EMK-Messungen in binären ladungsunsymmetrischen Salzschmelzen aus Bariumchlorid und Alkalimetallchloriden

EMF Measurements in Binary Chargeunsymmetrical Salt Melts of Barium- and Alkali Chlorides The EMF is measured of cells with transference of the type Cl₂[C]/MCl//MCl? BaCl₂(x)/[C]Cl₂ in the molten mixtures BaCl₂? MCl (M ? Li, Na, K, Rb, Cs). From the EMF values and values of activities from another independent methods the transference numbers of the cations Ba²⁺ and M⁺ relative to the chloride ion in the molten mixtures BaCl₂? (Li, Na, K) Cl are calculated. The values of activities for the system BaCl₂? LiCl are calculated from cryoscopic analysis of the phase diagram.     

Structural Study of Alkaline 1-Phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate Salts: An Example of Periodicity in Alkaline Cations

The alkaline 1-phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate salts, M[C₆H₅N₄CS] (M = Li ( 1 ), Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 )) were obtained and characterized by means of mass spectrometry (FAB⁺) and NMR (¹H; ¹³C) spectroscopy. The structures of Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 ) compounds were determined by X-ray diffraction methods. The ligand shows a rich variety of coordination patterns with the alkaline cations. The formation of a four-membered ring MSCN in the compounds with heavier alkali cations (K, Rb and Cs) is shown. In all the cations the coordination number around it increases with the ionic radius. Compounds with Cs⁺ and Rb⁺ exhibited the formation of Cs-C and Rb-C interactions with the phenyl group.     

Pulse radiolysis of alkali metal cations in isopropylamine: Correlation of optical absorption spectra with electron spin resonance data

Pulse radiolysis of alkali metal cations in isopropylamine indicates the formation of three distinct optical bands attributed to solvated electrons, e^?_s, ion-pairs (M⁺, e^?_s) and alkali anions M^?. It is found that the ion-pair spectra exhibit a distinct blue shift from that of e^?_s. Comparisons with results obtained in ethylamine, tetrahydrofuran and other solvents demonstrate that the position of the ion-pair band can be correlated with the percent atomic character observed by ESR for the “monomer” species in alkali metal solutions. Results are presented for the alkali metal series, Li, Na, K, Rb and Cs.     

Preparation and photoluminescent properties of Eu(III) containing M-layered silicates (M = Li,Na, K,Rb, Cs)

Eu(III) containing M-layered silicates (M = Li, Na, K, Rb, Cs) were prepared using the layered silicates, such as ilerite, magadiite, and kenyaite, as a host matrix and the luminescence properties were investigated. The results from the luminescence measurements indicated that the luminescence properties in the EuM-layered silicate system depended strongly on the types of host matrices and alkali cations. Among the EuM-layered silicates, EuM-ilerite exhibited the strongest luminescence intensity for all alkali cations, whereas EuM-kenyaite exhibited relatively weak luminescence intensity. The luminescence intensity was significantly increased by heat treatment at high temperature, mainly due to the phase change of host matrices and the presence of alkali cations in the host matrices. Particularly, the luminescence intensity of EuM-layered silicate calcined at 1,000 °C increased with the increase of the ion size of alkali cations.     

Die Infrarot- und RAMAN-Spektren der Alkalifluorosulfate

For the alkali fluorosulfates MSO₃F infrared spectra (M = Li, Na, K, Rb, Cs) and also RAMAN spectra (M = K, Rb, Cs) have been recorded. The results are discussed to get some information about the lattice structures. The C₃ axis of the anion has several possibilities of orientation in the unit cell for the salts with heavy cations.     

NMR spectroscopy of bismuth fluoride glasses with alkali cations

Results of the ⁷Li, ¹⁹F, and ²³Na NMR studies of ionic mobility in bismuth fluoride glasses in the systems BiF₃-LiF and BiF₃-MF-ZrF₄ (M = Li, Na, K, Cs) are summarized. Analysis of the ⁷Li, ¹⁹F, and ²³Na NMR spectra made it possible to reveal changes in the nature of ion motions in the fluoride, lithium and sodium sublattices of glasses upon temperature variation and to determine their types. The temperature ranges were found where main types of ion motions in the tested glasses are represented by diffusion of lithium ions, reorientations of fluorine-containing groups constituting the glass network, and diffusion of fluorine ions. The role of alkali cations in the formation of ionic mobility in bismuth fluorozirconate glasses is considered.     

