scholarly journals Aromatic B3 Ring Stabilized Group 2 Dimer, B3-Y-Y-B3 (Y = Be, Mg, Ca)

2021 ◽  
Author(s):  
Ritam Borah ◽  
Amlan Kalita ◽  
Farnaz Yashmin ◽  
Kangkan Sarma ◽  
Rinu Deka ◽  
...  
Keyword(s):  
Complex Formation ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Thermodynamic Consideration ◽  
Type Complex ◽  
Sandwich Type ◽  
Group 2

Quantum chemical calculations have been performed on B3 ring stabilized Y-Y interaction (Y = Be, Mg, Ca) to understand the possibility of binuclear sandwich type complex formation. Calculations indicate single reference character of the studied systems. The complexes have been found to be stable towards dissociation into different fragments. Thermodynamic consideration also indicates the favourability of their formation. Increase in aromaticity of the parent B3 ring upon complexation is observed which is expected to provide extra stability to the complexes.

scholarly journals Americium(iii) and europium(iii) complex formation with lactate at elevated temperatures studied by spectroscopy and quantum chemical calculations

2014 ◽  
Vol 43 (29) ◽  
pp. 11221-11232 ◽  
Author(s):  
Astrid Barkleit ◽  
Jerome Kretzschmar ◽  
Satoru Tsushima ◽  
Margret Acker
Keyword(s):  
Complex Formation ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Elevated Temperatures ◽  
Hydroxyl Group ◽  
Spectroscopic Techniques ◽  
Ft Ir

Spectroscopic techniques (NMR and ATR FT-IR) in combination with calculations (DFT) show that the hydroxyl group of the lactate is deprotonated under complex formation with Eu(iii).

Host - Guest Complexes of Bicyclic Hexaamine Cryptands - Prediction of Ion Selectivity by Quantum Chemical Calculations. III

2007 ◽  
Vol 60 (12) ◽  
pp. 889 ◽  
Author(s):  
Ralph Puchta ◽  
Roland Meier ◽  
Rudi van Eldik
Keyword(s):  
Density Functional Theory ◽  
Complex Formation ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Alkaline Earth ◽  
Ion Selectivity ◽  
Cavity Size ◽  
Functional Theory ◽  
Formation Energies

Density functional theory (B3LYP/LANL2DZp) calculations on the structures and complex formation energies were performed to predict the alkali and alkaline earth ion selectivity of the cryptands 1,4,7,10,13,16,21,24-octaazabicyclo(8.8.8)hexacosane (N2N2N2) 1, 3,6,10,13,16,19-hexaazabicyclo(6.6.6)icosane (sarcophagine) 2 and 1,3,6,8,10,13,16,19-octaazabicyclo(6.6.6)icosane (sepulchrate) 3. Compounds 2 and 3 favour binding of Li+ and Mg2+ and exhibit a cavity size similar to [2.1.1], whereas cryptand 1 has a cavity size similar to [2.2.2] and prefers the selective binding of K+ and Ba2+. The cryptand flexibility of 1 is attributed mainly to the groups adjacent to the bridgehead nitrogens, whereas the main guiding feature for the flexibility of 2 and 3 can be traced back to the coordination of the ethylenediamine spacer.

Infrared Spectra and Quantum Chemical Calculations of Group 2 MO2, O2MO2, and Related Molecules

1996 ◽  
Vol 100 (24) ◽  
pp. 10088-10099 ◽  
Author(s):  
Lester Andrews ◽  
George V. Chertihin ◽  
Craig A. Thompson ◽  
Janet Dillon ◽  
Susan Byrne ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Infrared Spectra ◽  
Quantum Chemical ◽  
Group 2

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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