Synthesis and structures of three new pyridine-containing oxazoline ligands of complexes for asymmetric catalysis

2021 ◽  
Vol 77 (9) ◽  
pp. 529-536
Author(s):  
Ewa Wolińska ◽  
Waldemar Wysocki ◽  
Danuta Branowska ◽  
Zbigniew Karczmarzyk
Keyword(s):  
Asymmetric Catalysis ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Ligand Conformation ◽  
Oxazoline Ligands

Three new chiral pyridine-containing oxazoline derivatives with fluorine and perfluoromethyl groups, namely, 2-({2-[(4S)-4-phenyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C21H16F3N3O, 2-({5-fluoro-2-[(4S)-4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C18H17F4N3O, and 2-({2-[(3aR,8aS)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C22H16F3N3O, as chiral ligands in metal-catalysed asymmetric reactions, were synthesized and characterized by spectral and X-ray diffraction methods. The conformation of the molecules is influenced by strong N—H...N hydrogen bonding and weak C—H...X (X = O and N) interactions. There are no intermolecular hydrogen bonds in the crystal structures of the analysed compounds. Hirshfeld surface analysis showed that the H...H contacts constitute a high percentage of the intermolecular interactions. The conformational analysis was performed by theoretical calculations using the density functional theory (DFT) method. The mechanism of complex formation in terms of the electron-withdrawing effect of the substituents on the oxazoline ring and the ligand conformation is discussed.

scholarly journals Theoretical Calculations on the Mechanism of Enantioselective Copper(I)-Catalyzed Addition of Enynes to Ketones

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 359 ◽  
Author(s):  
Hanwei Li ◽  
Mingliang Luo ◽  
Guohong Tao ◽  
Song Qin
Keyword(s):  
Density Functional Theory ◽  
Steric Hindrance ◽  
Phenyl Ring ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
Catalytic Cycle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Chiral Systems

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.

Synthesis of [Re2Cl4(O)2(µ-O)(3,5-lut)4] and investigation of its structure via X-ray and spectroscopic measurements and DFT calculations

2014 ◽  
Vol 68 (5) ◽  
Author(s):  
Sławomir Michalik ◽  
Jan Małecki ◽  
Natalia Młynarczyk
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Computational Study ◽  
Dft Method ◽  
Time Dependent ◽  
Electronic Transitions ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
The Density Functional Theory

AbstractA combined experimental and computational study of the dinuclear rhenium(V) complex containing (ReO)2(µ-O) core is presented in this article. The solid-state [Re2Cl4(O)2(µ-O)(3,5-lut)4] (3,5-lut = 3,5-dimethylpyridine) complex was characterised structurally (by single crystal X-ray diffraction) and spectroscopically (by IR, NMR, UV-VIS). The electronic structure was examined using the density functional theory (DFT) method. The spin-allowed electronic transitions were calculated using the time-dependent DFT method, and the UV-VIS spectrum was discussed.

First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
Double Perovskites ◽  
Functional Theory ◽  
Oxygen Vacancy Formation ◽  
The Density Functional Theory ◽  
And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

scholarly journals Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Laura Cecilia Bichara ◽  
Hernán Enrique Lanús ◽  
Evelina Gloria Ferrer ◽  
Mónica Beatriz Gramajo ◽  
Silvia Antonia Brandán
Keyword(s):  
Citric Acid ◽  
Force Field ◽  
Density Functional ◽  
Solid Phase ◽  
Dft Method ◽  
Electronic Charge ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Atoms In Molecules Theory ◽  
Best Fit

We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT) method with the B3LYP/6-31G∗ and B3LYP/6-311++ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF) methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242  together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs) and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM) for the dimer were carried out to study the charge transference interactions of the compound.

scholarly journals Chloroquine drug and Graphene complex for treatment of COVID-19

2020 ◽  
Author(s):  
Saeedeh Mohammadi ◽  
Mohammad Esmailpour ◽  
Mina Mohammadi
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Dft Method ◽  
Complex State ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electrical Properties ◽  
Suitable Structure ◽  
Drug Complex

Abstract This paper is a new step in helping the treatment of coronavirus by improving the performance of chloroquine drug. For this purpose, we propose a complex of chloroquine drug with graphene nanoribbon (GNR) scheme. We compute the structural and electrical properties and absorption of chloroquine (C18H26ClN3) and GNR complex using the density functional theory (DFT) method. By creating a drug and GNR complex, the density of states of electrons increases and the energy gap decreases compared to the chloroquine. Also, using absorption calculations and spectrums such as infrared and UV-Vis spectra, we showed that GNR is a suitable structure for creating chloroquine drug complex. Our results show that the dipole moment, global softness and electrophilicity for the drug complex increases compared to the non-complex state. Our calculations can be useful for increasing performance and reducing the side effects of chloroquine, and thus can be effective in treating coronavirus.

scholarly journals Experimental and Density Functional Theory Characteristics of Ibrutinib, a Bruton’s Kinase Inhibitor Approved for Leukemia Treatment

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ali I. Ismail
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Kinase Inhibitor ◽  
Theoretical Calculations ◽  
Dft Method ◽  
Vibrational Frequencies ◽  
Basis Sets ◽  
Electronic Transitions ◽  
Functional Theory ◽  
Leukemia Treatment

