Spiro linked compounds for use as active materials in organic light emitting diodes

Spiro-linkage of low molecular weight entities as a new structural concept for the design of new active materials for electroluminescent applications is presented. These spiro linked compounds result in nonpolymeric organic glasses with high thermal stability as can be derived from their high glass transition temperatures (T_g), and characterized by differential scanning calorimetry. Blue emitters based on spiro linked oligophenyles are presented. These compounds are soluble in common organic solvents and show high photoluminescence quantum efficiency in the solid state and high morphologic stability with glass transition temperatures up to 250°C. Charge transport materials based on spiro linked versions of 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) for electron transport, and spiro linked versions of triphenyldiamin derivatives (TPD) for hole transport show improved morphologic properties with nearly unchanged electronic properties compared to the parent compounds. High quality amorphous films can be prepared with the spiro compounds by vapor deposition as well as by simple spin coating.     

Value assignment of nutrient concentrations in five standard reference materials and six reference materials

A number of food-matrix reference materials (RMs) are available from the National Institute of Standards and Technology (NIST) and from Agriculture Canada through NIST. Most of these materials were originally value-assigned for their elemental composition (major, minor, and trace elements), but no additional nutritional information was provided. Two of the materials were certified for selected organic constituents. Ten of these materials (Standard Reference Material [SRM] 1,563 Cholesterol and Fat-Soluble Vitamins in Coconut Oil [Natural and Fortified], SRM 1,566b Oyster Tissue, SRM 1,570a Spinach Leaves, SRM 1,974a Organics in Mussel Tissue (Mytilus edulis), RM 8,415 Whole Egg Powder, RM 8,418 Wheat Gluten, RM 8,432 Corn Starch, RM 8,433 Corn Bran, RM 8,435 Whole Milk Powder, and RM 8,436 Durum Wheat Flour) were recently distributed by NIST to 4 laboratories with expertise in food analysis for the measurement of proximates (solids, fat, protein, etc.), calories, and total dietary fiber, as appropriate. SRM 1846 Infant Formula was distributed as a quality control sample for the proximates and for analysis for individual fatty acids. Two of the materials (Whole Egg Powder and Whole Milk Powder) were distributed in an earlier interlaboratory comparison exercise in which they were analyzed for several vitamins. Value assignment of analyte concentrations in these 11 SRMs and RMs, based on analyses by the collaborating laboratories, is described in this paper. These materials are intended primarily for validation of analytical methods for the measurement of nutrients in foods of similar composition (based on AOAC INTERNATIONAL's fat-protein-carbohydrate triangle). They may also be used as "primary control materials" in the value assignment of in-house control materials of similar composition. The addition of proximate information for 10 existing reference materials means that RMs are now available from NIST with assigned values for proximates in 6 of the 9 sectors of the AOAC triangle. Five of these materials have values assigned for total dietary fiber-the first such information provided for materials available from NIST.     

Determination of organic acids in Vaccinium berry standard reference materials

Nine organic acids (citric acid, galacturonic acid, glycolic acid, isocitric acid, malic acid, oxalic acid, quinic acid, shikimic acid, and tartaric acid) and two anions (phosphate and sulfate) were determined in a suite of Vaccinium berry-containing dietary supplement standard reference materials (SRMs). Following solvent extraction, three independent methods were utilized in the quantification of these compounds. The first method involved reversed-phase liquid chromatography with ultraviolet absorbance detection at 210 nm and isotope dilution mass spectrometry. The second method utilized ion chromatography with conductivity detection. Finally, gas chromatography with isotope dilution mass spectrometry detection was used following derivatization with N-methyl-N-trifluoroacetamide (MSTFA). The combined data from these methods was used for the assignment of organic acid levels in the seven candidate SRMs.     

Survey of reference materials for trace elements, nuclides and organic microcontaminants

The International Atomic Energy Agency (IAEA), in co-operation with the United Nations Environment Programme (UNEP), has recently prepared a survey on internationally available analytical reference materials for trace elements, nuclides and organic contaminants in biological, environmental and related matrices. The purpose is to help analysts to select reference materials for quality assurance that match as closely as possible, with respect to matrix type and concentrations of the measurands of interest, the “real” samples that are to be measured. The present version of the survey, which is available in the form of two cost-free printed volumes [1], contains over 10,000 certified and information values in 650 reference materials from 27 different producers. The 455 measurands listed include trace elements, major and minor elements, organic contaminants, organometallic compounds, radionuclides and stable isotopes. Currently, the database from which the survey has been produced is being modified and extended so as to make the data available in electronic form via the Internet. Received: 11 June 1997 / Revised: 7 July 1997 / Accepted: 9 July 1997     

