bluuebunny/crossref_metadata_2025 huggingface dataset:
Calixphyrins. Hybrid macrocycles at the structural crossroads between porphyrins and calixpyrroles
Authors: Sessler Jonathan L. , Zimmerman Rebecca S. , Bucher Christophe , Král Vladimír , Andrioletti Bruno
Published: October 2007

Calixphyrins are a class of hybrid molecules that lie at the structural crossroads between porphyrins and calixpyrroles. Porphyrins, long known for their versatile metal cation coordination chemistry, are macrocycles that contain only sp2-hybridized bridging meso carbon atoms within their framework. Calix[n]pyrroles, on the other hand, are porphyrin analogs that contain pyrroles bridged exclusively by sp3 meso carbon centers, and in recent years have been shown to display remarkable anion-binding properties. Calix[n]phyrins bear analogy to both the porphyrins and calixpyrroles and are macrocyclic analogs that contain a mixture of sp2- and sp3-hybridized meso carbon bridges. This leads to partial interruptions in the conjugation pathway of the molecule, introduces novel structural features, and leads to interesting anion and cation recognition properties. It also allows for modular syntheses. In the present paper, the chemistry of calix[n]phyrins, still at an early stage of exploration, is reviewed.
Unsaturated binuclear homoleptic metal carbonyls M2(CO)x (M = Fe, Co, Ni; x = 5, 6, 7, 8). Are multiple bonds between transition metals possible for these molecules?
Authors: Schaefer Henry F. , King R. Bruce
Published: October 2007

Modern density functional methods, which yield geometrical parameters and energies close to experimental values for known metal carbonyls such as Fe(CO)5 and Fe2(CO)9, have been extended to unsaturated binary binuclear metal carbonyls. Novel optimized structures have been discovered containing metal­metal multiple bonds, four-electron bridging carbonyl groups, and metal electronic configurations less than 18 electrons.
Benign by design. New catalysts for an environmentally conscious age
Authors: Thomas John Meurig , Raja Robert , Sankar Gopinathan , Bell Robert G. , Lewis Dewi W.
Published: October 2007

There is a pressing need for: (i) cleaner fuels (free of aromatics and of minimal sulfur content) or ones that convert chemical energy directly to electricity, silently and without production of noxious oxides and particulates; (ii) chemical, petrochemical, and pharmaceutical processes that may be conducted in a one-step, solvent-free manner, and that use air as the preferred oxidant; and (iii) industrial processes that minimize consumption of energy, production of waste or the use of corrosive, explosive, volatile and nonbiodegradable materials. All these needs and other desiderata, such as the in situ production and containment of aggressive and hazardous reagents, and the avoidance of use of ecologically harmful elements, may be achieved by designing the appropriate heterogeneous inorganic catalyst, which, ideally should be cheap, readily preparable, and fully characterizable, preferably under in situ reaction conditions. A range of nanoporous and nanoparticle catalysts, designed, synthesized, characterized, and tested by the authors and their colleagues, that meet most of the stringent demands of sustainable development and responsible (clean) technology is described. Specific examples that are highlighted include: (a) the production of adipic acid (precursor of polyamides and urethanes) without the use of concentrated nitric acid or the production of greenhouse gases such as nitrous oxide; (b) the production of caprolactam (precursor of nylon) without the use of oleum and hydroxylamine sulfate; and (c) the terminal oxyfunctionalization of linear alkanes in air. The topic of biocatalysis and sustainable development is also briefly discussed, and a cautionary note is sounded concerning fast screening methods for the discovery of new inorganic catalysts.
Applications of "planar-chiral" heterocycles in asymmetric catalysis
Authors: Fu Gregory C.
Published: October 2007

Planar-chiral derivatives of pyridine function as efficient catalysts for processes such as the kinetic resolution of primary amines and the desymmetrization/ring-opening of meso epoxides. Planar-chiral pyrrolyl and phospholyl derivatives serve as effective chiral ligands for a range of metal-catalyzed reactions, including the copper-catalyzed ring-expansion of oxetanes and the rhodium-catalyzed isomerization of allylic alcohols.
New developments in dimethyl carbonate chemistry
Authors: Tundo Pietro
Published: October 2007

Dimethylcarbonate (DMC) is a valuable methylating reagent which can replace methyl halides and dimethylsulfate in the methylation of a variety of nucleophiles. It couples tunable reactivity and unprecedented selectivity toward mono-C- and mono-N-methylation in the reactions of acidic CH2 and primary aromatic amines, respectively. In addition, it is a prototype example of a green reagent, since it is nontoxic, made by a clean process, and biodegradable, and it reacts in the presence of a catalytic amount of base thereby avoiding the formation of undesirable inorganic salts as by-products. Other remarkable reactions are those where DMC behaves as an oxidant: cyclic ketones are transformed into a,w-dimethyl esters with a reaction of atom efficiency of 1.0.
Use and distribution of organochlorine pesticides. The future in Africa
Authors: Wandiga Shem O.
Published: October 2007

