Sodium Tris Research Articles

Back to basic: Trials and tribulations of alkalizing agents in cancer.

clinicaltrials.gov, identifier NCT01350583, NCT01198821 and NCT01846429.

Ceric Ammonium Nitrate and Ceric Ammonium Chloride as Precursors for Ceric Siloxides: Ammonia and Ammonium Inclusion

Treatment of ceric ammonium nitrate (CAN) with sodium tris(tert‐butoxy)siloxide in THF afforded crystalline complexes [Ce{OSi(OtBu)3}3(NO3)(NH3)2(THF)] and [Ce{OSi(OtBu)3}4(NH3)2] featuring strong ammonia coordination. Conducting the CAN/NaOSi(OtBu)3 (1:4) reaction in acetonitrile gave ceric ate complex [Ce{OSi(OtBu)3}3(NO3)2(NH4)(NCCH3)] where the ammonium cation is embedded in the siloxy ligand sphere via hydrogen bonding. Salt‐metathetic conversion of ceric organo(R)ammonium hexachlorides (CACR, R = Me, Et) with NaOSi(OtBu)3 and sodium siloxides NaOSiR3 (R = Et, iPr) in THF allowed the isolation of ceric siloxide complexes [Ce{OSi(OtBu)3}4], [Ce(OSiEt3)4(THF)0.5], and [Ce(OSiiPr3)4]. Although the reaction products are prone to ate complex formation with the organoammonium chloride side products, the salt‐metathesis route gave good yields for homoleptic [Ce{OSi(OtBu)3}4]. The CACR/alkylsiloxide reaction mixtures also suffer from (photo)redox processes as revealed by the formation of trivalent [Ce(OSiiPr3)4(NMe4)], but can be further stabilized by pyridine coordination as shown for the solid‐state structure of [Ce(OSiiPr3)4(py)]. The siloxide complexes were characterized by NMR, DRIFT, UV/Vis spectroscopy and cyclic voltammetry, as well as paramagnetic susceptibility measurements, X‐ray structure, and elemental analysis. The electrochemical studies revealed an effective stabilization of the CeIV ion within the siloxy ligand environments.

Thermal Aggregation of Bovine Serum Albumin in Conventional Buffers: An Insight into Molecular Level Interactions

We have studied the effect of some conventional buffers, which are used frequently for biological research, on the thermal aggregation behavior of bovine serum albumin (BSA). The aggregation kinetics of BSA in buffer solutions were investigated by using UV–Vis spectroscopy. The buffers include sodium phosphate buffer, TRIS buffer and imidazole buffer at physiological pH (7.4). Dynamic light scattering and scanning electron microscopy have been employed to illustrate the size and morphology of protein aggregates. The molecular level interactions of buffer molecules with BSA was probed by various spectroscopic techniques, including UV–Vis, fluorescence, and circular dichroism. The results of this study reveal that the strong interactions of the buffers with protein’s folded/unfolded structures lead to stabilization/destabilization of BSA. We have also explored the possible binding sites of BSA for these buffers using a molecular docking technique.

Synthesis and Characterization of the First Nickel(II)‐Centered Single‐Side Tris‐Functionalized Anderson‐Type Polyoxomolybdate

The Ni‐centered Anderson‐type polyoxomolybdate [Ni(OH)3Mo6O18(OCH2)3CNH3]3– was prepared in a two‐step aqueous reaction by covalent postfunctionalization of [Ni(OH)6Mo6O18]4–, isolated as its sodium Tris–NH3 salt, and characterized by single‐crystal X‐ray diffraction, mass spectrometry, thermogravimetric analysis, and IR spectroscopy. The incorporation of a Tris–NH2 ligand into the framework of a heteropolymolybdate bearing a divalent heteroatom, which resulted in the single‐sided product, was shown for the first time.

Di-tert-butyl thiopyridazine boratrane complexes of Co, Ni and Cu

The thiopyridazine based scorpionate ligand sodium tris(3,5-di-tert-butyl-6-thioxopyridazin-1(6H)-yl)hydroborate (NaTntBu,tBu) with two tert-butyl substituents in ortho- and para-position of the thio group was synthesized and fully characterized. Corresponding metallaboratrane complexes [M{B(PntBu,tBu)3}Cl] (M=Co, Ni, Cu) as well as [M{B(PnMe,tBu)3}Cl] (M=Co, Ni) were prepared in good yields. All complexes were characterized by spectroscopic means as well as by single crystal X-ray diffraction studies exhibiting short metal boron bonds (between 2.0186(17)Å and 2.069(3)Å) compared to previously reported boratranes. The two tert-butyl groups attached to the heterocycle significantly increases the solubility of NaTntBu,tBu and the derived metal complexes in apolar solvents compared to the system bearing the smaller substituents. The higher steric demand of the tert-butyl versus methyl group enhances the distortion from trigonal bipyramidal towards square pyramidal which effects the electronic situation within the complexes evidenced by the elongated metal chlorine bond trans to boron.

