三硝基均苯三酚及其碱金属盐晶体的周期性密度泛函理论研究

对三硝基均苯三酚(TNPG)及其碱金属盐晶体进行DFT-B3LYP周期性计算研究, 求得其能带和电子结构, 探讨了结构-性能关系. 研究结果表明, 晶胞结构参数的计算值与实验值吻合较好. TNPG的导电性介于半导体和绝缘体之间, 而其碱金属盐均为半导体. 金属离子的引入使TNPG阴离子和金属阳离子通过配位键形成三维无限网状结构, 这种网状结构与晶体的半导体性质相关联. TNPG及其碱金属盐的前线轨道主要是由C—NO₂的原子轨道组成, 配位水和金属离子对前线轨道的组成没有贡献. TNPG碱金属盐的带隙均比TNPG的小, 根据“最易跃迁原理”可推测碱金属盐均比TNPG敏感, 这与实验事实相符. 同时, 金属离子的引入增大了酚羟基上的氧原子的活性, 这也可能是导致碱金属盐比TNPG敏感的原因之一.     

Thermal surface ionization of some complex salts

Thermal ionization on the surface of a heated wire is applied to the volatilization products of alkali salts of carboxylic and sulfonic acids, and to quaternary ammonium salts. The mass spectra of the alkali salts exhibit almost exclusively cationized molecules. They provide evidence for the evaporation of intact clustered molecules even under conditions of a slow rate of evaporation of the salts. The method appears to be of interest for selective detection of alkali salts from complex mixtures. With the ammonium salts [R₄N]⁺ ions are formed by thermal surface ionization of intact salt molecules. The evaporation of these molecules could be detected at rather low temperatures.     

Changes in the activity of Ru/Fe2O3 catalysts modified with alkali metal salts in the water-gas shift reaction

A study was undertaken to determine the activity of ruthenium catalysts, obtained by deposition of Ru₃(CO)₁₂ on products of iron oxide-hydroxide calcination modified with alkali metals, in the water-gas shift reaction. The activity depends on the kind of starting iron support, the ruthenium precursor and the amount of alkali metal salts. The most active were the catalysts obtained by deposition of Ru₃(CO)₁₂ on calcination products of σ-FeOOH, both modified and unmodified with alkali metal salts, and of α-FeOOH modified with alkali metal salts.     

Solvent effect on complexation reactions

The inclusion complexation of aromatic amines with cucurbit[6]uril (CB[6]) capped with alkali metal cations was studied spectrophotometrically. We showed that CB[6] capped with alkali metal cations forms a 1:1 inclusion complex with the aromatic amine guests (neutral organic molecules), independent of the length of guest molecules. The effects of salts on the inclusion constants of CB[6] in the presence of different alkali salts were examined and it was found that the inclusion constants increased in the order of alkali cation Cs⁺ < Na⁺ < K⁺, suggesting the interaction of amine guests with the capped alkali metal cation. Further, the structures of the inclusion complexation of aromatic amines with CB[6] were characterized by ¹H NMR measurements. Based on the results, the inclusion abilities of CB[6] capped with alkali metal cations are discussed.     

Sorption studies on regenerated cellulosic fibers in salt–alkali mixtures

The degrees of salt sorption were determined in lyocell and viscose fibers immersed in aqueous solutions of salt–alkali mixtures with the aim of using salt sorption as an indirect measure of changes to fiber accessibility in presence of alkali. The salt–alkali mixtures used were combinations of NaOH with NaCl or NaBr, and of KOH with KCl or KBr. In general, salt sorption in fibers increased with increase in alkali concentration up to 2 mol/l, and did not change significantly thereafter. The accessibility of Br⁻ salts was greater than the Cl⁻ salts, but that of the Na⁺ salts was greater than the K⁺ salts. These trends in salt sorption indicate that salt accessibility in fibers is not influenced by the size of hydrated salt ions, but by the forces of electrostatic attraction and repulsion between the charged fiber surface and salt cations and anions.     

Compounds of Alkali Metal Anions

Anions of sodium, potassium, rubidium, and cesium are stable both in suitable solvents and in crystalline solids. The latter can be prepared either by cooling a saturated solution or by rapid solvent evaporation. Thermodynamic arguments show that alkali metal anions can probably exist in saturated solutions of the alkali metals in any compatible solvent, but that below saturation, dissociation into the cation and solvated electrons is favored in highly polar solvents such as ammonia. The key to solvent-free salts of the alkali metal anions is stabilization of the cation by incorporation into a suitable crown or cryptand complex. By using such complexes it also appears possible to produce “electride” salts in which the charge of the complexed cation is balanced by a trapped electron. The chemical, electrical, and optical properties of salts of the alkali metal anions and “electrides” could provide useful applications.     

