bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential of group contribution methods for the prediction of phase equilibria and excess properties of complex mixtures
Authors: Gmehling Jürgen 
Published: October 2007

Abstract
Reliable knowledge of the thermophysical properties of pure compounds and their mixtures in the whole composition and a wide temperature and pressure range is a vital prerequisite for computer-aided synthesis, design, and optimization of chemical processes. Knowledge of the various phase equilibria is most important for the development of thermal separation processes (but also for other applications,such as the design of multiphase reactors, the prediction of the fate of a chemical in the environment,etc.).
Whereas 25 years ago, the main interest was directed to the development of predictive tools for vapor–liquid equilibria of subcritical compounds of similar size (ASOG, UNIFAC), 15 years later a proper description of the temperature dependence (excess enthalpies), the activity coefficients at infinite dilution, and solid–liquid equilibria of eutectic mixtures (including strong asymmetric systems) was achieved. After the combination with cubic equations of state [Soave–Redlich–Kwong (SRK), Peng–Robinson (PR)], the group contribution concept was extended to supercritical compounds [predictive SRK (PSRK)]. With the development of an adequate electrolyte model (LIFAC), the equation-of-state approach can even be used for systems with strong electrolytes. With the revision of the group interaction parameters, the extension of the parameter matrix (introduction of new structural groups, filling of parameter gaps), and the help of a large database (Dortmund Data Bank), the predicted results of group contribution methods were significantly improved and the range of applicability greatly extended. Furthermore, still-existing problems with the group contribution approach (proximity effects,etc.) were reduced.
With the help of a volume-translated PR equation of state and application of temperature-dependent and improved mixing rules, the remaining weaknesses of group contribution equations of state (such as poor results for liquid densities, excess enthalpies, and the problems with asymmetric systems) were minimized.
Materials in thermodynamic potential gradients
Authors: Martin M. 
Published: October 2007

Abstract
In materials that are exposed to thermodynamic potential gradients (i.e., gradients of chemical potentials, electrical potential, temperature, or pressure), transport processes of the mobile components occur. These transport processes and the coupling between different processes are not only of fundamental interest, but are also the origin of degradation processes, such as kinetic demixing and decomposition and changes in the morphology of the material, all of which are of great practical relevance.Two classes of materials will be considered: semi-and ion-conducting oxides and ion-conducting halides. In oxides, kinetic demixing of the cations in a multicomponent oxide and kinetic decomposition of the oxide under the influence of an applied thermodynamic potential gradient will be considered for homovalent oxide solid solutions and for heterovalently doped oxides. In ion-conducting halides, the morphological stability of solid/solid interfaces, which are driven by an external electrical potential gradient, is studied. Monte Carlo simulations show that the morphological stability of the interface is determined by the difference in the ionic conductivities of the two crystals.
Thermodynamics of membrane lipid hydration
Authors: Wennerström H. , Sparr E. 
Published: October 2007

Abstract
Zwitterionic or polar lipids that form lamellar phases swell in the presence of water to take up between 10 and 30 water molecules per lipid. The degree of the water uptake depends both on the state of the alkyl chains, liquid or solid, and on the nature of the polar group. The swelling behavior has been extensively characterized on the free-energy level through measuring the relation between the chemical potential of the water and the degree of swelling. In spite of the extensive studies of this type, consensus is still lacking concerning the molecular mechanism causing the swelling. The two main ideas that explain the existence of the effectively repulsive force between two opposing bilayers are (i) a water structure effect and (ii) thermal excitations of the lipid molecules. The first is from a thermodynamic perspective caused by a negative partial molar enthalpy of the water, whereas for the second, the repulsion is caused by positive entropy.
A further insight into the swelling behavior is obtained by simultaneously measuring the partial molar free energy and the partial molar enthalpy using a twin double calorimeter. Such measurements show for binary lipid–water and for ternary lipid –cholesterol –water systems that the first four water molecules enter the bilayer driven by a favorable enthalpic interaction, whereas for higher water contents, the partial free energy and the partial enthalpy have opposite signs. In spite of the fact that the partial free energy varies with water content in a similar way, the partial enthalpies depend strongly on the nature of the lipid sample. Thus, it is obvious that a molecular interpretation of the enthalpy values has to involve the lipid degrees of freedom. This is a strong indication that the interpretation of the free energies should also include the same degrees of freedom. This gives experimental evidence in favor of an interpretation of the molecular mechanism causing the swelling that involves changes in the thermal excitation of the lipid degrees of freedom.
Quantum aspects of low-temperature properties of crystals: A calorimetric study in interaction with spectroscopy and diffraction
Authors: Matsuo T. 
Published: October 2007

