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108 Result(s)
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Article
Circumambulatory Migrations of Arylazo Groups in Pentakis(methoxycarbonyl)- and Pentamethylcyclopentadienes
According to CAM–B3LYP/6-311++G(d,p) quantum chemical calculations, intramolecular migration of the arylazo group in pentamethyl 5-(aryldiazenyl)cyclopentadiene-1,2,3,4,5-pentacarboxylates follows a ...
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Article
Quantum-Chemical Study of the Structure of Amidinyltetramethoxycarbonylcyclopentadiene and Its Hg(II) and Tl(I) Complexes
It has been shown by DFT CAM-B3LYP/6-311++G(d,p) and CAM-B3LYP/6-311++G(d,p)/SDD calculations that the polydentate amidinyltetramethoxycarbonylcyclopentadienyl ligand and its Hg(II) and Tl(I) complexes are mos...
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Article
Luminescence Spectral Properties of 2-[2-Methyl(Acetyl, Tosyl)oxyphenyl]-5-(3,4,5-trimethoxy-phenyl)-1,3,4-oxadiazoles
Cyclodehydration of N′-aroylbenzohydrazides in thionyl chloride gave 2-(2-hydroxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1,3,4-oxadiazole and its 2-(2-methoxyphenyl) analog. Acetylation and tosylation of 2-(2-hydroxyp...
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Article
Structure elucidation of pentakis(methoxycarbonyl)- and amidinyltetrakis(methoxycarbonyl)cyclopentadienyl complexes of gold(I) by quantum chemistry methods
Density functional CAM-B3LYP/6-311++G(d,p)/SDD quantum chemical calculations of a gold(I) complex with the pentakis(methoxycarbonyl)cyclopentadienyl ligand Ph3PAu[C5(CO2Me)5] and gold(I) complexes with polydentat...
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Article
Optimal Head Loss Hydroelectric Power Plant Tower Receivers with Water Intake along the Entire Perimeter
Water receivers of all HPPs and PSPPs (pumped storage) that are optimal in regard to head loss are designed as equipment of these stations for turbine-mode operation. This article studies water receivers of hy...
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Article
Pentacarboxycyclopentadienes in Organic Synthesis
The review summarizes the literature data on the synthesis, structure, reactivity, and rearrangements of pentacarboxycyclopentadienes and their derivatives. Their potential for creating new chiral organic cata...
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Article
Design of the Supersonic Part of a Maximum Thrust Spatial Nozzle
The problem of obtaining the form of a spatial supersonic nozzle cross section that intersects the circular critical cross section of the nozzle and an output circuit inscribed in the given dimensions, which h...
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Article
Quantum chemical study of intramolecular rearrangements in 3-allyl-3-methyl-1,2-diphenylcyclopropene
3-Allyl-3-methyl-1,2-diphenylcyclopropene (1) and 3-allyl-2-methyl-1,3-diphenylcyclopropene (2) were shown by the DFT B3LYP/6-311++G(d,p) method to interconvert with the energy barriers ΔE≠ZPE(1→2) = 35.6 kcal mo...
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Article
Numerical Solution of the Vibration Suppression Problem for a Moving Web
Mechanical processes occurring in paper production are modeled. In a papermaking machine, paper moves in the form of a thin sheet. The characteristic thickness of a sheet varies from 0.1 mm (office paper) to 1...
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Article
2,5-Diaryl-1,3,4-oxadiazoles: synthesis, spectral-luminescent properties, and complexation with beryllium(ii)
Cyclization of aroylbenzohydrazides in SOCl2 was used to obtain 2,5-diaryl-1,3,4-oxadiazoles, and to study their spectral-luminescent properties. Oxadiazoles with phenyl or 2-methoxyphenyl substituents at positio...
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Article
Synthesis and Spectral-Luminescent Properties of 2-Aryl-5-butyl-1,3,4-oxadiazoles
2-Aryl-5-butyl-1,3,4-oxadiazoles have been obtained in 59–85% yield via refluxing of equimolar amounts of a benzoic acid hydrazide with trimethyl orthovalerate in o-xylene. The effects of electron-...