Qualitative and quantitative end-group analysis of a small molecular weight polyester by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used for qualitative and quantitative end-group analysis of a small molecular weight polyester, poly(2-butyl-2-ethyl-1,3-propylene phthalate). The presence of carboxyl-terminated linear and cyclic polyester oligomers was confirmed with the help of simple sample preparation methods. The presence of carboxyl end-groups in the polyester chains was verified through their formation of carboxylate salts with alkali metal cations. Cyclic oligomers were identified through deuterium exchange of the exchangeable protons of the polyester. Various inorganic salts were tested for salt formation of the carboxyl end-groups, but only the alkali metal salts proved effective. The influence of the alkali metal salts on the results of the quantitative end-group analysis was also studied. The relative amounts of differently terminated and cyclic oligomers were calculated when the alkali metal salts were used with different matrices. The results showed that both the salts and the matrices used in sample preparation can have a marked effect on the quantitative results of the end-group analysis. The measurements were carried out using 2,5-dihydroxybenzoic acid (DHB), 1,8, 9-trihydroxyanthracene (dithranol), and 2-(4-hydroxyphenylazo)benzoic acid (HABA) as matrix compounds. Dithranol and HABA repeatably exhibited similar results, and these results differed from those obtained with DHB probably because of the different ionization mechanisms in the MALDI process. Copyright-Copyright 2000 John Wiley & Sons, Ltd.     

Reactions of 1-alkylbenzimidazolium 3-imines with acetylenic compounds and benzaldehyde

1-Alkyl-3-aminobenzimidazolium salts react with dimethyl acetylenedicarboxylate or dibenzoylacelylene in the presence of base to produce unusual 1:1 adducts, 1-(2′-alkylaminophenyl)-pyrazole derivatives. Treatment of the 3-amino salts with benzaldehyde in the presence of alkali gives benzaldehyde 2-(N,N-acylalkylamino)phenylhydrazones. The same hydrazones are obtained by alkaline treatment of 1 -alkyl-3-benzaliminobenzimidazolium salts, which are prepared from the 3-amino salts and benzaldehyde.     

Determination of oxygen in alkali halide salts by proton activation and radiochemical separation

A lanthanum fluoride precipitation method for the separation of¹⁸F produced from the¹⁸O(p,n)¹⁸F reaction in alkali halide salts is described. This radiochemical separation method minimizes interferences from other positron emitters produced by proton bombardment and makes the accurate determination of ppm-level¹⁸O in complex alkali halide systems feasible. The interference from the¹⁹F(p,d)¹⁸F reaction is eliminated by keeping the proton energy less than 8.2 MeV. Applications of this technique to studies of dissolved oxide species in molten alkali halide salts are discussed.     

Synthesis,structures, and conformational characteristics of calixarene monoanions and dianions

The synthesis, complete characterization, and solid state structural and solution conformation determination of calix[n]arenes (n = 4, 6, 8) is reported. A complete series of X-ray structures of the alkali metal salts of calix[4]arene (HC4) illustrate the great influence of the alkali metal ion on the solid state structure of calixanions (e.g., the Li salt of monoanionic HC4 is a monomer; the Na salt of monoanionic HC4 forms a dimer; and the K, Rb, and Cs salts exist in polymeric forms). Solution NMR spectra of alkali metal salts of monoanionic calix[4]arenes indicate that they have the cone conformation in solution. Variable-temperature NMR spectra of salts HC4.M (M = Li, Na, K, Rb, Cs) show that they possess similar coalescence temperatures, all higher than that of HC4. Due to steric hindrance from tert-butyl groups in the para position of p-tert-butylcalix[4]arene (Bu(t)C4), the alkali metal salts of monoanionic Bu(t)C4 exist in monomeric or dimeric form in the solid state. Calix[6]arene (HC6) and p-tert-butylcalix[6]arene (Bu(t)C6) were treated with a 2:1 molar ratio of M(2)CO(3) (M = K, Rb, Cs) or a 1:1 molar ratio of MOC(CH(3))(3) (M = Li, Na) to give calix[6]arene monoanions, but calix[6]arenes react in a 1:1 molar ratio with M(2)CO(3) (M = K, Rb, Cs) to afford calix[6]arene dianions. Calix[8]arene (HC8) and p-tert-butylcalix[8]arene (Bu(t)()C8) have similar reactivity. The alkali metal salts of monoanionic calix[6]arenes are more conformationally flexible than the alkali metal salts of dianionic calix[6]arenes, which has been shown by their solution NMR spectra. X-ray crystal structures of HC6.Li and HC6.Cs indicate that the size of the alkali metal has some influence on the conformation of calixanions; for example, HC6.Li has a cone-like conformation, and HC6.Cs has a 1,2,3-alternate conformation. The calix[6]arene dianions show roughly the same structural architecture, and the salts tend to form polymeric chains. For most calixarene salts cation-pi arene interactions were observed.     

