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An efficient synthesis of unsolvated KB3H8 was achieved by the reaction of a liquid K–Na alloy with BH3·THF at room temperature. KB3H8 was found to release hydrogen and minor boranes by subsequent cleavage of its B–H and B–H–B bonds during pyrolysis, and yield K2B12H12 as a major product. [ABSTRACT FROM AUTHOR]

An efficient synthesis of unsolvated KB3H8 was achieved by the reaction of a liquid K–Na alloy with BH3·THF at room temperature. KB3H8 was found to release hydrogen and minor boranes by subsequent cleavage of its B–H and B–H–B bonds during pyrolysis, and yield K2B12H12 as a major product. [ABSTRACT FROM AUTHOR]

A new representative of rare-earth metal(III) fluoride oxoselenates( IV) derivatized with alkali metals could be synthesized via solid- state reactions. Colorless single crystals of CsSc3F6[SeO3]2 were obtained through the reaction of Sc2O3, ScF3, and SeO2 (molar ratio 1:1:3) with CsBr as reactant and fluxing agent. For this purpose, corundum crucibles embedded as liners into evacuated silica ampoules were applied as containers for these reactions at 700 °C for seven days. The new quintenary compound crystallizes in the trigonal space group P3¯ m1 with a = 565.34(4) and c = 1069.87(8) pm (c/a = 1.892) for Z = 1. The crystal structure of CsSc3F6[SeO3]2 contains two crystallographically different Sc3+ cations. Each (Sc1)3+ is surrounded by six fluoride anions as octahedron, while the octahedra about (Sc2)3+ are formed by three fluoride anions and three oxygen atoms from three terminal [SeO3]2- anions. The [(Sc1)F6]3- octahedra link via common F- vertices to six fac-[(Sc2)F3O3]6- octahedra forming 2 2∞{[Sc3F6O6]9-} layers parallel to (001). These layers are separated by oxygen-coordinated Cs+ cations (C.N. = 12), arranging for the charge compensation, while Se4+ cations within the layers surrounded by three oxygen atoms as ψ1-tetrahedral [SeO3]2- units complete the structure. EDX measurements confirmed the composition of the title compound and singlecrystal Raman studies showed the typical vibrational modes of isolated [SeO3]2- anions with ideal C3v symmetry. [ABSTRACT FROM AUTHOR]

In this study, lead-free (Na, K)NbO films were successfully deposited by RF magnetron sputtering and subsequent annealing treatment, in which a KNN atmosphere was projected to prevent the alkali metal volatilization. Effects of annealing temperatures on structure and electrical properties of the KNN thin films were investigated systematically. The results show that, with the temperature increasing, the KNN films started crystallization accompanying with volatilization of alkaline elements as well as phase transition. The particle size and surface quality of the film closely depended on annealing temperature and atmosphere. The (100) preferred orientation, large grain size, dense morphology, and annealing atmosphere all benefited the electrical properties of the KNN films. Notablely, the KNN films deposited at 200 °C and subsequent annealed at 650 °C showed a well polarization of 2 P = 20.8 μC/cm and coercive field 2 E of 200 kV/cm. [ABSTRACT FROM AUTHOR]

The crystal structure of cesium phenylacetylide, CsC2C6H5, was solved and refined from synchrotron powder diffraction data ( Pbca, Z = 8). Each Cs+ cation is coordinated by five ligands: four acetylide groups coordinate side-on and one end-on. A similar arrangement is found in the crystal structure of NaC2H ( P4/ nmm, Z = 2). There is a group-subgroup relationship between both structures. Most importantly, the crystal structure of CsC2C6H5 could only be solved with the help of synchrotron data, as the very good peak:noise ratio allowed the assignment of several very weak reflections, which finally led to the correct space group, in which a structural solution was possible using direct space methods. [ABSTRACT FROM AUTHOR]

All living species and life forms have an absolute requirement for bio-functional metals and acid–base equilibrium chemistry owing to the critical roles they play in biological processes. Hence, a great need exists for efficient methods to detect and monitor biometals and acids. In the last few years, great attention has been paid to the development of organic molecule based fluorescent chemosensors. The availability of new synthetic fluorescent probes has made fluorescence microscopy an indispensable tool for tracing biologically important molecules and in the area of clinical diagnostics. This review highlights the recent advances that have been made in the design and bioimaging applications of fluorescent probes for alkali metals and alkaline earth metal cations, including lithium, sodium and potassium, magnesium and calcium, and for pH determination within biological systems. [ABSTRACT FROM AUTHOR]

In the recently synthesized Lix (NH2)y(NH3)z Fe2Se2 family of iron chalcogenides, a molecular spacer consisting of lithium ions, lithium amide, and ammonia separates the layers of FeSe. It has been shown that upon variation of the chemical composition of the spacer layer, superconducting transition temperatures can reach Tc ~ 44 K, but the relative importance of the layer separation and effective doping to the Tc enhancement is currently unclear. Using state of the art band structure unfolding techniques, we construct eight-orbital models from ab initio density functional theory calculations for these materials. Within an RPA spin-fluctuation approach, we show that the electron doping enhances the superconducting pairing, which is of s± symmetry and explain the experimentally observed limit to Tc in the molecular spacer intercalated FeSe class of materials. [ABSTRACT FROM AUTHOR]

