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.     

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.     

Thermal analysis of macromolecules

This review traces the development of thermal analysis over the last 40 years as it was experienced and contributed to by the author. The article touches upon the beginning of calorimetry and thermal analysis of polymers, the development of differential scanning calorimetry (DSC), single run DSC and other special instrumentations, up to the recent addition of modulation to calorimetry. Many new words and phrases have been introduced to the field by the author and his students, leaving a trail of the varied interests one can have over 40 years. It began with cold crystallization and most recently the term oriented, intermediate phase was coined, creating in-between: extended chain crystals, the irreversible thermodynamics of melting of polymer crystals, dynamic differential thermal analysis (DDTA), the rule of constant increase ofC _p per mobile bead within a molecule at the glass transition temperature, superheating of polymer crystals, melting kinetics, crystallization during polymerization, the chain-folding principle, molecular nucleation, rigid amorphous phase, a system of classifying molecules, macroconformations, amorphous defects, rules for the entropy of fusion based on molecular shape and flexibility, single-molecule single-crystals, a system of classifying phases and mesophases, and condis phase.First and foremost I would like to acknowledge the unwavering support through my wife, Heidel, without whom many of the projects simply could not have been completed. Similarly, our children had to grow up knowing that often research and teaching had to take precedence. Without coworkers, little could have been accomplished. Of the about 120 postdoctoral fellows, graduate students, and technicians, most of whom contributed to the listed references, and many have participated on their own in this issue, goes my thanks for the bulk of the scientific work. Many friends and colleagues contributed with discussion and constructive criticism, some of them have also contributed in this collection of papers related to thermal analysis. Little work can be done without this interplay of ideas. The limited space has not permitted to give a full appreciation of the importance of the ideas drawn from the literature. These thousands of additional references can be found in the initial papers and reviews of the subjects treated.Material support was received from the three major instrument companies for thermal analysis equipment: TA Instruments, Inc.; Perkin-Elmer Corp.; and Mettler-Toledo, Inc. Without this help we would not always have been able to be at the forefront of instrumentation. Major financial support for the research came from outside the universities. I estimate that over the 40 years about 4 Megadollars were spent by government agencies, companies, and private foundations to support coworkers, myself during the summers, research equipment, expenses, and travel. A large amount of money, but not too much if one compares it to typical expenditures in the field of athletics (about 10 k$ per paper). Major sustained funding came from the Advanced Projects Agency (ARPA), the Office of Naval Research (ONR), the National Aeronautics and Space Agency (NASA), the Department of Energy (DOE), and, most prominently, the National Science Foundation (NSF). At present our work is supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, U.S. Department of Energy, under Contract DE-AC05-84OR21400 with Lockheed Martin Energy Systems, Inc. Industrial support is presently given by TA Instruments, Inc; ICI Paints; Exxon Res. and Eng. Co.; Shell Development Co.; Toray Research Center; and Mettler-Toledo, Inc.Last, but by no means least, I would like to thank Dr. E. Turi for the invitation to write this paper and for her untiring effort to entice so many of my students and friends to contribute to this issue of the Journal of Thermal Analysis.     

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.     

Experimental study of the bifurcation diagram in the Belousov-Zhabotinskii reaction

In the citric acid-Mn²⁺–H₂SO₄–KBrO₃ system a hysteresis phenomenon in the switching on and off of the oscillations has been observed. The possible bifurcation diagrams of the system are discussed.

---

-Mn⁺²–H₂SO₄–KBrO₃ . .

     

Relative enthalpies and related thermodynamic functions of some organic compounds by drop calorimetry

The values of thermodynamic functions of the following eight organic compounds under non-reacting conditions within the temperature range 298.15 – 550 K are given: N,N dimethylformamide, CHO · N(CH₃)₂; 4-nitro-1-chlorobenzene, Cl · C₆H₄ · NO₂; sodiump-nitrophenoxide, NO₂ · C₆H₄ · ONa; 1-methyl-2-pyrrolidone, 4,4-dinitrodiphenyl ether, (NO₂ · C₆H₄)₂O; 4,4-diaminodiphenyl ether, (NH₂ · C₆H₄)₂O; bis-(4-aminophenyl)methane, (NH₂ · C₆H₄)₂CH₂; bis(4-maleic acidimidphenyl)methane, The relative enthalpy was obtained from calorimetric data by drop calorimetry. The heat capacity and relative entropy are functions derived from the foregoing. The equations of the temperature variation of the relative enthalphy were obtained by computer processing of the calorimetric data by the least squares method. The parameters of solid-liquid transitions were determined from the discontinuity of the temperature variation of the relative enthalpy.

