Metalation ethers

Nitrosyl perchlorate Acetones, amines, diethyl ether, metal salts, organic materials... 

Most successful approaches involving addition reactions in the presence of chiral additives utilize organolithium, organomagnesium and the recently introduced organotitanium reagents, which are known to coordinate with amines, ethers, metal amides and alkoxides. 

Nitropropane Nitrosyl fluoride Nitrosyl perchlorate Nitrourea Nitrous acid Nitryl chloride Oxalic acid See under Nitromethane chlorosulfonic acid, oleum Haloalkenes, metals, nonmetals Acetones, amines, diethyl ether, metal salts, organic materials Mercury(II) and silver salts Phosphine, phosphorus trichloride, silver nitrate, semicarbazone Ammonia, sulfur trioxide, tin(IV) bromide and iodide Furfuryl alcohol, silver, mercury, sodium chlorate, sodium chlorite, sodium hypochlorite... 

T. Irie, K. Fukushi, T. Ido, T. Nozaki, Y. Kasida, F-18-labeled fluorination by crown ether metal fluoride. 1. On labeling F-18-21-fluoroprogesterone, Int. J. Appl. Radiat. Isot. 33 (1982) 1449-1452. 

As thus obtained, the acid is combined with one equivalent of water, and is, therefore, expressed by the formula, C10 Hs 0 HO. Hydrated sebacic acid forms light, white, pearly Beales, resembling benzoic acid in appearance indeed, it was considered by Berzelius to be identical with this acid. It has a very slightly acid taste, but reddens litmus. It fuses at 260° to an oily liquid, and, at a higher temperature, sublimes unchanged. It is much more soluble in hot than in cold water, and is readily dissolved by alcohol or ether. With the alkalies it forms soluble achates, but its salts, with ether metallic oxides, are for the most part insoluble, Liebig and RedteNbacher were the first to notice tins acid as a certain and delicate test of the presence of oleic acid. 

An enantioselective synthesis of CR)-amino acids has been developed which utilizes L-valine as the chiral auxiliary (81AG(E)798). The diketopiperazine cycZo-(L-Val-Gly) (780) was converted to its bis-lactim ether (781) by methylation with Meerwein s salt, and the ether metallated in the glycine portion by n-butyllithium. Alkylation of the delocalized... 

Crown ether Metal cation Ion-dipole Complex (cavitand) [K+([18] crown-6)]... 

Tetrahydronaphthalene t-Bntyl alcohol Cyclohexane Dicyclopentadiene Ethyl ether Metal acetylene Tetrahydrofnran Vinyl ethers... 

The dynamics of excitons in isotopically mixed naphthalene crystals has been reviewed and the effects of orientation of metal ion perturbers in naphthalene-crown ether metal ion complexes on the external heavy atom examined . ... 

The use of chiral stationary phases (CSP) in liquid chromatography continues to grow at an impressive rate. These CSPs contain natural materials such as cellulose and starch as well as totally synthetic materials, utilizing enantioselective and retentive mechanisms ranging from inclusion complexation to Ti-electron interactions. The major structural features found in chiral stationary phases include cellulose, starch, cyclodextrins, synthetic polymers, proteins, crown ethers, metal complexes, and aromatic w-electron systems. 

Multidentate conjugated ether-metal complexes (alkali/alkaline earth cations)... 

Crown ethers. Metal and crown ether complexes have to fulfill two requirements to form stable complexes. First, the coordination sphere of the metal must be stabilized by the crown ether and any complexing anions. A trivalent uranium coordination sphere is typically satisfied... 

The use of CDs for chiral separations has, to date, been the most common approach when using CE or MEKC, so it would be difficult to discuss and detail every aspect relating to their chemistry, effects on separation, and application in this held. The emphasis will, thus, be placed on a short description of the principle and mechanism of chiral separation, typical method development procedures, and an outline of the influential experimental parameters using CE and MEKC. References to recent published review and research literature will enable the reader to explore this vast area further. It is also beyond the scope of this short introductory review to actually outline the actual CE or MEKC separation principles in detail, but an in-depth discussion can be found in this encyclopedia and references to recent textbooks and can be readily found elsewhere. It must, of course, be pointed out that CDs are not the only useful chiral selectors that can be employed using electrophoretic techniques. The use of chiral surfactants (bile salts), crown ethers, metal-chelation agents, carbohydrates, proteins, and glycopeptides have all been used effectively [2]. 

Scope of the Problem. Petroleum hydrocarbons are the principal components in a wide variety of commercial products (e.g., gasoline, fuel oils, lubricating oils, solvents, mineral spirits, mineral oils, and crude oil). Because of widespread use, disposal, and spills, environmental contamination is relatively common. It is important to understand that petroleum products are complex mixtures, typically containing hundreds of compounds. These include various amounts of aliphatic compounds (straight-chain, branched-chain, and cyclic alkanes and alkenes) and aromatic compounds (benzene and alkyl benzenes, naphthalenes, and PAHs). In addition, many petroleum products contain nonhydrocarbon additives such as alcohols, ethers, metals, and other chemicals that may affect the toxicity of the mixture. 

Figure 4.9 A crown ether-metaL complex simulation using explicit solvent...

Figure 4.10 Simulated binding modes for crown ether-metal complexes Na+-[15]crown-5 (top left), Na+-[18]crown-6 (top right), K+-[15]crown-5 (bottom left), K+-[18]crown-6 (bottom right)...

With Sn2+ and Pb + based catalysts, two ligands are coordinated and the methoxy group of the activated alcohol can be involved in the crystalline field (ether-metal bond) and be responsible for a donor-type effect on the metal. The reactivity sequence is now reversed (Table I) ... 

These properties are mainly originated from the molecular structures of CNTs, which consist of graphene sheets rolled to form hollow cylinders with an extremely high aspect ratio [5]. Moreover, CNTs can be ether metallic or semiconducting tubes, depending on their diameter and/or chirality [5]. There are two types of CNTs SWNTs and MWNTs. Details, such as structure, synthesis methods, application and properties, are well documented [4], [5], [6]. 

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