114 research outputs found
1-Methyl-2,3-dihydro-1H-benzimidazole-2-selone
The title compound C8H8N2Se, is the product of the reaction of 2-chloro-1-methylbenzimidazole with sodium hydroselenide. The molecule is almost planar (r.m.s. deviation = 0.041 Å) owing to the presence of the long chain of conjugated bonds (Se=C—NMe—C=C—C=C—C=C—NH). The C=Se bond length [1.838 (2) Å] corresponds well to those found in the close analogs and indicates its pronounced double-bond character. In the crystal, molecules form helicoidal chains along the b axis by means of N—H⋯Se hydrogen bonds
Methyl 4,5-diacetoxy-1-oxo-2-phenylperhydro-4,6-epoxycyclopenta[c]pyridine-7-carboxylate ethanol solvate
The title compound, the product of an acid-catalysed Wagner–Meerwein skeletal rearrangement, crystallizes as an ethanol monosolvate, C20H21NO8·C2H6O. The title molecule comprises a fused tricyclic system containing two five-membered rings (cyclopentane and tetrahydrofuran) in the usual envelope conformations and one six-membered ring (piperidinone) adopting a flattened twist–boat conformation
2,25-Dioxo-27,28-diphenyl-30-oxa-29-thia-3,10,17,24-tetraazapentacyclo[24.2.1.112,15.04,9.018,23]triaconta-5,7,9(4),10,12,14,16,18,20,22,26,28-dodecaene chloroform disolvate
The macrocycle of the title compound, C36H24N4O3S·2CHCl3, contains a rigid framework with the nitrogen and oxygen heteroatoms pointing in towards the center of the macrocyclic cavity. The macrocycle is essentially planar (r.m.s. deviation = 0.027 Å) except for the thiophene ring. The dihedral angle between the thiophene ring plane and the mean plane of the central macrocyclic core including all atoms except sulfur is 21.6 (1)°. Four intramolecular hydrogen bonds occur: two are between the amide hydrogen atoms and the Schiff base nitrogen atoms, while the others are between the amide hydrogen atoms and the sulfur atom of the thiophene. The two solvate chloroform molecules are bound to the carbonyl oxygen atoms of the ligand by weak C—H⋯O hydrogen bonding. In addition, the structure reveals intermolecular Cl⋯Cl close contacts [3.308 (2), 3.404 (2) and 3.280 (2) Å] between the chloroform solvate molecules. In the crystal, the macrocycles form layers parallel to (101), with an interlayer distance of 3.362 (3) Å. This short distance is determined by the stacking interactions between the amide carbonyl and imine fragments of neighboring ligands
N,N′-Bis(2-aminophenyl)-3,4-diphenylthiophene-2,5-dicarboxamide acetonitrile solvate
In the title solvate, C30H24N4O2S·CH3CN, the substituted thiophene possesses approximate Cs(m) intrinsic symmetry, with the mirror plane passing through the S atom and the mid-point of the (Ph)C—C(Ph) bond. Despite the main backbone of the molecule being a long chain of conjugated bonds, it adopts a non-planar conformation due to the presence of various intra- and intermolecular hydrogen bonds. The hydrogen bonds result in twist configurations for both the amido and aminophenyl fragments relative to the central thiophene ring. There are two intramolecular Namine—H⋯O hydrogen bonds within the thiophene-2,5-dicarboxamide molecule that form seven-membered rings. In the crystal, the thiophene-2,5-dicarboxamide molecules form inversion dimers by four amide–amine N—H⋯N hydrogen bonds. The dimers are further linked into layers propagating in (100) both directly (via Namine—H⋯O hydrogen bonds) and through the acetonitrile solvate molecules (via amine–cyano N—H⋯N and CMe—H⋯O interactions)
Methyl (9aR*,10S*,11R*,13aS*,13bS*)-9-oxo-6,7,9,9a,10,11-hexahydro-5H,13bH-11,13a-epoxypyrrolo[2′,1′:3,4][1,4]diazepino[2,1-a]isoindole-10-carboxylate
The title compound, C17H18N2O4, is the methyl ester of the adduct of intramolecular Diels–Alder reaction between maleic anhydride and 1-(2-furyl)-2,3,4,5-tetrahydro-1H-pyrrolo[1,2-a][1,4]diazepine. The molecule comprises a fused pentacyclic system containing four five-membered rings (viz. pyrrole, 2-pyrrolidinone, tetrahydrofuran and dihydrofuran) and one seven-membered ring (1,4-diazepane). The pyrrole ring is approximately planar (r.m.s. deviation = 0.003 Å) while the 2-pyrrolidinone, tetrahydrofuran and dihydrofuran five-membered rings have the usual envelope conformations. The central seven-membered diazepane ring adopts a boat conformation. In the crystal, molecules are bound by weak intermolecular C—H⋯O hydrogen-bonding interactions into zigzag chains propagating in [010]. In the crystal packing, the chains are stacked along the a axis
1,3-Benzothiazole-2(3H)-selone
