bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solubility equilibria. From data optimization to process simulation
Authors: Königsberger Erich 
Published: October 2007

Abstract
Models that accurately predict solid–solute phase equilibria in aqueous electrolyte solutions are of mounting importance for numerous industrial processes, especially those operating at high temperatures, pressures, and concentrations. The incorporation of such electrolyte models into process simulators is in great demand. This communication will focus on thermodynamically consistent models that can simultaneously predict densities, heat capacities, and apparent molar enthalpies of multicomponent electrolyte mixtures together with activities of their constituents. Data optimization issues to be discussed include the CALPHAD (CALculation of PHAse Diagrams) method applied to electrolyte systems and the generation of robust models that extrapolate well outside the parameterization space. Recent development of software suitable for the simulation of industrial processes involving concentrated electrolyte solutions will be outlined.
Arsenic. An environmental problem limited by solubility
Authors: Magalhães M. Clara F. 
Published: October 2007

Abstract
Arsenic is a toxic element for animals and the majority of plants, in spite of evidence that it is also an essential element. The long-term intake of small doses of arsenic has a carcinogenic effect. There are well-identified regions where arsenic ground water concen- trations can reach values higher than 2 mg/L. Water purification and waste treatment techniques based on (1) precipitation of calcium, magnesium, and iron(III) arsenates, and/or (2) adsorption or coprecipitation of arsenic oxyanions are unlikely to produce aqueous solutions with arsenic concentrations below the guideline values proposed for arsenic dissolved in potable water and treated sewage effluents. As(III) species are more toxic than As(V) species. Arsenate species are predominant at moderate and high redox potentials, while arsenite species occur under more reducing conditions. Metal arsenites are much more soluble than the corresponding metal arsenates, and arsenites are adsorbed less by solid phases. Remediation techniques must consider the available information on solubility and adsorptive properties of As(III) and As(V). The less-soluble lead and barium arsenates are not suitable for arsenic decontamination. New remediation methods must consider solubility data for arsenic-containing materials and minerals.
Cation order/disorder in lithium transition-metal oxides as insertion electrodes for lithium-ion batteries
Authors: Zhecheva E. , Stoyanova R. , Alcántara R. , Lavela P. , Tirado J.-L. 
Published: October 2007

Abstract
Results on the local cation ordering in layered lithium-nickel/cobalt oxides and metal-substituted lithium-manganese spinels are presented. It is shown that electron spin resonance of Ni3+ and Mn4+ and magnetic susceptibility measurements are powerful tools to monitor the short-range cation ordering in these compounds, which is not accessible by diffraction techniques. Thus, owing to the different strength of the 90° and 180° Ni3+–O–Ni3+/2+ exchange interactions, the distribution of Ni3+/Ni2+ between the lithium and nickel layers in Li1–x
Ni1+x
O2 with 0 &lt; x &lt; 0.4 can be determined. For layered LiNi1–y
Co
y
O2 and spinel LiMn2–x
Co
x
O4 solid solutions, analysis of the temperature-independent EPR line width in terms of dipole–dipole and exchange interactions has been used to examine the local Ni3+/Co3+ and Mn4+/Co3+ ordering. The results obtained are correlated with the electrochemical intercalation of lithium in these compounds.
Aquatic chemistry and solubility phenomena of actinide oxides/hydroxides
Authors: Fanghänel Thomas , Neck V. 
Published: October 2007

Abstract
The present paper gives an overview of the solubility behavior of actinide oxides/hydroxides, taking into account hydrolysis reactions up to colloid formation. The analogies, systematic trends, and differences in the hydrolysis and solubility constants of actinides in the oxidation states An(III) to An(VI) correlate with the charge and size of the actinide ions. The formation of amorphous and crystalline solids and the discrepancies between the corresponding experimental solubility data may be explained as an effect of particle size. However, using thermodynamic data for the stable crystalline solids, the predicted solubilities are often significantly lower than experimental data (even in long-time experiments), indicating that the solubility is controlled by the surface properties. Typical examples are the known U(VI) solids schoepite and sodium diuranate. The most striking example is provided by the tetravalent actinides. Above the threshold of hydrolysis, the dissolution of microcrystalline or crystalline An(IV) oxides is found to be irreversible. The measured concentrations approach those of the amorphous hydroxides or hydrous oxides.
Solid–liquid equilibria in mixtures of molten salt hydrates for the design of heat storage materials
Authors: Voigt W. , Zeng D. 
Published: October 2007

