Mechanism and reactivity in the Morita–Baylis–Hillman reaction: the challenge of accurate computations

2017 ◽  
Vol 19 (45) ◽  
pp. 30647-30657 ◽  
Author(s):  
Zhen Liu ◽  
Chandan Patel ◽  
Jeremy N. Harvey ◽  
Raghavan B. Sunoj

A systematic density functional theory exploration of various reactive steps together with benchmark coupled cluster results are used to propose an accurate model of the mechanism of the Morita–Baylis–Hillman (MBH) reaction in organic chemistry.

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].


2020 ◽  
Author(s):  
Justin S. Smith ◽  
Roman Zubatyuk ◽  
Benjamin T. Nebgen ◽  
Nicholas Lubbers ◽  
Kipton Barros ◽  
...  

<p>Maximum diversification of data is a central theme in building generalized and accurate machine learning (ML) models. In chemistry, ML has been used to develop models for predicting molecular properties, for example quantum mechanics (QM) calculated potential energy surfaces and atomic charge models. The ANI-1x and ANI-1ccx ML-based eneral-purpose potentials for organic molecules were developed through active learning; an automated data diversification process. Here, we describe the ANI-1x and ANI-1ccx data sets. To demonstrate data set diversity, we visualize them with a dimensionality reduction scheme, and contrast against existing data sets. The ANI-1x data set contains multiple QM properties from 5M density functional theory calculations, while the ANI-1ccx data set contains 500k data points obtained with an accurate CCSD(T)/CBS extrapolation. Approximately 14 million CPU core-hours were expended to generate this data. Multiple QM properties from density functional theory and coupled cluster are provided: energies, atomic forces, multipole moments, atomic charges, and more. We provide this data to the community to aid research and development of ML models for chemistry.</p>


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Justin S. Smith ◽  
Roman Zubatyuk ◽  
Benjamin Nebgen ◽  
Nicholas Lubbers ◽  
Kipton Barros ◽  
...  

2014 ◽  
Vol 16 (15) ◽  
pp. 6931-6941 ◽  
Author(s):  
Vasily A. Ovchinnikov ◽  
Dage Sundholm

The 0–0 transitions of the electronic excitation spectra of the lowest tautomers of the four nucleotide (DNA) bases have been studied using linear-response approximate coupled-cluster singles and doubles (CC2) calculations.


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