Showing papers in "Pure and Applied Chemistry in 2007"
TL;DR: The second edition of the Glossary of Terms Used in Photochemistry [Pure Appl. Chem. 68, 2223-2286 (1996); ] has been both corrected and updated as discussed by the authors.
Abstract: The second edition of the Glossary of Terms Used in Photochemistry [Pure Appl. Chem. 68, 2223-2286 (1996); ] has been both corrected and updated. Terms have been added related to molecular anisotropy, the use of polarized radiation, nonlinear optical phenomena, and the emerging field of computation of excited species. Some changes have been introduced in this "Glossary" regarding the terms related to radiation energy to make this collection fully compatible with internationally agreed-upon terms. Many links are included to various Web pages listing quantities relevant to the work of photochemists and scientists using photochemical tools.
663 citations
TL;DR: In this article, the authors define terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products.
Abstract: This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into four sections-precursors, gels, solids, and processes- and the terms have been restricted to those most commonly encountered.
For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas.
467 citations
TL;DR: Accumulated evidence shows that both hydroxyl radical and ferryl [Fe(IV)=O]2+ can be formed under a variety of Fenton and Fenton-like reactions.
Abstract: Various aspects of the participation of Fenton chemistry in biology and medicine are reviewed. Accumulated evidence shows that both hydroxyl radical and ferryl (Fe(IV)=O) 2+ can be formed under a variety of Fenton and Fenton-like reactions. Some ex- amples of metal-independent hydroxyl radical production are included. Extracellular Fenton reaction is illustrated by the white rot and brown rot wood-decaying fungi. The natural and practical utilization of catechol-driven Fenton reaction is also presented.
363 citations
TL;DR: This critical review considers the existing clinical platinum drugs and those currently in commercial development, alongside the new designs including ruthenium anticancer and antimetastatic drugs in clinical trials, polynuclear drugs, organometallic drugs, titanium and gallium drugs, and emerging supramolecular metallo-drugs that act on DNA by noncovalent interactions.
Abstract: The field of metal-based anticancer drugs was initiated by cisplatin, one of the lead- ing agents in clinical use. Cisplatin acts by binding to DNA and forming 1,2 intrastrand cross-links. Its importance is reflected by the fact that it is estimated that 50-70 % of cancer patients are treated with a platinum drug (7). For some time, molecular designs in the met- allo-drug field remained obdurately anchored in cis-diamine platinum(II) chemistry, but now the field is evolving rapidly with a variety of alternate and very diverse designs being ex- plored. These designs give rise to new spectra of activity and potency and can circumvent cis- platin resistance. This critical review considers the existing clinical platinum drugs, and those currently in commercial development, alongside the new designs including ruthenium anti- cancer and antimetastatic drugs in clinical trials, polynuclear drugs, organometallic drugs, ti- tanium and gallium drugs, and emerging supramolecular metallo-drugs that act on DNA by noncovalent interactions. The rapid evolution of the field is being informed by post-genomic knowledge and approaches, and further dramatic step-change breakthroughs can be expected as a result; harnessing this knowledge and responding to and taking advantage of this new environment requires integration of chemistry and biology research.
272 citations
TL;DR: Liverworts produce a great variety of lipophilic terpenoids, aromatic compounds, and acetogenins, and many of these constituents have characteristic scents, pungency and bitter-ness, and display a quite extraordinary array of bioactivities and medicinal properties as discussed by the authors.
Abstract: Liverworts produce a great variety of lipophilic terpenoids, aromatic compounds, and acetogenins. Many of these constituents have characteristic scents, pungency, and bitter- ness, and display a quite extraordinary array of bioactivities and medicinal properties. These expressions of biological activity are summarized and discussed, and examples are given of the potential of certain lead compounds for structure-activity studies and synthesis.
200 citations
TL;DR: In this paper, a review of the state-of-the-art Li-air cells and batteries is presented, where the authors examine the properties of this unique system in terms of the effects of solubilities of reac- tants and products in both nonaqueous (aprotic) and aqueous electrolyte solutions.