Pesticides have been used in the continent for about eight decades. Major use has been in agriculture, livestock development, and disease vectors control. Recent international conventions have been made with little scientific data and information on the tropical situation. Rapid development of resistance to pesticides demands better scientific understanding of pest management. Tropical research data on organochlorine pesticides show rapid degradation pattern, low residue levels, and widespread distribution. Given the above, there is a need to factor into consideration tropical climatological calamities in any future pesticide policy. Continued use of pesticides is anticipated in the tropics.
From classical antimalarial drugs to new compounds based on the mechanism of action of artemisinin
Authors: Robert Anne , Benoit-Vical Françoise , Dechy-Cabaret Odile , Meunier Bernard
Published: October 2007

A short review of the antimalarial drugs currently used in human clinics is reported. The molecular aspect of the different possible mechanisms of action of artemisinin is documented, including recent data on heme alkylation. The preparation and the in vitro antimalarial activity of new modular molecules named "trioxaquines" are also presented.
Synthesis of nucleoside analogs and new Tat protein inhibitors
Authors: Ané A. , Prestat G. , Manh G. T. , Thiam M. , Josse S. , Pipelier M. , Lebreton J. , Pradère J. P. , Dubreuil D.
Published: October 2007

Two studies, concerning the synthesis of original nucleoside analogs regarded as an application of heterochemistry on thiaazaheterocycle systems from thiaazabutadienes are discussed. The preparation of new N- and C-nucleosides is presented. In the second part, the discovery of aromatic polycyclic derivatives as inhibitors of Tat protein is exposed. The work presented takes into account the participation of African partners in further synthetic research programs carried out in collaboration with the laboratory of Nantes.
UNESCO/IUPAC­CTC Global Program in Microchemistry
Authors: Bradley J. D.
Published: October 2007

It is widely believed that practical work is an essential part of chemistry education. However, in most countries there is no provision for such personal experiences, and even at universities, provision is limited. This problem has been recognized for many years by both UNESCO and IUPAC­CTC (Committee on Teaching of Chemistry), and a number of initiatives were taken to address it. The microchemistry program started four years ago aims to address the problem through promoting a small-scale, low-cost approach. This is done by means of introductory workshops for chemistry educators in different countries. The concept has been received enthusiastically in nearly 40 countries now, and pilot projects have been initiated in several of these.
Chemistry in the 21st century. A central science or a "back office" technical activity?
Authors: Good Mary L.
Published: October 2007

The science of chemistry underlies all of our work in the environmental area and in the new technologies exemplified by materials science and molecular physics. For these areas to progress, chemistry must continue to be a creative and innovative source of new ideas rather than just a handmaiden for currently identified problems in these closely allied areas of study.
Implementing green chemistry. An environmental policy for sustainability
Authors: Thornton Joe
Published: October 2007

A diverse cocktail of synthetic chemicals is now globally distributed in the environment, food web, and human tissues, posing significant health risks to humans and wildlife. The current approach to environmental regulation is inherently inadequate to address the scope and complexity of this problem. A fundamental shift in paradigm is required to protect human health and ecological systems from chemically induced damage. The concept of green chemistry represents a critical part of this shift, but it is not sufficient per se. Only if green chemistry is conceived as part of a new policy based upon precautionary, democratically guided implementation of sustainable production technologies will it contribute significantly to establishing an ecologically compatible production base.
Greening the curriculum. American Chemical Society education programs
Authors: Ware Sylvia A.
Published: October 2007

The American Chemical Society (ACS) Education and International Activities Division is currently working with the U.S. Environmental Protection Agency to produce a series of green chemistry educational materials. To date, products include a searchable, online annotated bibliography of green chemistry references; a collection of cases describing real-world green chemistry solutions; and a Web site for green chemistry materials and information. Various workshops, short courses, and symposia have been provided to share the green chemistry story. Two planning conferences of green chemistry experts have been held to provide direction to the project. In addition to an overview of the above products and services, the project goals and future plans will be described, and the ways in which green chemistry concepts are being integrated across the ACS educational programs in general.
Green chemistry in India
Authors: Kidwai M.
Published: October 2007

Our environment, which is endowed by nature, needs to be protected from ever-increasing chemical pollution. The challenge for the institution and industries is to come together and pursue development in the field of greener chemistry by reducing or eliminating the use and generation of hazardous substances. We have organized a national and international symposium for promoting green chemistry in India, which has provided the platform for interaction of concepts among the leading scientists. The main idea behind this to activate work toward green chemistry for which involvement of academic, industrial, and governmental and non-governmental bodies is needed collectively, which will help the designing and development of environment-friendly chemistry practices in India.
Emergence of a sustainable business community
Authors: Fiksel Joseph
Published: October 2007

Global population and environmental pressures are challenging multinational companies to develop new business strategies founded upon the principles of sustainabilityassuring that they can meet the needs of both present and future generations of customers and stakeholders. Corporate sustainability requires understanding the "triple bottom line", which includes economic, societal, and ecological performance. It involves designing products and processes with a full awareness of their life-cycle costs and benefits, and seeking new technologies to create more value with fewer resources. To put sustainability into practice, companies are beginning to transform their core business processes and develop environmentally and socially responsible products and services. Many are adopting the concepts of industrial ecology and green chemistry in an effort to transform their operations from a linear to a closed-loop business model. This changing climate is creating new opportunities for breakthrough research and development, ranging from nanotechnology to green chemistry.
Sustainability metrics for vehicles
Authors: Sullivan John L.
Published: October 2007

