scholarly journals The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

2018 ◽  
Vol 14 ◽  
pp. 1642-1654 ◽  
Author(s):  
Dominic Bernhard ◽  
Fabian Dietrich ◽  
Mariyam Fatima ◽  
Cristóbal Pérez ◽  
Hannes C Gottschalk ◽  
...  
Keyword(s):  
Vinyl Ether ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Cluster Method ◽  
Correct Prediction ◽  
Electronically Excited ◽  
Ether Oxygen ◽  
London Dispersion ◽  
Phenyl Vinyl

The structure of the isolated aggregate of phenyl vinyl ether and methanol is studied by combining a multi-spectroscopic approach and quantum-chemical calculations in order to investigate the delicate interplay of noncovalent interactions. The complementary results of vibrational and rotational spectroscopy applied in molecular beam experiments reveal the preference of a hydrogen bond of the methanol towards the ether oxygen (OH∙∙∙O) over the π-docking motifs via the phenyl and vinyl moieties, with an additional less populated OH∙∙∙P(phenyl)-bound isomer detected only by microwave spectroscopy. The correct prediction of the energetic order of the isomers using quantum-chemical calculations turns out to be challenging and succeeds with a sophisticated local coupled cluster method. The latter also yields a quantification as well as a visualization of London dispersion, which prove to be valuable tools for understanding the role of dispersion on the docking preferences. Beyond the structural analysis of the electronic ground state (S0), the electronically excited (S1) state is analyzed, in which a destabilization of the OH∙∙∙O structure compared to the S0 state is observed experimentally and theoretically.

Electronically excited states of membrane fluorescent probe 4-dimethylaminochalcone. Results of quantum chemical calculations

2011 ◽  
Vol 13 (20) ◽  
pp. 9518 ◽  
Author(s):  
Alexey N. Romanov ◽  
Samvel K. Gularyan ◽  
Boris M. Polyak ◽  
Ruslan A. Sakovich ◽  
Gennady. E. Dobretsov ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Quantum Chemical Calculations ◽  
Excited States ◽  
Quantum Chemical ◽  
Electronically Excited States ◽  
Electronically Excited

scholarly journals Direct alkenylation of indolin-2-ones by 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles: a novel approach

2013 ◽  
Vol 9 ◽  
pp. 809-817 ◽  
Author(s):  
Sandeep Kumar ◽  
Ramendra Pratap ◽  
Abhinav Kumar ◽  
Brijesh Kumar ◽  
Vishnu K Tandon ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Relative Stability ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Reaction Conditions ◽  
One Pot ◽  
Supramolecular Architectures ◽  
Novel Approach

A direct one-pot base-induced alkenylation of indolin-2-ones has been developed by using 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles. Different bases such as MeONa, NaH and t-BuONa have been used to optimize the reaction conditions to obtain the desired product. NaH in THF was found to be the most suitable for the alkenylation of indolin-2-ones. Reaction in the presence of other bases led to the formation of 1-aryl-3-methoxy/methylthio-5H-dibenzo[d,f][1,3]diazepin-6(7H)-ones. Quantum chemical calculations have been performed to explain the nature of the weak noncovalent interactions operating in the supramolecular architectures of alkenylated indoline-2-ones and to explain the relative stability of one of the tautomers with respect to the others.

scholarly journals A Robust Supramolecular Heterosynthon Assembled by a Hydrogen Bond and a Chalcogen Bond

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1309
Author(s):  
Shaobin Miao ◽  
Yunfan Zhang ◽  
Linjie Shan ◽  
Mingyuan Xu ◽  
Jian-Ge Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Isophthalic Acid ◽  
Stacking Interactions ◽  
Chalcogen Bond ◽  
Good Agreement

The 1:1 and 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole have been successfully synthesized and resolved; the noncovalent interactions in the crystal structures have been studied in detail by quantum chemical calculations. In both of the crystal structures, isophthalic acid and 2,1,3-benzoselenadiazole are bound together by a cyclic supramolecular heterosynthon assembled by an O–H···N hydrogen bond and a N–Se···O chalcogen bond. The crystal structures of the 1:1 and 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole and the crystal structure of pure isophthalic acid are very similar, which indicates that the [COOH]···[Se−N] cyclic heterosynthon can be an effective alternative to the strong [COOH]2 cyclic homosynthon. The quantum theory of atoms in molecules further recognizes the existence of the hydrogen bond and chalcogen bond. The results of quantum chemical calculations show that the strengths of the π···π stacking interactions in the 1:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole are almost the same as those in the 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole, and the strengths of the [COOH]···[Se−N] cyclic heterosynthons (about 9.00 kcal/mol) are less than the strengths of the much stronger [COOH]2 cyclic homosynthons (14.00 kcal/mol). These calculated results are in good agreement with those experimentally observed, demonstrating that, although not as strong as the [COOH]2 cyclic homosynthon, the [COOH]···[Se−N] cyclic heterosynthon can also play a key role in the crystal growth and design.

scholarly journals Charge transfer and ultrafast nuclear motions: the complex structural dynamics of an electronically excited triamine

2016 ◽  
Vol 7 (1) ◽  
pp. 619-627 ◽  
Author(s):  
Xinxin Cheng ◽  
Yan Gao ◽  
Fedor Rudakov ◽  
Peter M. Weber
Keyword(s):  
Charge Transfer ◽  
Real Time ◽  
Quantum Chemical Calculations ◽  
Structural Dynamics ◽  
Quantum Chemical ◽  
Time Resolved ◽  
Electronically Excited ◽  
Rydberg Fingerprint Spectroscopy ◽  
Complex Structural

Time-resolved Rydberg fingerprint spectroscopy combined with quantum chemical calculations reveals the complex structural dynamics and charge transfer in real time.

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>

Sign in / Sign up

Export Citation Format

Share Document