Abstract: A review is presented of the present state-of-the-art of Li-air cells and batteries. We examine the properties of this unique system in terms of the effects of solubilities of reac- tants and products in both nonaqueous (aprotic) and aqueous electrolyte solutions. Definite trends are observed, such as increasing cell-specific energy and capacity as both the oxygen solubility increases and viscosity decreases in organic solvents, but quantitative analyses are limited owing to the complex relations between solubility, solution viscosity, oxygen diffu- sion, and electrolytic conductivity. Adding to this complex relation is the dependence of the nature of the carbon-based air cathode (surface area and pore volume) upon practical specific capacities, which can be realized with Li-air cells that far exceed the specific energies and capacities of all present commercial metal-air and Li-ion cells and batteries.
177 citations
TL;DR: In this paper, a Z-scheme photocatalysis system employing visible-light-driven photocatalysts, Ru/SrTiO 3 :Rh and BiVO 4 for H 2 and O 2 evolution, and an Fe 3+ /Fe 2+ redox couple as an electron relay was developed.
Abstract: Photocatalytic water splitting is a challenging reaction because it is an ultimate so- lution to energy and environmental issues. Recently, many new powdered photocatalysts for water splitting have been developed. For example, a NiO (0.2 wt %)/NaTaO 3 :La (2 %) photo- catalyst with a 4.1-eV band gap showed high activity for water splitting into H 2 and O 2 with an apparent quantum yield of 56 % at 270 nm. Overall water splitting under visible light ir- radiation has been achieved by construction of a Z-scheme photocatalysis system employing visible-light-driven photocatalysts, Ru/SrTiO 3 :Rh and BiVO 4 for H 2 and O 2 evolution, and an Fe 3+ /Fe 2+ redox couple as an electron relay. Moreover, highly efficient sulfide photocat- alysts for solar hydrogen production in the presence of electron donors were developed by making solid solutions of ZnS with AgInS 2 and CuInS 2 of narrow band gap semiconductors. Thus, the database of powdered photocatalysts for water splitting has become plentiful.
155 citations
TL;DR: In this paper, the use of group 3 metal complexes for the ring-opening polymerization of lactide to give polylactides (PLAs) has been studied intensively due to their biocompatible and biodegradable properties and their potential applications in medical and agricultural fields.
Abstract: In this review, attention is focused on the use of group 3 metal complexes for the ring-opening polymerization (ROP) of lactide to give polylactides (PLAs). Synthesis of PLAs has been studied intensively due to their biocompatible and biodegradable properties and their potential applications in medical and agricultural fields. ROP of lactide, a cyclic di- ester of lactic acid, provides PLA. This review includes our recent research results and im- plications in developing new amino-bis(phenolate) group 3 initiators for the synthesis of polyesters.
143 citations
TL;DR: In this article, three photochemical reactions were investigated under solar irradiation conditions with moderately concentrated sunlight: the photoacylation of naphthoquinone with butyraldehyde and the dye-sensitized photooxygenations of citronellol and 1,5-dihydroxynaphthalene, respectively.
Abstract: Three photochemical reactions were investigated under solar irradiation conditions with moderately concentrated sunlight: the photoacylation of naphthoquinone with butyraldehyde and the dye-sensitized photooxygenations of citronellol and 1,5-dihydroxynaphthalene, respectively. All reactions were easily performed on multigram-to-kilogram scales using cheap and commercially available starting materials, and yielded important key intermediates for industrial applications.
134 citations
TL;DR: The glossary as mentioned in this paper is a revision of the IUPAC glossary for Chemists of Terms Used in Toxicology [Pure Appl. Chem.76, 1033] incorporating new and redefined terms from the glossary of terms used in Toxicokinetics.
Abstract: This glossary, a revision of the IUPAC \"Glossary for Chemists of Terms Used in Toxicology\" [Pure Appl. Chem.65, 2003 (1993)] incorporating new and redefined terms from the \"Glossary of Terms Used in Toxicokinetics\" [Pure Appl. Chem.76, 1033 (2004)], contains definitions and explanatory notes, if needed, for terms frequently used in the multidisciplinary field of toxicology. The glossary is compiled primarily for those scientists and others who now find themselves working in toxicology or requiring a knowledge of the subject, especially for hazard and risk assessment. Many medical terms are included because of their frequent occurrence in the toxicological literature. There are three annexes, one containing a list of abbreviations and acronyms used in toxicology, one containing a list of abbreviations and acronyms used by international bodies and by legislation relevant to toxicology and chemical safety, and one describing the classification of carcinogenicity according to the weight of evidence available.