Alkali metal salts of redox-active formazanate ligands were prepared, and their structures in the solidstate and in solution are determined. The nitrogen-rich [NNCNN] backbone of formazanates results in a varied coordination chemistry, with both the internal and terminal nitrogen atoms available for bonding with the alkali metal. The potassium salt K[PhNNC(p-tol)NNPh]·2THF (1-K) is dimeric in the solid state and even in THF solution, as a result of the K atom bridging via interaction with a terminal N atom and the aromatic ring of a second unit. Conversely, for the compounds Na[MesNNC(CN)NNMes]·2THF (2-Na) and Na[PhNNC(tBu)NNPh] (3-Na) polymeric and hexameric structures are found in the solid state respectively. The preference for binding the alkali metal through internal N atoms (1-K and 2-Na) to give a 4-membered chelate, or via internal/external N atoms (5-membered chelate in 3-Na), contrasts with the 6-membered chelate mode observed in our recently reported formazanate zinc complexes. [ABSTRACT FROM AUTHOR]

Every so often an experiment trying to give reliable evidence for a metallic hydrogen solid is reported. Such evidence is, however, not too convincing. As Eric Scerri has recently reiterated, 'the jury is still out on that issue' (Scerri ). This search stems from the common spectroscopy shared by the hydrogen atom and all the alkali metal atoms, and perhaps is guided by a desire to place hydrogen atop the alkali metals, in Mendeleiev's Table, reinforced by the fact pointed out by Scerri (The Periodic Table, its story and its significance, Oxford University Press, Oxford, , ) that there is no other obvious place for hydrogen in said Table. But H is a light gas at room temperature, while Li, Na, K and the other alkali elements form solid metal crystals. At very low temperatures, of course, hydrogen solidifies, but it is formed by H molecules (see for example, Van Kranendonk in Solid hydrogen, Plenum Press, New York, ). Our purpose here is to use a new argument to break this impasse: 'should H be grouped with the alkali metals with which it shares a common spectroscopy, but which solidifies in a completely different fashion?' This argument has been proposed before in a couple of papers in this journal to establish a similar question for He and the alkaline earths (Novaro in Found Chem 10:4, , Ramírez-Solís and Novaro in Found Chem, ), as is discussed in 'Precedents' section. [ABSTRACT FROM AUTHOR]

In this review, the recent advances in the development of in situ Raman spectroscopy and electrochemical techniques and their application for the study of lithium-ion batteries are revisited. It is demonstrated that, during a relatively short period of time (1995-2013), the spectroelectrochemical techniques used for the investigation of battery components, benefited directly from the tremendous advances of Raman technology. The most important step was the implementation of confocal Raman microscopy in the battery research, which opened the way to new and more sophisticated applications. This review shows how the discovery of new Raman techniques such as surface-enhanced Raman scattering, tip-enhanced Raman spectroscopy, spatially offset Raman spectroscopy as well as the integration of Raman spectrometers into non-optical microscopes, for example AFM and SEM, allowed to perform two or more analytical techniques on the same sample region, with an exceptionally high resolution. All these progresses led to new insights into battery materials and components such as electrodes and electrolytes, and helped to understand the electrode/electrolyte interface phenomena. This enhanced understanding allowed a deeper insight into important phenomena, as e.g., battery aging and the dynamic nature of the solid electrolyte interfaces in lithium batteries. The high relevance of the information provided by these techniques in the progress of battery modeling is another positive contribution. Another area of high practical significance for the battery field is the screening of electrode materials, which is facilitated by the availability of the data provided by spectroscopic methods. [ABSTRACT FROM AUTHOR]

A wide range catalyst screening with noble metal and oxide catalysts for a metal-air battery with an aqueous alkaline electrolyte was carried out. Suitable catalysts reduce overpotentials during the charge and discharge process, and therefore improve the round-trip efficiency of the battery. In this case, the electrodes will be used as optimized cathodes for a future lithium-air battery with an aqueous alkaline electrolyte. Oxide catalysts were synthesized via atmospheric plasma spraying. The screening showed that IrO, RuO, LaCaCo, MnO, and CoO are promising bi-functional catalysts. Considering the high price for the noble metal catalysts further investigations of the oxide catalysts were carried out to analyze their electrochemical behavior at varied temperatures, molarities, and in case of LaCaCoO a varying calcium content. Additionally all catalysts were tested in a longterm test to proof cyclability at varied molarities. Further investigations showed that CoO seems to be the most promising bi-functional catalyst of the tested oxide catalysts. Furthermore, it was shown that a calcium content of x = 0.4 in LCCO has the best performance. [ABSTRACT FROM AUTHOR]

Structures for interfacial watercondensed in pores and channelsof the fluorinated ionomer Nafion from low relative humidity atmospherewere probed through the use of Fourier transform infrared (FTIR) spectroscopyand support from classical and quantum chemical calculations. ModernFTIR spectra of H2O and the O–H stretching regionfor the deuterium-substituted HOD species interacting at the water–ionomerinterface in Nafion exchanged by sodium cations are reported and comparedto characteristics observed in the earlier studies that employed adispersive infrared spectrometer and unspecified spectral resolution.Molecular simulations that examine the orientations of water moleculesin the vicinity of ionomer were applied to understand the appearanceof multiple free O–H stretching bands and the effect of HODaddition. One computational approach was based on a classical forcefield model, and the other employed density functional theory (DFT)to investigate atomic-scale interactions of water with regions ofdifferent hydrophobicity and charge on a perfluorosulfonate ionomersegment. The results suggest hydrogen bonding stabilizes the typesof water–ionomer environments that can lead to multiple freeO–H stretching vibrational features in experimental spectra.The studies shed light on the structure of H2O at interfacesinside ion conducting membrane materials and have potential for applicationin elucidating structure at different types of water interfaces. [ABSTRACT FROM AUTHOR]

