bluuebunny/crossref_metadata_2025_split huggingface dataset:
Affinity electrochemical biosensors for pollution control
Authors: Mascini M. 
Published: October 2007

Abstract
Disposable, electrochemical DNA-based biosensors have been exploited for the determination of low-molecular-weight compounds with affinity for nucleic acids. The application is related to the molecular interaction between the surface-linked DNA obtained from calf thymus and the target pollutants or drugs, in order to develop a simple device for rapid screening of genotoxic or similar compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of the DNA immobilized on the electrode surface and investigated by chronopotentiometric or square-wave voltammetric analysis. The DNA biosensor is able to detect known intercalating and groove-binding compounds such as daunomycin, polychlorinated biphenyls (PCBs), aflatoxin B1, and aromatic amines. Applicability to river and waste water samples is discussed and reported.
Devices for ion-sensing and pX measurements
Authors: Thomas J. D. R. 
Published: October 2007

Abstract
Thirty years of ion-selective electrode (ISE) researches at the University of Wales, Cardiff are outlined. They summarize developments of PVC membrane ISEs, first for calcium and then of other systems, including the improved calcium dioctyl-phenyl-phosphate sensor for calcium and those of ion-exchangers, polyalkoxylates, and cyclic and acyclic polyethers for various anions and cations. Electrodes based on polyalkoxylates have interesting properties toward the polyethers themselves. Some ISE failure causes are discussed. Attention is given to applications, including analysis of wash liquors and nonionic surfactants, biomedical roles, and studies of sulfate-reducing bacteria activity. Coated-wire ISEs and ion-selective field effect transistors (ISFETs) are mentioned, as are other modes of ISE deployment. The review concludes with some fundamental features of PVC electrode membranes as determined by radiotracer, applied potential, and potentiostatic approaches.
Speciation dynamics and bioavailability of metals. Exploration of the case of two uptake routes
Authors: van Leeuwen Herman P. , Pinheiro José Paulo 
Published: October 2007

Abstract
The steady-state biouptake of metals from complex media is outlined for the case of two different uptake routes. The analysis comprises the limiting situations of inert and labile complexes, and distinguishes between bioinactive and bioactive (lipophilic) complexes. Depending on the dynamic features, fluxes of the different species may be either coupled or uncoupled. The role of the lipophilic ligands may be important in the overall uptake process. Some specific cases are discussed.
Detecting and circumventing sources of inaccuracy in flow analysis
Authors: Zagatto Elias A. G. , Rocha Fábio R. P. , Martelli Patrícia B. , Reis Boaventura F. 
Published: October 2007

Abstract
Mechanized procedures for chemical analyses are susceptible to systematic errors usually difficult to trace. This holds also for flow analysis that although accepted worldwide may sometimes yield inaccurate results. The present work focused on the development of a simple system able to detect and circumvent sources of inaccuracy. The versatility inherent in the multicommuted flow analyzers was exploited for real-time characterization of the source of inaccuracy and overcoming the problem for every assayed sample. Specific situations where the analytical results are more susceptible to inaccuracy are emphasized.
Green chemistry. Sustaining a high-technology civilization
Authors: Ghosh Anindya , Gupta Sayam S. , Bartos Michael J. , Hangun Yelda , Vuocolo Leonard D. , Steinhoff Bradley A. , Noser Christopher A. , Horner David , Mayer Sherry , Inderhees Kevin , Horwitz Colin P. , Spatz Jonathan , Ryabov Alexander D. , Mondal Sujit , Collins Terrence J. 
Published: October 2007

Abstract
By learning how to balance natural resource limitations and pollution prevention with economic growth, green chemistry will become the central science of sustainability. The elimination of persistent pollutants is vital for a sustainable civilization. To achieve this, the most important guiding concept is that the elemental composition of technology should be shifted toward the elemental composition of biochemistry. Oxidation chemistry is currently a prolific producer of persistent pollutants. Many arise from the use of chlorine, hypochlorite, or chlorine dioxide in large-scale oxidation processes. Oxidation chemistry can be greened by replacing these with catalyzed alternatives based on Nature's oxidizing agent, hydrogen peroxide. TAML® (TetraAmidoMacrocyclicLigand) iron catalysts, which were invented at Carnegie Mellon University, are widely patented and are being developed to activate H2O2 for commercial applications. TAML activators are water-soluble, easy to use, function well from neutral to basic pH, are not dominated by nonselective Fenton-like reactivity, are straightforward to synthesize, work effectively in minute concentrations, enable peroxide processes to occur at temperatures well below those of the processes targeted for replacement, and are amenable to modification for capturing novel selectivities. TAML activators are "dial-a-lifetime" catalysts: an activator can be chosen exhibiting a lifetime commensurate with the desired task.
Using neoteric solvents in oil shale studies
Authors: Koel M. , Ljovin S. , Hollis K. , Rubin J. 
Published: October 2007