133 citations
TL;DR: In this paper, Wang et al. showed that porous inorganic-organic hybrid frameworks have high potential for adsorption of small molecules because of their designability with respect to the co- ordination geometry around the central metal ion as well as size and probable multi-functional properties of bridging organic ligands.
Abstract: Remarkable advances in the recent development of porous compounds based upon coordination polymers have paved the way toward functional chemistry having potential ap- plications such as gas storage, separation, and catalysis. From the synthetic point of view, the advantage is a designable framework, which can readily be constructed from building blocks, the so-called bottom-up assembly. Compared with conventional porous materials such as zeolites and activated carbons, porous inorganic-organic hybrid frameworks have higher po- tential for adsorption of small molecules because of their designability with respect to the co- ordination geometry around the central metal ion as well as size and probable multi- functionality of bridging organic ligands. Although rigidity and robustness of porous framework with different degree of adsorption are the most studied properties of metal-or- ganic coordination frameworks, there are few studies on dynamic porous frameworks, which could open up a new dimension in materials chemistry.
TL;DR: Knowledge of the chemistry, bioactivity, and ecology of Piperaceae species provides preliminary clues for an overall interpretation of the possible role and occurrence of major classes of compounds.
Abstract: The chemistry of members of the family Piperaceae is of great interest owing to the variety of biological properties displayed. A survey of structural diversity and bioactivity re- veals that groups of species specialize in the production of amides, phenylpropanoids, lig- nans and neolignans, benzoic acids and chromenes, alkaloids, polyketides, and a plethora of compounds of mixed biosynthetic origin. Bioassays against Cladosporium cladosporioides and C. sphaerospermun have resulted in the characterization of various amides, prenylated phenolic compounds, and polyketides as potential classes of antifungal agents. Studies on the developmental process in seedlings of Piper solmsianum have shown that phenylpropanoid are produced instead of the tetrahydrofuran lignans found in adult plants. In suspension cul- tures of P. cernuum and P. crassinervium, phenylethylamines and alkamides predominate, whereas in the adult plants prenylpropanoids and prenylated benzoic acids are the respective major compound classes. Knowledge of the chemistry, bioactivity, and ecology of Piperaceae species provides preliminary clues for an overall interpretation of the possible role and oc- currence of major classes of compounds.
TL;DR: In this article, a new generation of chiral stationary phases (CSPs) consisting of immobilized poly- saccharide derivatives has been developed for both analytical and preparative chromatographies.
Abstract: The chromatographic separation of enantiomers using chiral stationary phases (CSPs) has significantly advanced. The esters and carbamates of polysaccharides coated on silica gel have been extensively studied and widely used as CSPs for high-performance liq- uid chromatography (HPLC). In order to overcome the strict solvent limitation on these coated CSPs, the preparation of a new generation of CSPs consisting of immobilized poly- saccharide derivatives has become increasingly important. The universal solvent compatibil- ity of the new CSPs provides flexibility in both analytical and preparative chromatographies.
TL;DR: These model reactions proceeded very rapidly with considerably large photonic efficiencies because of some distinct properties of microreactors for photoreactions, such as higher spatial illumination homogeneity and better light penetration through the entire reactor depth, and large surface-to-volume ratio in comparison with large-scale batch reactors.
Abstract: A microreaction system for organic photoreactions was developed, and the processes of diastereo-differentiating photosensitized reaction, photocatalytic oxidation and reduction of organic compounds, and amine N-alkylation were examined in microspace. These model reactions proceeded very rapidly with considerably large photonic efficiencies because of some distinct properties of microreactors for photoreactions, such as higher spa- tial illumination homogeneity and better light penetration through the entire reactor depth, and large surface-to-volume ratio in comparison with large-scale batch reactors. These re- sults suggest feasibility of microreaction systems on organic photoreactions.
