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Pretreatment of alumina particles fouled with bovine serum albumin (BSA) by 0.3% (v/v) gaseous ozone markedly accelerated the removal of BSA during alkali cleaning through partial decomposition of the BSA molecule. The results suggest that ozone pretreatment can reduce the NaOH concentration required for adequate alkali cleaning by at least one order of magnitude.
Sixteen lipophilic N-(X)sulfonyl carbamoyl lariat ethers with polyether ring sizes of 12-crown-4, 14-crown-4, 15-crown-5, and 18-crown-6 are utilized for competitive alkali metal cation extractions from aqueous solutions into chloroform. Variation of the electron-withdrawing properties of X in the series of methyl, phenyl, 4-nitrophenyl, and trifluoromethyl allows the influence of the acidity of the C(O)NHSO2X group in the side arm upon extraction efficiency and selectivity to be assessed. With X = trifluoromethyl, effective alkali metal cation extractions from acidic, neutral, and basic aqueous solutions are achieved. When the crown ether rings are 14-crown-4, 15-crown-5, and 18-crown-6, selectivities for Li+, Na+, and K+, respectively, are observed. Results are compared with those reported for analogous lariat ether carboxylic acids and phosphonic acid monoethyl esters.
Positive and negative thermal ionization ion mobility spectra (TI-IMS) of some sodium and potassium halides are reported here. The data provide the first measurement of the thermal ionization ion mobility spectrometry of inorganic compounds. A thin Nichrome filament was used as a thermionic ionization source. Sample was directly deposited on the filament, where it was heated and ionized. Each salt produced a different ion mobility pattern, but all sodium salts spectra were common in their first peak. This peak differs from the common peak observed in the spectra of potassium salts. The drift time of the second peak in all spectra was found to be linearly dependent on the size of the counteranion of the salt. Negative thermal ionization ion mobility spectra of alkali halides were also observed. An alkali halide salt (MX), in general, produced its own anion as well as some heavier ions that are thought to be hydrated X- (MX)n species. The capability of the method in quantitative analysis was demonstrated by measuring potassium impurity in sodium bromide. A detection limit of 0.01% K+ in NaBr and a linear rage of 3 orders of magnitude were obtained. The results from this study suggest that TI-IMS has potential as a field technique for the detection of some elements in samples.
Several azacrown ether derivatives, which are monoaza-12-crown-4, -15-crown-5, and -18-crown-6 and diaza-12-crown-4 and -18-crown-6, bearing one or two spirobenzopyran(s), which we call crowned spirobenzopyran or crowned bis(spirobenzopyran), were synthesized and were used as carriers for liquid membrane transport of alkali metal ions. The passive alkali metal transports through liquid membranes containing crowned spirobenzopyrans were carried out under dark, and UV- and visible-light irradiation conditions. The metal ion transport was accelerated and retarded by UV- and visible-light irradiation, respectively. On the other hand, the photoresponse of the metal ion selectivity in membrane transport by crowned spirobenzopyrans was different, depending on the kind of crown ether units. Especially, diaza-12-crown-4-bis(spirobenzopyran) exhibited an excellently selective and effective transporting ability for Li(+). The uphill transports of Li(+) through a liquid membrane containing monoaza-12-crown-4-spirobenzopyran or diaza-12-crown-4-bis(spirobenzopyran) were realized under the conditions where the same aqueous solution was used as the source and receiving phases with UV and visible lights being irradiated onto the boundary phases between the source and membrane phases and between the receiving and membrane phases, respectively. The uphill transport of Li(+) from the source to receiving phases through a liquid membrane containing a crowned spirobenzopyran was also attained by the proton-concentration gradient between the source and receiving phases under dark conditions, and the transporting ability was remarkably increased by photoirradiation.
In this Account strategies using zeolites as media to achieve chiral induction are presented. Diastereomeric excesses as high as 90% and enantiomeric excesses up to 78% have been obtained with selected systems within zeolites. The same systems show no asymmetric induction in solution. Chiral induction is dependent on the alkali ions present in the zeolites. Alkali ions control not only the extent of asymmetric induction but often the isomer being enhanced. Results of ab initio computations have allowed us to gain an insight into the observed selectivity within zeolites.