The public has growing concerns about the effects of human activity on the environment for both themselves and future generations. The concept being developed to address these environmental concerns, along with economic and social-equity considerations, is called "sustainable development". The business community has already started to address their contribution to environmental issues through collaborative efforts under organizations such as the World Business Council for Sustainable Development. That work has focused primarily on industrial and corporate environmental and economic performance through the development of eco-efficiency metrics, which are a measure of resources and materials consumed per unit output of product, sales, or value-added. While this development is important, it is not enough. Clearly, the environmental performance of the entire product system must also be elucidated. Otherwise, one might forget, for example, the power plant emissions of his or her so-called "zero-emission" vehicle. The metrics required to characterize sustainable practices and systems have yet to be developed. The set will include economic, environmental, and social-equity metrics. Because of their system-oriented environmental performance representation, life-cycle assessment metrics are certainly going to be included in such a set. A discussion of some potential life-cycle metrics follows.
Integrated emissions management for automotive painting operations
Authors: Kim B. R. , Kalis E. M. , Adams J. A.
Published: October 2007

An integrated scheme has been studied to reduce gaseous (volatile organic compounds [VOCs]), liquid (scrubber water), and solid (paint sludge) emissions from automotive painting operations by converting an existing spray-booth scrubber system to a bioreactor to capture and degrade VOCs and pyrolyzing paint sludge to produce an adsorbent. This paper describes the experimental results of 1) a pilot-scale study conducted at an assembly plant to evaluate the biological VOC removal using activated-sludge bioreactors and 2) a bench-scale study on VOC adsorption on paint-sludge adsorbents. The results indicate that the biological VOC removal is technically feasible (comparable VOC removal and less energy usage as compared to the widely used, vapor phase-activated carbon adsorption/thermal oxidation process) and economically feasible (one order of magnitude cheaper) and that paint-sludge adsorbents exhibited appreciable adsorption capacity. Implementation of the scheme requires more than technical and economical feasibility. The issues to be overcome include the inertia of past practices, overall systemic thinking, and moving targets (processes and regulations).
Developments in CO2 research
Authors: Behles Jacqueline A. , DeSimone Joseph M.
Published: October 2007

CO2 can be a good solvent for many compounds when used in its compressed liquid or supercritical fluid state. Above its critical temperature and critical pressure (Tc = 31 C, Pc = 73.8 bar), CO2 has liquid-like densities and gas-like viscosities, which allows for safe commercial and laboratory operating conditions. Many small molecules are readily soluble in CO2, whereas most macromolecules are not. This has prompted development of several classes of small molecule and polymeric surfactants that enable emulsion and dispersion polymerizations as well as other technological processes.
Supercritical fluid extraction of Z-sabinene hydrate-rich essential oils from Romanian Mentha hybrids
Authors: Pop Eugenia Gh. , Barth Danielle
Published: October 2007

The green solvent SC­CO2 was used to extract the volatile part, rich in thermolabile compounds, Z-sabinene hydrate and its acetate, from a Romanian mint hybrid. The best yield, 2.26%, was obtained at 92­94 bar, 50 °C (SFE 2). Kinetic study of SC­CO2 extraction and hydrodistillation and monitoring by gas chromatography (GC) and gas chromatography mass spectrometry (GC­MS) analysis established optimal conditions for SC­CO2 extracts with a high content of Z-sabinene hydrate (43.5%) and its acetate (19.15%) and flavor similar to plant material (P = 90­100 bar, T = 50 °C). Only at the beginning of hydrodistillation was it possible to obtain a high content of Z-sabinene hydrate (37.3%, after 70 min), but a high content of its acetate never could be reached. This study suggests a way to obtain Z-sabinene hydrate from a natural source and reveals the importance of mild conditions to keep what is valuable in nature.
Low-temperature manufacturing of fine pharmaceutical powders with supercritical fluid aerosolization in a Bubble Dryer®
Authors: Sievers R. E. , Huang E. T. S. , Villa J. A. , Kawamoto J. K. , Evans M. M. , Brauer P. R.
Published: October 2007

Aerosols play an important role in thin film deposition, fine powder generation, and drug delivery. Green processes to form aerosols are needed to eliminate the use of toxic organic solvents and minimize the production of liquid wastes and the emission of halogenated and oxidant-forming organic compounds. We have developed a new patented process, Carbon Dioxide-Assisted Nebulization with a Bubble Dryer® (CAN-BD), that can generate a dense aerosol with small droplet and microbubble sizes that are dried to form particles less than 3 µm in diameter [1­9]. The process uses carbon dioxide as an aerosolization aid, and this permits drying at lower temperature than usually needed in conventional spray-drying. Intimate mixing of supercritical carbon dioxide with aqueous protein solutions causes the formation of microbubbles, which are rapidly dried in less than 5 s. The process is more environmentally benign than traditionally used methods, and is superior when thermally unstable materials are being processed. Fine-particle pharmaceutical powders can be rapidly and easily made by this new CAN-BD process, requiring less energy and eliminating residues of toxicologically or environmentally objectionable solvents. Manufacturing dry powders of pharmaceuticals for pulmonary drug delivery and increasing bioavailability are the purposes of developing and marketing the new Temco Bubble Dryer.
Quasi-nature catalysis. Rhodium-catalyzed C­C bond formation in air and water
Authors: Huang Taisheng , Venkatraman Sripathy , Meng Yue , Nguyen Tien V. , Kort Daniel , Wang Dong , Ding Rui , Li Chao-Jun
Published: October 2007