Abstract
The liquefaction, gasification, and other chemical modifications of oil shale are challenging goals of chemistry and chemical engineering. The use of new solvent systems, such as supercritical fluids and ionic liquids, represents new avenues in the search of environmentally benign technologies. Supercritical fluid extraction (SFE) with carbon dioxide is particularly effective for the isolation of substances of medium molecular weight and relatively low polarity. At elevated temperatures it is possible to unite the breaking chemical bonds in the kerogen organic matter and convert the former into oil with extraction using supercritical fluids. Quantitative and qualitative information obtained at different temperatures during SFE is providing some insight into the speciation of hydrocarbons in geological samples. Ionic liquids were studied as potential solvents for kerogen extraction. However, these chemical processes are favored at elevated temperatures up to the thermal degradation temperature of kerogen, 400 C. There were observed significant differences in the chemical composition of extracted oil and from the oil from the classical semicoking process of oil shale. An additional application would be a combination of the two methodsthe use of supercritical carbon dioxide to recover nonvolatile organic compounds from room-temperature ionic liquid without using organic solvents.
Organometallic chemistry at the threshold of a new millennium. Retrospect and prospect
Authors: Halpern Jack 
Published: October 2007

Abstract
The evolution of organometallic chemistry during the second half of the 20th century has transformed chemical science and technology to a degree and in ways that have rarely been matched throughout the history of chemistry. These include the discovery of radically new types of chemical compounds; novel structures and bonding modes; unprecedented reactivity patterns; unsuspected roles of organometallic chemistry in biology; powerful new synthetic methodologies; new materials; and whole new classes of catalysts and catalytic processes of extraordinary versatility and selectivity. The impact of these developments, which still are unfolding, has been truly revolutionary. Some milestones in this remarkable chapter of chemical history, as well as challenges and opportunities confronting organometallic chemistry today, will be examined.
Organometallic pentalene complexes
Authors: Cloke F. Geoffrey N. 
Published: October 2007

Abstract
There has been a recent renaissance in the organometallic chemistry of pentalene, following the discovery of the first complexes incorporating pentalene η8-ligated to a single metal center. This short review outlines recent work in the author's laboratory on the preparation of silylated pentalene ligands and the subsequent synthesis of novel, monometallic, and bimetallic pentalene sandwich and half-sandwich complexes of the f- and d-block elements.
New olefin polymerization and copolymerization catalysts. Effect of coordinating functionalities
Authors: Sen Ayusman 
Published: October 2007

Abstract
The coordination of the functionalities that may be present either in the monomer or in the growing polymer chain to the metal center is a key impediment in the development of new transition metal-based catalysts for the insertion polymerization of polar monomers. Several examples are discussed to illustrate this problem. Additionally, it is shown that the reduction of the electrophilicity of the metal center is one way to decrease this interaction.
Racemic catalysis through asymmetric activation
Authors: Mikami Koichi , Korenaga Toshinobu , Matsumoto Yousuke , Ueki Makoto , Terada Masahiro , Matsukawa Satoru 
Published: October 2007

Abstract
"Asymmetric activation" provides a general strategy for the use of racemic catalysts not only with atropos but also tropos ligands without enantiomer resolution.
Novel coordination behavior of unsaturated hydrocarbon ligands on Pd-Pd bonds
Authors: Kurosawa Hideo , Murahashi Tetsuro 
Published: October 2007

Abstract
The dinuclear Pd (I) complexes containing substitutionally labile acetonitrile ligands [Pd2 (CH3CN) 2 (L) 2] (BF4) 2 [L = CH3CN (1) , PPh3 (2) ] were prepared. The complex 1 was demonstrated to serve as a versatile building block for synthesizing sandwich chain complexes made of conjugated polyenes and linear polypalladium chains. The complex 2 reacted with 2 equiv arylacetylenes to give dinuclear organopalladium complexes arising from formal [2s + 2p + 2p] addition with the Pd-Pd s bond participating as one component. The reaction of 2 with 1,3-butadiene afforded a complex regarded as an intermediate lying halfway on the [2s + 4p] reaction coordinate.
Recent advances in asymmetric catalysis. Synthetic applications to biologically active compounds
Authors: Genet Jean Pierre , Marinetti Angela , Ratovelomanana-Vidal Virginie 
Published: October 2007