A procedure has been proposed for the synthesis of monoazacrown ethers by reaction of N-benzyldiethanolamine with oligo(ethylene glycol) bis- p-toluenesulfonates in a two-phase system aromatic hydrocarbon-50% aqueous alkali, followed by removal of the benzyl group by catalytic hydrogenolysis. The maximal yields of N-benzylaza-12-crown-4, -18-crown-6, and -21-crown-7 were achieved by adding 4-10 equiv of LiCl, BaBr, and CsCl, respectively, to the reaction mixture, which probably indicated template effect. [ABSTRACT FROM AUTHOR]

We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby-Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectra--i.e., the transmission spectra--to inspect it for absorption at the wavelengths of the neutral sodium (Na I) doublet at λλ5889, 5895 and neutral potassium (K I) at λ7698. We used the transmission spectrum at Ca I λ6122--which shows strong stellar absorption but is not an alkali metal resonance line that we expect to show significant absorption in these atmospheres--as a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm theopreviously seen Na I absorption in HD 189733b at a level of (-5.26 ± 1.69) x 10-4 (the average value over a 12 Å integration band to be consistent with previous authors). Additionally, we tentatively confirm the Na I absorption seen in HD 209458b (independently by multiple authors) at a level of (-2.63 ± 0.81) x 10-4, though the interpretation is less clear. Furthermore, we find Na I absorption of (-3.16 ± 2.06) x 10-4 at <3σ in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Na I in HD 147506b and Ca I and K I in all four targets) are significant to ≥ 3σ, although we observe some features that we argue are primarily artifacts. [ABSTRACT FROM AUTHOR]

We report UV photodissociation (UVPD) and IR-UV double-resonance spectra of dibenzo-18-crown-6 (DB18C6) complexes with alkali metal ions (Li+, Na+, K+, Rb+, and Cs+) in a cold, 22-pole ion trap. All the complexes show a number of vibronically resolved UV bands in the 36 000-38 000 cm-1 region. The Li+ and Na+ complexes each exhibit two stable conformations in the cold ion trap (as verified by IR-UV double resonance), whereas the K+, Rb+, and Cs+ complexes exist in a single conformation. We analyze the structure of the conformers with the aid of density functional theory (DFT) calculations. In the Li+ and Na+ complexes, DB18C6 distorts the ether ring to fit the cavity size to the small diameter of Li+ and Na+. In the complexes with K+, Rb+, and Cs+, DB18C6 adopts a boat-type (C2v) open conformation. The K+ ion is captured in the cavity of the open conformer thanks to the optimum matching between the cavity size and the ion diameter. The Rb+ and Cs+ ions sit on top of the ether ring because they are too large to enter the cavity of the open conformer. According to time-dependent DFT calculations, complexes that are highly distorted to hold metal ions open the ether ring upon S1-S0 excitation, and this is confirmed by extensive low-frequency progressions in the UVPD spectra [ABSTRACT FROM AUTHOR]

Hyperbranched polycarboxylates (HBPC) with different alkali metal cations (Li, Na, and K) were prepared and characterized by H-NMR and thermal gravimetric analysis. Thin film humidity sensors based on HBPC and its composite with ZnO nanorods were fabricated. The morphologies of films of HBPC and the nanocomposite were investigated by atomic force microscopy, which revealed uniform distribution of ZnO nanorods in HBPC. The humidity-sensitive characteristics of HBPC and the nanocomposite were investigated at room temperature. It was found that the type of cations significantly affected the humidity-sensing behaviors of HBPC. In addition, the nanocomposite exhibited better humidity-sensitive properties than HBPC alone. Its impedance decreased for about three orders of magnitude over the range 19-97% RH, showing high sensitivity. Moreover, the nanocomposite exhibited fast response (∼ 9 and 10 s for response and recovery time between 97% RH and 33% RH, respectively) and small hysteresis (∼ 1.4% RH). The improved humidity-sensing behaviors of the nanocomposite over HPBC alone is explained by taking into account the hyperbranched structure of the polymer and the special interactions of the polymer and ZnO with water molecules. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Supercapacitor properties of MnO2 are studied generally in aqueous alkali metal salt solutions, often in a Na salt solution. During electrochemical discharge-charge processes, Na+ ions from the electrolyte get reversibly inserted/deinserted on the surface of MnO2 particles, which leads to redox reaction between MnOONa and MnO2. In the present study, it has been shown that MnO2 exhibits enhanced capacitance behaviour in a rare earth metal salt solution, namely, La(NO3)3 solution in comparison with NaNO3 and Mg(NO3)2 aqueous solutions. The specific capacitance increases with an increase in charge on the solution cation (Na+, Mg2+ and La3+). It is proposed that the number of surface sites for adsorption of cations remains unaltered in all solutions. The surface insertion of cation facilitates the reduction of Mn4+ in MnO2 to Mn3+ equivalent to the charge present on the cation. As the specific capacitance is related to the quantity of charge that is exchanged between the solid MnO2 and the aqueous solution, the trivalent cation (La3+) provides greater specific capacitance than in Mg(NO3)2 and NaNO3 electrolytes. Accordingly, the number of Mn(IV)/Mn(III) redox pairs involved in the neighbourhood of the adsorption site is one, two and three when Na+, Mg2+ and La3+ ions, respectively, are adsorbed. [ABSTRACT FROM AUTHOR]