The role of the amino-terminal region of myosin alkali 1 light chain (A1) in the interaction between actin and myosin subfragment-1 (S-1) was explored. Papain digestion of skeletal myosin filaments produced S-1 whose A1 was found to lose the basic 13 amino-terminal amino acid residues (A1'). We obtained three types of papain S-1 isoenzymes differing in their alkali light chain content: recombined papain S-1 (A1), papain S-1 (A1'), and papain S-1 (A2). Both the maximum turnover rate (Vmax) and the dissociation constant (Km) for actin-activated papain S-1 (A1') ATPase activity were similar to those for papain S-1 (A2) and remarkably larger than those for recombined papain S-1 (A1). The 13 amino-terminal residue peptide of A1 (N-pep) was isolated and characterized. 1H-NMR spectroscopy suggested that the N-pep was relatively immobilized in the presence of actin filaments. A cross-linking study suggested that N-pep binds to actin. The addition of N-pep to acto-S-1 (A1) made Km and Vmax for the actin-activated ATPase activity close to those for S-1 (A2). Removal of the trimethyl group from the N-pep suppressed the above effect on the actin-S-1 interaction. Our findings suggest that the amino-terminal region of A1 binds to the actin molecule to affect the mechanism of actin-activated S-1 ATPase.
It has been reported that ACA sequences in DNA are mutagenic hot spots in UV-induced mutagenesis and are sites of an alkali-sensitive lesion produced by UV irradiation. In order to characterize the UV-induced lesion of an ACA site, chemically synthesized trideoxyribonucleotide d(ApCpA) was irradiated with UV light and the alkali-sensitive photoproduct was isolated. The structure of this photoproduct was characterized as the trinucleotide containing 2-deoxyribonolactone at the internal residue by 2D DQF-COSY, FT-IR, FAB-MS, and chemical properties. It is known that this lesion is also produced by gamma-irradiation, neocarzinostatin, the 1,10-phenanthroline-copper complex, and hydrogen peroxide and is highly mutagenic because of its resistance to cleavage by certain apurinic/apyrimidinic (AP) endonucleases. Thus, 2-deoxyribonolactone may be one of the lethal DNA lesions induced by UV irradiation to organisms and one of the intermediates of UV-induced DNA strand breaks because the DNA strand is cleaved at this site with beta- and subsequent delta-elimination mechanisms.
The mechanisms of the carboxylations of lithium, potassium, rubidium, and cesium phenoxides are investigated by means of the DFT method with the LANL2DZ basis set. It is shown that the reactions of all alkali metal phenoxides with carbon dioxide occur via very similar reaction mechanisms. The reactions can proceed in the ortho and para positions. The exception is lithium phenoxide which yields only salicylic acid in the Kolbe-Schmitt reaction. It is found that the yield of the para substituted product increases with increasing the ionic radius of the alkali metal used. An explanation for this experimental and theoretical observation is proposed.
In this work, we used the molten chalcogenide flux synthetic method to form an analogous series of alkali samarium selenogermanates, with the general formula ASmGeSe(4) (A = K, Rb, Cs). Using a constant reactant stoichiometry, we relate the monoclinic KLaGeSe(4) structure type to the orthorhombic CsSmGeS(4) structure type. KSmGeSe(4) [in space group P2(1) with cell parameters a = 6.774(1) A, b = 6.994(1) A, c = 8.960(2) A, beta = 108.225(3) degrees, and V = 403.2(1) A(3) (Z = 2)], RbSmGeSe(4) [in space group P2(1)2(1)2(1) with cell parameters a = 6.7347(8) A, b = 7.0185(9) A, c = 17.723(2) A, and V = 837.7(2) A(3) (Z = 4)], and CsSmGeSe(4) [in space group P2(1)2(1)2(1) with cell parameters a = 6.707(2) A, b = 7.067(2) A, c = 18.334(6) A, and V = 869.1(5) A(3) (Z = 4)] were formed under identical synthetic conditions by changing the identity of the alkali ion from K to Rb or Cs, respectively. Additionally, with the substitution of sodium into the reaction, a triclinic structure with the approximate formula NaSmGeSe(4) was found with the cell parameters a = 6.897(2) A, b = 9.919(2) A, c = 11.183(2) A, alpha = 84.067(4) degrees, beta = 88.105(4) degrees, gamma = 73.999(4) degrees, and V = 731.5(3) A(3). In addition to single-crystal diffraction, Raman and diffuse reflectance UV-visible spectroscopic measurements have been used to characterize these compounds.