Metrological effectiveness of an analytical method for volatile organic compounds standard materials using post-column reaction GC/FID system

The metrological effectiveness of an analytical method using the post-column reaction GC/FID system was evaluated. The SI-traceable certified reference material (CRM), the eight ester phthalates mixture standard solution, was used as a sample. We assigned specific value to n-eicosane and it was used as an internal standard. A known quantity of n-eicosane was added to the CRM, and the mixture was measured with the post-column reaction GC/FID system. Six phthalate esters were chromatographically separated and determined. The assigned values by our system are in good agreement with the certified values of the CRM, and the combined uncertainties of the measurements by the present system were better than those of the CRM. Our method is classified as a primary ratio method and the specific values of many organic compounds can be assigned very precisely by using a small number of reference materials. Also, the method can make it possible to avoid the purity determination of raw materials and directly to assign their specific values after the preparation of the standard mixture. Conclusively, this post-column reaction GC/FID system is very effective for the chemical metrology.     

Milk and serum standard reference materials for monitoring organic contaminants in human samples

Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4′-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis.

The use of laboratory prepared reference materials in nutrient analysis

Summary The need for laboratory prepared reference materials is discussed as are experiences gained during five years of their use in the analysis of foods for trace nutrients. Ways of monitoring results are described and the possibility of providing certified reference materials for some of the B group vitamins in foods is examined.     

Low-Dimensional organic conductors as thermoelectric materials

We have developed a system to measure electrical resistivity, thermopower and thermal conductivity of tiny fragile organic conductors simultaneously. Figure of merit Z has been successfully determined from these transport coefficients for a two-dimensional organic conductor τ-(EDO-S,S-DMEDT-TTF)₂(AuBr₂)_1+y, (y≤0.875), where EDO-S,S-DMEDT-TTF is ethylenedioxy-S,S-dimethylethylenedithio-tetrathiafulvalene, for the first time.     

Biochar-based functional materials as heterogeneous catalysts for organic reactions

The development of cheap, effective and heterogeneous catalysts remains a substantial challenge in organic synthesis. Of the extensive heterogeneous catalysis, biochar materials have attracted increasing attention to be considered as an important class of support materials in organic reactions due to their distinctive characteristics such as high porosity, large specific surface area, high adsorption ability, excellent cation exchange capacity and outstanding stability. This review highlights recent advances over the past 5 years, outlining the synthetic methods of biochar materials and their applications as catalysts or catalyst supports in a range of organic reactions including oxidation, reduction, esterification, coupling, alkylation and multi-component reactions.     

Polybrominated diphenyl ether congeners and toxaphene in selected marine standard reference materials

Polybrominated diphenyl ether (PBDE) congeners and components of the complex mixture toxaphene are stable in the environment and readily bioaccumulated into wildlife and human tissues. PBDEs are presently used in large quantities worldwide as flame retardants in textiles, furniture, computer equipment, and cables. Toxaphene is a complex mixture of chlorinated bornanes and bornenes that was the most heavily used pesticide in the United States until it was banned in 1982; however, some countries continue to use toxaphene. The National Institute of Standards and Technology has quantified PBDE congeners and toxaphene in several available Standard Reference Materials (SRMs) using methods of gas chromatography with electron impact mass spectrometry (GC-EI-MS) and GC negative chemical ionization (NCI) MS, respectively. SRM 1588a Organics in Cod Liver Oil and SRM 1945 Organics in Whale Blubber were examined for PBDE congeners 47, 99, 100, 153, and 154, total toxaphene, and toxaphene congeners 26, 50, and 62. SRM 1946 Lake Superior Fish Tissue was also examined for total toxaphene and toxaphene congeners. The sum of the PBDE congeners (mean, (1 SD) wet basis) for SRM 1945 was 150 ng g^–1 (7 ng g^–1). The concentration of PBDE 47 in SRM 1588a was 82.7 ng g^–1 (2.8 ng g^–1). Other PBDEs were detected in SRM 1588a but were not quantified due their low levels. The total toxaphene (wet mass basis) was 1,210 ng g^–1 (127 ng g^–1), 1,960 ng g^–1 (133 ng g^–1), and 3,980 ng g^–1 (248 ng g^–1) in SRMs 1945, 1946, and 1588a, respectively. The values for PBDEs and toxaphene determined in the SRMs, while not certified, indicate that the SRMs will be suitable control materials for PBDE and toxaphene analyses.     

Drying and weighing of standard reference materials for titrimetric analysis, and the status of the faraday constant as an international standard

A review is given of the methods of drying standard reference materials, and handling them after drying. The status of the Faraday as an international reference standard for titrimetric analysis is also discussed.     