TL;DR: In this article, a summary of the oxylipin chemistry of marine diatoms, a major class of planktonic microalgae that discourage preda- tion from their natural grazers, zooplanktonic copepods, using chemical warfare, is given.
Abstract: Oxylipins are important signal transduction molecules widely distributed in ani- mals and plants where they regulate a variety of events associated with physiological and pathological processes. The family embraces several different metabolites that share a com- mon origin from the oxygenase-catalyzed oxidation of polyunsaturated fatty acids. The bio- logical role of these compounds has been especially studied in mammalians and higher plants, although a varied and very high concentration of these products has also been reported from marine macroalgae. This article gives a summary of our results concerning the oxylipin chemistry of marine diatoms, a major class of planktonic microalgae that discourage preda- tion from their natural grazers, zooplanktonic copepods, using chemical warfare. These ap- parently harmless microscopic cells produce a plethora of oxylipins, including short-chain unsaturated aldehydes, hydroxyl-, keto-, and epoxyhydroxy fatty acid derivatives, that induce reproductive failure in copepods through abortions, congenital malformations, and reduced larval growth. The biochemical process involved in the production of these compounds shows a simple regulation based on decompartmentation and mixing of preexisting enzymes and requires hydrolysis of chloroplast-derived glycolipids to feed the downstream activities of C 16 and C 20 lipoxygenases.
TL;DR: It is suggested that the therapeutic index (TI) of this novel peptide is significantly higher than for the other tested peptides, with high antibiotic activity and little undesired effects, and could be a useful starting point for further development of new peptide antibiotics.
Abstract: The effect of C-terminal amidation on the antimicrobial and hemolytic activities of antimicrobial peptides was studied using three cationic peptides which form amphiphilic α-helices when bound to membranes. The natural antimicrobial peptide PGLa, the designer- made antibiotic MSI-103, and the cell-penetrating "model amphipathic peptide" (MAP) are all amidated in their original forms, and their biological activities were compared with the same sequences carrying a free C-terminus. It was found that, in general, a free COOH-ter- minus reduces both the antimicrobial activity and the hemolytic side effects of the peptides. The only exception was observed for MSI-103, whose antimicrobial activity was not de- creased in the acid form. Having shown that the therapeutic index (TI) of this novel peptide is significantly higher than for the other tested peptides, with high antibiotic activity and lit- tle undesired effects, we suggest that it could be a useful starting point for further develop- ment of new peptide antibiotics.
TL;DR: Flavonoid profiling of wild-type plants and T-DNA insertion mutants and metabolic profiling of the omt1 mutant lacking a methyltransferase gene showed that AtOMT1 is involved not only in the production of lignins and sinapoyl esters but also in the methylation of flavonols forming isorhamnetin.
Abstract: The completion of the whole genome sequence of Arabidopsis thaliana has made it possible to explore the phytochemical genomics in this species by determining gene-to- metabolite correlation through the comprehensive analysis of metabolite accumulation and gene expression. In this study, flavonoid profiling of wild-type plants and T-DNA insertion mutants was analyzed using ultra-performance liquid chromatography (UPLC)/photodiode array detection (PDA)/electrospray ionization (ESI)/multiple-stage mass spectrometry (MS n ). Detailed analysis of the metabolite changes in the mutants suggested the functions of genes that have been mutated. In silico coexpression analysis of genes involved in flavonoid metabolism in Arabidopsis was performed using a publicly available transcriptome database of DNA microarrays. We inferred a coexpression framework model of the genes involved in the pathways of flavonol, anthocyanin, and proanthocyanidin synthesis, suggesting specific functions and coregulation of the genes of pathway enzymes and transcription factors. The metabolic profiling of the omt1 mutant lacking a methyltransferase gene narrowed down by the coexpression analysis showed that AtOMT1 (At5g54160) is involved not only in the pro- duction of lignins and sinapoyl esters but also in the methylation of flavonols forming isorhamnetin. These results suggest that the functional genomics approach by detailed target- metabolite profiling with transcriptome coexpression analysis provides an efficient way of identifying novel gene functions involved in plant metabolism.