Ultralong and single-crystalline Cd(OH)(2) nanowires were fabricated by a hydrothermal method using alkali salts as mineralizers. The morphology and size of the final products strongly depend on the effects of the alkali salts (e.g., KCl, KNO(3), and K(2)SO(4) or NaCl, NaNO(3), and Na(2)SO(4)). When the salt is absent, only nanoparticles are observed in TEM images of the products. The 1D nanostructure growth method presented herein offers an excellent tool for the design of other advanced materials with anisotropic properties. In addition, the Cd(OH)(2) nanowires might act as a template or precursor that is potentially converted into 1D cadmium oxide through dehydration or into 1D nanostructures of other functional materials (e.g., CdS, CdSe).
A ditopic receptor is shown to have an impressive ability to recognize and extract the ion pairs of various alkali halides into organic solution. X-ray diffraction analysis indicates that the salts are bound in the solid state as contact ion pairs. Transport experiments, using a supported liquid membrane and high salt concentration in the source phase, show that the ditopic receptor can transport alkali halide salts up to 10-fold faster than a monotopic cation or anion receptor and 2-fold faster than a binary mixture of cation and anion receptors. All transport systems exhibit the same qualitative order of ion selectivity; that is, for a constant anion, the cation selectivity order is K+ > Na+ > Li+, and for a constant cation, the anion transport selectivity order is I- > Br- > Cl-. The data suggest that with a ditopic receptor, the polarity of the receptor-salt complex can be lowered if the salt is bound as an associated ion pair, which leads to a faster diffusion through the membrane and a higher maximal flux.
Two new alkali metal borophosphates, K3[BP3O9(OH)3] and Rb3[B2P3O11(OH)2], were synthesized by applying solvothermal techniques using ethanol as solvent. The crystal structures were solved by means of single-crystal X-ray diffraction (K3[BP3O9(OH)3], monoclinic, C2/c (No. 15), a = 2454.6(8) pm, b = 736.3(2) pm, c = 1406.2(4) pm, beta = 118.35(2) degrees , Z = 8; Rb3[B2P3O11(OH)2], monoclinic, P2(1)/c (No. 14), a = 781.6(2) pm, b = 667.3(2) pm, c = 2424.8(5) pm, beta = 92.88(1) degrees , Z = 4). Both crystal structures comprise borophosphate chain anions. While for the rubidium compound a loop-branched chain motif is found as common for most of the chain anions in alkali metal borophosphates, the crystal structure of the potassium phase comprises the first open-branched chain with the highest phosphate content found so far in this group of compounds. Both chain anions are closely related to known anhydrous or hydrated phases, and the structural relations are discussed in terms of how the presence of OH groups and hydrogen bonds as well as number, charge, and size of charge balancing cations influence the 3D structural arrangement. The anionic entities are classified in terms of general principles of structural systematics for borophosphates.