Abstract
New chiral cationic ruthenium complexes have been used for the industrial synthesis of (+) -dihydrojasmonate. A new class of electron-rich C2-symmetric 2,4-disubstituted phosphetanes (CnrPHOS) was developed. Preliminary evaluation of their catalytic properties revealed high efficiency in rhodium and ruthenium-catalyzed asymmetric hydrogenations. A new stereochemical model is presented in which the phosphetane Rh-catalyzed hydrogenation follows an apparent stability-controlled mechanism.
Copper complexes for catalytic, aerobic oxidation of hydrocarbons
Authors: Murahashi Shun-Ichi , Komiya Naruyoshi , Hayashi Yukiko , Kumano Tatsuyuki 
Published: October 2007

Abstract
Catalytic oxidation of hydrocarbons can be performed efficiently upon treatment with tert-butylhydroperoxide or peracetic acid in the presence of a low-valent ruthenium catalyst. Furthermore, aerobic oxidation of hydrocarbons can be performed in the presence of acetaldehyde using ruthenium, iron, and copper catalysts. Copper derived from copper chloride/crown ether or copper chloride/crown ether/alkaline metal salts have proved to be efficient catalysts. Further study revealed that specific copper complexes formed from copper salts and acetonitrile are convenient and highly useful catalysts for the aerobic oxidation of unactivated hydrocarbons.
Asymmetric synthesis with "privileged" ligands
Authors: Bandini Marco , Cozzi Pier Giorgio , Umani-Ronchi Achille 
Published: October 2007

Abstract
Different types of chiral "privileged" ligands 1 and 2 in promoting enantioselective addition of allylating agents to aliphatic and aromatic aldehydes are described. Here, a new concept in the asymmetric allylation reaction is presented. Redox [Cr (Salen) ] mediated addition of allyl halides to carbonyl compounds is described, and mechanistic investigations are discussed. These results open access to the fascinating area of the catalytic redox processes mediated by metallo-Salen complexes.
Reactions of d0 alkylidene and amide complexes with silanes
Authors: Diminnie Jonathan B. , Liu Xiaozhan , Cai Hu , Wu Zhongzhi , Blanton Jaime R. , Chen Tianniu , Tuinman Albert A. , Quisenberry Keith T. , Vallet Catherine E. , Zuhr Ray A. , Beach David B. , Peng Zhihui , Wu Yun-Dong , Concolino Thomas E. , Rheingold Arnold L. , Xue Ziling 
Published: October 2007

Abstract
Reactions of silanes with d0 Ta alkylidene and Group 4 amide complexes were found to involve the initial attack on silicon atoms in the silanes by nucleophilic alkylidene carbon or amide nitrogen atoms. The reaction of (Me3SiCH2) 3Ta (PMe 3) [=CHSiMe3] (1) with H2SiR'Ph (R' = Me, Ph) gave (Me3SiCH2) 3Ta[=C (SiMe 3) SiHR'Ph] (2a-b). Similar reactions of these two silanes and (H2PhSi) 2CH2 with (Me3SiCH2) Ta (PMe3) 2[=CHR]2 (R = SiMe3, 3; CMe3, 4) yielded novel metallasilacyclobutadienes and a metalladisilacyclohexadiene, respectively. In comparison, the reactions between M (NMe2) 4 (M = Ti, Zr, Hf) and silanes were found to give aminosilanes and metal amide hydride species which were perhaps involved in the formation of titanium-silicon-nitride (Ti-Si-N) ternary materials.
Chemistry of 1,2-allenyl/propargyl metal species. A personal account
Authors: Ma Sheng-Ming , Zhang Ai-Bin 
Published: October 2007

Abstract
The Pd (0) -catalyzed coupling reaction of aryl and electron-deficient alkenyl halides with the organozinc reagents formed by the subsequent treatment of 1-phenylalk-1-ynes with n-BuLi and ZnBr2 with or without a catalytic amount of HgCl2 was studied. Both the allene-formation- and the alkyne-formation-type coupling reactions were observed, depending on the structures of organic halides and 1-arylalk-1-ynes.
Rare earth metal-based catalysts for the polymerization of nonpolar and polar monomers
Authors: Okuda Jun , Arndt Stefan , Beckerle Klaus , Hultzsch Kai C. , Voth Peter , Spaniol Thomas P. 
Published: October 2007