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Article
Circumambulatory Rearrangements of 5-Halo-1,2,3,4,5-pentaphenylcyclopentadienes
DFT quantum chemical calculations at the CAM-B3LYP/Def2TZVP level of theory showed that intramolecular migrations of halogens in 5-halo-1,2,3,4,5-pentaphenylcyclopentadienes (C5Ph5Hlg, Hlg = F, Cl, Br, I) involve...
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Article
Luminescence of Thin Films Based on 2,5-Diaryl-1,3,4-Oxadiazole and its Beryllium Chelate Complex
Chelate complexes BeL2 and ZnL2 with 2-[5-(2,4,6-trimethoxyphenyl)-1,3,4-oxadiazol-2-yl]phenol (HL) were synthesized. Their compositions were confirmed by thermogravimetric and IR spectroscopic analyses. Thin fil...
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Article
3,3-Sigmatropic Shifts of Allyl Group Along Cyclopentadiene Ring Perimeter
Reversible non-degenerate 3,3-sigmatropic shifts of the allyl group along the perimeter of the five-membered ring occurring with energy barriers ΔG°≠ = 28.5–30.2 kcal/mol (o-dichlorobenzene-d4) have been detected...
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Article
Synthesis and spectral luminescence properties of 2-aryl-5-methyl-1,3,4-oxadiazoles and zinc(ii) 2-(2-hydroxyphenyl)-5-methyl-1,3,4-oxadiazole complex
2-Aryl-5-methyl-1,3,4-oxadiazoles were synthesized by reflux of equimolar amounts of acyl hydrazides with triethyl orthoacetate in o-xylene. The obtained oxadiazoles, except for 2-(2-hydroxyphenyl)-5-methyl-1,3,4...
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Article
Reversible Rearrangements of 2,4,6-Trinitrophehyl Group in an Amidine System
Tautomeric 1,3-N, N′-migrations of 2,4,6-trinitrophenyl group in the derivatives of N, N′-diarylbenzamidine and N, N′-diarylformamidine have been studied by quantum-chemical simulations using the B3LYP/6-311++G(d...
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Article
Synthesis and Spectral-Luminescent Properties of 2,5-Diaryl-1,3,4-oxadiazoles and Their Chelate Complexes with Cadmium(II)
Cyclization of N′-(arylcarbonyl)benzohydrazides in SOCl2 has afforded 2-aryl-5-(4-octyloxyphenyl)-1H-1,3,4-oxadiazoles; the spectral-luminescent properties of the properties have been studied. The obtained cadmiu...
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Article
An Analytic Method of Calculating the Spirals of the Turbine Pits of Hydraulic Turbines Based on Different Laws of Variation of the Average Circumferential Velocity in Cross-Sections Along the Length of the Spiral
A new method of calculating the turbine spiral pits of hydraulic turbines with round cross-sections is proposed. The method generalizes techniques that are used today for determining the circular cross-section...
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Article
Luminescence Properties of 2-[2-Allyl(arenesulfonyl)oxyphenyl]- 5-(2,6-difluorophenyl)-1,3,4-oxadiazoles
The alkylation of 2-(2,6-difluorophenyl)-5-(2-hydroxyphenyl)-1,3,4-oxadiazole with allyl bromide gave 2-(2-allyloxyphenyl)-5-(2,6-difluorophenyl)-1,3,4-oxadiazole, and sulfonylation of the same substrate with ...
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Article
Spectral-Luminescent Properties of 2-(2,6-Difluorophenyl)-5-phenyl-[2-acetyl(benzoyl)oxyphenyl]-1,3,4-oxadiazoles
2-(2,6-Difluorophenyl)-5-phenyl(2-hydroxyphenyl)-1,3,4-oxadiazoles were synthesized by cyclization of N-(2,6-difluorobenzoil) derivatives of benzohydazide or salicylhydrazide in thionyl chloride. When acylating 2...