Alkalimetall-Cluster im Zeolith Y Darstellung,Eigenschaften, Reaktionen

Alkali Metal Clusters in Zeolite Y. Preparation, Properties, Reactions Alkali metal clusters (Type AB₃³⁺) were synthesized by reaction of alkali metal A (Li, Na, K, Rb, Cs) with the cations B (alkali, alkaline earth, and rare earth metals) of zeolite Y. The compounds were characterized by UV/VIS spectroscopy, oxidation by carbon oxides and organic halides, and adsorption of gases and polar molecules. The clusters are less reactive than the free alkali metals, the redox potential depends on the alkali metal as well as the cation of zeolite. Chemical interactions with typical ligands and with N₂, Ar, Kr, CO, CO₂, Benzene, and n-Hexane were observed. Reaction with ammonia leads to solvated electrons in zeolite's super-cage, stable up to 240 K.     

Complexation of Calix[4]arene With Alkali Metal Cations: Conformational Binding Selectivity and Cation-π Driven Inclusion

Hartree-Fock, second order Møller-Plesset perturbation theory, and density functional theory calculations were carried out to analyse the complexation of calix[4]arene with cationic species including H + and the alkali metal cations (Li + , Na + , K + , Rb + , and Cs + ). Special emphasis has been placed on conformational binding selectivity, and on the structural characterization of the complexes. Li + and Na + cations are located in the calix[4]arene lower rim. The larger cations (K + , Rb + , and Cs + ) complex preferentially with the calix[4]arene cone conformer, and their endo (inclusive) complexation is driven by cation- ~ interactions, leading in the case of K + to a structure that reflects a preferential interaction with two phenol rings. The endo complexation of Cs + with calix[4]arene is in agreement with X-ray diffraction data.     

Über Chalkogenolate. 96 [1]. Untersuchungen über Alkalimetalltrimethylsilylcarbonate

On Chalcogenolates. 96. Studies on Trimethylsilyl Carbonates of Alkali Metals The trimethylsilyl carbonates M[O₂COSi(CH₃)₃] with M = Li, Na, K, Rb, Cs have been prepared by reaction of Co₂ with the corresponding silanolate. Infrared spectra, electron absorption spectra, ¹H-NMR spectra as well as mass spectra are communicated. In aqueous solution the equivalent conductivities of [O₂COSi(CH₃)₃]^? have been determined by means of conductivity measurements. The diffusion coefficient of the ion was calculated. The dissociation constant of trimethylsilyl carbonic acid in water at 20°C is K_a = (4,83 ± 0,5) · 10^?10. The thermodynamic data of the dissociation were calculated.     

Synthesis and Structural Investigation of a Complete Series of Brightly Colored Alkali Metal 1,3-Dimethylviolurates

A complete series of alkali metal 1,3-dimethylviolurates M(Me₂Vio) was synthesized and fully characterized. The title compounds M(Me₂Vio)(H₂O) [M = Li ( 3 ), Na ( 4 )], K(Me₂Vio)(H₂O)_0.5 ( 5 ) and M(Me₂Vio) [M = Rb ( 6 ), Cs ( 7 )] were prepared by neutralizing 1,3-dimethylvioluric acid (= HMe₂Vio; 2 ) with 1 equiv. of the corresponding metal hydroxides MOH. The resulting salts exhibit striking colors ranging from orange-red ( 3 ) through purple ( 4 , 5 ) to bright blue ( 6 , 7 ). In contrast to the monohydrate 4 , the classical synthesis of sodium 1,3-dimethylviolurate from 1,3-dimethylbarbituric acid and NaNO₂ afforded the purple trihydrate Na(Me₂Vio)(H₂O)₃ ( 4a ). All new compounds have been fully characterized by their IR and NMR (¹H, ¹³C) spectra as well as elemental analyses. X-ray crystal structure determination revealed that the title compounds exist as one- (Li, Na), two- (K, Cs), or three-dimensional (Rb) coordination polymers in the solid state.     