TL;DR: The importance and applications of the recently designed synthetic tyrosinase inhibitors from the and other leading laboratories of the world, which have been published in recent years are reviewed.
Abstract: The enzyme tyrosinase is known to be a multifunctional copper-containing enzyme from the oxidase superfamily, which is the key protein involved in the biosynthesis of the large biological pigment, melanin. The enzyme catalyzes two distinct reactions of melanin biosynthesis, the hydroxylation of a monophenol and the conversion of an o-diphenol to the corresponding o-quinone. Inhibitors of this protein have a huge impact on industry and econ- omy. So a number of research groups around the world are engaged and are expending much effort in the discovery of these inhibitors. In this report, we review the importance and ap- plications of the recently designed synthetic tyrosinase inhibitors from our and other leading laboratories of the world, which have been published in recent years. In our continuing search for tyrosinase inhibitors from natural resources to semi- and full synthetic approaches, until now we discovered and reported a large number of mild to potent inhibitors of several classes, such as phenolics, terpenes, steroids, chalcones, flavonoids, alkaloids, long-chain fatty acids, coumarins, sildenafil analogs, bipiperidines, biscoumarins, oxadiazole, tetra- ketones, etc. The structure-activity relationships (SARs) of different classes of synthetic ty- rosinase inhibitors have also been discussed in this review.
TL;DR: In this article, the propagation rate coefficients for free-radical polymerization of methacrylic acid, MAA, in aqueous solution are presented, and the underlying k P values are from two independent sources, which both used the IUPAC-recommended technique of pulsed-laser-initiated polymerization (PLP) in conjunction with molar mass distribution (MMD) analysis of the resulting polymer by size-exclusion chromatography (SEC).
Abstract: Critically evaluated propagation rate coefficients, k p , for free-radical polymerization of methacrylic acid, MAA, in aqueous solution are presented. The underlying k P values are from two independent sources, which both used the IUPAC-recommended technique of pulsed-laser-initiated polymerization (PLP) in conjunction with molar mass distribution (MMD) analysis of the resulting polymer by size-exclusion chromatography (SEC). Different methods of measuring the MMD of the poly(MAA) samples have, however, been used: (i) direct analysis via aqueous-phase SEC and (ii) standard SEC with tetrahydrofuran as the eluent carried out on poly(methyl methacrylate) samples obtained by methylation of the poly(MAA) samples from PLP. Benchmark k p values for aqueous solutions containing 15 mass % MAA are presented for temperatures between 18 and 89 °C. The Arrhenius pre-exponential and activation energy of k p at 15 mass % MAA are 1.54 x 10 6 L mol -1 s -1 and 15.0 kJ mol -1 , respectively. Also reported are critically evaluated k p values for 25 °C over the entire MAA concentration range from dilute aqueous solution to bulk polymerization.
TL;DR: A short account of H-phosphonate chemistry and its application to the synthesis of biologically important phosphates and their analogs is given.
Abstract: In this review, a short account of H-phosphonate chemistry and its application to the synthesis of biologically important phosphates and their analogs is given.
TL;DR: In this paper, a simple donor-acceptor dyad, 9-mesityl-10-methylacridinium ion (Acr + -Mes), was developed to attain a long-lived and high-energy charge separated (CS) state without significant loss of excitation energy.
Abstract: As an alternative to conventional charge-separation functional molecular models based on multi-step long-range electron transfer (ET) within redox cascades, simple donor-acceptor dyads have been developed to attain a long-lived and high-energy charge- separated (CS) state without significant loss of excitation energy. In particular, a simple mo- lecular electron donor-acceptor dyad, 9-mesityl-10-methylacridinium ion (Acr + -Mes), is ca- pable of fast charge separation but extremely slow charge recombination. Such a simple molecular dyad has significant advantages with regard to synthetic feasibility, providing a va- riety of applications for photoinduced ET catalytic systems, including efficient photocatalytic systems for the solar energy conversion and construction of organic solar cells.