Abstract
Enthalpy of melting can be used to store heat in a simple way for time periods of hours and days. Knowledge of the solid –liquid equilibria represents the most important presumption for systematic evaluations of the suitability of hydrated salt mixtures. In this paper, two approaches for predicting solid–liquid equilibria in ternary or higher component systems are discussed using the limited amount of thermodynamic data available for such systems. One method is based on the modified Brunauer–Emmett–Teller (BET) model as formulated by Ally and Braunstein.
In cases of a strong tendency toward complex formation of salt components, the BET model is no longer applicable. Reaction chain models have been used to treat such systems. Thereby, the reaction chain represents a method to correlate step-wise hydration or complexation enthalpies and entropies and, thus, reduce the number of adjustable parameters. Results are discussed for systems containing MgCl2, CaCl2, ZnCl2, and alkali metal chlorides.
Isotope-abundance variations of selected elements (IUPAC Technical Report)
Authors: Coplen Tyler B. , Böhlke John Karl , De Bièvre P. , Ding T. , Holden N. E. , Hopple J. A. , Krouse H. R. , Lamberty A. , Peiser H. S. , Revesz K. , Rieder S. E. , Rosman K. J. R. , Roth E. , Taylor P. D. P. , Vocke R. D. , Xiao Y. K. 
Published: October 2007

Abstract
Documented variations in the isotopic compositions of some chemical elements are responsible for expanded uncertainties in the standard atomic weights published by the Commission on Atomic Weights and Isotopic Abundances of the International Union of Pure and Applied Chemistry. This report summarizes reported variations in the isotopic compositions of 20 elements that are due to physical and chemical fractionation processes (not due to radioactive decay) and their effects on the standard atomic-weight uncertainties. For 11 of those elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine, copper, and selenium), standard atomic-weight uncertainties have been assigned values that are substantially larger than analytical uncertainties because of common isotope-abundance variations in materials of natural terrestrial origin. For 2 elements (chromium and thallium), recently reported isotope-abundance variations potentially are large enough to result in future expansion of their atomic-weight uncertainties. For 7 elements (magnesium, calcium, iron, zinc, molybdenum, palladium, and tellurium), documented isotope variations in materials of natural ter- restrial origin are too small to have a significant effect on their standard atomic-weight uncertainties. This compilation indicates the extent to which the atomic weight of an element in a given material may differ from the standard atomic weight of the element. For most elements given above, data are graphically illustrated by a diagram in which the materials are specified in the ordinate and the compositional ranges are plotted along the abscissa in scales of (1) atomic weight, (2) mole fraction of a selected isotope, and (3) delta value of a selected isotope ratio.
Hierarchical transfer of stereochemical information in synthetic macromolecules
Authors: Cornelissen J. J. L. M. 
Published: October 2007

Abstract
In Nature, a wide variety of complex tasks (e.g., catalysis, transport, and information storage) is performed by biomacromolecules with precise composition, dimensions, and architecture. To achieve the precise organization required for efficient function, structural information is built into the smallest building blocks of biomacromolecules (i.e., amino and nucleic acids) and subsequently transferred in a hierarchical fashion to form larger quaternary structures. These construction principles have been an inspiration for synthetic and supramolecular chemists alike, and a number of synthetic biomimetic helical macromolecules have been reported in the recent literature. Here, some recent developments in the field of helical polyisocyanides will be reviewed in combination with new prospects on the self-organization of protein/polymer hybrid architectures.
Assemblies of conjugated polymers: Intermolecular and intramolecular effects on the photophysical properties of conjugated polymers
Authors: Kim Jinsang 
Published: October 2007

Abstract
Conjugated polymers are emerging materials for electronic applications due to the tunability of their properties through variation of their chemical structure. Their applications, which currently include light-emitting diodes (LEDs), field effect transistors (FETs), plastic lasers, batteries, and sensors, are expanding to many new areas. The two critical parameters that determine the function of conjugated polymer-based devices are chemical structure and nanostructure of a conjugated polymer in the solid state. While the physical properties of isolated polymers are primarily controlled by their chemical structure, these properties are drastically altered in the solid state due to electronic coupling between polymer chains as determined by their interpolymer packing and conformation. However, the development of effective and precise methods for controlling the nanostructure of polymers in the solid state has been limited because polymers often fail to assemble into organized structures due to their amorphous character and large molecular weight.
In this review, recent developments of organizing methods of conjugated polymers and the conformation and interpolymer interaction effects on the photophysical properties of conjugated polymers are summarized.
Aromatic core-modified expanded porphyrinoids with meso-aryl substitutents
Authors: Pushpan S. K. , Chandrashekar T. K. 
Published: October 2007