The capability of infrared multiple photon dissociation (IRMPD) spectroscopy to gain structural information on surfactant-based supramolecular aggregates has been exploited to elucidate intermolecular interactions and local organization of positively charged sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) aggregates in the gas phase. A detailed analysis of the stretching modes of the AOTNa CO and SO3−head groups allows one to directly probe their interactions with sodium counterions and to gain insight in their organization within the aggregate. Similarities and differences of the IRMPD spectra as compared to the infrared absorption spectrum of micellized AOTNa in CCl4have been analyzed. They strongly suggest a reverse micelle-like organization of AOTNa charged aggregates in the gas phase. Apart from low-abundance fragmentation channels of the AOTNa (molecule) itself, the main dissociation pathway of singly charged surfactant aggregates is the loss of neutral surfactant molecules, while doubly charged aggregates dissociate preferentially by charge separation forming singly charged species. In both cases, decomposition leads to the formation of the most energetically stable charged fragments. [ABSTRACT FROM AUTHOR]

The spectral luminescent properties of terbium(III) complexes of 4-carboxybenzo-15-crown-5 (L) and 4-carboxybenzo-18-crown-6 (L) are studied. The quenching of the luminescence of lanthanide by alkali metal ions is discovered, which is referred to as the formation of mixed Tb(III)-L-Na and Tb(III)-L-K complexes. The complexes are useful as molecular sensors for the luminescence determination of Na and K with the detection limits 1.5 and 25.0 μg/mL. Using the Tb(III)-L complex, sodium can be determined in the presence of a 1000-fold excess of potassium. The developed procedures are utilized for the determination of KCl in the Kalipoz medication in tablet form and the total sodium salts (NaCl, NaHCO) in the Trisol solution for infusions. [ABSTRACT FROM AUTHOR]

FT-IR (in solid state and solution), FT-Raman, UV and 1H, 13C NMR spectra of p-methoxybenzoic (p-anisic) acid and lithium, sodium, potassium, rubidium and caesium p-methoxybenzoates (p-anisates) were registered, assigned and analyzed. The structures of anisic acid and Li, Na and K p-anisates were optimised at the B3LYP/6-311++G** level. The IR spectra and NPA, ChelpG and MK atomic charges were calculated. The effect of metal ions on the electronic charge distribution in ligand was discussed. [ABSTRACT FROM AUTHOR]

5-((1, 3-Dioxoisoindolin-2-yl)methyl-2-hydroxybenzohydrazide (1) undergoes facile condensation with aromatic aldehydes to afford the corresponding N'-substituted-phenyl-5-((1,3-dioxoisoindolin-2-yl) methyl)-2- hydroxybenzohydrazide (2a-h) in good yields. Cyclocondensation of compounds (2a-h) with thioglycolic acid yields 5-((1,3-dioxoisoindolin-2-yl) methyl)-2- hydroxy-N-(4-oxo-2-substituted phenylthiazolidin-3-yl)benzamide (3a-h). These (3a-h) compounds were further reacted with benzaldehyde in the presence of sodium ethanolate affords, (Z) -N-(5-benzylidene-4-oxo-2-substituted phenylthiazolidin- 3-yl)-5-((1,3-dioxoisoindolin-2-yl)methyl)-2-hydroxybenzamide(4a-h). The structures of these compounds were established on the basis of analytical and spectral data. All the newly synthesized compounds were evaluated for their antibacterial and antifungal activities. [ABSTRACT FROM AUTHOR]

A new family of sandwich-type potytungstophosphates containing two different types of metals in the central belt, M'2M(PW9O34)212- (M' = Na or Li, M = Mn2+, CO2+ Ni2+, and Th2+) have been synthesized and characterized by infrared spectroscopy, 31P solution NMR spectroscopy, and elemental analysis. Compounds Na2CO2(PW9O34)212- (Na2Co2), Na2Ni2(PW9O34)212- (Na2Ni2), L2(PW9O34)212- (Li2NI2), Na2Mn2(PW9O34)212- (Na2Mn2), and U2Zn2+ (PW9O34)212- (Li2Zn2) were characterized by X-ray crystallography. All these compounds have similar structures, in which two transibon-metal ions and two alkali metal ions (sodium or lithium) are sandwiched between two [B-α-PW9O34]9- units; the transibon and alkali metals reside in the internal and external (solvent exposed) positions of the central belt, respectively. By adding UCI to aqueous solutions of compounds Na2M2, lithium-sodium exchanges in the external beit positions are observed by 31P solution NMR spectroscopy and X-ray crystallography. Magnetic measurements indicate ferromagnetic exchange interactions between the two Ni2+ ions in Na2Nr2 at 10-300 K and the two CO2+ ions in Na2Co2 at 6-30 K. In contrast, Na2Mn2 exhibits an antiferromagnetic interaction between the Mn2+ ions at 2-50 K. [ABSTRACT FROM AUTHOR]

