Search

The BrO(sub 3)F(sub 2)(super -) anion was prepared by reaction of BrO(sub 3)F with the fluoride ion donors KF, RbF, CsF, [N(CH(sub 3))(sub 4)][F], and NOF and is the only the fourth Br(VII) species to have been isolated in macroscopic quantities. The vibrational frequencies of the BrO(sub 3)F(sub 2)(super -) anion were determined by use of Raman and infrared spectroscopy and were assigned with the aid of electronic structure calculations.

A first complete series of racemic and enantiopure conducting salts are synthesized and characterized with metallic character, based on chiral oxazolines. Despite strongly related crystalline and electronic structures, the higher conductivity of pure enantiomers, lacking the disorder inherent to racemic mixture, demonstrates that the chiral donor route is very promising for the elaboration of other metallic salts.

The effect of low molecular-weight compounds on the equilibrium constant K(sub A) can be used to explore the energetics and molecular mechanism of protein- DNA interactions. The complex composed of the integrase Tn916 DNA-binding domain and its target DNA duplex was used to investigate the effects of salt and the nonionic osmolytes glycerol and sorbitol on sequence-specific protein-DNA association.

A critical and updated review of the phenomenon of salting-out for chemists and biologists, particularly those working in the health sciences and highlights of the ramifications of its use in chemistry, biochemistry and molecular biology is discussed. It was found that the salting effect depends mainly on the properties of the electrolyte, nonelectrolyte, and solvent that included the size, structure, charge density, polarizability, and hydration of the electrolyte and nonelectrolyte and the dielectric constant of the solvent.

A new radical cation salt [(ET).sub.5][Dy[(NCS).sub.6][NO.sub.3]] [multiplied by] ([C.sub.2][H.sub.5]OH based on a complex dysprosium anion was prepared by electrochemical oxidation of Bis (ethylenedithio)tetrathiafulvalene (ET) in a chlorobenzene-ethanol solution. Its crystal structure and conducting properties were studied. The salt has a layered crystal structure with a new type of packing of the radical cation layer, which is called [Omega] type. Its electrical properties show that this salt is a semiconductor.

A sensitive novel approach of using an amperometric ion detector for the flow injection analysis of salts has been developed. The detection methodology is based on measuring the current associated with the transfer of ions across polarized microinterfaces between the aqueous sample solution and a 2-nitrophenyloctyl ether--poly(vinyl chloride) gel phase, referred to as ionodes. Different sodium salts of fluoride, chloride, bromide, nitrate, and sulfate were investigated. It was found that by employing an amperometric pulse detection mode and pure water as eluent, the detection limit of the ionode detector could be lowered to ppt level of salt concentrations under flowing conditions.

A structural characterization of homoleptic phosphinophosphonium salts was undertaken to determine phosphine ligand exchange.

Enantiomerism was observed in chiral organic salts having crystallographically independent anion-cation pairs.

The first isomorphous triple salts of silver acetylide are reported.

Research has been conducted on the iron(II) chloride interaction with anhydrous hydroxylamine. The formation of the iron oxide cluster from this interaction is described.

Research is presented demonstrating the extraction of simple salts, normally only water soluble, from water into clusters of oligosaccharide chains which are attached to a rigid macrocycle.

A sodide and a potasside, stable at ambient temperatures, were synthesized and their properties reported.

There have been no published reports on the synthesis of optically active diaryliodonium salts or of their use in asymmetric synthesis. A study conducted the first synthesis and characterization of the chiral diaryliodonium salts, 1,1'-binaphthyl-2-yl(phenyl)iodonium tetrafluoroborates and their derivatives. The synthesis was conducted through BF3-catalyzed tin-lambda3-iodane exchange. These chiral diaryliodonium salts enable asymmetric alpha-phenylation of cyclic beta-keto esters. Experimental results are presented.

Research was conducted to examine the kinetics and products of beta,beta-disubstituted alkenyl(aryl)iodonium triflate fragmentations. The effects of electron-withdrawing groups on the reaction were also investigated. The values, in addition to experiments on stereoisomeric alkenyl(aryl)iodonium salts provide strong evidence of the generation of primary vinyl cations in solution.