Transition-metal catalysis is out-grown from dry-boxes where the use of inert gas atmosphere and the exclusion of moisture have been essential. Such a restriction undoubtedly imposes limitations in the application of these reactions in organic synthesis and in the recycling of the catalysts. This article discusses some recent advances of rhodium-catalyzed carbon­carbon bond formations under the natural conditions of air and water.
Improving self-defense in plants. Martial arts for vegetables
Authors: Moyna Patrick , Heinzen Horacio
Published: October 2007

From the dawn of agriculture there has been an ever-intensifying human effort to improve yields by having crops with enhanced biological similarity (i.e., characteristics of product, maturation time, height, color, etc.). The ultimate stage is to plant a crop where all individuals behave in exactly the same way, being clones of each other. This very intensive approach leads to loss of intrapopulation biodiversity and to unstable systems, prone to disastrous losses should anything go wrong.

Biological evolutionary success is usually derived from high adaptability to ever-changing external conditions. Highly specialized plants (such as certain orchids) or animals survive by correctly performing a high-wire act of enormous risk. External disbalances have catastrophic results on these species. Nature excels and corrects imbalances increased biodiversity within natural populations. Given this situation, we should study the defensive systems used by plants and improve on those natural systems.
Selectivity in analytical chemistry (IUPAC Recommendations 2001)
Authors: Vessman Jörgen , Stefan Raluca I. , van Staden Jacobus F. , Danzer Klaus , Lindner Wolfgang , Burns Duncan Thorburn , Fajgelj Aleš , Müller Helmut
Published: October 2007

The correct use of the term "selectivity" and its clear distinction from the term "specificity" are discussed. A definition of selectivity is given, and it is recommended that the use of this term be promoted and that the use of the term "specificity" be discouraged.
Molecular recognition at kappa opioid receptors
Authors: Portoghese Philip S.
Published: October 2007

Structure­activity relationships are rarely straightforward, and often are more complicated than they appear. For this reason, the use of site-directed mutagenesis as a complementary tool to analyze structure­activity relationships has been invaluable. Here, we illustrate how site-directed mutagenesis has led to greater insight into the molecular basis for molecular recognition of norbinaltorphimine and to the design of novel kappa antagonists. Given the paucity of high-resolution crystal structures for membrane-bound receptors, the use of a coordinated "two-dimensional" paradigm that involves molecular modification of both the ligand and the receptor, affords a useful approach to the study of molecular recognition. This paradigm has led to the design of highly potent and selective kappa opioid receptor antagonists that are derivatives of the delta opioid receptor antagonist, naltrindole.
Semicarbazide-sensitive amine oxidase. Its physiological significance
Authors: Magyar K. , Mészáros Z. , Mátyus P.
Published: October 2007

Although the existence of plasma- and tissue-bound semicarbazide-sensitive amine oxidases (SSAOs) has been recognized earlier, the physiological relevance of the enzyme still remains uncertain. Recent data suggest that elevated serum SSAO activity might cause endothelial injury. Formation of cytotoxic metabolites (e.g., formaldehyde) and increased oxidative stress might lead to initiation or progression of atherosclerosis. Significant positive correlation was found between serum SSAO activity and severity of atherosclerosis, and diabetic macrovascular complications. Effective and selective inhibitors of human SSAO might exert cytoprotective effect on endothelial cells. Compounds, having similar structure to mexiletine, were synthesized and studied relating to SSAO activity. The reference substrate was MDL-72974A. Unfortunately, our new compounds did not reach the potency of the reference substance using human serum samples. In conclusion, we suppose that vascular and soluble SSAO enzymes might have different inhibitor sensitivity. Further studies are required to determine whether the soluble or vascular isoform of SSAO will be the main therapeutic target in the future.
Chemical development of the vasopressin receptor 2 antagonist SR-121463
Authors: Hermecz István , Sánta-Csutor Andrea , Gönczi Csaba , Héja Gergely , Csikós Éva , Simon Kálmán , Smelkó-Esek Ágota , Podányi Benjámin
Published: October 2007

A facile convergent total synthesis of the selective, potent, and orally active V2 non-peptide antagonist, SR-121463, was developed by modification of the discovery route. One of the late intermediates, the sulfonyl chloride 1, was synthesized from 3-hydroxybenzoic acid (19) by regioselective sulfonation, O-methylation and amidation in four steps. Another late intermediate, indolin-2-one 2, was prepared from p-phenetidine (8) through the indolin-2-one 16, where the cyclohexanone moiety of 27 was introduced into the active 3-methylene group of 16 by sequential transformation using methyl acrylate and KOtBu. After formation of the cyclic ketal moiety of 13, its ring-opening was achieved by using NaBH4 in the presence of CCl3COOH. The morpholino group in 2 was introduced in accordance with the discovery approach, starting from the 2-hydroxyethoxy derivative 14 through the tosyloxy derivative 15 with morpholine in a one-pot reaction. In this way, the indolin-2-one 2 was synthesized from 8 in six steps. Finally, acylation of the indolin-2-one 2 was achieved with the sulfonyl chloride 1 in the presence of KOtBu in dimethyl sulfoxide (DMSO) at room temperature. This synthetic route proved to be applicable for the large-scale synthesis of SR-121463.
NMR spectroscopy in drug design
Authors: Heller Markus , Kessler Horst
Published: October 2007

