Electrical Conductance Studies in Aqueous Solutions with Ascorbate Ions

Conductivity measurements in dilute aqueous solutions of L-ascorbic acid, sodium-L-ascorbate, magnesium-L-ascorbate, calcium-L-ascorbate and ferrous-L-ascorbate were performed in the (288.15 to 323.15) K temperature range. The limiting molar conductances of the ascorbic anion, λ^∘(HAsc⁻, T), and the dissociation constants of ascorbic acid, K(T), were derived by the use of the Debye-Hückel equation for the activity coefficients and the Onsager and Quint and Viallard conductivity equations.     

Study of the winter and summer changes of the air composition in the church of Szalowa, Poland, related to conservation

The St. Michael Archangel’s Church in Szalowa, Poland, was selected for closer investigation with respect to the indoor/outdoor air exchange and its influence on the air quality and work arts preservation. Chemical composition, size and abundance of particulate matter and concentration of gases NO₂, SO₂, O₃ inside and outside the church were determined. To study seasonal variation of the weather condition (temperature, inversion level, wind direction) and the influence of seasonal sources of the air pollution (like heating of the nearby houses), samples were collected in winter and summer time. It was stated that suspended particulate matter inside the wooden church has in general an outdoor source. Several groups of particles were distinguished such as the organic ones, soil dust, nitrates and sulphates. In case of organic and soil dust particles, the concentration inside was higher than outside. From the results, in comparison to literature data, one can conclude that accumulation of particulate suspended matter in the church is more intense than in other types of buildings. Gaseous pollutants were detected but their concentration was negligible.     

Electrical Conductance Studies in Aqueous Solutions of Glutaric Acid,Disodium Glutarate and Sodium Hydrogen Glutarate

Conductivity measurements of glutaric acid and disodium glutarate in dilute aqueous solutions were performed in the 288.15 to 323.15 K temperature range. The limiting equivalent conductances of glutarate anions, λ ^o(HGlut⁻,T) and λ ^o(1/2Glut²⁻,T), and the dissociation constants of glutaric acid, K ₁(T) and K ₂(T), were derived by the use of the Onsager and the Quint and Viallard conductivity equations. The applied molecular model was successfully confirmed by analyzing the conductivities of sodium hydrogen glutarate at 298.15 K.     

Rubidium dimolybdate,Rb2Mo2O7, and caesium dimolybdate,Cs2Mo2O7

The crystal structures of dirubidium hepta­oxodimolybdate, Rb₂Mo₂O₇, and dicaesium hepta­oxodimolybdate, Cs₂Mo₂O₇, in the space groups Ama2 and P2₁/c, respectively, have been determined for the first time by single‐crystal X‐ray diffraction. The structures represent two novel structure types of monovalent ion dimolybdates, A₂Mo₂O₇ (A = alkaline elements, NH₄, Ag or Tl). In the structure of Rb₂Mo₂O₇, Mo atoms are on a twofold axis, on a mirror plane and in a general position. One of the Rb atoms lies on a twofold axis, while three others are on mirror planes. Two O atoms attached to the Mo atom on a mirror plane are located on the same plane. Rubidium dimolybdate contains a new kind of infinite Mo–O chain formed from linked MoO₄ tetra­hedra and MoO₆ octa­hedra alternating along the a axis, with two terminal MoO₄ tetra­hedra sharing corners with each octa­hedron. The chains stack in the [001] direction to form channels of an approximately square section filled by ten‐coordinate Rb ions. Seven‐ and eight‐coordinate Rb atoms are located between chains connected by a c translation. In the structure of Cs₂Mo₂O₇, all atoms are in general positions. The MoO₆ octa­hedra share opposite corners to form separate infinite chains running along the c axis and strengthened by bridging MoO₄ tetra­hedra. The same Mo–O polyhedral chain occurs in the structure of Na₂Mo₂O₇. Eight‐ to eleven‐coordinate Cs atoms fill the space between the chains. The atomic arrangement of caesium dimolybdate has an ortho­rhom­bic pseudosymmetry that suggests a possible phase transition P2₁/c→Pbca at elevated temperatures.     