Effect of biocides on the precipitation of calcium fluoride in the presence of anionic copolymeric inhibitors

ABSTRACTThe inhibitory efficiency of anionic copolymers and the effect of the biocides sodium hypochlorite, glutaraldehyde, and tris(hydroxymethyl)nitromethane on the precipitation behavior of calcium fluoride (CaF2) were studied. The efficiency of polymeric inhibitors was traced from conductivity measurements by using half-life (t1/2) method. X-ray diffraction parameters have been measured for calcium fluoride scale minerals. An anionic copolymer (K-798) acts as one of the best inhibitors for the precipitation process of the calcium fluoride in water as compared to K-775. It is assigned to the fact that the copolymer (K-798) contains both sulfonic acid and sulfonated styrene groups while the polymer (K-775) having only the sulfonic acid group. It was further observed that the biocides have no appreciable effect on the performance of the anionic polymeric inhibitors.

Crystallographic new light on an old complex: NaMg[Cr(oxalato)3]·9H2O and structure redetermination of the isomorphous aluminum(III) compound

The crystal structure of sodium and magnesium tris(oxalato)chromato(III) nona hydrate, NaMg[Cr(C2O4)3]·9H2O, has been determined by X-ray diffraction methods. It crystallizes in the trigonal P3c1 space group with (in the hexagonal setting) a = b = 16.9635(4), c = 12.5247(3) Å, and Z = 6 molecules per unit cell. The Cr(III) and sodium ions are in octahedral environments coordinated to three oxalate molecules and arranged in a honeycomb-like layered structure perpendicular to the crystal c-axis. There are three different octahedral [Mg(H2O)6]2+ hydrated ions that fill the honeycomb holes giving rise to electrically neutral Na[Mg(H2O)6][Cr(oxalato)3] crystal slabs. Neighboring slabs are bridged by the remaining three water molecules through H-bonds and therefore the whole crystal can be more properly described as Na[Mg(H2O)6][Cr(oxalato)3]·3H2O. Also, the structure of isomorphous NaMg[Al(C2O4)3]·9H2O compound has been re-examined and compared with the chromium(III) complex. Infrared and Raman spectra of both complexes were also recorded and briefly discussed.

Microenvironmental acidosis in carcinogenesis and metastases: new strategies in prevention and therapy.

Much effort is currently devoted to developing patient-specific cancer therapy based on molecular characterization of tumors. In particular, this approach seeks to identify driver mutations that can be blocked through small molecular inhibitors. However, this approach is limited by extensive intratumoral genetic heterogeneity, and, not surprisingly, even dramatic initial responses are typically of limited duration as resistant tumor clones rapidly emerge and proliferate. We propose an alternative approach based on observations that while tumor evolution produces genetic divergence, it is also associated with striking phenotypic convergence that loosely correspond to the well-known cancer “hallmarks”. These convergent properties can be described as driver phenotypes and may be more consistently and robustly expressed than genetic targets. To this purpose, it is necessary to identify strategies that are critical for cancer progression and metastases, and it is likely that these driver phenotypes will be closely related to cancer “hallmarks”. It appears that an antiacidic approach, by targetting a driver phenotype in tumors, may be thought as a future strategy against tumors in either preventing the occurrence of cancer or treating tumor patients with multiple aims, including the improvement of efficacy of existing therapies, possibly reducing their systemic side effects, and controlling tumor growth, progression, and metastasis. This may be achieved with existing molecules such as proton pump inhibitors (PPIs) and buffers such as sodium bicarbonate, citrate, or TRIS.