Argon-tagged alkali metal ion-crown ether complexes were generated in the gas phase and investigated using a combination of infrared predissociation (IRPD) spectroscopy, density functional, and symmetry-adapted perturbation theory (SAPT). The IRPD spectra of M+(12-crown-4 ether)Ar and M+(18-crown-6 ether)Ar, where M = Li, Na, K, Rb, and Cs, were collected in the CH stretching region, using the argon-messenger technique. The gas-phase neutral vibrations for each crown ether shift to higher frequency when complexed to an alkali metal ion. Similarities in the experimental IRPD spectra of Li+(12-crown-4 ether)Ar and Li+(18-crown-6 ether)Ar indicate that the binding of Li+is similar for both crown ethers. In the 12-crown-4 ether systems, there are trackable changes with ion size in the IRPD spectra until the point is reached where the ion is too large to bind to the interior of the macrocycle. Starting with Na+, the 18-crown-6 spectra vary only slightly as the ion size is increased. The overall profiles of the IRPD spectra indicate that a similar configuration of the complexes is adopted for the ions larger than Na+. The calculated SAPT interaction energies mirror the trends exhibited by the IRPD spectra and provide interesting insights on the roles of the different interaction energy components in binding the cation to the crown-ether. [ABSTRACT FROM AUTHOR]

In this paper, we describe two complementary nonlinear spectroscopy methods which both allow one to achieve Doppler-free spectra of atomic gases. First, saturated absorption spectroscopy is used to investigate the structure of the 5S1/2 - 5P3/2 transition in rubidium. Using a slightly modified experimental setup, Doppler-free two-photon absorption spectroscopy is then performed on the 5S1/2 - 5D5/2 transition in rubidium, leading to accurate measurements of the hyperfine structure of the 5D5/2 energy level. In addition, electric dipole selection rules of the two-photon transition are investigated, first by modifying the polarization of the excitation laser, and then by measuring two-photon absorption spectra when a magnetic field is applied close to the rubidium vapour. All experiments are performed with the same grating-feedback laser diode, providing an opportunity to compare different high-resolution spectroscopy methods using a single experimental setup. Such experiments may acquaint students with quantum mechanics selection rules, atomic spectra and Zeeman effect. [ABSTRACT FROM AUTHOR]

The gas-phase structures of alkali metal cationized lysine (Lys), α-N-methyllysine (NMeLys), and ϵ-N,N-dimethyllysine (Lys(Me)2) are investigated using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser and ab initiocalculations. The proton affinities of the compounds span a range of ∼20 kJ/mol. For NMeLys•M+, experiment and theory indicate that NMeLys is nonzwitterionic for M = Li and zwitterionic for M = Na and K. For Lys(Me)2•M+, experiment and theory indicate that Lys(Me)2is zwitterionic for M = Li, Na, and K. This is the first spectroscopic observation of the zwitterionic form of an amino acid complexed with Li+. The results are compared with IRMPD spectra reported previously for Lys and ϵ-N-methyllysine (Lys(Me)) complexed with Li, Na, and K, and new calculations performed at higher levels of theory for those ions. The combined experimental and theoretical results indicate that protonation in the zwitterionic forms of the these amino acids is favored at the more basic methylated amine site, but that any relationship between the proton affinity of the amino acid and the relative zwitterion stability of the alkali metal cationized amino acid is only indirect. These results provide additional evidence that proton affinities are not a reliable indicator of zwitterion stability for cationized amino acids because side chains can have very different effects on the stability of different conformers in the neutral, protonated, and metal cationized forms. [ABSTRACT FROM AUTHOR]

Energy levels, with classifications and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of sodium (Z=11). Wavelengths with classifications, intensities, and transition probabilities are also tabulated. In addition, ground states and ionization energies are listed. Where available, the hyperfine structure constants and the percentages of the leading components of the energy levels are included. For all ionization stages of sodium, at least some experimental data are available; however, for those for which only a few transitions have been measured, theoretical calculations or values obtained by isoelectronic fitting are reported. Similarly, theoretical or isoelectronically determined ionization energies are given when they are thought to be more accurate than the available experimental data would produce. [ABSTRACT FROM AUTHOR]

Abstract: The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR (1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons (1H NMR) and carbons (13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds. [Copyright &y& Elsevier]

Abstract: The influence of nitro-substituent in ortho, meta and para positions as well as lithium, sodium, potassium, rubidium and cesium on the electronic system of aromatic ring and the distribution of electronic charge in carboxylic group of the nitrobenzoates were estimated. Optimized geometrical structures were calculated (B3LYP/6-311++G∗∗). To make quantitative evaluation of aromaticity of studied molecules the geometric (AJ, BAC, I6 and HOMA) as well as magnetic (NICS) aromaticity indices were calculated. Electronic charge distribution was also examined by molecular spectroscopic study, which may be the source of quality criterion for aromaticity. Experimental and theoretical FT-IR, FT-Raman and NMR (1H and 13C) spectra of the title compounds were analyzed. The calculated parameters were compared to experimental characteristics of these molecules. [Copyright &y& Elsevier]

Abstract: We report new hybrid organic–inorganic membrane materials in which alkali cations are envisioned to diffuse along cation-π aromatic conduction pathways. The hierarchical generation of functional hybrid membrane materials has been realised in two steps. First, the self-assembling properties of 3-(ureidoarene)propyltriethoxysilane compounds in aprotic solvents were determined, revealing the formation of supramolecular oligomers. They led in a second sol–gel transcription step to self-organized hybrid membrane materials at nanoscopic scale. Finally they have been tested in dialysis transport experiments. The transport selectivity through self-organized membranes is due to the interaction of the partially hydrated ions with the hydrophilic or hydrophobic pathways within the matrix of the membrane. This interaction is governed by the energetic balance between the dehydration free energy and the binding energy of cation-π interaction with the aromatic moieties. [Copyright &y& Elsevier]