The reaction of chiral 1-acylpyridinium salts with prochiral zinc enolates of ketones and lactones has been investigated to determine whether the diastereoselective addition of prochiral metallo enolates to chiral 1-acylpyridinium salts is possible. Experimental results showed that functional groups in the C-2 side chain can undergo useful synthetic transformations in the presence of the dihydropyridone ring system.

A study was conducted to examine band filling control in a conducting system supporting donor pi molecules that is based on bis(ethylenedithio)tetrathiafulvalene cation radical salts. Inductively coupled plasma mass spectrometry was carried out to determine the ratio of M:M in crystal batches. Results indicated that Findings suggested partial electron transfers between donor and anion in doped crystals.

TMTTeN2M(CN)2 represents the first stable organic metals of the peri-ditellurium-bridged polyacene donor, TMTTeN. An examination of their crystal structures reveals three-dimensional networks through intermolecular Te***Te contacts. The Ag(CN)2- and Au(CN)2- salts exhibit high room temperature conductivities of 500-1000 S cm(super -1) and keep the metallic states down to low temperature. Quasi-three-dimensional Fermi surfaces were obtained from the extended Huckel tight-binding band calculation.

The cation radical salt of dimethylthiotetrathiafulvalene bisannulated tetraoxatetrathiatetracosane with linear pentaiodide and triiodide counterions were produced through electrocrystallization. Observations showed that inside the crystal, linear I5- and I3- are organized into a cage-like network, in which isolated cation radicals are found. The formation of linear I5- was also observed from the optical spectra.

A boratophosphazene reacts with the silver salts Ag(AsF6) and Ag(SbF6) to form a white precipitate of AgCl which is converted to crystalline arsenic(V) heterophosphazene and antimony(V) heterophosphazene, respectively. These products, which were generated by skeletal substitution of boron in an inorganic ring, are unique in that they feature high oxidation state group 15 elements beyond the first row.

A D(A)2.5 charge-transfer (CT) salt was prepared employing a neutral, stable free radical as a donor. The CT solid had a structure composed of (TCNQ)2 layers. Static magnetic susceptibility and ESR measurements indicated an antiferromagnetic ordering below 20 K. The salt was a semiconductor at room temperature and atmospheric pressure with a strongly pressure-dependent conductivity.

The saturation kinetics of diazo compounds decompositions catalyzed by rhodium(II) carboxylate salts were investigated. Specifically, the intramolecular Buchner reaction between a diazo ketone and rhodium pivalate or rhodium trichloroacetate in methylene chloride was observed under different substrate concentrations. The results showed the generation of a rhodium carbenoid to be the rate-determining step in the whole process.

The preparation of N-protected alpha-aminomethanesulfinate salts is discussed. Specifically, the synthesis of two classes of glycine analogs, namely, sodium salts and dicyclohexylammonium salts, is presented. The procedure involves the reaction of sodium methanesulfinate with acylating reagents under Schotten-Baumann conditions in argon. It requires the use or dioxane to solubilize and degassed solvents to prevent oxidation of the sulfinate.

The complexation of quaternary ammonium salts by a neutral host, cyclophane, in chloroform solution was investigated. As a comparison, the binding properties of macrocyclic analogs as hosts were also observed. The results, which revealed the involvement of organic cations in the cavity of the macrocyclic hosts, showed that host-guest complementarity influences the stability of the complex products.

The presence of simple nonbuffer salts in the lyophilized enzyme provided for the first time the radical elevation of enzymatic activity in organic solvents. The salt effect represents a general characteristic of the protein-salt matrix, and is neither salt not solvent specific. Interval diffusion influences the salt-rich substitution power.

The cation salt of the tetrafluoroaluminate anion was investigated because of the lack of evidence to support the existence of such a salt. The structure was determined to be a simple (AlF4-) anion associated with a (PSH+) cation. The anion is tetrahedral and 2-folded disordered around the Al-F(1) axis with average Al-F distances of 1.62 Angstrom and F-Al-F distance of 109 Angstrom. The closest contact between the coordinated fluoride and the chelated proton of the (PSH+) cation was 2.77 Angstrom, indicating that the anion exists with only van der Waals contacts to either cations or anions of the lattice.