---

Zusamenfassung Die Werte der thermodynamischen Funktionen folgender 8 organischer Verbindungen werden unter nicht-reagierenden Bedingungen im Temperaturbereich von 298.15 bis 550 K angegeben: Dimethylformamid, CHO · N(CH₃)₂;p-Nitrochlorbenzol, Cl · C₆H₄NO₂; Natrium-p-Nitrophenoxid, NO₂ · C₆H₄ONa; N-Methylpyrrolidon, 4-4-Dinitrodiphenyläther, (NO₂ · C₆H₄)₂O; 4-4-Diaminodiphenyläther, (NH₂C₆H₄)₂O; 4-- 4-Diaminodiphenylmethan, (NH₂ · C₆H₄)₂CH₂; 4-4-bis-Maleinimid-Diphenylmethan, Die relative Enthalpie wird aus kalorimetrischen Daten der Temperaturgefällekalorimetrie erhalten. Die Wärmekapazität und die relative Entropie sind Funktionen der erwähnten Werte. Die Gleichungen der Temperaturänderung der relativen Enthalpie wurden mittels Computerverarbeitung der kalorimetrischen Daten, mit der Methode der kleinsten Quadrate erhalten. Die Parameter der fest-flüssig Übergänge wurden an Hand der Diskontinuität der Temperaturänderung der relativen Enthalpie bestimmt.

---

Résumé On donne les valeurs des fonctions thermodynamiques des 8 composés organiques suivants, en conditions non réactionnelles, dans l'intervalle de températures 298.15–550 K: diméthylformamide CHO · N(CH₃)₂,p-nitrochlorobenzène Cl · C₆H₄ · NO₂,p-nitrophé noxysodium NO₂ · C₆H₄ · ONa, N-méthylpyrrolidone dinitrodiphényl-4,4 éther (NO₂ · C₆H₄)₂O, diaminodiphényl-4,4 méthane (NH₂ ·H ₄CH₂, 4-4 bis maléinimide diphénylméthane L'enthalpie relative a été obtenue à partir de données calorimétriques fournies par un calorimètre à chute. La chaleur spécifique et l'entropie relative sont des fonction dérivées de la précédente. Les équations donnant la variation de l'enthalpie relative en fonction de la température sont obtenues par traitement des données calorimétriques sur ordinateur par la méthode des moindres carrés. Les paramètres des transitions solide-liquide ont été déterminés à partir de la discontinuité de la variation de l'enthalpie relative avec la température.

---

, 298,15–550 , : — · N(CH₃)₂;- — l · ₆₄ · NO₂.- -NO₂·₆₄·ONa; N-—₃·N··₂·₂₂; 4,4- — (NO₂·₆₄)₂; 4,4- — (NH₂·₆₄)₂; 4,4- — (NH₂·₆₄)₂₂; 4,4-- —(₆₄.N. . :. )₂₂. . , . . - .

     

Activation of magnesia by hydrogen spillover

Magnesia aerogel activated by hydrogen spillover at 430 °C or at 200 °C becomes a catalyst for the hydrogenation of ethylene. This catalytic activity, observed already at 50 °C, is further enhanced by a treatment in oxygen at 430 °C.

---

, 430 200°C, . 50°C 430°C.

     

Contribution a l'etude des associations aminophenazone-uree aminophenazone-thiouree et aminophenazone-noxythioline

The phase diagrams for aminophenazone-urea (a), aminophenazone-thiourea (b) and aminophenazone-noxythioline (c), established by differential scanning calorimetry, transparency method and thermomicroscopy, revealed the presence of definite compounds (1–3). These compounds are formed during eutectic fusion for (a) and (c); the definite compound for (b) displays non-congruent fusion.

---

Zusammenfassung Aus den durch DSC ermittelten Phasendiagrammen für Aminophenazon-Harnstoff (a), Aminophenazon-Thioharnstoff (b) und Aminophenazon-Noxythiolin (c) sowie durch die Transparenzmethode und Thermomikroskopie wurde die Existenz der definierten Verbindungen (1–3) nachgewiesen. Diese Verbindungen werden im Falle von (a) und (c) in eutektischen Schmelzen gebildet. Die definierte Verbindung für (b) schmilzt nicht-kongruent.