A 6Li NMR structural study of mixtures of labeled methyllithium, n-butyllithium, and 3-aminopyrrolidine lithium amide has been achieved in THF at −78 °C. In the first part, the study was focused on the mixed aggregates formed between methyllithium and n-butyllithium. The spectral data suggest that the two reactants form a series of tetramers (MeLi) 4( n-BuLi) 4− n, of which abundance depends on the proportion of the two alkyllithiums following a purely statistical distribution. The labeled chiral lithium amide was next introduced in the sample, and the competitive formation of the amide−methyllithium and amide−butyllithium mixed dimers was monitored in situ. The NMR spectra show a juxtaposition of signals typical of the entities characterized separately, suggesting that there is no preferential formation of one aggregate over the others. [ABSTRACT FROM AUTHOR]

Background and PurposePrevious efforts to identify the protein content of stone matrix have been limited by the lack of technology necessary to analyze the highly insoluble protein-crystalline complex. Our study objective is to characterize the matrix of calcium oxalate monohydrate (COM) stones using a comprehensive proteomics approach.Materials and MethodsSeven pure COM stones were powdered, and proteins were extracted using four different buffer solutions. Detergent cleanup spin columns or concentrators were used to remove detergent and to exchange buffers before trypsin digestion. Tryptic peptides were analyzed with reversed-phase, high-performance liquid chromatography (RP-HPLC) and tandem mass spectrometry (MSMS) using a QSTAR Pulsar iquadrapole time of flight mass spectrometer. Tandem mass spectra were searched against National Center for Biotechnology Information human nonredundant database using ProteinPilot™ 1.0 software (Applied Biosystems, Inc.) for protein hits; peptide MSMS spectra were manually inspected.ResultsOf the four buffers, only 2 sodium dodecyl sulfate (SDS) samples had normal HPLC and MSMS elution patterns. We identified 68 distinct proteins with >95 confidence. More than 50 of the proteins have not been previously identified in stone matrix. Of particular note, a significant number of inflammatory proteins were identified, including immunoglobulins, defensin α-3, clusterin, complement C3a, kininogen, and fibrinogen.ConclusionsSDS reducing buffer was efficient at solubilizing proteins from stone matrix for further MS-based proteomic analysis. A variety of cellular, structural, and plasma proteins comprise COM stone matrix. Several of the stone proteins are involved in cell injury pathways, which suggests that inflammation plays a role in human COM stone formation. [ABSTRACT FROM AUTHOR]

Abstract  The methods of coulometric titration and electrode impedance spectroscopy are used in studying the behavior of carbon film electrodes free of binding and conducting additives in the course of reversible lithium intercalation from nonaqueous electrolytes. The electrodes with the high and low degrees of graphitization are studied. The measurements are performed in the frequency range from 105 to 10−2 Hz with the lithium concentration in intercalate varied from 0.025 mol/cm3 (corresponds to LiC6) to a state free of lithium. The factors responsible for the hysteresis in charge-discharge curves, the versions of equivalent circuits (EC) suitable for modeling the impedance spectra of Li x C6 electrodes, the dependence of EC parameters and the lithium diffusion coefficient on the concentration are discussed. It is shown that all experimental impedance spectra can be adequately modeled by a common general EC. The concentration dependences are consistent with the earlier data of pulse methods. The diffusion coefficient varies approximately from 10−12 to 10−13 cm2/s. [ABSTRACT FROM AUTHOR]

Abstract  A method of electrochemical impedance spectroscopy was used to study the reversible lithium intercalation from nonaqueous electrolyte into tin films with the thickness of 0.1–1 μm. The impedance spectra of lithium-tin (Li x Sn) electrodes have a complicated shape depending on the electrode state and prehistory; they reflect the occurrence of several consecutive and parallel processes, including the lithium migration, diffusion, and accumulation. The formation of a solid-electrolyte layer on the surface at Li intercalation into Sn is observed. Equivalent circuits are proposed that adequately model the experimental data on the Li x Sn electrodes both freshly prepared and after prolonged cycling. Problems associated with the choice of equivalent circuits and determination of their parameters, the accuracy of the diffusion coefficient determination, the trends in the parameters’ variation with electrode potential (composition) are discussed. [ABSTRACT FROM AUTHOR]

The gas-phase structures of alkali-metal cation complexes of threonine (Thr) are examined using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser in conjunction with quantum chemical calculations. Spectra of Li(Thr) and Na(Thr) are similar and relatively simple, whereas K(Thr), Rb(Thr), and Cs(Thr) include distinctive new IR bands. Measured IRMPD spectra are compared to spectra calculated at a B3LYP/6-311G(d,p) level to identify the structures present in the experimental studies. For the smaller metal cations, the spectra match those predicted for charge-solvated structures in which the ligand exhibits tridentate coordination, M1N,CO,OH, binding to the amide and carbonyl groups of the amino acid backbone and to the hydroxyl group of the side chain. K(Thr), Rb(Thr), and Cs(Thr) exhibit evidence of the charge-solvated complex, M3COOH, in which the metal cation binds to the carboxylic acid group. Evidence for a small population of the zwitterionic analogue of this structure, ZWCO2-, is also present, particularly for the Cscomplex. Calculations indicate that the relative stability of the M3COOH structure is very strongly dependent on the size of the metal cation, consistent with the range of conformations observed experimentally. The present results are similar to those obtained previously for the analogous M(Ser) complexes, although there are subtle distinctions that are discussed. [ABSTRACT FROM AUTHOR]