The formation of (alpha-haloalkylidene)carbenes from vinyl halides through alpha- and beta-elimination processes was studied. The base-induced nucleofugalities from (Z)-(beta-halovinyl)phenyliodonium salts were dehydrohalogenate and subsequently subjected to alpha- and beta-elimination. Results reveal that the generation of (alpha-haloalkylidene)carbenes involves both the alpha-elimination of the phenyliodonio groups and the anti beta-elimination of hydrogen halides.

High school chemistry teachers can introduce an independent, problem-solving experiment as part of a stoichiometry course. Each student is asked to prepare a different water-insoluble salt. Students must select a reactant salt and make a calculation on the basis of solution concentration. The teacher then reviews safety guidelines and checks the accuracy of the students' calculations. Most students obtain approximately 90% isolate. A sample student report is provided.

A bioprocess in which molten salts help break down tough, energy-containing cellulose molecules without creating unwanted by-products, has reportedly been developed by researchers at Lawrence Berkeley National Laboratory in California. […]

The extraction efficiency of salt transport by cation carriers which is affected by anion transfer to the membrane phase is investigated. The addition of anion receptors to cation carriers in the membrane phase enhances salt transport when cation carriers alone do not transport salt.

A study investigated 20 synthesized crystals for use as parent systems which consistently direct the adoption of a host structure even in the presence of substantial building block alterations. The experiment relates to attempts to address packing problem issues in largely organic systems whose crystalline structures and porous natures mimic those of traditional inorganic zeolites. It is possible to chemically modify the alcohol host molecule silver(I)trifluoromethanesulfonate system with a covalent bond to an introduced guest molecule without destroying overall crystalline topology.

Several alkylammonium and bipyridinium salts of hyponitrous acid and hyponitrite salts were synthesized by the reaction of the corresponding amine in either anhydrous diethyl ether or absolute ethanol with hyponitrous acid. Single-crystal X-ray crystallographic data were gathered. Differential scanning calorimetric data showed exothermic decomposition of the hyponitrite species. The pentahydrate and anhydrous forms of Na2N2O2 showed unique thermal decomposition behavior.

The application of alkylnitrilium salts in intermolecular electrophilic aromatic acylation reactions was demonstrated in the total synthesis of both O-methylsterigmatocystin via xanthone and of xanthone, which can be converted to 11-hydroxy-O-methylsterigmatocystin. A new carbonyl protecting group that expands the tolerance of the xanthone nucleus to chemical modification was also developed. The addition of n-butyllithium and dehydration promoted by silica gel chromatography easily led to the formation of the protected alkenyl xanthene. These approaches together offer a general methodology for the synthesis of complex xanthone natural products.

A new anhydrous LiCl salt highly reactive to coordinating agents is prepared by reacting powdered metallic lithium with 1-chlorobutane. The product is then dissolved in poly(ethylene glycol) (PEG) with a molecular weight of 400 to create a series of PEG 400/(LiCl)x electrolytic complexes with 0

This paper investigates the generation of convective layers on sidewalls of a solar pond with fertilizer salts. The fertilizer salts used in the pond are urea, potassium nitrate (KN[O.sub.3]), mono ammonium phosphate (MAP) and mono potassium phosphate (MKP). Furthermore, the paper reports the effects of the surface roughness heights of the wall, on the growth of the generated convective layers and the stability of the solar pond. It was found that urea and potassium nitrate tend to have the least active generated convective layers in the 90 [degrees] and 30 [degrees] tanks when compared with the other salts investigated, while mono ammonium phosphate resulted in less activities for the layers generated in the vertical tank. The mono potassium phosphate showed less activity for the convective layers in the 60 [degrees] tank. The addition of surface roughness to the inclined wall reduced the growth of the convective layers by as much as 55.6% as the height of the surface roughness was increased.

The reactivity of BrNO(sub 2) and ClNO(sub 2) with bromide was investigated in a Knudsen-cell reactor in the presence of solid sea-salt aerosol. A BrNO(sub 2) source based on the reaction of molecular bromine with solid KNO(sub 2) was developed to better understand the fate of BrNO(sub 2) in the reactor. Experimental results showed that the lifetime of BrNO(sub 2) is on the order of 10 s and is restricted by heterogeneous decomposition reactions.