Morphine,the Proteus of organic molecules

This feature article encapsulates the senior author's longstanding interests in opiate chemistry and attempts to place it within an historical context and against the backdrop of related work by others who have viewed morphine as one of the pinnacles of natural product synthesis. Biomimetic and 'bioanalogous' routes to the morphine skeleton are discussed followed by approaches based on the elaboration of phenanthrene platforms. The latter include an asymmetric synthesis of ent-morphine developed in our laboratory.     

Electrochemistry of organic,bioactive compounds and biopolymers

Monatshefte für Chemie - Chemical Monthly -     

Kinetics, products, and mechanisms of secondary organic aerosol formation

Secondary organic aerosol (SOA) is formed in the atmosphere when volatile organic compounds (VOCs) emitted from anthropogenic and biogenic sources are oxidized by reactions with OH radicals, O(3), NO(3) radicals, or Cl atoms to form less volatile products that subsequently partition into aerosol particles. Once in particles, these organic compounds can undergo heterogenous/multiphase reactions to form more highly oxidized or oligomeric products. SOA comprises a large fraction of atmospheric aerosol mass and can have significant effects on atmospheric chemistry, visibility, human health, and climate. Previous articles have reviewed the kinetics, products, and mechanisms of atmospheric VOC reactions and the general chemistry and physics involved in SOA formation. In this article we present a detailed review of VOC and heterogeneous/multiphase chemistry as they apply to SOA formation, with a focus on the effects of VOC molecular structure on the kinetics of initial reactions with the major atmospheric oxidants, the subsequent reactions of alkyl, alkyl peroxy, and alkoxy radical intermediates, and the composition of the resulting products. Structural features of reactants and products discussed include compound carbon number; linear, branched, and cyclic configurations; the presence of C[double bond, length as m-dash]C bonds and aromatic rings; and functional groups such as carbonyl, hydroxyl, ester, hydroxperoxy, carboxyl, peroxycarboxyl, nitrate, and peroxynitrate. The intention of this review is to provide atmospheric chemists with sufficient information to understand the dominant pathways by which the major classes of atmospheric VOCs react to form SOA products, and the further reactions of these products in particles. This will allow reasonable predictions to be made, based on molecular structure, about the kinetics, products, and mechanisms of VOC and heterogeneous/multiphase reactions, including the effects of important variables such as VOC, oxidant, and NO(x) concentrations as well as temperature, humidity, and particle acidity. Such knowledge should be useful for interpreting the results of laboratory and field studies and for developing atmospheric chemistry models. A number of recommendations for future research are also presented.     

Synthesis, characterization, and application of metal organic framework nanostructures

The considerable number of important physical properties, including optical, electronic, and magnetic properties, of Prussian blue (PB) analogues have attracted fundamental and industrial interest. Nevertheless, the gas sorption properties of PB coordination compounds were only investigated very recently. In this work, we report the synthesis and gas sorption properties of PB nanocomposites with different size and shape obtained by using poly(vinylpyrrolidone) (PVP), chitosan, and dioctyl sodium sulfosuccinate (AOT) as stabilizers and structure directing agents. All three porous nanocrystals show high and selective CO(2) adsorption over CH(4) or N(2). No distinct relationship was found between the size (or shape) of the nanosorbents and their gas uptake capacities. To our knowledge, this is the first report on the use of PB nanocomposites for CO(2) capture applications.     

Microdetermination of selenium,tellurium, and arsenic in organic compounds

Summary A method is described for determination of selenium, tellurium and arsenic in organic compounds. Decomposition is carried out either by oxygen-flask combustion or by wet digestion with sulphuric and nitric acids. The analysis is completed by argentometric titration, at pH 8–8.5, of the selenite, tellurite or arsenate formed. Halogens can often be determined simultaneously, and procedures are given for dealing with metal-containing compounds. Results obtained are within the usual limits for microanalysis (±0.3%).

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Zusammenfassung Eine Methode zur Bestimmung von Selen, Tellur und Arsen in organischen Verbindungen wurde beschrieben. Deren Zerstörung erfolgt entweder im Sauerstoffkolben oder durch nasse Veraschung mit Salpetersäure-Schwefelsäure. Die Endbestimmung erfolgt argentometrisch bei pH 8–8,5. Oftmals kann gleichzeitig auch Halogen bestimmt werden. Arbeitsvorschriften für Organometallverbindungen wurden angegeben. Die Ergebnisse liegen innerhalb der üblichen Fehlergrenzen von ±0,3%.

     

Synthesis of a stable,foamable, gold-containing organic carboxylate polymer

The functionalized polyethylene acrylic acid copolymers Primacor 1430 (P1430, containing 9.5% acrylic acid) and Primacor 5980 (P5980, containing 20% acrylic acid) have been used to synthesize gold/polymer dispersions and gold/polymer ionomers, respectively. When [Ph₃PAu]⁺ is bonded directly to the carboxylate, work-up of the polymer leads to decarboxyation and metallic gold formation. However, ionic bonding of [(Ph₃P)₂Au]⁺, and related bis phosphine cations produce workable, foamable polymers. Analysis shows samples from these reactions to contain between 4–15 wt % of Au depending on the type of gold complex used and the reaction conditions. The gold/polymer (ionomer) sample with about 12% Au has been worked to mold sheets of foam. © 1993 John Wiley & Sons, Inc.     

