Asymmetric Pd-NHC*-catalyzed coupling reactions

Very high asymmetric inductions result in the Pd-catalyzed intramolecular arylation of amides to give 3,3-disubstituted oxindoles when new in situ-generated chiral N-heterocyclic carbene (NHC*) ligands are employed. Structural studies show that conformational locking to minimize allylic strain is the key to understanding the function of these ligands. New applications of these ligands in the frontier area of asymmetric coupling reactions involving C(sp3)-H bonds are detailed. Highly enantioenriched fused indolines are accessible using either preformed- or in situ-generated Pd-NHC* catalysts. Remarkably, this occurs at high temperature (140-160 °C) via excellent asymmetric recognition of an enantiotopic C-H bond in an unactivated methylene uni

Control of metal-directed self-assembly by metal–amine interactions

The complexation of a tweezers ligand with zinc perchlorate in the absence and presence of amines in methanol solution was explored. L2Zn2(ClO4)4 was a thermodynamic product of the reaction in the absence of an amine. The complex was shown to interact with aliphatic amines resulting in the formation of a Zn–N(amine) bond. If metal–ligand complexation was carried out in the presence of an amine the formation of a trinuclear zinc complex L3Zn36+ was observed. Moreover the transformation of complex L2Zn24+ to L3Zn36+ occurred, when the former was subjected to an amine in the amount, which is sufficient to coordinate more than one amino group on each zinc atom. Complexes ligand-zinc-amine were shown to be kinetically stable, and the method of their preparation was crucial to the purity of the final complexes. L3Zn36+ was favored under kinetic control: reagent concentration 10−5M, slow addition of zinc perchlorate to the mixture of an amine and the ligand. Under thermodynamic control (fast mixing of reagents, concentration 10−2–10−3 M) formation of a mixture of complexes was observed. All pure complexes and their mixtures were characterized using UV-Vis, ROESY, PFGSE NMR and ESI-MS techniques. On the basis of DFT calculations the mechanism of influence of an amine on self-assembly was suggested

ОСТРОЕ ОТРАВЛЕНИЕ НИТРАТОМ НАТРИЯ В НЕВРОЛОГИЧЕСКОЙ ПРАКТИКЕ

This article describes a clinical case of a patient with acute cerebrovascular accident, acute respiratory failure and acute coronary syndrome. The ischemic lesion was associated with sodium nitrate, poisoning and its metabolite nitrite which resulted in increased methemoglobin concentration in blood and manifested as reversible discirculatory encephalopathy, respiratory disorder and myocardial damage. The article shows figures, reflecting changes in the biochemical composition of blood and changes in the electrocardiogram. The purpose of this study is to demonstrate clinical features of acute poisoning with sodium nitrate.В данной статье приводится описание клинического случая развития у пациента одновременно клинических симптомов острого нарушения мозгового кровообращения, острой дыхательной недостаточности и острого коронарного синдрома. Причиной развития ишемического поражения в данном случае явилось отравление нитратом натрия и его метаболитом — нитритом натрия, которое привело к повышенному содержанию метгемоглобина в крови, что в клинической картине выразилось обратимыми дисгемической энцефалопатией, нарушением дыхания и повреждением миокарда. В статье представлены графики и рисунки, отражающие изменения в биохимическом составе крови и на электрокардиограмме. Целью данной работы является демонстрация особенностей клинической картины острого отравления нитратом натрия и его метаболитом

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

We describe a multidentate tripodal ligand in which three pendant arms carrying di(2-picolyl)amine units are linked to the ortho positions of a tris(o-xylyl) scaffold, providing N(CH[subscript 2]-o-C[subscript 6]H[subscript 4]CH[subscript 2]N(CH2py)[subscript 2])[subscript 3] (L). Reaction of L with CuCl[subscript 2] in the presence of hexafluorophosphate anion afforded blue cubes of [(CuCl)[subscript 3]L](PF[subscript 6])[subscript 3]·5H[subscript 2]O (1). Crystallographic studies of 1 revealed that the three symmetry-related arms each coordinate a {Cu[superscript II]Cl} unit, and two molecules of 1 are connected to one another through a Cu(μ-Cl)[subscript 2]Cu bridge, extending the molecular structure to form a two-dimensional (2-D) layer. These 2-D layers pack in an ABCABC... fashion with PF[subscript 6]– anions located in between. Reaction of 1 with a stoichiometric amount of perrhenate ion afforded blue plates of [(CuCl)[subscript 3]L](PF[subscript 6])(ReO[subscript 4])[subscript 2]·3H[subscript 2]O (2). Compound 2 has the same lattice structure as 1, but the tricopper unit backbone now traps one ReO[subscript 4]– anion through Coulombic interactions. In addition, three molecules of 2 are bridged by a perrhenate ion, forming a Cu[subscript 3](μ[superscript 3]-ReO[subscript 4]) cluster, to give a different 2-D structure displaying a rare tridentate bridging ReO[subscript 4]– mode. Thus, in addition to classic perrhenate trapping through weak Coulombic interactions, 2 represents an exceptional example in which the ReO[subscript 4]– anion is immobilized in an extended framework through tight covalent interactions. The interlamellar PF[subscript 6]– anions in 1 can be exchanged with other anions including perrhenate, perchlorate, or periodate. The structural similarity between perrhenate and pertechnetate makes these materials of potential interest for pertechnetate trapping