Abstract
Some of the molecular and ionic crystals containing hydrogen undergo phase transitions only when they are deuterated. This indicates that not only the intermolecular potential energy, but also the kinetic energy of the nuclei are involved in an essential way in the mechanisms of the transitions. The quantum effects implied by these observations are discussed in terms of tunneling of protons and deuterons. Experimental evidence for deuteration-induced phase transitions and nuclear tunneling states accumulated by low temperature calorimetry, far infrared spectroscopy,and neutron diffraction is discussed.
Exploring the entire conformational space of proteins by high-pressure NMR
Authors: Akasaka Kazuyuki 
Published: October 2007

Abstract
A protein in solution is a thermodynamic entity, spanning, in principle, the entire allowed conformational space from the fully folded N to the fully unfolded U. Although some alternately or partially folded higher-energy conformers may coexist with N and U, they are seldom detected spectroscopically because their populations are usually quite low under physiological conditions. I describe here a new type of experiment, a combination of multidimensional NMR spectroscopy with pressure, that is capable of detecting and analyzing structures and thermodynamic stability of these higher-energy conformers. The idea is based on the finding that under physiological conditions the conformational order of a globular protein normally decreases in parallel with its partial molar volume (negative δV), so that under equilibrium conditions, the population is shifted to a less and-less-ordered conformer with increasing pressure. In principle, with the high space resolution of the multidimensional NMR, the method enables one to explore protein structure and stability in atomic detail in a wide conformational space from N to U with pressure and temperature as variables. The method will provide us with a strong basis for understanding the fundamental phenomena of proteins:function, folding, and aggregation.
Significance of impurities in the safety evaluation of crop protection products (IUPAC Technical Report)
Authors: Ambrus Á. , Hamilton D. J. , Kuiper H. A. , Racke K. D. 
Published: October 2007

Abstract
There may be substantial differences in the chemical composition of technical-grade products of the same active ingredient manufactured under different conditions, from different raw materials, or by different routes of synthesis. Resulting differences in impurity content may significantly affect the toxicological properties of pesticide products. Relevant impurities are those that may exhibit pronounced toxic effects compared to the active ingredient, affect phytotoxicity or physical properties of formulations, result in undesirable residues in food,or cause environmental contamination. The first safety assessment of an active ingredient by a regulatory body considers toxicological data developed on a representative batch of technical products, with the assumption that the material produced commercially by the original or generic manufacturers has an equal or higher content of active ingredient and contains the same or fewer impurities at equal or lower concentrations as the fully characterized technical product used in the toxicological tests. Three steps are essential for ensuring the safety of commercial technical- grade pesticide products, whether produced by the original manufacturer or by generic manufacturers. First, the identity and chemical structure of the impurities must be elucidated.This should include positive identification of major (=1 %) and all toxicologically or environmentally relevant impurities, and characterization of minor impurities (>0.1 %). Second, in addition to recognition of a minimum active ingredient content, official specifications should also list relevant impurities and their maximum permissible concentrations.Implementation of these specifications should be aided by a decision-making scheme for establishing similarity of subsequently evaluated technical products. Third, appropriate analytical methods for the detection and quantification of impurity levels should be developed and employed in a quality-monitoring program associated with the manufacturing and formulation process.
Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)
Authors: Imasaka Totaro , Moore D. S. , Vo-Dinh T. 
Published: October 2007