We report a series of calix[4]arene Mo(VI) dioxo complexes M2RC4MoO2 (M = alkali metal, R = H or Bu(t)) that were fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. Molybdocalix[4]arene structures can be controlled via lower rim deprotonation, groups at para positions of calix[4]arene, and alkali metal counterions. Mono deprotonation at the lower rim leads to calix[4]arene Mo(VI) monooxo complexes RC4MoO (R = H, Bu(t), or allyl), and full deprotonation gives rise to calix[4]arene Mo(VI) dioxo complexes. Structural studies indicate that HC4 Mo(VI) dioxo complexes easily form polymeric structures via cation-pi interaction and coordination between different calixarene units. However, Bu(t)C4 Mo(VI) dioxo complexes tend to form dimers or tetramers due to steric hindrance of the tert-butyl groups at para positions in calixarene. The structures of the reduced side products A and C were determined by X-ray diffraction studies. The mechanism of RC4MoO formation from the reaction of calixarene monoanions with MoO2Cl2 appears to include the addition of a calixarene -OH group across a Mo=O bond.
Higher aggregated alkali-metal compounds are usually obtained with increasing radius of the metal. Alkali-metal salts derived from the sterically crowded triazenido ligand Tph2N3H [Tph = C6H3-2,6-(C6H2-2,4,6-iPr3)2] do not obey this principle. Interestingly, these compounds show inverse aggregation behavior in the solid state: the potassium and cesium salts crystallize as discrete monomers in which the cations interact with flanking arene rings of the diaryltriazenido ligands, whereas the lithium derivative is dimeric with a more conventional heteroatom-bridged structure.
The alkali metal salts [TCALi4] (1), [TCANa4] (2), and [TCALK4] (3) of fully deprotonated p-tert-butyltetrathiacalix[4]arene (H(4)TCA) are readily available from the reactions of thiacalix[4]arene and n-BuLi, NaH, or KH as deprotonating reagents. Crystals of the sodium salts 2 and the potassium salt 3 suitable for X-ray diffraction were obtained in the form of the pyridine solvates [(TCA)2Na8.8py] (2.8py) and [(TCA)2K(8).8py] (3.8py). These molecules are dimers in the solid state but are structurally not related. In addition, the reaction of H(4)TCA and lithium hydroxide afforded the structurally characterized complex [(TCA)Li5(OH).4THF] (4). The molecular structure of 4 as well as the structures of 2.8py and 3.8py reveal a close relationship to the corresponding alkali metal salts of the calix[4]arenes.
We report the ab initio structure solutions of C(6)H(5)OM (M = K, Rb, Cs) by high-resolution powder X-ray diffraction. The compounds, which are of interest for reactions of the Kolbe-Schmitt type, are isostructural. The crystal structures are orthorhombic, space group Pna2(1), Z = 12, with lattice parameters (a, b, c in Å) 14.1003(1), 17.9121(1), and 7.16475(1) for the K compound, 14.4166(2), 18.2028(2), and 7.4009(1) for the Rb compound, and 14.8448(2), 18.5070(2), and 7.6306(1) for the Cs compound. They have a chain structure [M([6])] along the crystallographic c axis. This is a very unusual arrangement in which two different alkali-metal coordination spheres are observed: a distorted octahedron and a 3-fold oxygen coordination. In the latter, the 3-fold-coordinated unsaturated alkali metals additionally show weak interactions with phenyl rings. We also give powder patterns for the compounds with M = Li, Na. The former crystallizes in the monoclinic space group P2(1)/a with lattice parameters a = 22.594 Å, b = 4.7459 Å, c= 10.053 Å, and beta = 97.82 degrees with Z = 8, but no structure solution was possible. The powder pattern for the Na phenolate is in agreement with the earlier single-crystal structure.
