Ueber die Methoden zur mechanischen Bodenanalyse

Ohne Zusammenfassung     

Studies in qualitative inorganic analysis. XX

Summary Existing tests for differentiating carbonate and hydrogen carbonate are shown to be unreliable. New tests have been developed which enable carbonate and hydrogen carbonate to be differentiated readily; cyanate and other anions may also be tested for in the mixture. The recommended tests are applicable in the presence of other anions.Preliminary water extraction is done to remove hydrogen carbonates and soluble carbonates and cyanates. The insoluble portion is then treated with hydrochloric acid; the evolution of carbon dioxide confirms insoluble carbonates or cyanates. The latter are confirmed by making the solution alkaline and testing for ammonia. Insoluble carbonate is tested for by extracting another portion of the sample with water and treating the residue with acetic acid. Cyanates do not react under these conditions.The original water extract is divided into three parts: one portion is treated with hydrochloric acid; the evolution of carbon dioxide indicates that any of the three ions may be present. A further portion is treated with phenolphthalein. The red colour indicates soluble carbonate. Barium chloride is added until the colour is discharged; slow evolution of carbon dioxide in the cold or on gently warming indicates the presence of hydrogen carbonate. The third portion is made alkaline and boiled to expel any ammonia present from ammonium salts. The solution is then acidified, made alkaline again and then tested for ammonia. A positive test indicates that soluble cyanates are present.

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Zusammenfassung Bekannte Reaktionen zur Unterscheidung von Carbonat und Hydrogencarbonat erwiesen sich als ungeeignet. Daher wurden neue Tests ausgearbeitet; Cyanat und andere Anionen können dabei gleichfalls nachgewiesen werden.Zunächst wird zur Entfernung von Hydrogencarbonat, löslichen Carbonaten und Cyanaten mit Wasser extrahiert. Der unlösliche Anteil wird mit Salzsäure behandelt; die Freisetzung von Kohlendioxid zeigt unlösliche Carbonate oder Cyanate an. Letztere werden nachgewiesen, indem man alkalisiert und auf Ammoniak prüft. Unlösliche Carbonate sind durch Extraktion einer weiteren Probe mit Wasser und Ansäuern des Rückstandes mit Essigsäure nachweisbar. Cyanate reagieren unter diesen Bedingungen nicht.Der wäßrige Extrakt wird in drei Teile geteilt. Ein Teil wird mit Salzsäure behandelt; Kohlendioxidentwicklung zeigt die Gegenwart einer der drei Ionenarten an. Ein weiterer Teil gibt mit Phenolphthalein Rotfärbung, wenn lösliche Carbonate vorliegen. Man setzt Bariumchlorid bis zur Entfärbung zu: langsame Kohlendioxidentwicklung in der Kälte oder bei leichtem Erwärmen zeigt Hydrogencarbonat an. Der dritte Teil wird alkalisiert und durch Kochen vollständig von Ammoniak aus Ammoniumsalzen befreit. Dann säuert man an, alkalisiert wieder und prüft auf Ammoniak. Ein positives Ergebnis zeigt das Vorhandensein löslicher Cyanate an.