Abstract
When cooled to a temperature of a few K using supersonic jet expansion into a vacuum, a molecule exists in the lowest vibrational level of the ground electronic state and is isolated at collision-free conditions. The absorption or excitation/fluorescence spectrum is then greatly simplified, when transitions occur from this single vibrational level to a limited number of vibrational levels in the excited electronic state. This method, called supersonic jet spectrometry, is a powerful analytical technique because of its high selectivity, since the chemical species can be accurately identified and selectively quantified using the sharp spectral features even for large molecules. Supersonic jet spectrometry has distinct advantages over other low-temperature spectrometries,in that it can be combined with gas-phase separation and detection techniques such as chromatography or mass spectrometry. Therefore, this spectrometric technique can be used as a versatile analytical means, not only for basic research on pure substances, but also for practical trace analysis of chemical species in multicomponent samples (e.g., in biological monitoring or in environmental monitoring).
Electron-transfer reactions studied by laser-induced optoacoustics: Learning about chromophore-medium (protein) interactions
Authors: Braslavsky S. E. 
Published: October 2007

The ability of time-resolving enthalpy (ΔH) and structural volume (ΔV) changes in the nano- to µs time range offered by laser-induced optoacoustic spectroscopy (LIOAS) opens the possibility of a stepwise thermodynamic analysis of chromophore-medium interactions upon photoinduced reactions in biological systems. We applied LIOAS to biological photoreceptors, as well as to model systems, with the purpose of understanding the origin of ΔV in electron-transfer (ET) reactions in those systems. The linear correlation between the counterion-dependent volume changes and ΔH for the free-radical formation upon ET quenching of erythrosin dianion triplet, 3Er2-, by Mo(CN)84- and of Ru(bpy)32+ by MV2+ is interpreted in terms of an enthalpy–entropy compensation owing to the strong influence of the counterions on the water hydrogen-bond network in which the reactants are embedded. The relatively large entropic term determined for radical formation thus originates in water rearrangements during the process. The increasing contraction in acetonitrile, propionitrile, butyronitrile, and valeronitrile for the ET quenching of 3Zn-tetraphenylporphin by 1,4-benzoquinone is understood by considering the increasing interaction strength between the electron-pair donor nitriles and ZnTPP+. Thus, in polar environments, specific chromophore-medium (solvent or proteins) interactions, in addition to electrostriction, should be considered to explain the time-resolved ΔV and ΔH values.
Regio- and stereoselective functionalization of electron-deficient alkenes by organosilicon compounds via photoinduced electron transfer
Authors: Mizuno K. , Hayamizu T. , Maeda Hajime 
Published: October 2007

Regio- and stereoselective photoallylation of electron-deficient alkenes by use of allylic silanes via photoinduced electron transfer has been described. Similar photoinduced functionalization reactions such as arylmethylation, alkylation, and silylation can be achieved by using a variety of organosilicon compounds. These photoreactions proceed via radical cations of organosilicon compounds and radical anions of electron-deficient alkenes as reactive intermediates. The key step of the photoreactions is the attack of carbon radicals, which are generated from the radical cations of organosilicon compounds, on the radical anions of alkenes. The mechanism of the regio- and stereoselective photofunctionalization is discussed.
Atomic weights of the elements 2001 (IUPAC Technical Report)
Authors: Loss R. D. 
Published: October 2007

The biennial review of atomic-weight, Ar(E), determinations and other cognate data have resulted in changes for the standard atomic weights of the following elements:	FromToZinc65.39 ± 0.0265.409 ± 0.004Krypton83.80 ± 0.0183.798 ± 0.002Molybdenum95.94 ± 0.01 95.94 ± 0.02Dysprosium162.50 ± 0.03162.500 ± 0.001 Presented are updated tables of the standard atomic weights and their uncertainties estimated by combining experimental uncertainties and terrestrial variabilities. In addition, this report again contains an updated table of relative atomicmass values and half-lives of selected radioisotopes. Changes in the evaluated isotope abundance values from those published in 1997 are relatively minor and will be published in a major review of each element in 2003. Many elements have a different isotopic composition in some nonterrestrial materials. Some recent data on parent nuclides that might affect isotope abundances or atomic-weight values are included in this report for the information of the interested scientific community.
Regulatory limits for pesticide residues in water (IUPAC Technical Report)
Authors: Hamilton D. J. , Ambrus Á. , Dieterle R. M. , Felsot A. S. , Harris C. A. , Holland P. T. , Katayama A. , Kurihara N. , Linders J. , Unsworth J. , Wong S.-S. 
Published: October 2007