The process of preclinical drug discovery consists of two steps: finding of initial hits (binding ligands to a medicinal relevant target, usually a protein) and lead optimization. Nuclear magnetic resonance spectroscopy is a powerful tool that can provide valuable information to every step of drug development. NMR is commonly used for characterizing the structure and molecular dynamics of target or ligand molecules. During the structure-based lead optimization, NMR provides insight into the structural and dynamical properties of the target-ligand complex. Recently, the use of NMR in the lead finding process by screening technologies has been shown. For the latter use, new techniques have also been developed. Those techniques, in combination with high throughput, have lead to an efficient screening of libraries composed of small molecules. In this article, the role of NMR during the discovery of a drug candidate is described.
New chemical structures of hypolipidemic and antiplatelet activity
Authors: Chilmonczyk Z. , Siluk D. , Kaliszan R. , Łozowicka B. , Popławski J. , Filipek S.
Published: October 2007

Elevated lipid level is supposed to be one of the main risk factors of atherosclerosis and subsequent cardiovascular disease (and is connected to mortality). Therefore, lipid lowering is one of the major targets in cardiovascular disease treatment and prevention. Also, blood platelets play a pivotal role in the development of atherosclerosis and fatal thrombus formation in the course of coronary heart disease. Therefore, there is a great necessity to acquire drugs inhibiting platelet aggregation and clot generation. The present paper reviews new chemical structures in development for the treatment and prevention of hyperlipidemia, atherosclerosis, and subsequent cardiovascular disease. The authors' recent results are also reported regarding synthesis of a new group of a-asarone analogs. These compounds were identified as an original class of agents exhibiting hypolipidemic and antiplatelet (mice, rats) activities. Although the mechanism of the compounds' pharmacological activity has not been identified, quantum-mechanical calculations allowed structural requirements to be described that correspond to the activity (a hypothetical pseudoreceptor structure). Since it is known that asarone and its derivatives may exhibit genotoxicity, calculations were carried out to identify derivatives of possibly low genotoxic activity.
Opioid and sigma receptor studies. New developments in the design of selective sigma ligands
Authors: Ronsisvalle Giuseppe , Marrazzo Agostino , Prezzavento Orazio , Cagnotto Alfredo , Mennini Tiziana , Parenti Carmela , Scoto Giovanna M.
Published: October 2007

New racemic and chiral methyl 2-{[4-(4-chlorophenyl)-4-hydroxypiperi-din-1-yl]methyl}-1-phenylcyclopropanecarboxylate derivatives were synthesized in order to obtain sigma ligands with increased affinity and selectivity compared to (+)-MPCB and haloperidol. The cis-(±)-7 racemic mixture showed a better binding affinity and selectivity than the (±)-8 trans isomers. Between the two cis enantiomers, (+)-7, with configuration (1R,2S), showed a very high affinity and the best selectivity for s1. All compounds synthesized (7­9) showed a reduced or negligible affinity for opioid and dopaminergic D1 and D2 receptors. Nociceptive in vivo test confirms that (+)-7 (namely MR200), such as non-selective antagonist haloperidol, increased the analgesic effect induced by the k opioid selective ligand U50,488H and reversed the inhibiting effect of (+)-pentazocine on analgesia.
Generic source-based nomenclature for polymers(IUPAC Recommendations 2001)
Authors: Maréchal E. , Wilks E. S.
Published: October 2007

The commission has already published two documents on the source-based names of linear copolymers and nonlinear polymers; however, in some cases this nomenclature leads to ambiguous names. The present document proposes a generic source-based nomenclature that solves these problems and yields clearer source-based names. A generic source-based name comprises two parts:

polymer class (generic) name followed by a colon

2) the actual or hypothetical monomer name(s), always parenthesized in the case of a copolymer

The formula, the structure-based name, the source-based name, and the generic source-based name of the polymer are given for each example in the document. In some cases, only generic source-based give unambiguous names, for example, when a polymer has more than one name or when it is obtained through a series of intermediate structures. The rules concern mostly polymers with one or more types of functional group or heterocyclic system in the main chain, but to some extent they are also applicable to polymers with side-groups, carbon-chain polymers such as vinyl or diene polymers, spiro and cyclic polymers, and networks.