Abstract
Porphyrins are the most widespread of all prosthetic groups found in Nature. The ubiquity of their functions in Nature led researchers around the globe to focus their attention on these highly colored macrocycles. The interdisciplinary interest generated by porphyrins resulted in the syntheses of modified porphyrins, which can be put to a variety of uses in medicine and industry. A brief overview of the synthetic methodologies resulting in the formation of aromatic meso-aryl-substituted core-modified aromatic heterocyclic ring-inserted expanded porphyrinoids like sapphyrins, smaragdyrins, rubyrins, hexaphyrins, heptaphyrins, and octaphyrins reported to date are discussed in this article.
Use of the term "recovery" and "apparent recovery" in analytical procedures (IUPAC Recommendations 2002)
Authors: Burns D. T. , Danzer Klaus , Townshend A. 
Published: October 2007

Abstract
The terms recovery and apparent recovery are recommended to avoid confusion caused by the use of the term recovery to cover two distinct situations. These situations deal with: (a) the yield of a preconcentration or extraction stage of an analytical process (where recovery is recommended) and (b) the quantity observed value/reference value, obtained using an analytical procedure that involves a calibration graph (where apparent recovery is recommended).
Critical evaluation of stability constants of phosphonic acids (IUPAC Technical Report)
Authors: Popov Konstantin , Rönkkömäki Hannu , Lajunen Lauri H. J. 
Published: October 2007

Abstract
The following reference citations were incorrect:
Page 1643: replace 93SC with 93SK
Page 1657: replace H+: 98KK with H+: 98KA
Page 1657: replace Cu2+: 98KK with Cu2+: 98KA
Page 1668: replace 90S with 90SW
Page 1673: replace 68BE with 67BE
Page 1666: replace 95WJ J.M. Wagener and N.V. Jarvis. S. Afr. J. Chem. 28, 85 (1995) with 95WJ J.M. Wagener and N.V. Jarvis. S. Afr. J. Chem. 48, 85 (1995)
Page 1666: replace 95I with 95IU
Page 1668: replace 90K A T. Kiss with 90KA T. Kiss
Chemical crop protection research. Methods and challenges
Authors: Müller U. 
Published: October 2007

Abstract
Chemical crop protection, today a well-established technology to support sustainable production of food, feed, and fiber, will continue to play an important role in agribusiness in spite of the emergence of novel biotechnological solutions. Scientific progress in chemistry, biology, and molecular biology has revolutionized the way of searching for new agrochemicals over the past decade. Requirements, primarily in terms of safety to humans and the environment, have also changed. The search for and the development of novel agrochemicals with novel modes of action, improved safety profiles, and adapted to the changing requirement of the food and feed production chain are more than ever the challenge.
Advances in biocatalytic synthesis. Enzyme-triggered asymmetric cascade reactions
Authors: Glueck S. M. , Mayer S. F. , Kroutil Wolfgang , Faber K. 
Published: October 2007

Abstract
Organic compounds can be transformed through enzyme-triggered domino (or cascade) reactions via several (inseparable) consecutive steps in an asymmetric fashion to yield nonracemic products. Despite the fact that these sequences often involve the occurrence of highly reactive unstable intermediates, the overall efficiency of these processes can be high, provided that the reaction rates of the individual steps match each other in order to minimize side reactions.
Synthetic studies on the marine natural product halichondrins
Authors: Choi Hyeong-wook , Demeke Damtew , Kang F.-A. , Kishi Y. , Nakajima K. , Nowak P. , Wan Z.-K. , Xie C. 
Published: October 2007

