Salts selenium chemistry

Jensen was an efficient transmitter of the tradition of sulfur chemistry in Denmark, and several young scientists were inspired by him. For example, Bechgaard became a leading figure in the successful search for organic metals and superconductors ("Bechgaa salts") via his deep insight into sulto and selenium chemistry. 

Rock salt semiconductors, 22 141 dating, 21 317-318 selenium occurrence in, 22 78 Rock surface chemistry, in volumetric sweep efficiency, 18 621 Rock varnish, photocatalytic origin of, 19 100-101... 

Perfluoroalkyl)dibenzothiophenium salts and their selenium and tellurium analogs are novel perfluoroalkylating agents. The synthesis and reactivity of these compounds are covered by T. Umemoto (Ibaraki, Japan). Finally, the first detailed survey of the chemistry of 1,3-oxazinium and 3-azapyrylium salts for over twenty years is provided by S. Lukyanov (Rostov-on-Don, Russia). 

Miniaturization of HPLC-ICP-MS is an important issue in bioanalytical chemistry when small amounts of sample (e.g., single cells) need to be investigated.33 ICP-MS (with an octopole collision cell) in combination with nano-HPLC (75 pun column) was optimized for the detection of selenopeptides in a selenium-yeast protein digest after 100-fold preconcentration on a C18 capillary precolumn (300 (im column for salt removal and cleanup).34 Under identical separation and preconcentration conditions, electrospray MS/MS (using Nanospray qQqToF-MS - QSTAR from Applied... 

Although there are similarities between the chemistry of the chalcogenide elements, the properties of selenium and tellurium clearly lie between those of non-metallic sulfur and metallic polonium. The enhancement in metallic character as the group is descended is illustrated in the emergence of cationic properties by polonium, and marginally by tellurium, which are reflected in the ionic lattices of polonium(IV) oxide and tellurium(IV) oxide and the formation of salts with strong acids. 

The best known selenaaromatic ionic systems are seleninium salts having a selenium atom placed in a six-membered ring. The synthesis and chemistry of selenopyrylium, 1-benzo-, 2-benzo- and dibenzoselenopyrylium salts have been extensively studied since the applications of these compounds in medicine and material chemistry [7, 215, 216], Very few general methods exist for the synthesis of selenopyrylium salts from acyclic precursors. The majority of the methods that are most commonly employed rely on the formation of the salts from another heterocyclic system by either an elimination process or by an aromatization. 

There are general reviews on heterocyclic syntheses by cycloaddition reactions of isocyanates and on the use of heterocyclic cations in preparative organic chemistry. More specific topics are 5-hydroxymethylfuran-2-carb-aldehyde, isobenzofurans and related ort/io-quinonoid systems, the conversion of 2//-cyclohepta[Zj] furan-2-one (1) into derivatives of azulene, the synthesis of indoles from o-alkylphenyl isocyanides, and abnormal Fischer indolization reactions of o-methoxyphenylhydrazones. Two reviews on isoindoles have appeared and a lecture on highly conducting charge-transfer complexes that are based on heterocyclic selenium and tellurium donors has been reprinted.Recent advances in the chemistry of imidazole and in the use of nitro-imidazoles as radiosensitizers have been summarized. There have been reviews on benzimidazole A -oxides and on dihydrobenzimidazoles, benzimidazolones, benzimidazolethiones, and related compounds. Other topics are synthetic applications of 1,3-dithiolium and 1,3-oxathiolium salts and of isoxazoles, the chemistry of benzisoxazoles, 2-amino-oxazoles, 5-oxazolones (2), furoxans, benzofuroxans, and related systems, the synthesis of five-membered meso-ionic compounds, and tetrazoles. ... 

Zn 45.30%. ZnSe. Prepd by mixing a soln of a zinc salt and potassium selenide Berzelius, cited in Mellor s Comprehensive Treatise on Inorganic and Theoretical Chemistry 10, 776 <1930) by passing selenium vapor over zinc heated in vacuo Moser, Doctor, Z. Anorg. Chem. 118, 284 (1921) by passing H,Se into a methanol soln of zinc acetate Nitsche, U.S. pat. 2,805,917 (1957 to du Pont) from ZnSe.N,H4 (zinc selenide hydrazinate) Conn el of.. U.S. pat. 3,014,779 <1961 lo... 

Parts 2 and 3 of the comprehensive review of the chemistry of thiazole have appearedthese include chapters on meso-ionic thiazoles and on cyanine dyes derived from thiazolium salts, and also one on selenazole and its derivatives. The chemistry of selenazole is also included in a review of selenium-nitrogen heterocycles. An account of the chemistry of thiazolidin-4-ones (which includes 2,4-diones but not rhodanine and isorhodanine) updates an earlier review. Reviews on cyclic sulphur-nitrogen compounds and on the synthesis and transformations of nitrogen- and sulphur-containing bicyclic heterocycles have appeared. More general reviews, which contain chemistry relevant to this section, cover reactions based on the onium salts of aza-aromatics, the synthesis of... 

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