Prepared by a Working Group consisting of R. E. Bareiss (Germany), R. B. Fox (USA), K. Hatada (Japan), K. Horie (UK), A. D. Jenkins (UK), J. Kahovec (Czech Republic), P. Kubisa (Poland), E. Maréchal (France), I. Meisel (Germany), W. V. Metanomski (USA), I. Mita (Japan), R. F. T. Stepto (UK), and E. S. Wilks (USA)
Quantum chemical B3LYP/cc-pvqz computation of ground-state structures and properties of small molecules with atoms of Z ≤ 18 (hydrogen to argon)(IUPAC Technical Report)
Authors: Janoschek Rudolf
Published: October 2007

Since density functional theory (DFT) achieved a remarkable break-through in computational chemistry, the important general question "How reliable are quantum chemical calculations for spectroscopic properties?" should be answered anew. In this project, the most successful density functionals, namely the Becke B3LYP functionals, and the correlation-consistent polarized valence quadruple zeta basis sets (cc-pvqz) are applied to small molecules. In particular, the complete set of experimentally known diatomic molecules formed by the atoms H to Ar (these are 214 species) is uniformly calculated, and calculated spectroscopic properties are compared with experimental ones. Computationally demanding molecules, such as open-shell systems, anions, or noble gas compounds, are included in this study. Investigated spectroscopic properties are spectroscopic ground state, equilibrium internuclear distance, harmonic vibrational wavenumber, anharmonicity, vibrational absolute absorption intensity, electric dipole moment, ionization potential, and dissociation energy. The same computational method has also been applied to the ground-state geometries of 56 polyatomic molecules up to the size of benzene. Special sections are dedicated to nuclear magnetic resonance (NMR) chemical shifts and isotropic hyperfine coupling constants. Each set of systems for a chosen property is statistically analyzed, and the above important question "How reliable...?" is mathematically answered by the mean absolute deviation between calculated and experimental data, as well as by the worst agreement. In addition to presentation of numerous quantum chemically calculated spectroscopic properties, a corresponding updated list of references for experimentally determined properties is presented.
Evolution and revolution in instrumentation for plasma-source mass spectrometry
Authors: Hieftje Gary M. , Barnes James H. , Grøn Ole A. , Leach Andrew M. , McClenathan Denise M. , Ray Steven J. , Solyom David A. , Wetzel William C. , Denton M. Bonner , Koppenaal David W.
Published: October 2007

Plasma-source mass spectrometry, usually in the form of inductively coupled plasma mass spectrometry (ICP-MS), has matured into a widely accepted method for ultra-trace multielemental analysis. However, the method exhibits shortcomings. For example, it does not provide adequate precision for isotope ratio measurements if many isotopes are to be determined. Moreover, isobaric overlaps (spectral interferences) can be very troublesome in some situations. Similarly, matrix interferences can adversely affect many determinations. Yet, it is in the area of high-speed transient measurements that ICP-MS perhaps suffers its greatest weakness. When sampling devices such as flow injection, laser ablation, electrothermal vaporization, or chromatography are employed, the user must choose between broad elemental or isotopic coverage and signal-to-noise ratio (S/N). In turn, compromised S/N means lower precision or poorer detection limits. Here, new instrumentation aimed at overcoming these limitations will be described. One system, based on a time-of-flight mass spectrometer, provides excellent detection limits, resolving power better than commercial quadrupole mass filters, precision of at least 0.02% rsd in a ratioing mode, and extraordinarily high speed for use with transient sampling devices. The second instrument is based on a sector-field mass spectrometer but, unlike other such units, is equipped with a focal-plane array detector. So equipped, the system can detect a broad mass range at once.
Exploring new opportunities with sum-frequency nonlinear optical spectroscopy
Authors: Shen Y. R.
Published: October 2007

Over the last decade, infrared-visible sum-frequency generation has been developed into a powerful vibrational spectroscopic technique, especially for surface studies. We give here a brief review of the technique and a few recent applications of the technique to liquid and polymer surfaces. We also describe how the technique has found unique applications in our studies of surface melting of ice, ferroelectric ice films, and molecular chirality in chiral liquids. Doubly resonant sum-frequency generation as surface-specific two-dimensional spectroscopy is discussed.
Subtle order in settling suspensions
Authors: Ackerson B. J. , Lei X. L. , Tong P.
Published: October 2007

A dilute suspension of uniform, non-Brownian spheres settles slowly in a viscous solvent. The initially well-mixed system showing Poisson or random occupancy statistics evolves to a system having reduced number fluctuations, but otherwise appearing random. The reduced number fluctuations are consistent with recent measurements of velocity fluctuations in settling suspensions. These experimental results test the assumptions leading to the theoretical predictions by Calflisch and Luke that the velocity fluctuations increase without limit with increasing sample dimension. The theoretical prediction assumes Poisson occupation statistics contrary to our observations.
Charge-stabilized colloidal suspensions. Phase behavior and effects of confinement
Authors: Klein R. , von Grünberg H. H.
Published: October 2007