Extracting DNA from within intact foraminiferal shells

Abstract Here we present an evaluation of several methods for extracting DNA from within intact foraminiferal shells. We tested 12 lysis buffers under carefully optimised incubation conditions, evaluating their success in terms of efficiency in evacuating cellular material, crude DNA yield, PCR success, and final shell integrity. A number of the buffers tested produced excellent results. The most successful method utilized a lysis buffer containing Sodium N-lauroyl sarcosine, Guanidinium isothiocyanate, Isopropanol, TRIS and NaCl, incubated at 75 °C for 24 h, followed by chloroform extraction and ethanol precipitation. High yields of DNA were produced, with no signs of PCR inhibition, and the foraminiferal shells were left completely intact. Retaining the shell of individual specimens presents a significant advance, allowing for direct comparisons between shell morphology and genotype data, which could greatly enhance the utility of foraminifera as palaeoproxies of past climate change.

Fluorescence Properties of Penta‐ and Hexacoordinate Coumarin Silicates – Unusual Behavior of Sodium Tris(4‐methylcoumarin‐6,7‐diolato)silicate in Solvent Mixtures

AbstractFluorescent penta‐ and hexacoordinate silicates were synthesized from 6,7‐dihydroxy‐4‐methylcoumarin (4‐methylesculetin, 4‐ME), tetramethyl orthosilicate and substituted aminopropylsilanes, respectively. Extinction coefficients, Stokes shifts, and quantum yields of fluorescence were determined and compared with 4‐ME. Optical properties of these compounds are sensitive to the polarity of solvents. The fluorescence quenching was investigated in methanol/water mixtures. The title compound sodium tris(4‐methylcoumarin‐6,7‐diolato)silicate (4) shows different behavior from all other compounds investigated.

A solvatochromic study of silicates and borate containing 4‐nitrocatechol ligands

AbstractSolvatochromism of 4‐nitrocatechol (1), tetra‐n‐butylammonium 2‐hydroxy‐4‐nitrophenolate (2), sodium tris(4‐nitrobenzene‐1,2‐diolato)silicate (3a), tetra‐n‐butylammonium tris(4‐nitrobenzene‐1,2‐diolato)silicate (3b), pyrrolidinium tris(4‐nitrobenzene‐1,2‐diolato)silicate (3c), (3‐amino‐1‐propyl)‐bis(4‐nitrobenzene‐1,2‐diolato)silicate (4a), and (N,N‐diethyl‐3‐amino‐1‐propyl)‐bis(4‐nitrobenzene‐1,2‐diolato)silicate (4b) as well as potassium bis(4‐nitrobenzene‐1,2‐diolato)borate (5) has been studied in a set of common solvents. The origin of the solvent‐induced UV/vis band shifts of 1–3c, and 5 has been determined by means of Linear Solvation Energy Relationship (LSER) using the empirical Kamlet–Taft and Catalán solvent parameter sets, respectively. The solvent‐induced UV/vis band shift of the negatively charged moiety of all solvatochromic dyes studied is mainly a function of the hydrogen‐bond donor (HBD) strength and the dipolarity/polarizability of the solvent as shown by multiple regression analyses. HBD solvents cause a hypsochromic shift of the UV/vis band due to specific solvation of the anion site. Oppositely, increasing dipolarity/polarizability of the solvent induces a bathochromic shift of the UV/vis absorption band. The donor strength of the solvent has an influence on the UV/vis band shift since ion pair formation occurs in solvents of low relative permittivity. This is shown by the impact of the counter ion of sodium tris(4‐nitrobenzene‐1,2‐diolato)silicate (3a) compared to tetra‐n‐butylammonium tris(4‐nitrobenzene‐1,2‐diolato)silicate (3b). The influence of the counter ion on the position of the UV/vis absorption band occurs in the same way as HBD solvents do. Na+ and the pyrrolidinium ion, respectively, have a stronger influence than the tetra‐n‐butylammonium ion on the solvatochromic band shift due to the stronger cation–anion interaction. Copyright © 2008 John Wiley & Sons, Ltd.

Chemoselective Reduction of Aldehydes over Ketones with Sodium Tris(hexafluoroisopropoxy)borohydride

Chemoselective reduction of aldehydes in the presence of ketones was achieved using sodium tris(hexafluoroisopropoxy)borohydride which can be stored as a THF solution.