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Résumé On montre que les procédés de recherche qui existent actuellement pour différencier le carbonate de l'hydrogéno-carbonate ne sont pas exacts. On a mis au point de nouvelles réactions permettant de distinguer rapidement un carbonate d'un hydrogéno-carbonate; on peut aussi rechercher les cyanates et d'autres anions dans le mélange. Les procédés de recherche que l'on recommande peuvent s'appliquer en présence d'autres anions.On effectue l'extraction préliminaire par l'eau pour séparer les hydrogénocarbonates, les carbonates solubles et les cyanates. La partie insoluble est alors traitée par l'acide chlorhydrique; le dégagement de gaz carbonique indique la présence de carbonates ou de cyanates insolubles. On confirme l'existence de ces derniers en rendant la solution basique et en faisant l'essai á l'ammoniac. On caractérise les carbonates insolubles en extrayant par l'eau une autre portion de l'échantillon et en traitant le résidu par l'acide acétique. Les cyanates ne réagissent pas dans ces conditions.L'extrait par l'eau initial est divisé en trois parties: l'une est traitée par l'acide chlorhydrique; le dégagement de gaz carbonique indique que l'un des trois ions peut être présent. Une autre est traitée par la phénolphtaléine. L'apparition d'une coloration rouge indique un carbonate soluble. On ajoute du chlorure de baryum jusqu'á disparition de la coloration; un faible dégagement de gaz carbonique á froid ou sous chauffage doux montre la présence d'un hydrogéno-carbonate. La troisiéme partie est rendu alcaline et soumise á l'ébullition pour éliminer l'ammoniac des sels d'ammonium. On acidifie alors la solution, on la rend de nouveau alcaline et on fait ensuite l'essai á l'ammoniac. Une réaction positive indique la présence de cyanates solubles.

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Part XIX: Mikrochim. Acta [Wien]1964, 179.     

Probing the oxyferrous and catalytically active ferryl states of Amphitrite ornata dehaloperoxidase by cryoreduction and EPR/ENDOR spectroscopy. Detection of compound I

Dehaloperoxidase (DHP) from Amphitrite ornata is a heme protein that can function both as a hemoglobin and as a peroxidase. This report describes the use of 77 K cryoreduction EPR/ENDOR techniques to study both functions of DHP. Cryoreduced oxyferrous [Fe(II)-O(2)] DHP exhibits two EPR signals characteristic of a peroxoferric [Fe(III)-O(2)(2-)] heme species, reflecting the presence of conformational substates in the oxyferrous precursor. (1)H ENDOR spectroscopy of the cryogenerated substates shows that H-bonding interactions between His N(ε)H and heme-bound O(2) in these conformers are similar to those in the β-chain of oxyferrous hemoglobin A (HbA) and oxyferrous myoglobin, respectively. Decay of cryogenerated peroxoferric heme DHP intermediates upon annealing at temperatures above 180 K is accompanied by the appearance of a new paramagnetic species with an axial EPR signal with g(⊥) = 3.75 and g(∥) = 1.96, characteristic of an S = 3/2 spin state. This species is assigned to Compound I (Cpd I), in which a porphyrin π-cation radical is ferromagnetically coupled with an S = 1 ferryl [Fe(IV)═O] ion. This species was also trapped by rapid freeze-quench of the ambient-temperature reaction mixture of ferric [Fe(III)] DHP and H(2)O(2). However, in the latter case Cpd I is reduced very rapidly by a nearby tyrosine to form Cpd ES [(Fe(IV)═O)(porphyrin)/Tyr(?)]. Addition of the substrate analogue 2,4,6-trifluorophenol (F(3)PhOH) suppresses formation of the Cpd I intermediate during annealing of cryoreduced oxyferrous DHP at 190 K but has no effect on the spectroscopic properties of the remaining cryoreduced oxyferrous DHP intermediates and kinetics of their decay. These observations indicate that substrate (i) binds to oxyferrous DHP outside of the distal pocket and (ii) can reduce Cpd I to Cpd II [Fe(IV)═O]. These assumptions are also supported by the observation that F(3)PhOH has only a small effect on the EPR properties of radiolytically cryooxidized and cryoreduced ferrous [Fe(II)] DHP. EPR spectra of cryoreduced ferrous DHP disclose the multiconformational nature of the ferrous DHP precursor. The observation and characterization of Cpds I, II, and ES in the absence and in the presence of F(3)PhOH provides definitive evidence of a mechanism involving consecutive one-electron steps and clarifies the role of all intermediates formed during turnover.     