---

- (a), - () - (), , , . ((a)) (), () .

     

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.

---

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.

     

Aryloxydihydropyrans. XII. Configuration and conformations of 8-(3,4-dihydro-2-pyranyloxy)quinoline derivatives

The configuration and conformations of stereoisomeric 4R-8-(3,4-dihydro-2-pyranyloxy)quinolines were studied by means of their PMR spectra. It was established that the trans isomers of the investigated compounds have primarily a half-chair conformation and display an anomeric effect. A sofa conformation is proposed for the labile cis isomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 607–610, May, 1976.     

Leitfähigkeitsmessungen in Phosphoroxychlorid, 3. Mitt. Triäthylamin

Zusammenfassung Am Beispiel des Triäthylamins wird das Leitfähigkeitsverhalten eines gekoppelten Dissoziationsgleichgewichtes mit nichtleitender Zwischenstufe (ABC⁺+D^–) untersucht.Mit 3 AbbildungenZugleich 14. Mitteilung der Reihe: Das Solvosystem Phosphoroxychlorid.2. Mitt:M. Baaz undV. Gutmann, Mh. Chem.90, 256 (1959).     

Zero-Dimensional Nanodots on One-Dimensional Nanowires: Reductive Deposition of Metal Nanoparticles on Silicon Nanowires

We review herein the surface chemical properties of silicon nanowires (SiNWs) and show how SiNWs can be used as platforms in doing chemistry in the nanorealm. In particular, the surfaces of HF-treated SiNWs (which are H-terminated) exhibit interesting chemical reactivities towards reductive deposition of metal ions such as silver, copper, palladium, etc., giving rise to metal particles or aggregates on the SiNW surfaces. By varying the concentration of the metal ions in solution, nanostructures of these metals of different shapes, sizes, and morphologies can be fabricated. The reductive growth of ligated Au–Ag clusters of single size, shape, composition, and structure, on the SiNWs was also investigated. Two interesting phenomena, the sinking cluster and the cluster fusion processes, were observed by TEM. These assemblies of metal nanoparticles on silicon nanowires may be considered as zero-dimensional nanodots, on one-dimensional nanowires. It is hoped that fabrication of these metallic nanodots on silicon nanowires will lead to new and novel composite materials of importance in nanotechnology.     

On stochastic models of solid-state reactions

The Avrami model of solid-state reactions or transformations has frequently been presented and compared with other stochastic models. The equation often applied is shown to be merely a simplification of the full Avrami model equation (FAME). A convenient procedure for application of the FAME to the kinetics of solid-state reactions is proposed.

---

Zusammenfassung Das Avrami'sche Modell von Festkörperreaktionen wurde häufig dargestellt und mit anderen stochastischen Modellen verglichen. Hier wird gezeigt, dass die häufig verwendete Gleichung eine Vereinfachung der Vollständigen Avrami'schen Modellgleichung (FAME) darstellt. Die Anwendung der FAME auf die Kinetik von Festkörperreaktionen wird vorgeschlagen und eine geeignete Verfahrensweise empfohlen.

---

, . , . , .

     

A constitutional diagram of the system VC0.88−HfC0.98−(MoC)

The system VC_0.88–HfC_0.98–MoC was investigated by means of melting point, differential-thermoanalytical, X-ray diffraction and metallographic techniques on hot pressed and heat treated as well as melted alloy specimens and a constitutional diagram from 1500°C through the melting range established.The small miscibility gap within the HfC–MoC system (T _c=1630°C) interacts at lower temperatures with the solvus in a monotectoid-like reaction at 1575°C. Additions of VC to the HfC–MoC solid solution gradually increase its critical temperature.Solid state phase behaviour and melting behaviour was established within the isopleths VC_0.88–MoC as well as within (V_0.5Hf_0.5)C–MoC and (V_0.75Hf_0.25)C–(Hf_0.75Mo_0.25)C.Phase equilibria within VC_0.88–HfC–MoC are characterized by an extreme large miscibility gap at 1500°C connecting the VC–HfC and HfC–MoC systems.Originating at the VC–HfC binary an eutectic trough proceeds into the VC–HfC–MoC ternary with rising temperatures, connecting the maximum critical point of the disappearing miscibility gap [(V_0.31Hf_0.49Mo_0.20)C] by a limiting tie line (2750±20°C). Isothermal sections have been calculated assuming regular solutions.With 5 Figures     

