Hydrazones

Conclusions Study of the IR spectra, and theoretical and experimental values of the dipole moment, has shown that the nicotinoyl- and isonicotinoylhydrazones exist as mixtures of the EE'E and EE'Z rotational forms of the syn isomer in solution; the salicylide derivatives as mixtures of the EE'Z and EZ'Z forms. The EEE form is sterically hindered by the intramolecular hydrogen bonding.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 335–339, February, 1977.     

Determination of total,and bound Se in sera by INAA

In this study we report on the comparison between the total selenium in serum (total Se) with that which is apparently bound to high molecular weight (>12,000 D) species, presumably proteins (bound Se). Nine hundred seventy seven (977) serum samples arising out of a population-based epidemiological study were prepared in duplicate for the determination of total Se by pipeting directly into irradiation vials; and separate duplicate aliquots were dialyzed against DI water for the determination of bound Se. All samples were analyzed by neutron activation analysis via^77mSe (17.4 s). A small dialyzable Se component (6%) (free Se), defined as the difference between the total Se minus the bound Se, was identified.     

Macromolecular conformations at the water-air interface: Interactions between alpha and beta conformations of polypeptides

Bidimensional miscibility between alpha and beta conformations of polypeptides was investigated at the water-air interface in the 15°–30°C temperature range. The polypeptides were poly--methyl-L-glutamate (PGMG), poly--benzyl-L-glutamate (PGBG) and poly--benzyl-L-aspartate (PBBA). The polypeptide conformations, alpha or beta, were checked by IR spectroscopy using the MIR technique.The spreading isotherms for mixed monolayers alpha-PGMG/alpha-PGBG and beta-PGMG/beta-PBBA showed bidimensional miscibility both for alpha-alpha and beta-beta mixtures.For the alpha-alpha system, attractive interactions among the polypeptide alphahelices were found (G_mix<0) and the driving factor appeared to be the entropic one (packing). Compressibility moduli and surface potential measurements showed a fluidification effect of alpha-PGBG on mixed monolayers. In the case of beta-beta mixed monolayers, ideal behaviour was observed and no fluidification effect detected.Scanning electron micrographs made on collapsed monolayers showed hexagonal structures for alpha-alpha mixtures and no well-defined or characterized features for the beta-beta system.     

Chromogenic Receptors: Versatility of the Colorimetric Recognizing Behavior

This article briefly reviews our recent achievement in developing synthetic chromogenic receptors which are characterized by combining recognition and optical sensing functions; synthesis of several kinds of azomethine-derived calixarenes is described, as well as some colorimetric recognizing behavior for chemically or biologically significant guests ranging from cations to chiral amine derivatives.     

Analyses of hazardous substances in biological materials

Summary The interest of the Commission for the Investigation of Health Hazards of Chemical Compounds in Work Area of the German Science Foundation in practical, sensitive and specific methods for monitoring the limit values led to the establishment of the working group Analytical Chemistry in 1969. A loose-leaf collection Analysen in biologischem Material and 3 volumes of an English edition have since been published. In the meantime the German edition of Analyses in biological materials has been supplemented ten times, including 100 methods for the measurement of about 170 parameters; the English edition is in 3 volumes with 45 selected methods. The volumes include only standard operational procedures that are suitable for routine use. The reliability of the analytical procedures is defined and checked for these reasons and because they satisfy the requirements of statistical quality control. The analytical methods published by the Working Group Analytical Chemistry are recommended by pertinent guidelines and regulations for use in Germany.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Interplay of Thermochemistry and Structural Chemistry,the Journal (Volume 13, 2002) and the Discipline

As practiced disciplines, structural chemistry and thermochemistry need not be related. In the current study they are: the contents of the journal Structural Chemistry (Vol. 13) for the year 2002 have been reviewed and then most articles that appeared therein were given a thermochemical commentary, spin or slant.     

Zur Frage des Einsatzes ionenspezifischer Elektroden in der Automation

Zusammenfassung Es wurden Untersuchungen mit anionenspezifischen Membranelektroden nach Pungor durchgeführt. Dazu werden Reproduzierbarkeit, Eichfunktion, Einstellzeiten bei auf- und absteigender Konzentration und Querempfindlichkeit im Hinblick auf den Einsatz in automatischen Systemen behandelt. Es wird vorgeschlagen, für die Angabe der Selektivität einen p-Sel analog zum pH zu verwenden, die Behandlung eines Analysensensorsystems wird vorgenommen.

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On the use of ion-specific electrodes in automation

Investigations on anion-specific membrane electrodes are described. Problems of reproducibility, calibration, time-response in respect of in- and decreasing concentrations and sensitivity to interfering ions are demonstrated and discussed with regard to automation. It is proposed to define a p-sel for the selectivity constant analogue to pH and a calculation method for an Analysis-Sensor-System is shown.