受体型有机光伏材料苝二酰亚胺

苝二酰亚胺作为一种典型的n型材料,具有可见光区强吸收、光和热稳定性较高等突出优点,近年来应用到有机光伏达电池中。本文介绍了苝二酰亚胺及其各种衍生物的结构和性质,综述了其用作有机光伏受体材料（包括小分子型苝二酰亚胺材料、含苝二酰亚胺受体单元的给体-受体双功能分子和含苝二酰亚胺受体单元的给体-受体双缆型聚合物材料）的最新研究进展。     

The search for organic nutrient standards

Summary The search for organic nutrient standards is approached from two sides. On the one hand, useful standards are selected from currently available SRMs; on the other hand, a representative food is developed representing the daily intake of a typical consumer. It is a composite of 201 foods, collected and prepared in a table-ready fashion.     

Quantitative analysis of oxide materials by laser-induced breakdown spectroscopy with argon as an internal standard

Laser-induced breakdown spectroscopy (LIBS) is demonstrated as a quantitative technique for geochemical analysis. This study demonstrates the applicability of LIBS to multielemental analysis of minerals using argon as an internal standard. Laser-induced breakdown spectroscopy has been applied to measure elements in oxide form. In the present study, the contents of several oxides, such as Fe₂O₃, CaO and MgO, in geological samples from the Tierga Mine (Zaragoza, Spain) were analyzed by LIBS. An argon environment was used to eliminate interference from air at atmospheric pressure. Furthermore, argon was used as an internal standard. The result was enhanced signal and enhanced linearity of the calibration curves. The Fe₂O₃, CaO and MgO concentrations determined by LIBS were compared with the results obtained using another analytical technique, inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations found using LIBS were in good agreement with the values obtained by ICP-OES.     

Biomineralization as an inspiration for materials chemistry

Living organisms are well known for building a wide range of specially designed organic-inorganic hybrid materials such as bone, teeth, and shells, which are highly sophisticated in terms of their adaptation to function. This has inspired physicists, chemists, and materials scientists to mimic such structures and their properties. In this Review we describe how strategies used by nature to build and tune the properties of biominerals have been applied to the synthesis of materials for biomedical, industrial, and technological purposes. Bio-inspired approaches such as molecular templating, supramolecular templating, organized surfaces, and phage display as well as methods to replicate the structure and function of biominerals are discussed. We also show that the application of in situ techniques to study and visualize the bio-inspired materials is of paramount importance to understand, control, and optimize their preparation. Biominerals are synthesized in aqueous media under ambient conditions, and these approaches can lead to materials with a reduced ecological footprint than can traditional methods.     

Three new mussel tissue standard reference materials (SRMs) for the determination of organic contaminants

Three new mussel tissue standard reference materials (SRMs) have been developed by the National Institute of Standards and Technology (NIST) for the determination of the concentrations of organic contaminants. The most recently prepared material, SRM 1974b, is a fresh frozen tissue homogenate prepared from mussels (Mytilus edulis) collected in Boston Harbor, Massachusetts. The other two materials, SRMs 2977 and 2978, are freeze-dried tissue homogenates prepared from mussels collected in Guanabara Bay, Brazil and Raritan Bay, New Jersey, respectively. All three new mussel tissue SRMs complement the current suite of marine natural-matrix SRMs available from NIST that are characterized for a wide range of contaminants (organic and inorganic). SRM 1974b has been developed to replace its predecessor SRM 1974a, Organics in Mussel Tissue, for which the supply is depleted. Similarly, SRMs 2977 and 2978 were developed to replace a previously available (supply depleted) freeze-dried version of SRM 1974a, SRM 2974, Organics in Freeze-Dried Mussel Tissue. SRM 1974b is the third in a series of fresh frozen mussel tissue homogenate SRMs prepared from mussels collected in Boston Harbor starting in 1988. SRM 1974b has certified concentration values for 22 polycyclic aromatic hydrocarbons (PAHs), 31 polychlorinated biphenyl congeners (PCBs), and 7 chlorinated pesticides. Reference values are provided for additional constituents: 16 PAHs, 8 PCBs plus total PCBs, 6 pesticides, total extractable organics, methylmercury, and 11 trace elements. PAH concentrations range from about 2 ng g^–1 dry mass (cyclopenta[cd]pyrene) to 180 ng g^–1 dry mass (pyrene). PCB concentrations range from about 2 ng g^–1 dry mass (PCB 157) to 120 ng g^–1 dry mass (PCB 153). The reference value for total PCBs in SRM 1974b is (2020 ± 420) ng g^–1 dry mass. Pesticide concentrations range from about 4 ng g^–1 dry mass (4,4-DDT) to 40 ng g^–1 dry mass (4,4-DDE). SRM 2977 has certified values for 14 PAHs, 25 PCB congeners, 7 pesticides, 6 trace elements, and methylmercury. Reference values for 16 additional PAHs and 9 inorganic constituents are provided, and information values are given for 23 additional trace elements. SRM 2978 has certified and reference concentrations for 41 and 22 organic compounds, respectively, and contains contaminant levels similar to those of SRM 1974b. Organic contaminant levels in SRM 2977 (mussels from Guanabara Bay, Brazil) are typically a factor of 2 to 4 lower than those in SRM 1974b and SRM 2978. The organic contaminant concentrations in each new mussel tissue SRM are presented and compared in this paper. In addition, a chronological review of contaminant concentrations associated with mussels collected in Boston Harbor is discussed as well as a stability assessment of SRM 1974a.Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Two new marine sediment standard reference materials (SRMs) for the determination of organic contaminants