Metal concentrations in scleractinean corals determined by instrumental neutron activation analysis and atomic absorption spectrometry

Five species of scleractinean corals, extracted from the Northern Havana reef, were studied by INAA and AAS. Selected specimens were sectioned in foot, center and head parts before pulverization procedure. INAA for different irradiation and decay time regimes in a reactor allowed the determination of: Na, Mg, Al, Cl, Sc, Cr, Co, Th, Lu, Eu, Ce, Hf, La and Sr. AAS was performed in a Pye Unicam Model 929 spectrometer. Cu, Mn, Ni, Zn, and Fe were detected. Ca concentration in all species was also established. Obtained Metal-Calcium ratios for Sr, Cu, Zn, Cr, Co, Fe, Mn, Ni and Sc are compared with reported values.     

Particle size determination of platinum, palladium and rhodium

Simple and sufficiently accurate equations are suggested for calculating the particle size of most frequently used supported or unsupported platinum metal catalysts from the amount of chemisorbed gas.

---

, .

     

Non-exchangeable organically bound tritium (OBT): its real nature

Denaturation experiments show that the larger part of organically bound tritium (OBT) consists of buried tritium and is not bound to carbon, as has been traditionally assumed. The logistical growth analysis of hydrogen isotopes in dry plant matter reveals a larger rate of increase of OBT than organically bound hydrogen (OBH). This is reflected by tritium accumulation for 1.4 and 2 in the primary hydration shell and in the base-pairing hydrogens of DNA respectively. If tritons and protons are considered as quantum mechanical entities, the accumulative tritium transfer from water to the hydrogen bonds of biopolymers is generally valid. Growth experiments confirm the assumed rapid isotope exchange in vivo, which is not observed in vitro by denaturation.     

Chromium (III) trihalide complexes of 4-aminobenzophenone

Summary The following chromium(III) complexes of 4-aminobenzophenone have been prepared and investigated by infrared and electronic spectra and magnetic susceptibility measurements: CrCl₃L, CrCl₃L₂ (pink and brown), CrCl₃L₃, CrCl₃L₆, CrBr₃L₂, CrBr₃L₃, CrBr₃L₄, CrBr₃L₆, CrBr₃L₇ and CrBr₃L₈. The CrBr₃ complexes were each isolated in a yellow and a red form. In the red CrBr₃ and in the yellow CrBr₃L₂ the ligand is bonded through the amine nitrogen. The CrCl₃ complexes are probably molecular complexes.     

Analysis of gamma-radioactivity of “hot particles” released after the Chernobyl accident

A particulate form (hot particles) of the radioactive fallout in Poland after the accident at the Chernobyl Nuclear Plant has been studied. Parameters of the effective reactor campaign are obtained from the characteristics of -activity of the hot particles. The numerical INV program written to calculate time evolution of eight isotopes in the reactor is described. On the basis of these calculations the measured hot particles are classified into two groups: those originating from the first load and those from younger fuel rods. A procedure for dating younger hot particles is proposed. The results of the analyses constitute a basis for other investigations of hot particles.     

M?glichkeiten und Konsequenzen der elektronischen Datenverarbeitung im chemisch-analytischen Labor

Zusammenfassung Zur Bewältigung der stetig wachsenden Datenflut werden sowohl in der Produktionsanalyse als auch im chemischen Forschungslabor in vermehrtem Maße elektronische Rechner eingesetzt. Es werden Probleme der Meßwerterfassung, der Dimensionierung der Anlage und die damit verknüpften Programmierungsfragen behandelt.Zwei Datenverarbeitungskonzepte, im on-line- bzw. off-line-Betrieb werden im Zusammenhang mit dem chemisch-analytischen Labor beschrieben und gegenübergestellt.

---

Possibilities and consequences of electronic data processing in the analytical laboratory

The increasing amount of data produced in chemical research laboratories, as well as in production control, leads more and more to the introduction of electronic computers.The paper describes the problems related to the acquisition of data, the choice of a suitable system and the programming involved. Two concepts of EDP in on-line and in off-line resp., in connection with the analytical laboratory, are described and compared.