Synthesis and some Reactions of Alkali Metal Carbamotelluroates

Sodium and potassium carbamotelluroates [M(R₂NCOTe), M = Na, K, Rb, Cs] were synthesized in moderate to good yields by reacting carbamoyl chloride with the corresponding alkali metal tellurides. The salts readily reacted with trimethylsilyl chloride to form O‐trimethylsilyl carbamotelluroate (R₂NCTeOSiMe₃), which further reacted with RbF and CsF to lead to the corresponding heavy alkali metal carbamotelluroates. These salts reacted with alkyl iodide and carbamoyl chlorides to give the corresponding Te‐alkyl carbamotelluroates and dicarbamoyl tellurides in moderate yields.     

Temperature dependence of electric conductivity of molten binary mixtures of alkali and rare-earth metals chlorides

The temperature dependences of the specific and molar electric conductances of CeCl₃-MCl and LnCl₃-KCl (M=Li, Na, K, and Cs; Ln=Er and Yb) molten binary mixtures of various compositions were studied. The size of the cations of alkali and rare-earth metals was demonstrated to affect the intensity of the interactions of the components of the systems. Deviations of the molar conductance isotherms from additivity and dependence of the isotherms on the ratio between the mixture components were explained by the formation of complexes in the melts.     

Effect of various inorganic cations (Li,Na, K and Cs) and silica sources on the synthesis of the silica analogue of zeolite NCL-1 (Si-NCL-1)

The role of various inorganic cations such as Li, Na, K and Cs has been studied in the hydrothermal synthesis of the silica polymorph of zeolite NCL-1 (Si-NCL-1). The crystallization time decreases in the order (Cs + Na) > K > Na> (Li + Na) under otherwise identical gel composition and crystallization conditions. Further, the synthesis has been standardized using different silica sources including various fumed silicas with different surface area and particle size, through optimizing the OH⁻/Si molar ratio by adding the required amount of alkali hydroxide in the synthesis gel. Among different silica sources (fumed silicas, tetraethyl orthosilicate, silica sol etc.), fumed silicas with smaller particles (~0.007 μn) like Sigma S-5005, S-5130, and Cab-O-Sil-M5 were found to be quite effective and preferable for the synthesis of Si-NCL-1 molecular sieves. These materials were characterized through XRD, IR, SEM, sorption and surface area measurements.     

Study of Ion-Exchanged Microporous Lithosilicate Na-RUB-29 Using Synchrotron X-Ray Single-Crystal Diffraction and Li MAS NMR Spectroscopy

Synchrotron X-ray single-crystal diffraction analyses revealed that as-synthesized and Na-exchanged RUB-29 (Cs_1−x, Na_x)₁₄Li₂₄[Si₇₂Li₁₈O₁₇₂]·yH₂O (x=0, 0.9) displays the lattice symmetry I222. With increasing ion-exchange time, the Na cations preferentially replace Cs in the larger sites located at the intersections of the 10MR/10MR/8MR channels. The smaller Cs sites are then replaced. While Na cations are easily incorporated on the Cs sites, most of non-framework Li cations remain in the channel system. Relocation of Li cations onto new sites within the channels was observed only after 13 days of ion exchange. Using high-field (14.1 T) NMR spectroscopy, at least six separate ⁶Li resonances could be resolved for the first time by solid-state ⁶Li MAS NMR spectroscopy and assigned to Li in the framework and non-framework sites of the microporous lithosilicate materials. The fate of Li in both framework and extra-framework sites during exchange was also followed by ⁶Li MAS NMR spectroscopy with an Na-exchanged RUB-29 powder sample.     