Accumulation of cesium in glue balls of spiders' orb webs

Spiders capture prey by applying sticky coating substances to the spiral line of their orb webs. The main constituents of these sticky substances are glycoproteins and salts. This sticky substance is an intelligent material. Salt plays a key role regarding the properties of the sticky substance. Spiders typically weave a new orb webs by recycling used orb webs, and salts, typically salts of the alkali metals sodium and potassium, were therefore assumed to be recycled in this process. Here, we fed cesium (Cs) carbonate (which is an alkali metal salt) to spiders (Araneus ventricosus) to test this hypothesis. After feeding, we mapped the sticky substance in the spiders' orb web using an in-house time-of-flight secondary ion mass spectrometer with high lateral resolution. The results showed that Cs ion was ingested and integrated into the sticky substance, and it showed properties similar to those of sodium ion and potassium ion.     

Dodecahydroxy-closo-dodecaborate(2-).

The cesium salt of the icosahedral borane anion dodecahydroxy-closo-dodecaborate(2-), Cs(2)[closo-B(12)(OH)(12)], Cs(2)1, was prepared by heating cesium dodecahydro-closo-dodecaborate(2-), Cs(2)[closo-B(12)H(12)], Cs(2)2, with 30% hydrogen peroxide. The other alkali metal salts A(2)1 (A = Li, Na, K, Rb) precipitated upon addition of ACl to warm aqueous solutions of Cs(2)1. The ammonium salt, [NH(4)](2)1, and the (mu-nitrido)bis(triphenylphosphonium) salt, [PPN](2)1, were obtained similarly. The [H(3)O](2)1 salt precipitated upon acidification of aqueous solutions of Cs(2)1 with hydrochloric acid. The solubility of these salts in water was determined by measuring the boron content of saturated aqueous solutions of A(2)1 (A = Li, Na, K, Rb, Cs), [H(3)O](2)1, and [NH(4)](2)1 using ICP-AES. Although these salts are derived from a dianion with twelve pendant hydroxyl groups, the alkali metal salts surprisingly displayed low water solubilities. Water solubility decreases with a decrease in the radius of A(+), except for the lithium salt, which is slightly more soluble than the potassium salt. The [H(3)O](2)1 and the [NH(4)](2)1 salts provide rare examples of water-insoluble hydronium and ammonium salts. The low water solubility of the A(2)1 salts is attributed to the dianion's pendant hydroxyl groups, which appear to function as cross-linking ligands. Four alkali metal salts, A(2)1 (A = Na, K, Rb, Cs), were characterized in the solid state by single-crystal X-ray crystallography. These data revealed intricate networks in which several anions are complexed through their hydroxyl groups to each alkali metal cation. In addition, the anions are engaged in hydrogen bonding with each other and, if present, with water of hydration. This cross-linking results in the precipitation of aggregated salts. Cation coordination numbers decrease with cation radius. Thus, cesium and rubidium are ten-coordinate, whereas potassium is seven-coordinate and sodium is six-coordinate. The geometry of anion 1(2)(-) is independent of cation identity; the B-B and B-O bond lengths of the various A(2)1 salts (A = Na, K, Rb, Cs) are identical.     

Two-component polymer films of palladium and fullerene with covalently linked crown ether voids: effect of cation binding on the redox behavior

Redox active films have been generated via electrochemical reduction in a solution containing palladium(II) acetate and fulleropyrrolidine with covalently linked crown ethers, viz., benzo-15-crown-5 and benzo-18-crown-6. In these films, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. Films show ability to coordinate alkali metal cations from the solution. Therefore, in solutions containing salts of alkali metal cations, benzo-15-crown-5-C₆₀/Pd and benzo-18-crown-6-C₆₀/Pd films are doped with cations coordinated by crown ether moiety and anions of supporting electrolyte which enter the film to balance positive charge. These films are electrochemically active in the negative potential range due to the reduction of the fullerene moiety. Reduction of the polymer is accompanied by the transport of supporting electrolyte ions between solution and solid phase. In solution containing alkali metal salts, the process of film reduction is accompanied by the transport of anions from the film to the solution. In the presence of tetra(alkyl)ammonium salts, transport of cations from the solution to the film takes place during the polymer reduction.     