Two new marine sediment standard reference materials (SRMs), SRM 1941b Organics in Marine Sediment and SRM 1944 New York/New Jersey Waterway Sediment, have been recently issued by the National Institute of Standards and Technology (NIST) for the determination of organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, and chlorinated pesticides. Both sediment SRMs were analyzed using multiple analytical methods including gas chromatography/mass spectrometry (GC/MS) on columns with different selectivity, reversed-phase liquid chromatography with fluorescence detection (for PAHs only), and GC with electron capture detection (for PCBs and pesticides only). SRM 1941b has certified concentrations for 24 PAHs, 29 PCB congeners, and 7 pesticides, and SRM 1944 has certified concentrations for 24 PAHs, 29 PCB congeners, and 4 pesticides. Reference concentrations are also provided for an additional 58 (SRM 1941b) and 39 (SRM 1944) PAHs, PCB congeners, and pesticides. SRM 1944, which was collected from multiple sites within New York/New Jersey coastal waterways, has contaminant concentrations that are generally a factor of 10–20 greater than SRM 1941b, which was collected in the Baltimore (Maryland) harbor. These two SRMs represent the most extensively characterized marine sediment certified reference materials available for the determination of organic contaminants.Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Polymer/carrier composites as materials and reactors for organic synthesis

In this work new polymer/carrier composites are described which serve as novel materials in flow-through reactors for polymer-supported organic solution-phase synthesis. Monolithic polymer/carrier columns are prepared by a new precipitation polymerization process inside the void pore volume of megaporous glass carrier materials. Chemical functionalization of the internal polymer phase with chlorosulfonic acid or trimethylamine generates small, interconnected ion-exchange resin beads with a diameter of 1-3 microm which can be used for a large variety of organic syntheses. These monolithic rods are incorporated into an appropriate casing and can conveniently be operated in the flow-through mode. Important successful applications are polymer-assisted solution-phase reductions, oxidations and Horner-Emmons olefinations. Additionally, the use of these monolithic columns as catalytic microreactors and their performance in selected reactions are described.     

Playing with organic radicals as building blocks for functional molecular materials

The literature has shown numerous contributions on the synthesis and physicochemical properties of persistent organic radicals but there are a lesser number of reports about their use as building blocks for obtaining molecular magnetic materials exhibiting an additional and useful physical property or function. These materials show promise for applications in spintronics as well as bistable memory devices and sensing materials. This critical review provides an up-to-date survey to this new generation of multifunctional magnetic materials. For this, a detailed revision of the most common families of persistent organic radicals-nitroxide, triphenylmethyl, verdazyl, phenalenyl, and dithiadiazolyl-so far reported will be presented, classified into three different sections: materials with magnetic, conducting and optical properties. An additional section reporting switchable materials based on these radicals is presented (257 references).     

Use of different types of mesoporous materials as tools for organic synthesis

Mesoporous materials have been investigated as auxiliary agents for organic synthesis comprising reactants with widely different solubility characteristics. The finely divided oxide material was immersed in an aqueous solution of a water-soluble reactant, potassium iodide, and the loaded particles were kept under stirring in the hydrophobic reactant, 4-tert-butylbenzyl bromide, or in a hydrocarbon solution of this reactant. The reaction proceeded well in alumina and silica of either bicontinuous cubic or hexagonal geometry. It was shown for silica that the particle size was an important parameter; the smaller the size the faster the reaction. Titania gave a much lower reaction rate than alumina and silica. It was found that the hexagonal mesoporous alumina could be reused either as a slurry or in a column procedure. Attempts were also made to use hydrophobic mesoporous materials, either mesoporous graphite or mesoporous oxide treated with chlorotrimethylsilane, in the reversed mode. The hydrophobic solid was then immersed in a solution of the hydrophobic reactant and subsequently dispersed in an aqueous solution of the water-soluble reactant. Two nucleophilic substitution reactions and one oxidation reaction were investigated but the yields were low in all cases.