Abstract
In connection with the de elopment of a practical synthesis of the right half, and its analog E7389, of halichondrin B, an efficient and scalable synthesis of the two major building blocks is reported. In addition, a new synthesis of the C20–C26 segment via a regiospecific and stereoselecti e SN2' process is presented. A sulfonamide class of ligands is shown to be effective for asymmetric Ni/Cr-mediated reactions under both stoichiometric and catalytic conditions, and the X-ray structure reveals this class of ligands to be tridentate. On the basis of three X-ray structures, a possible mechanism is suggested for this process. Stable and crystalline Cr(III)/sulfonamide complexes are shown to be effective for catalytic Cr-mediated coupling reactions of allyl, alkenyl, and alkyl halides with aldehydes, and some examples for application of the stoichiometric and catalytic asymmetric processes are presented.
Synthesis of azaheterocycles from oxime derivatives
Authors: Narasaka K. 
Published: October 2007

Abstract
Electrophilic amination of Grignard reagents has been accomplished by using O-sulfonyloximes as amination reagents. Benzophenone O-sulfonyloxime derivatives react with Grignard reagents on sp2 nitrogen, yielding primary amines by successive hydrolysis of the resulting N-alkylimines.
Various cyclic imines are synthesized by Pd-catalyzed reaction from olefinic oxime derivatives. That is, treatment of O-pentafluorobenzoyloximes of olefinic ketones with a catalytic amount of Pd(PPh3)4 and triethylamine affords nitrogen-containing heterocycles, such as pyrroles, pyridines, isoquinolines, spiro-imines, and aza-azulenes. This reaction proceeds via the initial formation of alkylideneaminopalladium(II) species generated by oxidative addition of the oximes to the Pd(0) complex, and the following intramolecular amination on the olefinic moiety.
Cyclic imines are prepared from γ,δ-unsaturated O-acetyloximes by treatment with acetic acid and 1,4-cyclohexadiene in the presence of a catalytic amount of 1,5-naphthalene-diol. γ,δ-Unsaturated ketone O-methoxycarbonyloximes are transformed to 2-bromomethyl-3,4 dihydro-2H-pyrroles by the action of a catalytic amount of Cu(I) bromide dimethyl sulfide complex and lithium bromide.
Stereocontrolled total synthesis of (+)-vinblastine
Authors: Yokoshima Satoshi , Ueda T. , Kobayashi S. , Sato A. , Kuboyama Takeshi , Tokuyama H. , Fukuyama T. 
Published: October 2007

Abstract
Stereocontrolled total synthesis of (+)-vinblastine (1) has been achieved using a novel radical-mediated indole synthesis developed in our laboratories. The isothiocyanate 18, prepared readily from quinoline 17, underwent a facile addition of the malonate anion to give 19. The o-alkenylthioanilide 19 was then converted to indole 20 by radical cyclization and protection. (−)-Vindoline (2) was prepared from this key intermediate 20 in a highly efficient manner. The indole core of the 11-membered intermediate 3 was constructed similarly from quinoline. The critical coupling reaction between 2 and the chloroindolenine derived from 3 proceeded with complete control of stereochemistry to give the desired product 66 in 97 % yield, which could be successfully converted to (+)-vinblastine (1).
Applications of tert-butanesulfinamide in the asymmetric synthesis of amines
Authors: Ellman J. A. 
Published: October 2007

Abstract

tert-Butanesulfinamide is prepared using catalytic enantioselective methods in two steps from the extremely inexpensive oil waste by-product, tert-butyl disulfide. Direct condensation of tert-butanesulfinamide with aldehydes and ketones provides tert-butanesulfinyl imines in uniformly high yields. The tert-butanesulfinyl group activates the imines for the addition of many different classes of nucleophiles, serves as a powerful chiral directing group, and after nucleophilic addition is readily cleaved by treatment with acid. A wide range of highly enantioenriched amines, including α-branched and α,α-dibranched amines, α- and β-amino acids, 1,2 and 1,3-amino alcohols and α-trifluoromethyl amines are efficiently synthesized using this methodology.
Application of cascade processes toward heterocyclic synthesis
Authors: Padwa A. 
Published: October 2007