National governments introduced residue limits and guideline levels for pesticide residues in water when policies were implemented to minimize the contamination of ground and surface waters. Initially, the main attention was given to drinking water.Regulatory limits for pesticide residues in waters should have the following characteristics: definition of the type of water, definition of the residue, a suitable analytical method for the residues, and explanation for the basis for each limit.Limits may be derived by applying a safety factor to a no-effect-level, or from levels occurring when good practices are followed and also passing a safety assessment, or from the detection limit of an analytical method, or directly by legislative decision.The basis for limits and guideline values issued by WHO, Australia, the United States, New Zealand, Japan, Canada, European Union, and Taiwan is described, and examples of the limits are provided. Limits have been most commonly developed for drinking water, but values have also been proposed for environmental waters, effluent waters, irrigation waters, and livestock drinking waters. The contamination of ground water is of concern because it may be used as drinking water and act as a source of contamination for surface waters. Most commonly, drinking water standards have been applied to ground water.The same terminology may have different meanings in different systems. For example, guideline value (GV) in WHO means a value calculated from a toxicology parameter, whereas in Australia, a GV is at or about the analytical limit of determination or a maximum level that might occur if good practices are followed. In New Zealand, the GV is the concentration where aesthetic significance is influenced.The Australian health value (HV) is conceptually the same as the WHO GV. The New Zealand maximum acceptable value (MAV) and the Canadian maximum acceptable concentration (MAC) are also conceptually the same as the WHO GV.Each of the possible ways of defining the residues has its merits. A residue limit in water expressed as the sum of parent and toxicologically relevant transformation products makes sense where it is derived from the acceptable daily intake (ADI). For monitoring purposes, where it is best to keep the residue definition as simple as possible for the sake of practical enforcement and economy, theparent or a marker residue is preferable. It is also possible for parent and degradation products (hydrolysis and photolysis products and metabolites) to become physically separated as the water moves through soil strata, which suggests that separate limits should be set for parent and important degradation products.The Commission has made 12 recommendations for regulatory limits for pesticide residues in water. The recommendations will act as a checklist for authorities introducing or revising limits or guidelines for pesticide residues in water.
New discoveries at the interface of boron and carbon chemistries
Authors: Hawthorne M. Frederick 
Published: October 2007

Abstract
The continued growth of polyhedral borane chemistry is illustrated by the successful synthesis of [closo-B12(OH)12]2 –by the H2O2 oxidation of [closo-B12H12,]2. The hydroxylated species reacts with common organic reagents to produce 12-fold degenerately substituted carboxylate esters, ethers, and carbamate esters. The ether derivatives undergo facile and reversible redox reactions in which the B12 scaffold serves as a one-or two-electron donor giving stable oxidation states described by [closo -or hypercloso-B12OR)12]n with n = −2,−1,and 0. The loss of polyhedral electrons is compensated by back-bonding from the attached ether oxygen substituents. Structural comparisons are presented along with representative reaction chemistry. Derivatives that bear functional groups on the termini of the 12-fold set of substituents provide a vast array of potential applications. To distinguish these new polyfunctional icosahedral species from dendrimers,they have been designated as closomers.
Reactions of boranes and metallaboranes with phosphines
Authors: Barton Lawrence , Volkov Oleg , Hata Mitsuhiro , McQuade Paul , Rath Nigam P. 
Published: October 2007