The title compound, C7H5NSSe, is the product of the reaction of 2-chlorobenzothiazole with sodium hydroselenide. The molecule is almost planar (r.m.s. deviation = 0.018 Å) owing to the presence of the long chain of conjugated bonds (Se=C—N—C=C—C=C—C=C). The geometrical parameters correspond well to those of the analog N-methylbenzothiazole-2(3H)-selone, demonstrating that the S atom does not take a significant role in the electron delocalization within the molecule. In the crystal, molecules form centrosymmetric dimers by means of intermolecular N—H⋯Se hydrogen bonds. The dimers have a nonplanar ladder-like structure. Furthermore, the dimers are linked into ribbons propagating in [010] by weak attractive Se⋯S [3.7593 (4) Å] interactions
Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1-Methylimidazolium Thiocyanate
We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Brønsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate-based protic ionic liquids for the ring-opening of donor-acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1-methylimidazolium thiocyanate under mild metal-free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three-membered ring affording pyrrolidine-2-thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time-efficient step. The ability of 1-methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)-annulation with 1-acyl-2-(2-hydroxyphenyl)cyclopropane, epoxide ring-opening and other organic transformations
ОБОБЩЕННЫЙ МЕТОД АВТОМАТИЗИРОВАННОГО ПРОЕКТИРОВАНИЯ ТЕХНОЛОГИЧЕСКИХ ПРОЦЕССОВ ИЗГОТОВЛЕНИЯ МИКРОЭЛЕКТРОМЕХАНИЧЕСКИХ АКСЕЛЕРОМЕТРОВ
A generalized method for the automated design of technological processes for the production of MEMS accelerometers is developed. This method is based on two methods: the method of selecting a standard technological processes and the method of searching for analogues of individual subsystems and elements of MEMS accelerometers, which will increase the efficiency of design work by reducing the cost and time of manufacture. Within the framework of the method, decision-making model to select the type of MEMS accelerometer for its functionally constructive parameters, model for searching analogues of individual subsystems and MEMS accelerometer elements, as well as a model for selecting equipment that, based on 4 indicators: productivity, energy efficiency, equipment price, service have been developed.Разработан обобщенный метод автоматизированного проектирования технологических процессов изготовления микроэлектромеханических (МЭМС) акселерометров, который в отличие от существующих основан на двух методах: методе выбора типового технологического процесса и методе поиска аналогов отдельных подсистем и элементов МЭМС акселерометров, что позволит повысить эффективность проектных работ за счет снижения стоимости и времени изготовления. В рамках указанного метода разработана модель принятия решений о выборе типа МЭМС акселерометра по его функционально-конструктивным параметрам, модель поиска аналогов отдельных подсистем и элементов МЭМС акселерометров, а также модель выбора оборудования на основе четырех показателей: производительность, энергоэффективность, стоимость оборудования, срок службы
НИЗКОТЕМПЕРАТУРНАЯ ПЛАЗМА МАГНЕТРОННОГО РАЗРЯДА
The article investigates a low-temperature plasma of the magnetron discharge of a device used for the synthesis of dielectric films by reactive cathode sputtering. The aim of the study is to determine the temperature characteristics of plasma particles and a sputtered substance, as well as the mechanism for the formation of a chemical bond between sputtered atoms and active gas molecules. A study of the composition and energy parameters of the plasma, as well as the chemical composition of the particles obtained by sputtering, was carried out by a spectroscopic method. The quantitative composition was determined by a mass spectrometer to determine the composition of the sputtered particles.В статье исследуется низкотемпературная плазма магнетронного разряда устройства, используемого для синтеза диэлектрических пленок реактивным катодным распылением [1]. Целью исследования является определение температурных характеристик частиц плазмы и распыленного вещества, а также механизма образования химической связи между распыленными атомами и молекулами активного газа. Исследование состава и энергетических параметров плазмы, а также химический состав полученных при распылении частиц вещества, проведен спектроскопическим методом. Количественный состав определялся масс-спектрометром для определения состава распыленных частиц
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