Abstract
The synthesis of rare earth metal half-sandwich hydrido complexes [Ln (h5:h1-C5Me 4SiMe2NCMe3) (THF) (µ-H) ] 2 (Ln = Y, Lu) through s-bond metathesis of the easily accessible alkyl complexes [Ln (h5:h1-C5Me 4SiMe2NCMe3) (CH2 SiMe3) (THF) ] was developed. The dimeric yttrium hydrido complexes are highly fluxional, and a monomer-dimer equilibrium is present. They were tested as single-site, single-component catalysts for the polymerization of ethylene and styrene, as well as alkyl acrylate and acrylonitrile. The hydrido complexes polymerize ethylene slowly and form isolable mono (insertion) products with styrene. The yttrium n-alkyl complexes [Y (h5:h1-C5Me 4SiMe2NCMe3) (R) (THF) ] [R = (CH2) nCH3, n = 3-9], prepared by the mono (insertion) of a-olefins, initiate polymerization in a relatively controlled manner. Thus, styrene was polymerized by the n-alkyl complex to give atactic polystyrenes with somewhat enriched syndiotacticities.
New P-chirogenic diphosphines and their use in catalytic asymmetric reactions
Authors: Imamoto Tsuneo 
Published: October 2007

Abstract
Enantiomerically pure (S,S) -1,2-bis[(o-alkylphenyl) phenylphosphino]ethanes (o-alkylphenyl = o-methylphenyl, o-ethylphenyl, o-isopropylphenyl, 5',6',7',8'-tetrahydro-naphthyl) , (S,S) -1,2-bis (alkyl-methylphosphino) ethanes (alkyl = t-butyl, 1-adamantyl, 1-methylcyclo-hexyl, 1,1-diethylpropyl, cyclopentyl, cyclohexyl) (abbreviated as BisP*) , and (R,R) -1,1-bis (alkylmethylphosphino) methanes (alkyl = isopropyl, t-butyl, cyclohexyl, phenyl) (abbreviated as MiniPHOS) were prepared from phosphorus trichloride via short routes using phosphine-boranes as intermediates. The crystal structures of cationic rhodium complexes, [Rh ((S,S) -1,2-bis ((phenyl) (5',6',7',8'-tetrahydronaphthyl) phosphino) ethane) (cod)]BF4, [Rh ((S,S) -t-Bu-BisP* (nbd))]BF4, and [Rh ((R,R) -t-Bu-MiniPHOS) 2]PF6, clearly indicate the ideal asymmetric environments. These ligands exhibited an excellent to almost perfect level of enantioselectivity in asymmetric hydrogenations of a-dehydroamino acid derivatives and other catalytic asymmetric reactions.
Names for muonium and hydrogen atoms and their ions(IUPAC Recommendations 2001)
Authors: Koppenol W. H. 
Published: October 2007

Abstract
Muons are short-lived species with an elementary positive or negative charge and a mass 207 times that of the electron. These recommendations concern positive muons, given the short lifetime of negative muons. A positive muon mimics a light hydrogen nucleus, and names are given in analogy to existing names for hydrogen-containing compounds. A particle consisting of a positive muon and an electron (µ+ e -) is named "muonium" and has the symbol Mu. Examples: "muonium chloride," MuCl, is the equivalent of deuterium chloride, 2 HCl or DCl; "muoniomethane", CH 3 Mu, is the product of the muoniation of methane;and NaMu is "sodium muonide."
Nomenclature of structural and compositional characteristics of ordered microporous and mesoporous materials with inorganic hosts(IUPAC Recommendations 2001)
Authors: McCusker L. B. , Liebau F. , Engelhardt G. 
Published: October 2007

Abstract
A system of terms applicable to ordered microporous and mesoporous materials is proposed, and rules for writing a standardized crystal chemical formula for such materials are presented. The recommendations are based both on common usage and on a systematic classification scheme. The nomenclature has been developed to encompass all inorganic materials with ordered, accessible pores with free diameters of less than 50 nm. The crystal chemical formula describes the chemical composition of both the guest species and the host, the structure of the host, the structure of the pore system, and the symmetry of the material. This formula can be simplified or expanded to suit the user's requirements.
Twentieth century developments in photochemistry. Brief historical sketches
Authors: Roth Heinz D. 
Published: October 2007

