Volatile iridium(I) complexes with β-diketones and cyclooctadiene: syntheses,structures and thermal properties

A series of volatile mixed-ligand iridium(I) complexes [Ir(cod)(L)] (cod = cyclooctadiene-1,5, L = R¹C(O)CHC(O)R², R¹ = CF₃, R² = CF₃ – hfac 1, Me – tfac 2; ^tBu – ptac 3, Ph – btfac 4, R¹ = R² = Me – acac 5; ^tBu – thd 6) was synthesized and investigated in terms of usage in metal-organic chemical vapor deposition processes. Compounds 3 and 4 were obtained for the first time. All compounds were investigated by elemental analysis, NMR spectroscopy, thermogravimetry, and mass spectrometry. Crystal structures of 2–4 and 6 were determined by single-crystal XRD. The influence of β-diketonate ligand on the thermal properties of complexes in condensed and gas phase was revealed. The following volatility order was arranged: L = hfac 1 > tfac 2 ≈ ptac 3 > acac 5 > thd 6 > btfac 4. Complexes 1 and 6 vapors demonstrated the lowest and the highest thermostability, respectively.     

Effect of preparation conditions on the composition,structure, and properties of iron–molybdenum catalyst

X-ray phase analysis, synchronous thermal analysis, and IR spectroscopy were used to study the process in which an iron-molybdenum catalyst for partial oxidation of methanol to formaldehyde is prepared. The influence exerted by the pH of the medium on the composition, structure, and properties of the oxide Fe–Mo catalyst was examined. It was found that the amount of the active component in a sample obtained at pH 2 is the largest, and the sample exhibits the best activity in the reaction of methanol oxidation to formaldehyde. The possibility was examined of the occurrence of side reactions in which carbon monoxide is converted. It was found that the conversion occurs only on samples obtained at pH > 2.     

Emission of Nitrogen Molecules at Tight Focusing of Femtosecond Laser Pulses in Air

Russian Physics Journal - A numerical model describing the dynamics of plasma particle density upon filamentation of femtosecond emission in air is presented. The simulation results are in good...     

Computer simulation and study of radiation defects in graphene

Computer simulation has been used to study the properties of radiation defects in a graphene sheet. Several possible stable configurations of 3D radiation defects in graphene have been simulated. Several types of absorbed species were calculated involving a single carbon atom and a dumbbell absorbed at graphene sheet surface and a dumbbell configuration at a vacancy created by radiation knocking out a carbon atom. The calculations also included the effect of structural relaxation. The defect caused by the atom being displaced from the structure converted the sheet from metallic to semiconducting.     

Emission characteristics of hydrogen-oxygen flames

The emission spectra of hydrogen-oxygen flames are discussed. High temperature measurements of the radiative characteristics of the OH group in flames are described. The spectral absorption coefficients and the integral intensities of the hydroxyl bands are analyzed. A method for determining the nonequilibrium radiative cooling of hydrogen-oxygen flames using experimental data, their temperatures, and nonequilibrium coefficients is described and the results are examined.     

The Analytical Solutions of 2D Stationary Broadwell Kinetic Model

The present communication is devoted to the calculation of some explicit stationary solutions of the four-velocity Broadwell kinetic model in two spatial dimensions. The method of the truncated Painlevé expansion is employed and two classes of solutions are constructed. It is shown that these solutions satisfy the special boundary value problem in a rectangle.     

4,5-Dihydroxyimidazolidin-2-ones in α-ureidoalkylation of N-carboxy-, N-hydroxy-, and N-aminoalkylureas 2. α-Ureidoalkylation of N-(hydroxyalkyl)ureas

Russian Chemical Bulletin - The α-ureidoalkylation of N-(hydroxyalkyl)ureas (ureido alcohols) with 1,3-H2- and 1,3-Me2-4,5-dihydroxyimidazolidin-2-ones was systematically studied. The yields...     

Stationary solutions of the kinetic Broadwell model

We consider a stationary discrete model of the Boltzmann equation for four velocities (the Broadwell model). We obtain new exact automodel solutions of the model corresponding to an incompressible and a compressible gas. We show that one class of solutions satisfies the problem of gas evaporation and condensation on the boundary of a disk and external space. The system turns out to be strongly nonequilibrium, and continuous medium equations are not applicable to it.     

Liquid-phase parallel synthesis of combinatorial libraries of substituted 6-carbamoyl-3,4-dihydro-2H-benzo[1,4]thiazines

In this work, we explored several original combinatorial derivatization patterns for the 3,4-dihydro-2H-1,4-benzothiazine scaffold. The synthesis begins with commercially available 4-chloro- and 4-fluoro-3-nitrobenzoates and employs a sequence of moderate and high-yielding reactions that display a relatively high substituent tolerance. Simple manual techniques for parallel reactions were coupled with easy workup and purification procedures to give high-purity final products. The developed approach was easily adaptable for parallel synthesis of more than 2600 novel 2H-benzo[1,4]thiazine-6-carboxylic acid amides, which were efficiently prepared in a semiautomatic fashion using special CombiSyn synthesizers.