TL;DR: Boron derivatives are becoming key reagents in radical chemistry as mentioned in this paper, where an organoboron derivative is used as a radical initiator, a chain-trans-fer reagent, and a radical precursor.
Abstract: Boron derivatives are becoming key reagents in radical chemistry. Here, we de- scribe reactions where an organoboron derivative is used as a radical initiator, a chain-trans- fer reagent, and a radical precursor. For instance, B-alkylcatecholboranes, easily prepared by hydroboration of alkenes, represent a very efficient source of primary, secondary, and terti- ary alkyl radicals. Their very high sensitivity toward oxygen- and heteroatom-centered radi- cals makes them particularly attractive for the development of radical chain processes such as conjugate addition, allylation, alkenylation, and alkynylation. Boron derivatives have also been used to develop an attractive new procedure for the reduction of radicals with alcohols and water. The selected examples presented here demonstrate that boron-containing reagents can efficiently replace tin derivatives in a wide range of radical reactions.
TL;DR: In this paper, a Ni-based catalytic system with a self-organized nanostructured catalyst has been designed to perform chemical transformation in high yield, under mild conditions.
Abstract: The synthetic application and mechanistic aspects of transition-metal (Ni, Pd, Pt) catalyzed addition of E-E and E-H (E=S, Se) bonds to alkynes were investigated in detail. This study revealed major factors controlling the selectivity of such addition reactions. A new Ni-based catalytic system with a self-organized nanostructured catalyst has been designed to perform chemical transformation in high yield, under mild conditions.
TL;DR: In this article, the use of renewable resources, especially vegetable oils, has to compete more and more with the increasing demand for bioenergy, which could cause an unbalanced supply and demand in the future or even a threat for the increasing need for food in certain areas of the world.
Abstract: In concepts for new products, performance, product safety, and product economy criteria are equally important. They are taken into account already when the raw materials base for a new industrial product development is defined. Here, renewable resources gain-again after the earlier "green trend" in the 1980s-increasing attention as an alternative raw materials source compared to fossil feedstock. The industrial use of carbohydrates, proteins, and vegetable oils aligns perfectly with the principles of Responsible Care and is an important part of green chemistry and sustainability in general. Since the 1950s, oleochemistry has grown to a major research and technology area in several institutions and industries. A large variety of products based on fats and oils have been developed since then for different uses, such as specialties for polymer applications, biodegradable mineral oil replacements for lubricants, and surfactants and emulsifiers for the home and personal-care industries. However, at present it seems that the use of renewable resources, especially vegetable oils, has to compete more and more with the increasing demand for bioenergy, which could cause an unbalanced supply and demand in the future or even a threat for the increasing demand for food in certain areas of the world.
TL;DR: In this paper, the effect of solvents on the spectra, absorption, or emission of substances is referred to as solvatochromism; it is due to solute/solvent nonspecific and specific interactions, including dipole/dipole, dipole-induced dipole, dispersion interactions, and hydrogen bonding.
Abstract: The effect of solvents on the spectra, absorption, or emission of substances is called solvatochromism; it is due to solute/solvent nonspecific and specific interactions, including dipole/dipole, dipole-induced/dipole, dispersion interactions, and hydrogen bonding. Thermo-solvatochromism refers to the effect of temperature on solvatochromism. The mo- lecular structure of certain substances, polarity probes, make them particularly sensitive to these interactions; their solutions in different solvents have distinct and vivid colors. The study of both phenomena sheds light on the relative importance of the solvation mechanisms. This account focuses on recent developments in solvation in pure and binary solvent mix- tures. The former has been quantitatively analyzed in terms of a multiparameter equation, modified to include the lipophilicity of the solvent. Solvation in binary solvent mixtures is complex because of the phenomenon of "preferential solvation" of the probe by one compo- nent of the mixture. A recently introduced solvent exchange model allows calculation of the composition of the probe solvation shell, relative to that of bulk medium. This model is based on the presence of the organic solvent (S), water (W), and a 1:1 hydrogen-bonded species (S-W). Solvation by the latter is more efficient than by its precursor solvents, due to probe/solvent hydrogen-bonding and hydrophobic interactions. Dimethylsulfoxide (DMSO) is an exception, because the strong DMSO/W interactions probably deactivate the latter species toward solvation. The relevance of the results obtained to kinetics of reactions is briefly discussed by addressing temperature-induced desolvation of the species involved (re- actants and activated complexes) and the complex dependence of kinetic data (observed rate constants and activation parameters) in binary solvent mixtures on medium composition.