Reactions of the Ru3(CO)10(μ-Ph2PCH2PPh2) cluster with enynes RCH=CHC≡CR (R is phenyl or ferrocenyl). Formation of indenone derivatives of triruthenium clusters

The thermal reaction of Ru₃(CO)₁₀(-Ph₂PCH₂PPh₂) (1) with enyne PhCH=CHCCPh afforded the trinuclear ruthenium clusters Ru₃(CO)₆{₃-P(Ph)CH₂PPh₂}{₃-C(Ph)=CHCC(Ph)(1,2-C₆H₄)C(=0)} (2), Ru₃(-H)(CO)₅{₃-P(Ph)CH₂PPh₂}{₃-C(Ph)=CHCC(Ph)(1,2-C₆H₄)C(—0)} (3), and Ru₃(CO)₆(-CO){₃-P(Ph)CH₂PPh₂}{₃-C(C=CPh₂)CH=C(H)Ph} (4) and also two isomers of Ru₃(CO)₅(-CO)(-Ph₂PCH₂PPh₂){₃-C₄Ph₂(CH=CHPh)₂} (5a and 5b). Clusters 2, 3, and 4 were characterized by IR spectroscopy, ¹H and ³¹P NMR spectroscopy, and X-ray diffraction analysis. The reaction of complex 1 with enyne FcCH=CHCCFc gave rise to the Ru₃(CO)₆{₃-P(Ph)CH₂PPh₂}{₃-C(Fc)=CHCC(Fc)(1,2-C₆H₄)C(=0)} (6) and Ru₃(-H)(CO)₅{₃-P(Ph)CH₂PPh₂}{₃-C(Fc)=CHCC(Fc)(1,2-C₆H₄)C(—0)} (7) clusters. According to the spectral data, the latter compounds are isostructural to complexes 2 and 3, respectively.     

Electrical Conductance and Volumetric Studies in Aqueous Solutions of DL-Pyroglutamic Acid

Conductivity measurements of DL-pyroglutamic acid and sodium pyroglutamate in dilute aqueous solutions were performed in the 288.15–323.15 K temperature range. The limiting molar conductances of pyroglutamate anion, λ^o(pGlu⁻, T) and the dissociation constants of pyroglutamic acid, K(T) were derived from the Onsager, and the Quint and Viallard conductivity equations. Densities of aqueous solutions with molalities lower than 0.5 mol-kg⁻¹ were determined at 5 K intervals from T = 288.15 K to 333.15 K. Densities served to evaluate the apparent molar volumes, V_2,φ(m, T), the cubic expansion coefficients, α (m,T) and the changes of the isobaric heat capacities with respect to pressure, (∂ C_P/∂ P)_T,m. They were correlated qualitatively with the changes in the structure of water when pyroglumatic acid is dissolved in it.     

Complex Formation of Phosphoryl- and Thiophosphorylacylacetonitriles with Different Cations

The enols R 1 R 2 P(E)(CN)C = CR 3 OH (E = O or S) gave in solutions either neutral metal complexes ML x or M(OH) y L x . The anionic ambidentate ligands are coordinated through E and O atoms in solutions, and O, E, and N atoms in in crystals.     

The intragastrointestinal fate of paclitaxel-loaded micelles: Implications on oral drug delivery

The goal of the present study is to elucidate the intragastrointestinal fate of micellar delivery systems by monitoring fluorescently labeled different micelles and the model drug paclitaxel (PTX). Both in vitro and ex vivo leakage studies showed fast PTX release in fluids while micelles remained intact, except in fed-state simulated intestinal fluid and fasted-state pig intestinal fluid, thus referring to the intact absorption of micelles and PTX leakage in the gastrointestinal tract with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) micelles showing higher stability than other micelles. All groups of micelles were absorbed intact in Caco-2 and Caco-2/HT29-MTX cell models and the absorption of TPGS micelles was found to be higher than other micelles. The transport of the micelles across Caco-2/Raji (1.6%–3.5%), Caco-2 (0.8%–1%), and Caco-2/HT29-MTX (0.58%–1%) cell monolayers further verified the absorption of micelles and their subsequent transport; however, more TPGS micelles transported across cell monolayers than other groups. Moreover, the histological examination also confirmed that micelles entered the enterocytes and were transported to basolateral tissues and TPGS showed the stronger ability of penetration than other groups. Thus, these results are succinctly presenting the absorption of intact micelles in GIT confirmed by imaging evidence with prior leakage of the drug, uptake by enterocytes and the transport of micelles that survive the digestion by enterocytes and mainly by microfold cells in material nature dependent way with TPGS showing better results than other groups. In conclusion, these results identify the mechanism by which the gastrointestinal tract processes micelles and point to the likely use of this approach in the design of micelles-based therapies.     

Synthesis and structure of a heptanuclear nickel(II) complex uniquely exhibiting four distinct binding modes,two of which are novel,for a hydroxamate ligand

The reaction of 2-(dimethylamino)phenylhydroxamic acid (2-dmAphaH) with NiSO(4).6H2O gives the complex [Ni7(2-dmAphaH-1)2(2-dmApha)8(H2O)2]SO(4).15H2O uniquely exhibiting four distinct hydroxamate binding modes, two of which are novel, and showing both antiferromagnetic and ferromagnetic interactions in contrast to [Cu5(2-dmAphaH-1)4(HSO4)2(MeOH)2].2MeOH, a strongly antiferromagnetic metallacrown formed with CuSO(4).5H2O.