     

A variational coupled cluster theory for closed shells using a propagator modification procedure

A general partial summation method for including arbitrary classes of diagrams to all orders in the coupled cluster based size consistent energy functional for closed shell states is developed. Since the various reduced density matrices which appear in the energy functional are essentially the time-independent analogues of the corresponding many body Green functions, it is possible to derive Dyson-like equations for these quantities. By expanding the associated proper self energy parts in terms of the T-amplitudes, one can carry out partial summations in the reduced density matrices and thus in energy. At a higher level, higher order terms in a proper self energy can also be generated by renormalizing the internal propagators in it, and considering only the irreducible self-energy terms.     

Synthese höherkondensierter Ringsysteme durch intermolekulare Dehydrierung verschiedener Moleküle unter Verknüpfung und Ringschluß.

Zusammenfassung Es wird gezeigt, daß demClarschen Terrylen eine andere Struktur zukommen dürfte und sein Dibromterrylen ein KW, vermutlich das Quaterrylen ist.Mit 3 Abbildungen.     

Computer-aided library search of combined LC-Retention and diode-array-UV-spectral data

An automated library search system for computer-aided identification of organic compounds using combined UV-spectral and LC-retention data, as acquired by HPLC with linear diodearray-UV-detection, is presented.The keystone of the system is a set of similarity indices which have been developed on the basis of mathematical-statistical models of the reproducibility of the spectral and retention data. The similarity indices have the form of a significance probability, a quantity originating from the general theory of hypothesis testing. The output of the LC-UV retrieval system is a compound identity or a list of identities (if any) for which the relevant similarity index has a value above a preset threshold. The data base used in this investigation contained 186 sets of UV-spectral and LC-retention data of 74 organophosphorus pesticides measured from standard solutions under various experimental conditions. A test set consisted of 186 alternative data sets of the same compounds as contained in the data base, however measured under different experimental conditions. The performance of the LC-UV reproducibility-based retrieval (LUVRR) system was evaluated using recall/reliability plots. The results appeared to be quite promising: for 95% of the unknowns, the target reference (correct positive) was on top of the hit list with a similarity index value being significantly higher than values found for false positives.The software is written in Pascal. The present (experimental) version of the system runs on a Data General Eclipse MV/4000 minicomputer.     

Von den unabhängigen Reaktionen

Zusammenfassung Es wird der Begriff derunabhängigen Reaktionen dargelegt, die chemische und mathematische Methode der Ermittlung dieser Reaktionen dargetan und auf ihre Bedeutung verwiesen.     

The principle of increasing mixing character and some of its consequences

The Principle of Increasing Mixing Character, previously postulated by one of us (and derived for the case of an ensemble of isolated systems obeying a master equation) as a stronger version of the second law of thermodynamics, is re-derived using von Neumann's density matrix formulation of statistical mechanics. To make the principle more convenient for applications, it is reformulated in terms of Mixing Homomorphic Functions, a set of state functions all of which must increase in an allowed irreversible process in an-isolated system. The entropy is one such function, but no one function, and no finite set of functions, suffices to determine the increase of mixing character. The principle is extended to the case of a system which is not isolated, but in contact with a heat bath, for which it takes a form which we name the Principle of Decreasing Mixing Distance from the equilibrium distribution. As examples, applications are made to two simple cases: diffusion in an ideal solution, and chemical reactions in ideal gas mixtures.     

State-of-the-art in organic elemental micro and ultramicro analysis

Summary Nernst developed a quartz torsion microbalance in 1903. In consequence of this pioneering work, Emich in the Technical University of Graz, Austria, had systematized a series of chemical operations in microscale as well as a microchemical analysis. Further advances in technique and method of organic microanalysis had been accomplished by Pregl in Graz in 1912. His work had been strongly supported by a new microbalance which was known as Kuhlmann microbalance. Pregl's original methods of analysis were arranged and published in 1916 as Die quantitative organische Mikroanalyse. It is still noteable that the Nobel prize of 1933 had been presented to Dr. Pregl. In accordance with a combination of electronic microbalance and computer techniques, organic elemental microanalysis has grown to include advanced instrumentation and on-line computation. Successful adaptation of microchemical analysis has expanded today not only to pure organic compounds, but on industrial intermediates, polymers, food additives and many other compositions. The paper includes a discussion of the relative merits of traditional and modern analytical techniques together with the progression of microbalances. Recent developments in organic micro and ultramicro analysis in Japan are also described.     

Transverse photothermal deflection spectroscopy (PDS) applied to thermal diffusiyity measurements

Transverse photothermal deflection spectroscopy(PDS) is applied for the determination of thermal diffusivities of solid surfaces. The theory of PDS is briefly recalled and some approximated analytical formulae concerning the transverse configuration are derived. In materials where the thermal diffusivity is smaller than that of the air, the dependence of the deflection angle on the displacement between pump and probe beams is shown to have a minimum that relates to the thermal diffusivity, thereby allowing its straightforward measurement. Measurements carried out on Al₂O₃ samples with different porosities at room temperature show a good agreement between experiment and theory.