Bis(trimethylsilyl)-diimin: Zur reaktion mit alkalimetallen

Bis(trimethylsilyl)diimine (BSD) is reduced by alkali metals (Li, Na, K) in diethyl ether to the dianion (BSD^2?) and in tetrahydrofuran to the radical anion (BSD^-). The radical anion is thermally unstable and decomposes (a) to nitrogen and bis(trimethylsilyl) amide and (b) to bis(trimethylsilyl) amide, bis(trimethylsilyl) hydrazide and azide. The ratio of the yields of reaction (a) and (b) depends on the alkali metal cation, the temperature and the solvent.     

Synthesis of N-Alkyl and N-H-Carbazoles through SNAr-Based Aminations of Dibenzothiophene Dioxides

Alkyl amines have become available for the synthesis of diverse N-alkyl carbazoles through twofold S_NAr aminations of dibenzothiophene dioxides by using alkali metal bases. Of particular importance is the choice of counter cations on alkali metal bases, that is, i) the use of Li base for the efficient intermolecular reaction and ii) the sequential addition of heavier alkali metal bases (Na, K, or Cs) to promote intramolecular cyclization in a one-pot manner. This protocol also enables the cascade synthesis of N-H-carbazoles by using 2-phenylethylamine by removal of the 2-phenethyl group from N-(2-phenethyl) carbazoles in a single operation.     

Determination of alkali metals in high-temperature Bi-containing superconductors by ICP-AES

Lowering of the detection limits of the alkali elements in Bi-containing superconductors was achieved by optimization of the carrier gas flow rate in ICP-AES. The contents of the alkali metals in the final superconducting products, obtained on the basis of the Li, Na, K, Rb and Cs doped Bi-containing materials, were investigated. A significant decrease of their concentrations after the synthesis was found. The limits of detection with respect to the dissolved solid were as follows: 1.0×10^–4% Li, 1.0×10^–3% Na, 7.7×10^–4% K and 9.7×10^–4% Rb. The relative standard deviation was not more than 0.6 % for Li, 1% for Na and 2% for K and Rb.     

A New Extraction System Based on Isopropyl Salicylate and Trioctylphosphine Oxide for Separating Alkali Metals

It was established that isopropyl salicylate can be used similarly to 1,3-diketones as a key component for a new efficient extraction system for selective separation of alkali metal cations. According to DFT modeling of complexes of isopropyl salicylate and 1,3-diketone with alkali metal cations (Li⁺, Na⁺, K⁺), six-membered metallacycles are formed whose stability decreases along the series Li > Na > K, which results in the observed enhanced affinity to lithium. The extraction ability of isopropyl salicylate is manifested in the presence of trioctylphosphine oxide (TOPO). The newly obtained complexes of isopropyl salicylate with alkali metal cations as well as their extracts in a mixture with TOPO are characterized by means of FT-IR, Raman, and NMR spectroscopy. The probable structure of the extracted lithium complex is presumed and the role of TOPO in the extraction process is investigated in detail. Extraction experiments showed extremely high separation coefficients for Li/Na and Li/K pairs in the extraction from a model multi-component solution.     

Alkali Metal Covalent Bonding in Nickel Carbonyl Complexes ENi(CO)3−

The alkali metal‐nickel carbonyl anions ENi(CO)₃^? with E=Li, Na, K, Rb, Cs have been produced and characterized by mass‐selected infrared photodissociation spectroscopy in the gas phase. The molecules are the first examples of 18‐electron transition metal complexes with alkali atoms as covalently bonded ligands. The calculated equilibrium structures possess C_3v geometry, where the alkali atom is located above a nearly planar Ni(CO)₃^? fragment. The analysis of the electronic structure reveals a peculiar bonding situation where the alkali atom is covalently bonded not only to Ni but also to the carbon atoms.     

Alkali metal zinc vanadates

The phase composition of the M₂O-ZnO-V₂O₅ (M = Li, Na, K, Rb, Cs) systems at subsolidus temperatures is investigated. Three groups of double vanadates are identified: M₂Zn(VO₃)₄ for M = K, Rb, or Cs; M₂ZnV₂O₇ for M = Na, K, or Rb; and MZnVO₄ for M = Li or Cs. Double pyrovanadate Rb₂ZnV₂O₇ is synthesized for the first time. Phase diagrams are designed for all systems. Comparative phase-formation features of the systems in the alkali oxide series are considered.