Chemistry of indole

The condensation of salts of 1-methyl-2-aminoindole with aldehydes in excess alkali gives Schiff bases, while salts of 1-methyl-3-arylidene-2-iminoindolines are obtained in the absence of alkali. The latter may give 12-aryl-5,7-dimethylindolo[2,3-b]--carbolines (I) on reaction with excess 1-methyl-2-aminoindole. Dihydro compounds (II) are formed as intermediates.See [1] for communication XXXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1368–1373, October, 1972.     

Reaction of epoxy compounds with salts of thioacids

Conclusions 1. When the alkali metal salts or the ammonium salts of O,O-dialkyl thiophosphates or O,O-dialkyl dithiophosphates are reacted with epoxy compounds the latter undergo thioepoxidation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 353–358, February, 1971.     

Organocatalysis of nucleophilic substitution reactions by the combined effects of two promoters fused in a molecule: oligoethylene glycol substituted imidazolium salts

Oligoethylene glycol substituted imidazolium salts were synthesized as promoters for a range of S_N2 reactions, and their efficiency was examined. These tailor-made organic promoters enhanced the nucleophilicity of alkali metal salts significantly through the combined effects of two promoters (oligoethylene glycols and imidazolium salts) in a single molecule. The effects of the oligoethylene glycol side chain length, ionic liquid anions, nucleophiles, and substrates were investigated systematically. [hexaEGmim][OMs] and [dihexaEGim][OMs] showed the highest efficiency for S_N2 reactions using alkali metal salts. The role of the terminal hydroxyl groups of the oligoethylene glycol moiety was assessed by examining the relative S_N2 yields of chlorination and bromination. The results showed that the hydrogen bonding strength of the hydroxyl groups with the nucleophile is very important. The mechanism for the excellent promotion of S_N2 reactions by oligoEGILs was examined by quantum chemical calculations. The results showed that the oxygen atoms in the oligoethylene glycol portion and the ionic liquid anion act on the counter cation K⁺ or Na⁺ as a Lewis base, to enhance the reactivity of the metal salts significantly.     

Nitropyridines: III. Synthesis of meta-terphenyls by recyclization of nitropyridinium salts

A two-component Hantzsch synthesis was applied to preparation of nitropyridines and their quaternary salts from various enamines and chalcones based on nitroacetophenone. The recyclization of nitropyridinium quaternary salts under the treatment with an aqueous-alcoholic alkali led to preparation of 5′-methylamino-2′-nitro-m-terphenyl derivatives.     

Iron-catalysed propylene epoxidation by nitrous oxide: dramatic shift of allylic oxidation to epoxidation by the modification with alkali metal salts

A dramatic shift of allylic oxidation to epoxidation has been observed during the oxidation of propylene by N(2)O when the FeO(x)/SBA-15 catalyst is modified with alkali metal salts, and the roles of alkali metal salts are to suppress the reactivity of lattice oxygen and to induce an iron coordination structure effective for epoxidation with N(2)O.     

Identification of isothiocyanates (Mustard oils) and liquid primary amines via the formation of 1-substituted 2-tetrazoline-5-thione

The oscillometric method is suggested for the determination of alkali salts of organic acids in non-aqueous media. In the titrations of organic sodium and potassium salts the influence of water content and dielectric constant of non-aqueous solvents on the slopes of the titration curves was investigated. Errors obtained were in the range of±0.6 to 1.5%.     

Asymmetric Michael reaction of diethyl malonate with crotonaldehyde catalyzed by chiral aminocarboxylates,amino alcoholates,and amino phenolates

Alkali metal salts of substituted (S)-prolines, alkali metal alkoxides of (S)-prolinol, and Na salts of chiral substituted 2-amino-2"-hydroxy-1,1"-binaphthyls can catalyze the asymmetric Michael reaction of diethyl malonate with crotonaldehyde to give adducts in >90% yields with ee up to 40%. The influences of the catalyst structure, the nature of the alkali metal cation, temperature, the solvent, and salt additives on the reaction outcome were studied.