The diacetone glucose (DAGH, 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose) monoanion DAG binds as a terminal alkoxo ligand to a variety of transition metals. When it is used in excess, with respect to the oxidation state of the metal, homoleptic anionic complexes [M'(DAG)(6)](3)(-) are formed. Such complexes contain oxygen-rich cavities between pairs of DAG ligands appropriate for binding alkali metal cations. The anionic complexes have been obtained by using [Li(DAG)], 1, and [Na(DAG)], 2, whose syntheses and characterization are reported here. The reaction of 1 and 2 with [V(DAG)(3)] gave [V(DAG)(6)Li(3)], 3, and [V(DAG)(6)Na(3)], 4, respectively. An alternative synthesis of 3 and 4 involves the metathesis reaction of 1 and 2 with [VCl(3)(thf)(3)]. This strategy also led to the synthesis of [Cr(DAG)(6)Li(3)], 5, and [Ti(DAG)(6)Li(3)], 6. Three pairs of DAG shape a cavity appropriate for three lithium cations in the case of complexes 3, 5, and 6; a cavity is formed for three sodium cations in the case of 4, where the alkali cation is in a tetrahedral O(4) environment. In the anionic manganese derivative [Mn(Cl)(DAG)(4)](3)(-), the four DAG units arrange in such a way as to bind four Li cations, which form a cationic cage [Mn(Cl)(DAG)(4)Li(4)](+), and Cl(-) is bound inside as [Mn(Cl)(DAG)(4)Li(4)(&mgr;(4)-Cl)], 7. Crystallographic details: 4, prism, P2(1), a = 14.735(10) Å, b = 15.033(9) Å, c= 21.021(10) Å, beta = 107.34(2) degrees, V= 4445(5) Å(3), Z = 2, and R = 7.60; 5, prismatic, C2, a = 22.671(9) Å, b = 18.785(5) Å, c = 13.886(4) Å, beta = 126.39(2) degrees, V= 4761(3) Å(3), Z = 2, and R = 7.32; 6, prismatic, P2(1), a= 13.888(5) Å, b = 18.750(5) Å, c= 17.933(5) Å, beta = 91.84(2) degrees, V = 4667(2) Å(3), Z = 2, and R = 8.75; 7, prismatic, P2(1), a = 13.306(7) Å, b= 21.311(11) Å, c = 13.376(6) Å, beta = 95.01(2) degrees, V = 3779(3) Å(3), Z = 2, and R = 9.33.
Dithiocarboxylic acids and their trimethylsilyl esters were found to readily react with potassium, rubidium, and cesium fluorides to give the corresponding alkali metal dithiocarboxylates 3-5 in moderate to good yields. A series of tetramethylammonium dithiocarboxylates 8 have been prepared in good yields by the reaction of sodium dithiocarboxylates 7 with tetramethylammonium chloride. The structures of potassium (3b), rubidium (4g), cesium (5f), and tetramethylammonium 4-methylbenzenecarbodithioates (8e) and tetramethylammonium 2-methoxybenzenecarbodithioate (8f) were characterized crystallographically. These heavier alkali metal salts (3b, 4g, 5f) have a dimeric structure [(RCSSM)(2), M = K, Rb, Cs] in which the two dithiocarboxylate groups are chelated to the metal cations which are located on the upper and lower sides of the plane involving the two opposing dithiocarboxylate groups. The K(+) cations interact with the tolyl fragment of a neighboring molecule, while the Rb(+) and Cs(+) cations interact with two neighboring tolyl fragments, in which the ipso and ortho carbons are positioned close to the metals. The interaction number of the metals with surrounding atoms is 8 for K(+) and Rb(+) and 12 for Cs(+). The C-S distances of the dithiocarboxylate group are different for the potassium salt 3b. In contrast, those of the rubidium salt 4g and cesium salt 5f are equal. Similarly, the chelating sulfur-metal bond distances of 3b are different, while those of 4g and 5f are almost equal. The dihedral angles of the phenyl ring and dithiocarboxylate plane increase in the order of the K, Rb, and Cs salts. The structural analysis of sodium 4-methylbenzenecarbodithioate (7g) revealed the presence of 4-CH(3)C(6)H(4)CS(2)Na(0.36). In contrast, the tetramethylammonium salts 8 are monomeric where the cation moieties are located out of the dithiocarboxylate plane. The potassium 3, rubidium 4, and cesium dithiocarboxylates 5 readily reacted with methyl iodide or triorganotin chlorides at room temperature to give the corresponding methyl 9 and triorganotin dithioesters 10 in good yields. At 0 degrees C, the reactivity of the rubidium 4 and cesium salts 5 to methyl iodides decreases dramatically compared with those of the sodium salts 7 and potassium salts 3.