A novel route to perovskite lead zirconate titanate from glycolate precursors via the sol–gel process

AbstractA perovskite lead zirconate titanate was synthesized by the sol‐gel process, using lead glycolate, sodium tris(glycozirconate) and titanium glycolate as the starting precursors. For the mole ratio Pb:Zr:Ti of 1:0.5:0.5 [Pb(Zr0.5Ti0.5)O3], TGA‐DSC thermal analysis indicated that the percentage of ceramic yield was 55.8, close to the calculated chemical composition value of 49.5. The exothermic peak occurred at 268 °C below the theoretical Curie temperature of 400 °C. The pyrolysis of Pb(Zr0.5Ti0.5)O3 of the perovskite phase was investigated in terms of calcination temperature and time. The structure obtained was of the tetragonal form when calcined at temperatures below 400 °C; it transformed to the tetragonal and the cubic forms of the perovskite phase on calcination above the Curie temperature, as verified by X‐ray data. The lead zirconate titanate synthesized and calcined at 400 °C for 1 h had the highest dielectric constant, the highest electrical conductivity and the dielectric loss tangent of 10 190, 0.803 × 10−3 (Ω.m)−1 and 1.513 at 1000 Hz, respectively. The lead zirconate titanate powder synthesized has potential applications as an electronic material. Copyright © 2008 John Wiley & Sons, Ltd.

A novel route to perovskite lead zirconate from lead glycolate and sodium tris(glycozirconate) via the sol–gel process

AbstractA perovskite lead zirconate was synthesized, using lead glycolate and sodium tris (glycozirconate) as the starting precursors, by the sol–gel process. The obtained molar ratio Pb:Zr of PbZrO3 was 0.9805:1. The TGA–DSC characterizations indicated that the percentage of ceramic yield was 56.4, close to the calculated chemical composition of 59.6. The exothermic peak occurred at 245.7 °C, close to the theoretical Curie temperature of 230 °C. The pyrolysis of PbZrO3 of the perovskite phase was investigated in terms of calcination temperature and time. The structure obtained was the orthorhombic form when calcined at low temperature at 300 °C for 1 h; it transformed to the monoclinic and cubic forms of the perovskite phase at higher temperatures above the Curie temperature as verified by X‐ray data. The lead zirconate synthesized and calcined at 300 °C for 1 h has the highest dielectric constant, the highest electrical conductivity and the dielectric loss tangent of 2267, 3.058 × 10−4 (Ω m)−1 and 2.484 at 1000 Hz, respectively. The lead zirconate powder produced has potential applications as materials used in microelectronics and microelectromechanical systems. Copyright © 2007 John Wiley & Sons, Ltd.

Oxo−Molybdenum(VI,V,IV) Complexes of the Facially Coordinating Tris(mercaptoimidazolyl)borate Ligand: Synthesis, Characterization, and Oxygen Atom Transfer Reactivity

A series of monooxo-Mo(IV,V) and dioxo-Mo(VI) complexes of the "soft" tripodal ligand, sodium tris(mercaptoimidazolyl)borate (NaTm(Me)), have been synthesized as potential oxygen atom transfer (OAT) models for sulfite oxidase. Complexes have been characterized by X-ray crystallography, cyclic voltammetry, and EPR, where appropriate. Oxygen atom transfer kinetics of Tm(Me)MoO(2)Cl, both stoichiometric and catalytic, have been studied by a combination of UV-vis and (31)P NMR spectroscopies under a variety of conditions. OAT rates are consistent with previously established relationships between redox potential/reactivity and mechanistic studies. The analysis of these complexes as potential structural and functional analogues of relevance to molybdoenzymes is further discussed.

Rheology and Heat Treatment of Zirconia Based Gels Synthesized from Sodium Glycozirconate Precursor

Zirconia based gels were prepared by the sol-gel route using sodium tris(glycozirconate)complex as precursor synthesized directly from the reaction of inexpensive and readily available compounds via the one step method. Rheological technique was used to investigate the sol-gel transition of zirconium based materials at different water/alkoxide ratios and reaction temperatures. The gelation time was determined from the evolution of the storage and loss moduli versus time at various frequencies using the Winter-Chambon criterion. The effect of an increase of the hydrolysis ratio and /or temperature was an enhancement of the kinetics of crosslink reactions, thus decreasing the gelation time. The variation of the gelation time versus temperature could be described by Arrhenius law. Furthermore, zirconia powders prepared from the thermal treatment at 500°C were analyzed by X-ray diffraction and the BET technique.