σ‐Alkylpalladium Intermediates in Intramolecular Heck Reactions:Isolation and Catalytic Activity

The isolation of σ‐alkylpalladium Heck intermediates, possible when β‐hydride elimination is inhibited, is a rather rare event. Performing intramolecular Heck reactions on N‐allyl‐2‐halobenzylamines in the presence of [Pd(PPh₃)₄], we isolated and characterized a series of stable bridged palladacycles containing an iodine or bromine atom on the palladium atom. Indolyl substrates were also tested for isolation of the corresponding complexes. X‐ray crystallographic analysis of one of the indolyl derivatives revealed the presence of a five‐membered palladacycle with the metal center bearing a PPh₃ ligand and an iodine atom in a cis position with respect to the nitrogen atom. The stability of the σ‐alkylpalladium complexes is probably a consequence of the strong constraint resulting from the bridged junction that hampers the cisoid conformation essential for β‐hydride elimination. Subsequently, the thus obtained bridged five‐membered palladacycles were proven to be effective precatalysts in Heck reactions as well as in cross‐coupling processes such as Suzuki and Stille reactions.     

Amperometric ion sensors based on laser-patterned composite polymer membranes

A polymer membrane for the selective amperometric transfer and sensing of molecular ions has been designed and characterised. The membrane was formed from two polymer layers, a supporting film of polyethylene terephthalate on which an electrolyte film containing polyvinylchloride is cast. The polyester layer has a laser-etched pattern of circular micro-holes in one region. These hole structures are arranged in a rectangular geometry and measure 22 μm in diameter with separation distances of 105 μm and 120 μm. The polyvinylchloride underlayer is a composite system comprised of a 2-nitrophenyl octyl ether plasticising solution containing an electrolytic salt of tetrabutylammonium tetrakts-(4-chlorophenyl)borate. In this way, an array of micro-interfaces between an analyte solution and a PVC gel electrolyte is formed and used as a liquid|liquid interface for the amperometric monitoring of ion transfer reactions. The membrane was characterised in terms of the voltammetric response to choline transfer. The study includes an examination of the fabrication methodology, materials composition and membrane structure.     

The synthesis of a new dithiophosphonic acid and its coordination properties toward Ni(II): A combined NMR and X-ray diffraction study

In order to investigate the coordination properties of the new, dianionic, S-donor ligand 4-methoxophenyldithiophosphonate (L), a dithiophosphonate salt of L(H₂pz)₂ formula was prepared (Hpz = pyrazole), characterized by multinuclear solution and solid state NMR, and subsequently employed in the synthesis of two Ni(II) metal complexes of [NiL₂](H₂pz)₂ and [NiL₂](HNEt₃)₂ formula. The latter species were fully characterized by a combined NMR and X-ray diffraction study, allowing to disclose interesting structural features, such as subtle deformations of the ligand (and their influence on the magnetic resonance properties of the ³¹P nuclei), imposed by distinct hydrogen-bond patterns.     

An overview of indoor radon risk reduction in the United States

Radon in the indoor environment is a recognized environmental hazard. The Environmental Protection Agency (EPA) has established several programs to develop, demonstrate, and transfer radon mitigation technology. Administration and management of these programs are shared by EPA's Office of Radiation Programs and Office of Research and Development. One measure of success of these programs is that, by 1990, approximately 90,000 houses have been professionally mitigated in the United States. Future success depends, in part, upon strong motivational campaigns conducted in local communities with regional and national support.     

Local Rules: Emergence on Organizational Landscapes

This paper proposes that the theory of local rules provides a model for explaining organizational behavior as an emergent property of a fitness landscape. While local rule theory has its genesis in evolutionary biology, this paper links it to work in computational mathematical organizational theory. It further proposes that there are conditions, characterized by coadaptation, under which rules will survive in relatively stable forms, and other conditions, characterized by competition, under which local rules will change. The paper then discusses how catastrophe analysis can provide insights into changing patterns of organizational interactions. A discussion of methodology outline shows developments in agent-based simulation modeling can contribute to the development of local rule theory.