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Zusammenfassung Die transverse photothermische Reflektionsspektroskopie (PDS) wird zur Bestimmung der thermischen Diffusivität von festen Oberflächen herangezogen. Die Theorie der PDS wird kurz dargelegt und einige sich auf die transverse Konfiguration beziehenden analytischen Näherungsgleichungen abgeleitet. Es wird gezeigt, daß bei Materialien mit kleinerer thermischer Diffusivität als Luft die Abhängigkeit des Deflektionswinkels von der Ablenkung zwischen Pumpen- und Probenstrahl ein Minimum aufweist, das mit der thermischen Diffusivität im Zusammenhang steht und somit deren zuverlässige Messung ermöglicht. An Al₂O₃-Proben unterschiedlicher Porosität bei Raumtemperatur ausgeführte Messungen zeigen gute Übereinstimmung von Experiment und Theorie.

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. , . , , , , . , , .

     

The time evolution of the pair distribution function of polymeric systems

Summary The stress tensor of a polymeric system, solution or melt, is the sum of single molecule terms which may be expressed as integrals involving the distribution function in the phase space of a single molecule and intermolecular terms which involve the distribution function in the configuration space of pairs of molecules. The evaluation of the single molecule terms is usually based on the solution of the diffusion equation in the configuration space of a single molecule. In the present development, an analogous diffusion equation in the configuration space of a pair of molecules is developed. The development is based on a generalization of the time-smoothing ideas introduced by Kirkwood. Expressions are obtained for the various friction coefficients as time correlation functions.     

Structural Transformations in Polydisperse Ferrofluids

Real polydisperse ferrofluid is modeled by a bidispersed magnetic colloid composed of large and small particles. It is assumed that the energy of magnetodipole interaction for small particles is much lower and that of large particles is substantially higher than their thermal energy. Therefore, large particles can combine into the chain and droplet aggregates that are present in a sea of small particles. The influence of small particles on the structurization in the ensemble of large particles is studied. It is shown that small particles can either prevent or stimulate these structural transformations depending on the parameters of a medium.     

Preparation of La(OH)3 colloids and tactoid structures

Summary Lanthanum(III) hydroxide colloids have been prepared by in situ and repeptization method. The in situ colloids were aggregated in schiller layers. The formation of the sol is a relatively slow process which accounts for a good uniformity of the particles size. The characteristic lateral array of the colloidal particles in Schiller layers could be destroyed by simple shaking the sample. Lanthanum(III)hydroxide sols prepared by the repeptization method were needle-shaped and not tactoidally orientated.

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Zusammenfassung Lanthan(III)hydroxid-Kolloide wurden in situ und durch Repeptisation hergestellt. Eine regelmäßige Aggregation der Kolloidteilchen wurde nur bei in situ bereiteten Solen beobachtet (SchillerSchichten). Die Bildung der Sole ist ein verhältnismäßig langsamer Prozeß, was mit der ziemlich engen Verteilung der Teilchengr6ßen zusammenhängen k6nnte. Die Schiller-Schichten werden durch Schütteln zerstört. Ein durch Repeptisation gebildetes Lanthan (III)hydroxid war nadelförmig ausgebildet und nicht taktoidal aggregiert.

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With 5 figures

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*) Our thanks are due to Dr. N. LjubeN for the electron microscopy work.     

Hot atom chemistry of mixed cristals 35 years of research

A historical survey of the author's contribution to the progress of solid state hot atom chemistry including more personal commentaries is presented.Presented at the International Seminar on the Chemistry of High Energy Atoms, Tokyo Institute of Technology, Ookayama, Meguro-ko, Tokyo 152, Japan, October 28–30, 1992, organised by T. MATSUURA, Institute for Atomic Energy, Rikkyo University, Nagasaka, Yokosuka 240-01, co-editor of the Handbook of Hot Atom Chemistry. I thank Professor MATSUURA for the permission to publish my contribution to the seminar slightly modified compared with the version submitted in the seminar proceedings.     

The diagram lattice as structural principle A. New aspects for representations and group algebra of the symmetric group B. Definition of classification character,mixing character,statistical order,statistical disorder; A general principle for the time evolution of irreversible processes

It is the aim of this paper to demonstrate the significance of the diagram lattice. This lattice was defined in order to achieve structural insight into the phenomenon of chirality in chemistry. In this context, Theorie der Chiralitätsfunktionen [1] may serve as reference. In the introduction of the present paper a summary of the relevant theorems and definitions is given and a few examples of the diagram lattice are graphically illustrated. Parts A and B can be read independently and presuppose knowledge only of the introduction. Part A is of special interest for mathematicians, Part B and [1] for physicists and chemists.In Part A theorems on the representations of the group _n and certain subgroups of it and on the structure of the group algebra are developed. In Part B the concept classification character with the two complementary aspects of identification and distinction is derived. With the interpretation mixing character the partial order relation gains an interpretation through a mixing process, which can be expressed by a bistochastic matrix. This results in another equivalent definition of the diagram lattice. Interpreted as mixing character of a statistical distribution a diagram represents statistical order and statistical disorder by its row partition and column partition respectively. These concepts and the corresponding lattice structure lead to the hypothesis of growing mixing character as a criterion for the time evolution of isolated systems. The criterion of increasing entropy provides a much weaker condition. A discussion of the master equation leads to a proof of the principle of growing mixing character.[/p]