfer to a broad selection of nitrogen containing bi- and polydentate molecules considered as potential ligands have been determined. Results are compared with data obtained with semiempirical and UV-Vis spectroscopic data. Close correlations for the investigated molecules are observed. Systematic differences in properties of molecules with and without the keto moiety can be explained by invoking molecular orbital and surface interaction arguments. Similar structural arguments can be used to explain the behaviour of 2,4,6-tripyridin-2–yl[1,3,5]triazine. UV-Vis data match closely those derived from HOMO-LUMO calculations for these molecules.

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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Oligosaccharide analysis by graphitized carbon liquid chromatography–mass spectrometry

Structural analysis of complex mixtures of oligosaccharides using tandem mass spectrometry is regularly complicated by the presence of a multitude of structural isomers. Detailed structural analysis is, therefore, often achieved by combining oligosaccharide separation by HPLC with online electrospray ionization and mass spectrometric detection. A very popular and promising method for analysis of oligosaccharides, which is covered by this review, is graphitized carbon HPLC–ESI-MS. The oligosaccharides may be applied in native or reduced form, after labeling with a fluorescent tag, or in the permethylated form. Elution can be accomplished by aqueous organic solvent mixtures containing low concentrations of acids or volatile buffers; this enables online ESI-MS analysis in positive-ion or negative-ion mode. Importantly, graphitized carbon HPLC is often able to resolve many glycan isomers, which may then be analyzed individually by tandem mass spectrometry for structure elucidation. While graphitized carbon HPLC–MS for glycan analysis is still only applied by a limited number of groups, more users are expected to apply this method when databases which support structural assignment become available.

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.