The gas-phase structures of alkali-metal cation complexes of serine (Ser) are examined using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser, in conjunction with ab initio calculations. Spectra of Li(Ser) and Na(Ser) are similar and relatively simple, whereas Cs(Ser) includes distinctive new IR bands, and K(Ser) and Rb(Ser) exhibit intermediate behavior. Measured IRMPD spectra are compared to spectra calculated at a B3LYP/6-311G(d,p) level to identify the structures present in the experimental studies. On the basis of these experiments and calculations, the only conformations accessed for the complexes to the smaller alkali-metal cations, Liand Na, are charge-solvated structures involving tridentate coordination to the amine and carbonyl groups of the amino acid backbone and to the hydroxyl group of the side chain, M1N,CO,OH. For the cesiated complex, a band corresponding to a zwitterionic structure, ZWCO2-, is clearly visible. K(Ser) and Rb(Ser) exhibit evidence of the charge-solvated analogue of the zwitterions, M3COOH, in which the metal cation binds to the carboxylic acid group. Calculations indicate that the relative stability of the M3COOH structure is very strongly dependent on the size of the metal cation, consistent with the range of conformations observed experimentally. [ABSTRACT FROM AUTHOR]

Abstract  Silver nanoparticle synthesized from chemical reduction has been successfully utilized as a matrix in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) of peptides. Acting as a substrate to adsorb analytes, as well as a transmission medium for UV laser, silver nanoparticle was found to assist in the desorption/ionization of peptides with little or no induced fragmentation. The size of the nanoparticle was typically in the range of 160 � 20 nm. One of the key advantages of silver nanoparticle for peptides analysis is its simple step for on-probe sample preparation. In addition, it also minimizes the interferences of sodium dodecyl sulfate (SDS) surfactant background signal, resulting in cleaner mass spectra and more sensitive signal, when compared to α–cyano-4-hydroxycinnamic acid (CCA) matrix. [ABSTRACT FROM AUTHOR]

Various sample presentation configurations for elemental analysis in aqueous media by laser-induced breakdown spectroscopy (LIBS) have been tested and analyzed. Direct and quantitative comparison between the two different sample presentation methods, plasma excitation within water bulk and on the surface in a water jet, has been carried out using the same LIBS system under the same experimental conditions. Temporal characteristics of light emitted from the plasma induced in both the water bulk and the jet surface containing calcium (Ca) were recorded and presented. Spectral data recorded under optimum detection gating conditions showed that the signal-to-noise ratio (S/N) for excitation in the water jet configuration is approximately 10 times higher than that in the bulk excitation, the actual values of enhancement being dependent on the element type. The typical spectra of aqueous samples containing sodium (Na), calcium (Ca), zinc (Zn), cadmium (Cd), and mercury (Hg) were detected and the signal-to-noise ratios were evaluated and compared for the sample presentation configurations under considerations. The results suggest that for better sensitivity of detection, a simple water jet sample presentation configuration could be designed and implemented for cost-effective commercial use of this technique for elemental analysis in a water environment. [ABSTRACT FROM AUTHOR]

The behavior of B, Cr, Se, As, Pb, Cd, and Mo in the leachates generated from two combustion residues, coal-fired power plant fly ash and municipal solid waste incineration ash, during precipitation of ettringite is presented. Experiments also were performed using modeled waste leachates as well as controlled solutions containing all the investigated elements. Moreover, to determine the possible effect of pH, lime treatment was conducted using the waste and modeled leachates. Results indicated the removal of B, Se, and Cr from the leachates because of incorporation of their oxyanions in the ettringite structure. The removal of B could further be explained by considering the structure of ettringite and monosulfoaluminate. The removal of Pb also occurred, probably because of lime-induced precipitation of Pb(OH)2. Similarly, the removal of As was observed as a result of lime-induced precipitation of Ca3(AsO4)2 and incorporation into the ettringite structure. On the other hand, the precipitation of ettringite did not reduce the concentrations of Mo and Cd because of the complex nature of these elements in the leachates. The results also suggest that the presence of high amounts of constituents such as Cl-, an alkali metal in the solution, also affected ettringite precipitation behavior. Moreover, elemental speciations as well as the presence of other constituents in the solution affected the incorporation by ettringite. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to build a good theoretical and experimental basis for the further study of changes in structure and spectra of the O,O-diethyldithiophosphate anion upon its adsorption on the surfaces of transition metal sulfides. Infrared and Raman spectra of potassium O,O-diethyldithiophosphate were recorded. High level quantum chemical calculations were carried out to optimize the molecular geometry of both the potassium salt and its anion. Vibrational force constants were calculated from the second derivative of the molecular energy function with respect to the Cartesian coordinates of the atoms. With the aid of the optimized geometry and the calculated vibrational force constants a normal coordinate analysis was carried out to characterize the molecular vibrational modes and to assign the vibrational frequencies. [Copyright &y& Elsevier]