The Poisson­Boltzmann (PB) equation is used to investigate effective colloid-interface interactions and the phase behavior of charge-stabilized colloidal suspensions. When a colloidal particle, immersed in an electrolyte, approaches an interface, which may be neutral (such as air) or charged (like electrodes, glass, etc.), image charge effects plus the deformation of the colloidal ion atmosphere by the interface lead to an effective interaction which can be attractive or repulsive, depending on the surface charge density and the dielectric constants of the interface and the electrolyte. Two cases are considered: i) a spherical particle near a like-charged interface, and ii) a rod-like particle in the vicinity of an oppositely charged interface. The latter serves as a model for the adsorption of (anionic) DNA on a cationic membrane, and it is shown that the effective attraction, induced by the release of counterions on approach of the DNA to the membrane, makes up an essential contribution to the total DNA-membrane effective interaction. To understand the phase behavior of charge-stabilized colloidal suspensions, we study a PB cell model of a bulk suspension and investigate how the PB equation can best be linearized. It is found that the previously predicted gas­liquid phase coexistence results when the PB equation is linearized about the Donnan potential. No indication of such a spinodal instability could, however, be found, when the free energy is evaluated using the numerical solution of the full PB equation. This suggests that the predicted gas­liquid phase coexistence is an artifact of the linearization.
Guidelines for the representation of pulse sequences for solution-state nuclear magnetic resonance spectrometry (IUPAC Recommendations 2001)
Authors: Davies Antony N. , Lambert Jörg , Lancashire Robert J. , Lampen Peter , Conover Woody , Frey Michael , Grzonka Michael , Williams Evan , Meinhart Douglas
Published: October 2007

In drawing up the specifications for a standard for multidimensional nuclear magnetic resonance spectroscopy (NMR) it became clear that the spectroscopic data content needed to be qualified by experimental condition information especially pertaining to the pulse sequences used to obtain the free induced decays or spectra. Failure to include this information not only severely inhibits the ability of subsequent data handling packages to work with the experimental data, but also makes interpretation of the final results virtually impossible.

This paper has been produced in collaboration with the NMR spectrometer manufacturers in an attempt to get agreement on a definitive list of the most frequently used pulse sequence programs. The list includes entries where common agreement has been reached as to the acronym to name the experiment and the key instrument independent parameters needed to report concisely.

It is not intended to restrict in any way the freedom of manufacturers or users to develop new and novel experimental pulse sequences, but should aid reporting of experimental data where the more common sequences are in use.
JCAMP-DX. A standard format for the exchange of ion mobility spectrometry data (IUPAC Recommendations 2001)
Authors: Baumbach Jörg Ingo , Davies Antony N. , Lampen Peter , Schmidt Hartwig
Published: October 2007

The relatively young field of ion mobility spectrometry has now advanced to the stage where the need to reliably exchange the spectroscopic data obtained worldwide by this technique has become extremely urgent. To assist in the validation of the various new spectrometer designs and to assist in inter-comparisons between different laboratories reference data collections are being established for which an internationally recognized electronic data exchange format is essential.

To make the data exchange between users and system administration possible, it is important to define a file format specially made for the requirements of ion mobility spectrometry. The format should be computer readable and flexible enough for extensive comments to be included. In this document, we define a data exchange format, agreed on by a working group of the International Society for Ion Mobility Spectrometry at Hilton Head Island, USA (1998) and Buxton, UK (1999).

This definition of this format is based on the IUPAC JCAMP-DX protocols, which were developed for the exchange of infrared spectra [1] and extended to chemical structures [2], nuclear magnetic resonance data [3], and mass spectra [4]. This standard of the Joint Committee on Atomic and Molecular Physical Data is of a flexible design. The International Union of Pure and Applied Chemistry have taken over the support and development of these standards and recently brought out an extension to cover year 2000 compatible date strings and good laboratory practice [5]. The aim of this paper is to adapt JCAMP-DX to the special requirements of ion mobility spectra [6].
NMR nomenclature. Nuclear spin properties and conventions for chemical shifts(IUPAC Recommendations 2001)
Authors: Harris Robin K. , Becker Edwin D. , Cabral de Menezes Sonia M. , Goodfellow Robin , Granger Pierre
Published: October 2007

A unified scale is recommended for reporting the NMR chemical shifts of all nuclei relative to the 1H resonance of tetramethylsilane (TMS). The unified scale is designed to provide a precise ratio, Ξ, of the resonance frequency of a given nuclide to that of the primary reference, the 1H resonance of TMS in dilute solution (volume fraction, φ < 1%) in chloroform. Referencing procedures are discussed, including matters of practical application of the unified scale. Special attention is paid to recommended reference samples, and values of Ξ for secondary references on the unified scale are listed, many of which are the results of new measurements.

Some earlier recommendations relating to the reporting of chemical shifts are endorsed. The chemical shift, δ, is redefined to avoid previous ambiguities but to leave practical usage unchanged. Relations between the unified scale and recently published recommendations for referencing in aqueous solutions (for specific use in biochemical work) are discussed, as well as the special effects of working in the solid state with magic-angle spinning. In all, nine new recommendations relating to chemical shifts are made.

