scholarly journals Свойства оптических керамик КО1 и КО2 при модификации их поверхности углеродными нанотрубками

2019 ◽  
Vol 45 (15) ◽  
pp. 37
Author(s):  
Н.В. Каманина ◽  
С.В. Лихоманова ◽  
Ю.Р. Загидуллина
Keyword(s):  
Carbon Nanotubes ◽  
Refractive Index ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Inorganic Materials ◽  
Deposition Technique ◽  
Optical Ceramic ◽  
Essential Change ◽  
Basic Parameters ◽  
Branched Surface

The research results of the modification of the properties of the optical inorganic materials, such as: optical ceramic КО1(MgF2) and КО2(ZnS) have been presented. Essential change of the basic parameters of these inorganic matrixes, which surface has been modified with the carbon nanotubes under the application of the laser oriented deposition technique, has been established. The main features of the carbon nanotubes have been taken into account, which have been connected with their branched surface, large hardness of the C-C bonds and small value of the refractive index. Analytical and quantum-chemical calculations as well as the experimental results have been presented, which have been connected with the change of the spectral, mechanical and wetting characteristics of the chosen inorganic matrixes.

scholarly journals CARBON STRUCTURES AS EFFECTIVE MODIFIERS OF THE MATERIALS’ BASIC PROPERTIES

2017 ◽  
Vol 5 ◽  
pp. 1135-1142
Author(s):  
Natalia Kamanina
Keyword(s):  
Carbon Nanotubes ◽  
Quantum Dots ◽  
Refractive Index ◽  
Optical Properties ◽  
Second Harmonic ◽  
Inorganic Materials ◽  
Mechanical Parameters ◽  
Ir Laser ◽  
Carbon Structures ◽  
Spatial Frequencies

Because of the unique energetic, refractive and photoconductive characteristics of effective nano-objects, especially carbon nanotubes, the modification of optical properties of the organic and inorganic materials can be considered as the preferable one via the use of the nanostructuration process. Emphasis has been given to the incorporation of nanoobjects directly in the materials’ body and on their surface. Under the conditions of a surface treatment of the inorganic structures, an IR-laser at the wavelength of 10.6 micrometers was used to orientate carbon nanotubes deposited in the electric field of 100-600 V×cm-1. Dramatic spectral and mechanical parameters changes have been found. Refractive features of the nanostructured organics have been studied via applying the second harmonic of the pulsed Nd-laser at different spatial frequencies and under the nanoparticles sensitization doping such as fullerenes, carbon nanotubes, shungites, quantum dots, and graphenes. A drastically obtained laser-induced refractive index has been established. A prediction has been proposed to extend the area of the application of the systems considered.

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

The Nature of Chemisorbed CO2 in Zeolite A

2019 ◽  
Author(s):  
Przemyslaw Rzepka ◽  
Zoltán Bacsik ◽  
Andrew J. Pell ◽  
Niklas Hedin ◽  
Aleksander Jaworski
Keyword(s):  
Solid State ◽  
Ir Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Surface Coverage ◽  
Gas Mixtures ◽  
Mas Nmr ◽  
Significant Fraction ◽  
Zeolite A

Formation of CO<sub>3</sub><sup>2-</sup> and HCO<sub>3</sub><sup>-</sup> species without participation of the framework oxygen atoms upon chemisorption of CO<sub>2</sub> in zeolite |Na<sub>12</sub>|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H<sub>2</sub>O or acid groups. A combined study by solid-state <sup>13</sup>C MAS NMR, quantum chemical calculations, and <i>in situ</i> IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO<sub>3</sub><sup>-</sup>. However, at a low surface coverage of physisorbed and acidic CO<sub>2</sub>, a significant fraction of the HCO<sub>3</sub><sup>-</sup> was deprotonated and transformed into CO<sub>3</sub><sup>2-</sup>. We expect that similar chemisorption of CO<sub>2</sub> would occur for low-silica zeolites and other basic silicates of interest for the capture of CO<sub>2</sub> from gas mixtures.

Mechanistic Investigation of Rh(I)-Catalyzed Asymmetric Suzuki-Miyaura Coupling with Racemic Allyl Halides

2019 ◽  
Author(s):  
Lucy van Dijk ◽  
Ruchuta Ardkhean ◽  
Mireia Sidera ◽  
Sedef Karabiyikoglu ◽  
Özlem Sari ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Experimental Studies ◽  
Mechanistic Investigation ◽  
Allyl Halides

A mechanism for Rh(I)-catalyzed asymmetric Suzuki-Miyaura coupling with racemic allyl halides is proposed based on a combination of experimental studies and quantum chemical calculations. <br>

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