Five C 10 iridoid glycosides (shanzhiside methyl ester, lamalbide, lamiide, sesamoside, and 5‐desoxysesamoside) were examined by electrospray ionization mass spectrometry (ESI‐MS). Considerable differences were observed in positive ion and negative ion mode. Only the positive ion spectra were useful for molecular mass determination on the basis of molecular alkali metal adducts, with the exception of two iridoids containing all 5β‐OH, 7β‐OH and 8β‐OH groups. Fragment characteristics for distinct functionalities were observed. Chelation studies of each iridoid with three different alkali metals were also conducted. [ABSTRACT FROM AUTHOR]

We present an experimental study of the dynamics of a magneto–optical trap (MOT) loaded from an alkali dispenser current controlled source. In our experimental vacuum conditions and for a low trapping force MOT the trap loading process critically depends on the dispensers working regime. This allows to completely characterize the dispensers–MOT system and to determine the best loading conditions. [ABSTRACT FROM AUTHOR]

Using the Raman scattering spectra, we investigated the ordering of the structural units in the cation sublattice and the photorefractive properties of lithium niobate single crystals of variable composition, i.e., nominally pure ones with different Li/Nb ratios and those doped with the nonphotorefractive cations Mg2+, Gd3+, and Y3+. It is shown that at low concentrations of Mg2+, Gd3+, and Y3+ the magnitude of the photorefractive effect is substantially determined by the ordering of the structural units of the cation sublattice. It has been found for the first time that the intensity of the line corresponding to the bridge valence vibrations of oxygen atoms in the octahedrons of NbO6 is sensitive to the dipole ordering of the cation sublattice of the crystal. [ABSTRACT FROM AUTHOR]

The FT-IR, FT-Raman and 1H and 13C NMR spectra of lithium, sodium, potassium, rubidium and caesium picolinates were recorded, assigned and compared in the Li → Na → K → Rb → Cs series and analysed. Experimental, vibrational and NMR spectra were interpreted with the aid of calculated data from density functional theory at the B3PW91/6–311 ++ G** level. Distance, angles and dipole moments and also aromaticity indices (HOMA, EN, GEO, I6) for the optimized structures of picolinic acid and sodium picolinate were calculated. Comparison of theoretical and experimental (x-ray) data and the application of Bader's theory enabled us to evaluate the intramolecular interactions in picolinic acid. Also, the influence of the carboxylic anion structure and the nature of metal–ligand bonding on the electronic charge distribution in the aromatic ring was investigated. The degree of perturbation in the electronic system of the ligand under the influence of metal in the Li → Cs series was investigated with the use of statistical methods (principal component analysis) and calculated aromaticity indices. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Double monooxalates MPuO2C2O4 · nH2O with NH and Cs+ ions in the outer sphere were isolated from weakly acidic aqueous solutions of Pu(V). The unit cell parameters of these compounds were determined. The ammonium salt is isostructural to its neptunyl(V) analog; its structure is characterized by the monodentate cation-cation interaction of plutonyl(V) ions. Cesium plutonyl(V) salt isolated from a solution is not isostructural to the neptunyl(V) compound and is easily dehydrated at room temperature to form tetrahydrate, which transforms to dihydrate at 110°C. The latter compound, according to the IR spectra, can have a network system of cation-cation bonds involving PuO. [ABSTRACT FROM AUTHOR]

Ethane adsorption on the hydrogen, sodium, and zinc forms of faujasite brings about polarization anisotropy of the C-H stretching vibrations. This anisotropy shows itself most clearly as perturbation of the vibrational mode analogous to the breathing C-H mode ν1 of free ethane. The relative intensity and the low-frequency shift of the absorption band due to the distorted ν1 mode increase with increasing perturbation caused by the C2H6-adsorption site interaction. The polarizing power of adsorption sites increases in the order H+ < Na+ < Zn2+. The C-H stretching vibrations in ethane adsorbed on the cationic forms of the Y zeolite are not symmetry-forbidden; accordingly, adsorbed ethane gives more absorption bands than gaseous ethane. The interaction between ethane and zinc cations in the Y zeolite structure eliminates not only the symmetry forbiddenness but also the twofold degeneracy of the C-H stretches. [ABSTRACT FROM AUTHOR]

The nature and surroundings of lithium cations in lithium-exchanged X and A zeolites following loading with the alkali metals Na, K, Rb, and Cs have been studied through 7Li solid-state NMR spectroscopy. It is demonstrated that the lithium in these zeolites is stable with respect to reduction by the other alkali metals. Even though the lithium cations are not directly involved in chemical interactions with the excess electrons introduced in the doping process, the corresponding 7Li NMR spectra are extremely sensitive to paramagnetic species that are located inside the zeolite cavities. This sensitivity makes 7L1 NMR a useful probe to study the formation, distribution, and transformation of such species. [ABSTRACT FROM AUTHOR]

Electronic absorption spectra of GaCl3 and Ga2O3 solutions in molten alkali metal chlorides and in NaCl-KCl-NaF and LiF-NaF melts were measured by reflection-absorption spectroscopy. The spectral data showed that the main structural units in the solutions are complexes GaHlg (Hlg = Cl, F) with T d symmetry and GaOHlg with C3 v symmetry, respectively. Molecular oxygen occurring in molten systems as an admixture causes exchange decomposition with formation in all the melts of molecular complexes of chlorine, Cl2Cl−, with C∝ v symmetry. [ABSTRACT FROM AUTHOR]