Standardized nuclear spin data are also presented in tabular form for the stable (and some unstable) isotopes of all elements with nonzero quantum numbers. The information given includes quantum numbers, isotopic abundances, magnetic moments, magnetogyric ratios and receptivities, together with quadrupole moments and line-width factors where appropriate.
Photocatalytic transformation of organic compounds in the presence of inorganic ions
Authors: Calza Paola , Pelizzetti Ezio
Published: October 2007

The influence of halide ions on the photocatalytic process on titanium dioxide has been investigated carefully. Chloride and bromide ions, acting as hole scavengers, generate active radical species (e.g., ·Cl and ·Br) that participate in reactions with the organic compounds and the transient intermediates. Chloride and bromide ions have shown to deeply inhibit the degradation rate of chloroform and tetrachloromethane and to modify both the qualitative and quantitative distribution of their intermediates formed during the degradation process. In the presence of bromide, CBrCl3 is detected as intermediate during CCl4 degradation, while in the presence of chloride, formation of CCl4 is observed in the CHCl3 degradation. Fluoride ions, differently from the other halides, cannot be oxidized by the valence hole and may be used as a diagnostic tool in mechanistic studies. The influence of fluoride on phenol has been investigated, and, by choosing appropriate experimental conditions, it was possible to evaluate the role of the different active species in the photocatalytic process.
Titania-based heterogeneous photocatalysis. Materials, mechanistic issues, and implications for environmental remediation
Authors: Rajeshwar Krishnan , Chenthamarakshan C. R. , Goeringer Scott , Djukic Miljana
Published: October 2007

Using hexavalent chromium [Cr(VI)] and methylene blue (MB) as model substrates, we discuss three aspects of TiO2-based heterogeneous photocatalysis. We show first that a given TiO2 sample may not be simultaneously optimal for photocatalytically driving the reduction of Cr(VI) and the oxidation of MB. We further show that a TiO2 sample that strongly adsorbs either of these substrates in the dark is not optimal as a photocatalyst. The other two aspects concern circumventing the rather poor surface catalytic properties and visible light photoresponse of TiO2, respectively. Strategies revolving around the visible light photoexcitation of the substrate itself and metal-modification of the TiO2 surface, are described as possible solutions.
New inhibitors for copper corrosion
Authors: Vastag Gy. , Szöcs E. , Shaban A. , Kálmán E.
Published: October 2007

The study of the effectiveness of several potential copper corrosion inhibitors in acidic media was studied. The investigated thiazole derivative functional groups contain heterocyclic atoms such as nitrogen, sulfur, and oxygen. Thiazole derivatives, 5-benzylidene-2,4-dioxotetrahydro-1,3-thiazole (BDT) 5-(4¢-isopropylbenzylidene)-2,4-dioxotetrahydro-1,3-thiazole (IPBDT), 5-(3¢-thenylidene)-2,4-dioxotetrahydro-1,3-thiazole (TDT), and 5-(3¢,4¢-dimetoxybenzylidene)-2,4-dioxotetrahydro-1,3-thiazole (MBDT) were tested for copper corrosion inhibition properties. The electrolyte solution was 0.1 M Na2SO4.

In situ information on corrosion and inhibition processes can be obtained using different techniques. Electrochemical measurements (EIS), in situ scanning probe microscopy (SPM), in addition to quartz crystal microbalance (QCM) measurements were applied. Those methods are very useful owing to their high sensitivity and resolution. Dynamic STM and AFM measurements on Cu(111) single-crystal electrode with and without the addition of some inhibitors were performed.

The presence of the isopropyl group in the case of IPBDT produced far better protection against copper corrosion in acidic sulfate-containing media than the rest of the derivatives.
Intramolecular cyclization of propargyl derivatives using environmentally friendly methodologies
Authors: Duñach E. , Esteves A. P. , Freitas A. M. , Lemos M. A. , Medeiros M. J. , Olivero S.
Published: October 2007

The electrochemical intramolecular cyclization of propargyl derivatives containing a carbon­halogen bond in N,N'-dimethylformamide at constant current in a diaphragmless cell has been developed using Ni(II) complexes as electron-transfer mediators.
Degradation of dye effluent
Authors: Lorimer J. P. , Mason T. J. , Plattes M. , Phull S. S. , Walton D. J.
Published: October 2007

Solutions of both basic and acidic dyes were subject to sonolysis, electrolysis, and sonoelectrolysis. Only basic dyes were decolorized by ultrasound alone. Removal of the acidic dye Sandolan Yellow required the use of an electrooxidation process. The rate of electrochemical decolorization in the absence of ultrasound was dependent on the type of electrolyte, the electrolyte concentration, the reaction temperature, and the current density. The sonoelectrooxidation of Sandalon Yellow needed to be performed in a sealed cell to minimize the effects of ultrasonic degassing.
Direct electrochemistry of redox proteins or enzymes at various film electrodes and their possible applications in monitoring some pollutants
Authors: Hu Naifei
Published: October 2007

Water-insoluble films modified on the surface of solid electrodes may provide a unique microenvironment for electron transfer of some redox proteins or enzymes. The film materials can be two-tail surfactants, or composites of polyion-surfactant or clay-surfactant. Both surfactant and composite films cast on surface of electrodes are self-assembled into an ordered multibilayer structure, which is very similar to the bilayer structure of biological membrane. Amphiphilic polymers can also be used for making films. Incorporated heme proteins such as myoglobin (Mb), hemoglobin (Hb), or horseradish peroxidase (HRP) in these films demonstrated reversible voltammetry. Studies of direct electrochemistry of these proteins in various films by our group are reviewed in this paper. The protein films may provide a good model for study of electron transfer process in biological systems. The electrocatalytic properties of the protein films may also be applied to monitor some pollutant substrates.