One-pot synthesis and characterization of novel sodium tris(glycozirconate) and cerium glycolate precursors and their pyrolysis

A low-cost and facile route to the synthesis of bimetallic glycolato zirconate (Na 2Zr(C 2H 4O 2) 3) and homometallic glycolato cerate (Ce(C 2H 4O 2)), which can be used as alkoxide precursors for sodium zirconium oxide (and/or zirconia by sol–gel process) and ceria materials, has been developed from the reaction of inexpensive starting materials via the oxide one-pot synthesis (OOPS) process. Both complexes were directly synthesized from zirconium hydroxide/cerium hydroxide and ethylene glycol using base as catalyst. Sodium hydroxide was used in the synthesis of sodium tris(glycozirconate) complex while both triethylenetetramine (TETA) as catalyst and trace amount of sodium hydroxide as co-catalyst were used in the case of cerium glycolate complex. The structures of obtained products were investigated using FTIR, TGA, DSC, 1 H and 13 C NMR, elemental analyses, EDS and mass spectroscopy. Pyrolysis studies delineate the effects of temperature on the decomposition processes whereby sodium tris(glycozirconate) and cerium glycolate precursors transform into Na 2O·ZrO 2 and CeO 2, respectively. The resulting sodium zirconium oxide and ceria, after pyrolysis at 600 °C for 3 h, had BET surface areas of about 62 and 70 m 2 g −1, respectively, and show monomodal pore size distributions in the mesopore region.

Synthesis of Tetrahemispheraplexes with Ammonium, Alkylammonium or Alkaline Metal Ions as Exohedral Guests via Self‐Assembly or Guest Exchange

AbstractTo study the interplay between the steric demand of the guest and the space available at the host, we have prepared the tetraammonium complexes {(NH4)4∩[Mg4(L1/2)6]} 1, tetrakis(methylammonium) complexes {(Me‐NH3)4∩[Mg4(L1/2)6]} 2, tetrakis(ethylammonium) complex {(Et‐NH3)4∩[Mg4(L1)6]} 3, and mixed sodium tris(ethylammonium) complex {Na(Et‐NH3)3∩[Mg4(L2)6]} 4. The tetrahemispheraplexes 1−4 were available in one‐pot syntheses. The tetrakis(alkylammonium) clusters {(R1−NH3)4∩[Mg4(L1)6]} 5 and the mixed diammonium‐bis(p‐methoxybenzylammonium) cluster {(NH4)2(R2−NH3)2∩[Mg4(L1)6]} 6, however, were prepared by exchange of the ammonium ions of 1a by alkylammonium ions. Similarly, exchange of the four ammonium ions of 1b by alkaline metal cations afforded the tetraalkaline metal tetrahemispheraplexes {M4∩[Mg4(L2)6]} 7.

Synthesis of Tetrahemispheraplexes with Ammonium, Alkylammonium or Alkaline Metal Ions as Exohedral Guests via Self‐Assembly or Guest Exchange

AbstractTo study the interplay between the steric demand of the guest and the space available at the host, we have prepared the tetraammonium complexes {(NH4)4∩[Mg4(L1/2)6]} 1, tetrakis(methylammonium) complexes {(Me‐NH3)4∩[Mg4(L1/2)6]} 2, tetrakis(ethylammonium) complex {(Et‐NH3)4∩[Mg4(L1)6]} 3, and mixed sodium tris(ethylammonium) complex {Na(Et‐NH3)3∩[Mg4(L2)6]} 4. The tetrahemispheraplexes 1−4 were available in one‐pot syntheses. The tetrakis(alkylammonium) clusters {(R1−NH3)4∩[Mg4(L1)6]} 5 and the mixed diammonium‐bis(p‐methoxybenzylammonium) cluster {(NH4)2(R2−NH3)2∩[Mg4(L1)6]} 6, however, were prepared by exchange of the ammonium ions of 1a by alkylammonium ions. Similarly, exchange of the four ammonium ions of 1b by alkaline metal cations afforded the tetraalkaline metal tetrahemispheraplexes {M4∩[Mg4(L2)6]} 7. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Preparation, photoluminescence and thermal stability of sodium tris(pyridine dicarboxylato) europate(III) complex incorporated into silica matrix

Silica-based composite materials incorporated with sodium tris(pyridine dicarboxylato) europate(III), SiO2 : Na3Eu(DPA)3, where H2DPA is 2,6-pyridine dicarboxylic acid, were prepared by a sol-gel method. Photoluminescent properties of SiO2 : Na3Eu(DPA)3 composite were studied after heat treatment between room temperature and 600 °C. The strong red emission of SiO2 : Na3Eu(DPA)3 was intensified by heat-treatment under appropriate conditions. The thermal stability of Na3Eu(DPA)3·9H2O and its silica-based composite was examined. The results demonstrate that SiO2 : Na3Eu(DPA)3 composite material possesses very good thermal stability with intense visible fluorescence, and may be applied as a potential luminescent material.