Crystal structure of a TbIII–CuII glycinehydroxamate 15-metallacrown-5 sulfate complex

The core of the title complex, bis[hexaaquahemiaquapentakis(μ3-glycinehydroxamato)sulfatopentacopper(II)terbium(III)] sulfate hexahydrate, [TbCu5(SO4)(GlyHA)5(H2O)6.5]2(SO4)·6H2O (1), which belongs to the 15-metallacrown-5 family, consists of five glycinehydroxamate dianions (GlyHA2−; C2H4N2O2) and five copper(II) ions linked together forming a metallamacrocyclic moiety. The terbium(III) ion is connected to the centre of the metallamacrocycle through five hydroxamate oxygen atoms. The coordination environment of the Tb3+ ion is completed to an octacoordination level by oxygen atoms of a bidentate sulfate and an apically coordinated water molecule, while the copper(II) atoms are square-planar, penta- or hexacoordinate due to the apical coordination of water molecules. Continuous shape calculations indicate that the coordination polyhedron of the Tb3+ ion in 1 is best described as square antiprismatic. The positive charge of each pair of [TbCu5(GlyHA)5(H2O)6.5(SO4)]2 2+ fragments is compensated by a non-coordinated sulfate anion, which is located on an inversion center with 1:1 disordered oxygen atoms. Complex 1 is isomorphous with the previously reported compounds [LnCu5(GlyHA)5(SO4)(H2O)6.5]2(SO4), where Ln III = Pr, Nd, Sm, Eu, Gd, Dy and Ho.

Extension of the method for identifying crystals in the composition of wine sediment

Одной из функций технохимического контроля в виноделии является обеспечение разливостойкости готовой продукции. Для этого необходима система методов и тестов, позволяющих оценить склонность вин к помутнениям физико-химического характера, также установить причины появления осадков, образующихся в случае недостаточной технологической обработки вин или при нарушениях условий их хранения. В случае кристаллического осадка общепринятым методом идентификации калиевой или кальциевой природы виннокислой соли является воздействие 10 %-ными растворами соляной и серной кислот. Указанные кислоты в более высокой концентрации являются прекурсорами, применение которых строго регламентируется на законодательном уровне. Целью данной работы являлось обоснование возможности применения общедоступных реактивов при анализе кристаллического осадка вин. Объектами исследований являлись растворы неорганических кислот и сульфата натрия в качестве источника сульфат-аниона, кристаллический осадок вин, а также промышленные препараты битартрата калия и тартрата кальция. Показано, что эффективной заменой соляной и серной кислот для растворения кристаллов является азотная кислота. Предложен новый реагент для идентификации калиевой и кальциевой природы осадка, представляющий водный раствор азотной кислоты (10 %) и сульфата натрия (не менее 15 %). Растворение виннокислых кристаллов в капле данного препарата свидетельствует, что кристаллообразующим катионом является калий; появление отдельных звездчатых, игольчатых структур или их сростков демонстрирует присутствие кальция. Усовершенствованная методика предназначена для применения в рамках технохимического контроля в лабораториях винодельческих предприятий, профильных учебных и научных заведений. One of functions of techno-chemical control in winemaking is to ensure wine stability of the finished product after bottling. This requires a system of methods and tests to assess the tendency of wines to haziness of physicochemical nature, as well as to establish the appearance origin of sediment formed as a result of insufficient technological processing of wines or violation of the storage conditions. In the context of crystal sediment, the action of 10% solutions of hydro-chloric and sulfuric acids is a generally accepted method for identifying the potassium or calcium nature of tartrate salts. In a higher concentration, these acids are precursors, using of which is strictly regulated at the legislative level. The purpose of this work was to substantiate the possibility of using generally available reagents in the analysis of crystal sediment of wines. The objects of research were solutions of inorganic acids and sodium sulfate as a source of sulfate-anion, crystal sediment of wines, as well as commercial preparations of potassium bitartrate and calcium tartrate. It is indicated that nitric acid is an effective substitution for hydrochloric and sulfuric acids to dissolve crystals. New reagent, constituting aqueous solution of nitric acid (10%) and sodium sulfate (not less than 15%), is proposed for identifying the potassium or calcium nature of the sediment. Dissolving of tartaric crystals in a drop of this preparation indicates that potassium is a crystal-forming cathion; the appearance of single stellar, needle-like structures or their intergrowth demonstrates presence of calcium. The extended technique is intended for application as a part of techno-chemical control in laboratories of winemaking enterprises, industry-specific educational and scientific institutions.

Square network based upon the molecular salt of the tetraprotonated photoproduct rtct-tetrakis(pyridin-4-yl)cyclobutane and the sulfate anion

The formation and crystal structure of a hydrated molecular salt that results in a square network is reported. The crystalline solid is based upon the tetraprotonated photoproduct rtct-tetrakis(pyridin-4-yl)cyclobutane (4H- rtct -TPCB)4+ along with two sulfate anions (SO4 2−) and eight waters of hydration, namely, 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)tetrapyridinium bis(sulfate) octahydrate, C24H24N4 4+·2SO4 2−·8H2O. The fully protonated photoproduct acts as a four-connecting node within the square network by engaging in four charge-assisted N+—H...O hydrogen bonds to the sulfate anion. The observed hydrogen-bonding pattern in this square network is akin to T-silica, which is a metastable form of SiO2. The included water molecules and sulfate anions engage in numerous O—H...O hydrogen bonds to form various hydrogen-bonded ring structures.

Crystal structure of hyoscyamine sulfate monohydrate, (C17H24NO3)2(SO4)(H2O)

The crystal structure of hyoscyamine sulfate monohydrate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Hyoscyamine sulfate monohydrate crystallizes in space group P21 (#4) with a = 6.60196(2), b = 12.95496(3), c = 20.93090(8) Å, β = 94.8839(2)°, V = 1783.680(5) Å3, and Z = 2. Despite the traditional description as a dihydrate, hyoscyamine sulfate crystallizes as a monohydrate. The two independent hyoscyamine cations have different conformations, which have similar energies. One of the cations is close to the minimum-energy conformation. Each of the protonated nitrogen atoms in the cations acts as a donor to the sulfate anion. The hydroxyl group of one cation acts as a donor to the sulfate anion, while the hydroxyl group of the other cation acts as a donor to the water molecule. The water molecule acts as a donor to two different sulfate anions. The cations and anions are linked by complex chains of hydrogen bonds along the a-axis. The powder pattern has been submitted for inclusion in the Powder Diffraction File™ (PDF®).

Sodium Sulfate (Na2SO4) Detection Using Graphene Coated Microfiber

We investigate the coating of graphene onto the silica microfiber sensor for sodium sulfate measurement at room temperature. The graphene obtained from graphene-polylactic acid filament was coated onto the microfiber based on drop casting methods. In this work, the graphene acts as cladding to interact with analyte as well as functions to trap either sodium cation or sulfate anion and increases the effective refractive index of the cladding. The sensor has a good sensitivity of 0.82 dBm/% and resolution of 1.16 %. The sensitivity and resolution of the sensor were increased by the coating of graphene layer.