Synthesis and evaluation of thiosemicarbazones functionalized with furyl moieties as new chemosensors for anion recognition

A family of heterocyclic thiosemicarbazone dyes (3a-f and 4) containing furyl groups were synthesized in good yields, characterized and their response in acetonitrile in the presence of selected anions was studied. Acetonitrile solutions of 3a-f and 4 show absorption bands in the 335-396 nm range which are modulated by the electron donor or acceptor strength of the heterocyclic systems appended to the thiosemicarbazone moiety. Fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulphate, nitrate, acetate and cyanide anions, were used in recognition studies. From these anions, only sensing features were seen for fluoride, cyanide, acetate and dihydrogen phosphate. Two clearly different chromo-fluorogenic behaviours were observed, (i) a small shift of the absorption band due to the coordination of the anions with the thiourea protons and (ii) the appearance of a new red shifted band due to deprotonation. For the latter effect, a change in the colour solution from pale yellow to purple was observed. Fluorescence studies were also in agreement with the different effects observed in the UV/Vis titrations. In this case, hydrogen bonding interactions were visible through the enhancement of the emission band, whereas deprotonation induced the appearance of a new red-shifted emission. Logarithms of stability constants for the two processes (complex formation + deprotonation) for receptors 3a-f in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec V1.1.18 program. Semi-empirical calculations to evaluate the hydrogen-donating ability of the receptors and a prospective electrochemical characterization of compound 3b in the presence of fluoride were also performed.Fundação para a Ciência e a Tecnologia (FCT), Acções Integradas Luso-espanholas/CRUP, Generalitat Valenciana

Дослідження комбінаційних характеристик вітчизняних радіонепрозорих тканин М1, М2 та М3

The research of domestic radio-stable fabrics M1, M2 and M3 for determination of shielding factor for different combinations of the fabrics has been performed. It is defined screening coefficient both in case of horizontal and in case of vertical layout of the fabrics. In the research it is used the following installation. When the receiving antenna was in the dielectric box enveloped each of three fabrics in different combinations. The results of measurement show that combinations of the fabrics M1-M2 and M2-M3 have the same parameters and higher screening coefficient. However, combination M1-M3 have wider band but smaller screening coefficient. Fig.: 6. Refs: 12 titles.Проведены исследования отечественных радионепрозрачных тканей М1, М2 и М3 на определение суммарного коэффициента экранирования при разных комбинациях их использования. Измерения произведены как при горизонтальном, так и при вертикальном расположении волокон. В исследовании была использована установка, в которой передающая антенна находилась внутри диэлектрического корпуса, который обворачивался поочередно тканями в разных комбинациях: М1-М2, М2-М3 и М1-М3. Результаты измерений показали, что комбинации тканей М1-М2 и М2-М3 имеют схожие характеристики и большие коэффициенты экранирования, однако комбинация М1-М3 имеет большую полосу экранирования, хотя и с меньшим коэффициентом экранирования. Ил.: 6. Библиогр.: 12 наим.Проведено дослідження вітчизняних радіонепрозорих тканин М1, М2 та М3 на визначення сумарного коефіцієнта екранування при різних комбінаціях їхнього застосування. Виміри проведено як при горизонтальному, так і при вертикальному розташуванні волокон. У дослідженнях використано установку, в якій передавальна антена знаходилася всередині діелектричного корпусу, що обгортався по черзі тканинами у різних комбінаціях: М1-М2, М2-М3 та М1-М3. Результати вимірювань показали, що комбінації тканин М1-М2 та М2-М3 мають подібні характеристики і більші коефіцієнти екранування, проте комбінація М1-М3 має більшу смугу екранування, хоча і з меншим коефіцієнтом екранування

The screening of the compounds with antiaggregation activity among benzimidazole and xantine

Antiaggregation activity of first synthesized benzimidazole and xantine derivatives has been studied. Differences in impact of the compounds on blood coagulability have been shown. We have synthesized L-65, on active compound, that suppresses platelet aggregation and has an acetylsalicylate acid-like effect. The results obtained concerning the screening of bioactive substances are promising

ACUTE POISONING WITH SODIUM NITRATE IN NEUROLOGICAL PRACTICE

This article describes a clinical case of a patient with acute cerebrovascular accident, acute respiratory failure and acute coronary syndrome. The ischemic lesion was associated with sodium nitrate, poisoning and its metabolite nitrite which resulted in increased methemoglobin concentration in blood and manifested as reversible discirculatory encephalopathy, respiratory disorder and myocardial damage. The article shows figures, reflecting changes in the biochemical composition of blood and changes in the electrocardiogram. The purpose of this study is to demonstrate clinical features of acute poisoning with sodium nitrate