Review of the QuEChERS method for the analysis of organic pollutants: Persistent organic pollutants,polycyclic aromatic hydrocarbons,and pharmaceuticals

In multi-residue pesticide analysis, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method has replaced less efficient traditional extraction methods due to its many advantages. In addition to pesticide analysis, this method has been widely used for the detection and analysis of pharmaceuticals, polycyclic aromatic hydrocarbons (PAHs), and several persistent organic pollutants (POPs), including dioxins, polychlorinated biphenyls, perfluoroalkyl substances, and brominated flame retardants in food, biological, and environmental matrices. The analysis of PAHs and POPs is challenging due to the properties of the target compounds and their low concentrations in complex matrices. This review summarizes previously reported the QuEChERS extraction approaches to the analysis of a wide range of analytes. The QuEChERS approaches, which include dispersive solid phase extraction (d-SPE), have generally been combined with either gas chromatography–mass spectrometry (GC–MS) or liquid chromatography–mass spectrometry (LC–MS) analysis. Further on, in recent years, GC and LC-tandem mass spectrometry has been utilized with the QuEChERS extraction due to its high selectivity, sensitivity, and specificity. This enables the extraction methods for target analytes to be modified through the selection of different extraction solvents, salt formulations, and buffers for salting-out partitioning and the selection of different d-SPE and SPE sorbents for the clean-up process. The most significant advantage of this method is that concentration steps are not required. This review aims to provide an up-to-date overview of information regarding the modification of extraction techniques based on target compounds and sample matrices.     

Ambipolar, high performance, acene-based organic thin film transistors

We present a high performance, ambipolar organic field-effect transistor composed of a single material. Ambipolar molecules are rare, and they can enable low-power complementary-like circuits. This low band gap, asymmetric linear acene contains electron-withdrawing fluorine atoms, which lower the molecular orbital energies, allowing the injection of electrons. While hole and electron mobilities of up to 0.071 and 0.37 cm2/V.s, respectively, are reported on devices measured in nitrogen, hole mobilities of up to 0.12 cm2/V.s were found in ambient, with electron transport quenched. These devices were fabricated on octadecyltrimethoxysilane-treated surfaces at a substrate temperature of 60 degrees C.     

Isolation, identification and quantitation of urinary organic acids

An application of the HISLIB program for the comparison of gas chromatographic-mass spectrometric profiles of urinary organic acids isolated by extraction and ion-exchange methods is described. Ion-exchange methods are clearly superior to solvent extraction in terms of the variety of compounds isolated. However, the former method has practical difficulties which make solvent extraction more attractive for rapid analyses. For the compounds isolated by both methods, the precision of analysis is similar, with standard deviations of relative concentration in the range 10--30% for most compounds.     

Stability,encapsulation and large-area fabrication of organic photovoltaics

Organic photovoltaics(OPVs) have become a timely research topic for their advantages of light weight, low cost, low toxicity,environmental adaptability, flexibility, and large-area manufacture, especially after non-fullerene acceptor ITIC reported in 2015.The highest power conversion efficiency(PCE) is currently above 18% for OPV. However, there are still imparities in the efficiency of OPVs when compared with silicon-based photovoltaics, as well as in their shelf life. Compared with inorganicbased photovoltaics, the efficiency of large-area OPVs is lower and the life time of OPVs is shorter. Therefore, such inferior performance of large-area OPVs restricts the commercial development. Based on these constraints, this paper reviews the research work regarding OPVs into three aspects: stability, encapsulation technology, and recent large-area preparation technologies.     

Thin-layer chromatography of organic sulphates, phosphates and nitrates

Inorganic oxyanions and their corresponding organic esters, such as sulphates, phosphates and nitrates, have been separated by thin-layer chromatography on cellulose and silica gel plates.     

The cross-coupling reactions of organic halides with organic derivatives of tin,mercury and copper catalyzed by palladium

The palladium-catalyzed cross-coupling of organic halides with organometallic compounds of tin, mercury and copper is discussed. It is shownn that the “ligandless” palladium complexes RPdXL₂ (L = solvent), in which solvent molecules act as weak donating ligands, are the most active catalysts for reactions of organotin compounds. It is found that nucleophilic catalysis is an efficient method of activatioin of organomercury and organocopper compounds in cross-coupling reactions. In the presence of iodide ion the palladium-catalyzed reactions of these compounds proceed under mild conditions giving high yields of cross-coupling products.     

Contrapolarization,a new concept in organic reactivity

Contrapolarization is reactivity umpolung on a transitory time scale. It is a rather general phenomenon of considerable significance in organic reactivity. Its existence was not pointed out earlier because there has been an ingrained belief that nucleophiles (donors) and electrophiles (acceptors) always play nothing other than their proper roles, The versatility of the more recently developed reagents based on phosphorus, sulfur, and selenium is due, in large part, to their capacity and ease to undergo contrapolanzing changes. Recognition of this capacity and thorough analysis of synthetic requirements may help design new reactions/reagents of even greater selectivity and applications.     

Structural, thermal, and nmr studies of hexafluorides with organic cations

Three new hexafluoro complexes are studied: (EDA)TiF₆, (A)₂- SiF₆, and (Py)₂TiF₆ (EDA is the ethylenediamine ion, A is the aniline ion, and Py is thepyridine ion). These compounds are representatives of a wide family of crystals, which are prospective for practical and fundamental research but have been studied insufficiently. The structure of (EDA)TiF₆ was solved by the single crystal X- ray diffraction method (at room temperature): space group A2/a, a =10.655, b =8.7081, c =7.9704 å, Β =95.032?. For all compounds studied, thermal, dielectric, and NMR measurements have been performed. Thermal measurements indicate that (EDA)TiF₆, (Py)₂TiF₆, and (A)₂SiF₆ have phase transitions at 130, 195,and 248 K;173, 230, and 288 K, respectively. The presence of a phase transition in (EDA)TiF₆ was confirmed by dielectric measurements.¹H and¹⁹F NMR spectra were recorded, and spin- lattice relaxation times T₁ were measured in a wide range of temperatures. The NMR data are analyzed from the viewpoint of the nature of internal mobility in the crystals under analysis.