Abstract
In the 20th century, photochemistry blossomed from a poorly defined to a highly sophisticated science. Early breakthroughs in exploratory photochemistry and the underlying physical principles led to new diverse, yet inter-related areas of research. The alluring goal of asymmetric synthesis with circularly polarized light proved elusive. The discovery of the electron brought a gradual awakening to the idea of electron transfer. Time-resolved spectroscopy developed from ms to fs resolution. The field of photosynthesis progressed from an interest in function and structure of photosynthetic pigments to the isolation and structure elucidation of photosynthetic reaction centers (rhodobacter sphaeroides), to the detailed kinetics of sequential electron-transfer steps in natural and synthetic light-harvesting systems.
Photoactive pyrene-containing receptors for transition-metal ions
Authors: Fages Frédéric , Leroy Stéphanie , Soujanya Tirapattur , Sohna Jean-Ernest Sohna 
Published: October 2007

Abstract
Photoresponsive molecular receptors based on the photophysical properties of the pyrene chromophore were designed to exhibit tunable fluorescence emission upon binding of transition-metal ions.
Looking at the photodynamics of individual fluorescent molecules and proteins
Authors: García-Parajó M. F. , Veerman J.-A. , Kuipers L. , van Hulst N. F. 
Published: October 2007

Abstract
The photodynamics of individual molecules and fluorescent proteins has been investigated in real time. In the case of organic molecules, both the triplet state lifetime and intersystem crossing yield appear to vary in time and space. In the case of autofluorescent proteins, light-driven "on-off" fluorescence emission has been observed, with a behavior that is consistent with the existence of a long-lived dark state.
Molecular photovoltaics that mimic photosynthesis
Authors: Grätzel Michael 
Published: October 2007

Abstract
Learning from the concepts used by green plants, we have developed a photovoltaic cell based on molecular light absorbers and mesoporous electrodes. The sensitized nanocrystalline injection solar cell employs organic dyes or transition-metal complexes for spectral sensitization of oxide semiconductors, such as TiO2, ZnO, SnO2, and Nb2O5. Mesoporous films of these materials are contacted with redox electrolytes, amorphous organic hole conductors, or conducting polymers, as well as inorganic semiconductors. Light harvesting occurs efficiently over the whole visible and near-IR range due to the very large internal surface area of the films. Judicious molecular engineering allows the photoinduced charge separation to occur quantitatively within femtoseconds. The certified overall power conversion efficiency of the new solar cell for standard air mass 1.5 solar radiation stands presently between 10 and 11. The lecture will highlight recent progress in the development of solar cells for practical use. Advancement in the understanding of the factors that govern photovoltaic performance, as well as improvement of cell components to increase further its conversion efficiency will be discussed.
Important photochemical processes in the atmosphere
Authors: Moortgat Geert K. 
Published: October 2007

Abstract
Among the many important roles played by ozone in the atmosphere is the role it plays in the generation of OH radicals, which are responsible for initiating the oxidation of a wide variety of atmospheric trace constituents. The OH production occurs dominantly from the formation of the excited O(1D) species in the UV photolysis of ozone, followed by the reaction of O(1D) with H2O vapor. The photochemistry of ozone is very complex, as the relatively weak bonds in ozone allow different states of the O and O2 photoproducts to be accessed. Recent detailed studies have now revealed that different photolysis channels are occurring in the 290­375 nm spectral range, the region of importance for the generation of OH radicals in the lower atmosphere. The measured temperature-dependent quantum yields for the production of O(1D) atoms reflect the importance of the longer "wavelength tail" formation with regard to the enhanced OH production. Other significant atmospheric photolysis processes involving carbonyl compounds are reported. Direct photodissociation rates were measured in the outdoor photoreactor EUPHORE in Valencia and compared with model calculations. For most of the carbonyl compounds the effective quantum yields are significantly below unity.
Photophysics of π-conjugated metal­organic oligomers
Authors: Li Yiting , Whittle C. Ed , Walters Keith A. , Ley Kevin D. , Schanze Kirk S. 
Published: October 2007

Abstract
The optical absorption and photoluminescence properties of PPE-type p-conjugated oligomers that contain a 2,2-bipyridine-5,5¢-diyl metal coordinating unit have been examined. The spectra of the free oligomers are compared with those that contain ­Re(CO)3Cl and ­Ru(bpy)22+ chromophores chelated to the bpy-diyl unit.
Protein dynamics detected by the time-resolved transient grating technique
Authors: Terazima Masahide 
Published: October 2007

Abstract
Dynamics of two proteins [myoglobin and photoactive yellow protein (PYP)] initiated by photoexcitation were studied by the time-resolved transient grating (TG) and photo-acoustic methods. For both proteins, the temporal profiles of the TG signals showed new features that have not been detected before by the transient absorption method. These dynamics were attributed to the volume change, which is caused by the protein dynamics apart from the chromophores.