AbstractThe reactions ofN-acyliminium ions with tethered π-bonds are among the most important methods for preparing complex nitrogen-containing heterocycles. Pummerer-based cyclizations are also finding widespread application in both carbo- and heterocyclic syntheses. As part of a program concerned with new methods for alkaloid synthesis, we became interested in using a linked Pummerer/N-acyliminium ion cyclization sequence since we felt that this combination offers unique opportunities for the assemblage of complex target molecules. A synthetic method that combines transformations of different reaction types significantly broadens the scope of such procedures in synthetic chemistry. α-Thiocarbocations generated from the Pummerer reaction of β-phenylsulfinylmethyl-α,β-unsaturated amides can be intercepted by the adjacent amido group to produce transient amino- substituted furans, which undergo subsequent Diels-Alder cycloadditions. Using thisdomino amido-Pummerer/Diels-Alder cascade, we were able to assemble novel polycyclic systems in a single operation. The key step in the process involves the generation of a reactiveN-acyliminium ion by fragmentation of an amino-substituted [4+2] cycloadduct. The successful synthesis of a number of alkaloids by this sequence of reactions reveals the usefulness and importance of this unique domino cascade.
Unified strategy for the synthesis of C-aryl glycosides
Authors: Martin S. F. 
Published: October 2007

Abstract
A unified approach for the synthesis of the four major groups of C-aryl glycosides has been developed. The strategy incorporates two integrated approaches, the first of which features the [4+2] cycloaddition of a glycosyl furan with a substituted benzyne followed by the acid-catalyzed opening of the resultant adduct. The second route involves the sequential palladium-catalyzed opening of a benzyne-furan cycloadduct with an iodo glycal followed by oxidation of the resultant dihydronaphthol ring and reduction of the glycal moiety. The utility of this strategy has been established by a concise formal synthesis of the C-aryl glycoside antibiotic galtamycinone.
Critical evaluation of stability constants and thermodynamic functions of metal complexes of crown ethers (IUPAC Technical Report)
Authors: Arnaud-Neu Francoise , Delgado Rita , Chaves Sílvia 
Published: October 2007

Abstract
Stability constants and thermodynamic functions of metal complexes of crown ethers in various solvents published between 1971 and the beginning of 2000 have been critically evaluated. The most studied crown ethers have been selected: 1,4,7,10 tetraoxacyclododecane (12C4), 1,4,7,10,13 pentaoxacyclopentadecane (15C5), and 1,4,7,10,13,16 hexaoxacyclooctadecane (18C6). The metal ions chosen are: alkali and alkaline earth metal ions, Ag+, Tl+, Cd2+, and Pb2+. The solvents considered are: water, methanol, ethanol, and their mixtures, as well as acetonitrile, N,N'-dimethylformamide, dimethylsulfoxide, and propylene carbonate. The published data have been examined and grouped into two categories, “accepted” and “rejected”. The “accepted” values were considered as: (i) recommended (R), when the standard deviations (s.d.) on the constant K or on Δr
H were inferior to 0.05 lg unit or inferior to 1 kJ mol−1, respectively; (ii) provisional (P), when s.d. is superior to 0.05 and inferior to 0.2 for lg K or s.d. is superior to 1 and inferior to 2 kJ mol−1 for Δr
H; (iii) recommended 1 (R1), if the values were obtained by a single research group, but were considered reliable in comparison with related systems, and considering that the research team usually presents R-level values for other similar systems.
Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report)
Authors: Kratz J. V. 
Published: October 2007

Abstract
In this paper, the chemical properties of the transactinide elements rutherfordium, Rf (element 104); dubnium, Db (element 105); and seaborgium, Sg (element 106) are critically reviewed. The experimental methods for performing rapid chemical separations on a time scale of seconds are reviewed, and comments are given on the special situation with the transactinides for which the chemistry has to be studied with single atoms. There follows a systematic description of theoretical predictions and experimental results on the chemistry of Rf, Db, and Sg - their mutual comparison and evaluation. The literature cited has the cutoff date of March 1999. The more recent chemical identification of bohrium, Bh (element 107), and of hassium, Hs (element 108), should be evaluated in a future Part II of this report.
Inspirations from nature. New reactions, new therapeutic leads, and new drug delivery systems
Authors: Wender P. A. , Baryza J. L. , Brenner S. E. , Clarke M. O. , Gamber Gabriel G. , Horan J. C. , Jessop T. C. , Kan Cindy , Pattabiraman K. , Williams T. J. 
Published: October 2007

Abstract
Studies in our laboratory focus on problems in chemistry (new reactions and synthesis), biology (novel modes of action), and medicine (new therapeutic leads and drug delivery systems). These interconnected and often synergistic activities are inspired by an interest in novel structures, frequently from nature, that possess unique modes of action and significant clinical potential. Described herein are some examples of recent work from our laboratory that have led to new transition metal-catalyzed reactions, a new and remarkably potent therapeutic lead, and new drug delivery systems that are in clinical trials.