TL;DR: In this paper, a comprehensive experimental and computational phase studies of the ZrO 2 -REO 1.5 (RE = La, Nd, Sm, Gd, Dy, Yb) are summarized.
Abstract: Results of the comprehensive experimental and computational phase studies of the systems ZrO 2 -REO 1.5 (RE = La, Nd, Sm, Gd, Dy, Yb) are summarized. Various experimen- tal techniques, X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM), differential thermal analysis (DTA), and high-temperature calorimetry are employed to study the phase transfor- mation, phase equilibria between 1400 and 1700 °C, heat content and heat capacity of the materials. A lot of contradictions in the literature are resolved, and the phase diagrams are re- constructed. Based on the experimental data obtained in this work and literature, the systems ZrO 2 -REO 1.5 are thermodynamically optimized using the CALPHAD (CALculation of PHase Diagram) approach. Most of the experimental data are well reproduced. Based on the present experiments and calculations, some clear characteristic evolutions with the change of the ionic radius of doping element RE +3 can be concluded.
TL;DR: In contrast, rare earth and other metal complexes have been found to be water-compatible as mentioned in this paper, owing to preferential reactions of the Lewis acids with water rather than the substrates.
Abstract: Lewis acid catalysis has attracted much attention in organic synthesis because of unique reactivity and selectivity attained under mild conditions. Although various kinds of Lewis acids have been developed and applied in industry, these Lewis acids must be generally used under strictly anhydrous conditions. The presence of even a small amount of water handles the reactions owing to preferential reactions of the Lewis acids with water rather than the substrates. In contrast, rare earth and other metal complexes have been found to be water-compatible. Several catalytic asymmetric reactions in aqueous media, including hydroxy-methylation of silicon enolates with an aqueous solution of formaldehyde in the presence of Sc(OTf) 3 -chiral bipyridine ligand or Bi(OTf) 3 -chiral bipyridine ligand, Sc- or Bi-catalyzed asymmetric meso-epoxide ring-opening reactions with amines, and asymmetric Mannich-type reactions of silicon enolates with N-acylhydrazones in the presence of a chiral Zn catalyst have been developed. Water plays key roles in these asymmetric reactions.
TL;DR: In this paper, deprotonation of terminal epoxides and aziridines with organolithium/diamine combinations or lithium amides allows the regio- and stereoselective formation of α-lithiated species.
Abstract: Deprotonation of terminal epoxides and aziridines with organolithium/diamine combinations or lithium amides allows the regio- and stereoselective formation of α-lithiated species. Judicious choice of reaction conditions allows these species to operate as nucleo- philes, enolate equivalents, vinyl cation equivalents, or carbenes.
TL;DR: In this short period of time, molecular shuttles have moved from little more than laboratory curiosities to truly functional molecular machines.
Abstract: Stimuli-responsive molecular shuttles are rotaxanes in which the macrocycle can be translocated from one position on the thread to a second site in response to an external trigger. Here, we present a brief overview of the contributions of the Leigh group to the field from 2001 to 2006. In this short period of time, molecular shuttles have moved from little more than laboratory curiosities to truly functional molecular machines.
TL;DR: Methods for crop protection based on semiochemicals show advantages over methods based on conventional insecticides and some examples of such simple signals, which are now used for monitoring and suppression of pest insects are focused on.
Abstract: Methods for crop protection based on semiochemicals show advantages over methods based on conventional insecticides. Applications of semiochemicals for insect pest management have, however, been limited. Some recent studies carried out in an interdisciplinary research program by five research groups in Sweden are presented. In spite of the chemodiversity in nature, it is striking that many simple and common compounds are important as chemical signals. This paper focuses on some examples of such simple signals, which are now used for monitoring and suppression of pest insects.