Abstract
This paper reports extensions of the well-established field of phosphine–borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2 [(Fe(C5H4)2]}, are formed in reactions of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9]. Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10] and [9,9-(PPh3)2-nido-9,7,8-RhC2B8 H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(µ-dppm)]-closo -1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron vertices in the cage, [1,1-(ç2-dppe)-3-(ç1-dppm)-closo-1,2-RhSB 9H8], a mixed ligand system, and {9,9-ç2-[(ç2-BH3)PPh2PCH2 PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described as is an example of a bidentate phosphine-polyhedral borane adduct [NR4][B11H12(dppm)] in which the borane cage is isoelectronic with [B11H14]–. Finally, a novel oxidative coupling reaction promoted by Cp2ZrCl2/n-BuLi to form the new nonaborane cage system, arachno -B9H11(PPh3)2, an unusual homolog of the well-known species B10H12(PPh3)2, is reported.
Two-electron aromatics containing three and four adjacent boron atoms
Authors: Präsang C. , Mlodzianowska A. , Geiseler G. , Massa W. , Hofmann M. , Berndt A. 
Published: October 2007

Abstract
A two-electron aromatic bis (tris-trimethylsilylmethylene)-substituted tetraborane(4) was found to be a useful precursor for the synthesis of two-electron aromatic tetraboranes(6), triboracyclopropanates,as well as tetraboranes(6) distorted toward triboracyclopropanates with boryl bridges. Bishomo two-electron aromatics with a borata bridge and a protonated borata bridge, respectively, are also presented.
Role of B(C6F5)3 in catalyst activation, anion formation, and as C6F5 transfer agent
Authors: Bochmann Manfred , Lancaster Simon J. , Hannant Mark D. , Rodriguez Antonio , Schormann Mark , Walker Dennis A. , Woodman Timothy J. 
Published: October 2007

Abstract
The versatile reactivity of B(C6F5)3 in alkene polymerization reactions is summarized. Adduct formation with basic anions such as CN– and NH2– gives extremely weakly co- ordinating diborates, which are the basis of some of the most active polymerization catalysts known to date. By contrast, the reaction of B(C6F5)3 with zirconium half-sandwich complexes leads to extensive C6F5 transfer, including the surprising formation of borole-bridged triple decker complexes. Main group alkyls undergo such C6F5 exchange reactions very readily unless donor ligands are present. Borate salts of new three-coordinate zinc alkyl cations proved to be highly effective catalysts for the ring-opening polymerization of epoxides and lactones.
Boron clusters for medicinal drug design: Selective estrogen receptor modulators bearing carborane
Authors: Endo Yasuyuki , Yoshimi Tomohiro , Miyaura Chisato 
Published: October 2007

Abstract
The molecular shape and hydrophobicity of dicarba-closo -dodecaboranes may allow a new medical application as biologically active molecules. Recently, we have developed potent estrogen receptor (ER) agonists bearing carborane cage. The most potent compound (BE120) exhibited activity at least several times greater than that of 17 beta-estradiol in luciferase reporter gene assay and ER alpha binding. We also designed and synthesized estrogen antagonists on the basis of the structure of BE120, and we noticed the characteristic features of compound (BE360) having carborane cage and two phenols. The ER binding affinity of BE360 is comparable to that of estradiol. To examine in vivo estrogenic activity of the compound in bone, ovariectomized (OVX) mice were given BE360 or estradiol subcutaneously for 4 weeks. Treatment with BE360 at 1–30 µg/day dose-dependently restored bone loss in OVX mice to sham level without estrogenic action in uterus. These results suggest its possible application to osteoporosis as a new type of selective ER modulator.
Rearrangements in the nona-and azanonaborane clusters
Authors: El-Zaria M. , Dörfler U. , Gabel D. 
Published: October 2007

Abstract
In the conversion of nonaboranes B9H13SMe2 to azanonaboranes B8NH11-NHR, one boron atom is lost. This boron atom was identified, and a pathway for the rearrangement of the cluster is proposed, based on the fate of covalently labeled boron atoms.