Ibrutinib, a Bruton’s tyrosine kinase that plays an essential role in the B-cell development and cancer cells, has been recently approved to treat chronic, lymphocytic, and other types of leukemia. This study focused on investigating ibrutinib by its electronic transitions, vibrational frequencies, and electrospray mass spectra. The experimental peaks for electronic spectrum were found at 248.0 and 281.0 nm, whereas the νC = 0 stretching frequency was found at 1652.4 and 1639.19 cm−1. These experimental properties were compared with the corresponding theoretical calculations in which density functional theory was applied. The optimized structure was obtained with the calculations using a hybrid function (B3LYP) and high-level basis sets [6-311G++(d,p)]. Most of the calculated vibrational frequencies showed a relatively good agreement with the experimental ones. The electronic transitions of ibrutinib calculated using time-dependent DFT method were performed at two different solvation methods: PCM and SMD. The mass spectrum of ibrutinib, its fragments, and its isotopic pattern agreed well with the expected spectra.

scholarly journals Theoretical Investigation of Energetic Salts with Pentazolate Anion

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1783
Author(s):  
Hao-Ran Wang ◽  
Chong Zhang ◽  
Bing-Cheng Hu ◽  
Xue-Hai Ju
Keyword(s):  
Density Functional ◽  
Dft Method ◽  
Functional Theory ◽  
Calculated Density ◽  
The Density Functional Theory ◽  
Energetic Salts ◽  
Vertical Electron Affinity ◽  
The Difference ◽  
Nitrogen Contents ◽  
Experimental Density

Energetic salts based on pentazolate anion (cyclo-N5−) have attracted much attention due to their high nitrogen contents. However, it is an enormous challenge to efficiently screen out an appropriate cation that can match well with cyclo-N5−. The vertical electron affinity (VEA) of the cations and vertical ionization potential (VIP) of the anions for 135 energetic salts and some cyclo-N5− salts were calculated by the density functional theory (DFT). The magnitudes of VEA and VIP, and their matchability were analyzed. The results based on the calculations at the B3LYP/6-311++G(d,p) and B3LYP/aug-cc-pVTZ levels indicate that there is an excellent compatibility between cyclo-N5− and cation when the difference between the VEA of cation and the VIP of cyclo-N5− anion is −2.8 to −1.0 eV. The densities of the salts were predicted by the DFT method. Relationship between the calculated density and the experimental density was established as ρExpt = 1.111ρcal − 0.06067 with a correlation coefficient of 0.905. This regression equation could be in turn used to calibrate the calculated density of the cyclo-N5− energetic salts accurately. This work provides a favorable way to explore the energetic salts with excellent performance based on cyclo-N5−.

scholarly journals DFT Studies on the Antioxidant Activity of Naringenin and Its Derivatives: Effects of the Substituents at C3

2019 ◽  
Vol 20 (6) ◽  
pp. 1450 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu
Keyword(s):  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Resonance Effect ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Dft Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Selection Of

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.

scholarly journals Dopamine/2-Phenylethylamine Sensitivity of Ion-Selective Electrodes Based on Bifunctional-Symmetrical Boron Receptors

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 283 ◽  
Author(s):  
Martyna Durka ◽  
Krzysztof Durka ◽  
Agnieszka Adamczyk-Woźniak ◽  
Wojciech Wróblewski
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Phenylboronic Acid ◽  
Dft Method ◽  
Polymeric Membranes ◽  
Ion Selective Electrodes ◽  
Functional Theory ◽  
Potentiometric Selectivity ◽  
The Density Functional Theory ◽  
Sensitivity And Selectivity

Piperazine-based compounds bearing two phenylboronic acid or two benzoxaborole groups (PBPA and PBBB) were applied as dopamine receptors in polymeric membranes (PVC/DOS) of ion-selective electrodes. The potentiometric sensitivity and selectivity of the sensors towards dopamine were evaluated and compared with the results obtained for 2-phenylethylamine. Since the developed electrodes displayed strong interference from 2-phenylethylamine, single-molecule geometry optimizations were performed using the density functional theory (DFT) method in order to investigate the origin of dopamine/2-phenylethylamine selectivity. The results indicated that phenylboronic acid and benzoxaborole receptors bind dopamine mainly through the dative B–N bond (like 2-phenylethylamine) and the potentiometric selectivity is mainly governed by the higher lipophilicity of 2-phenylethylamine.

scholarly journals Stability of Ar(H2)2 to 358 GPa

2017 ◽  
Vol 114 (14) ◽  
pp. 3596-3600 ◽  
Author(s):  
Cheng Ji ◽  
Alexander F. Goncharov ◽  
Vivekanand Shukla ◽  
Naresh K. Jena ◽  
Dmitry Popov ◽  
...  
Keyword(s):  
Density Functional ◽  
Equations Of State ◽  
External Pressure ◽  
Ultrahigh Pressure ◽  
Optical Absorption Spectroscopy ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Impurity Atoms ◽  
The Density Functional Theory ◽  
Ordering Transition

“Chemical precompression” through introducing impurity atoms into hydrogen has been proposed as a method to facilitate metallization of hydrogen under external pressure. Here we selected Ar(H2)2, a hydrogen-rich compound with molecular hydrogen, to explore the effect of “doping” on the intermolecular interaction of H2 molecules and metallization at ultrahigh pressure. Ar(H2)2 was studied experimentally by synchrotron X-ray diffraction to 265 GPa, by Raman and optical absorption spectroscopy to 358 GPa, and theoretically using the density-functional theory. Our measurements of the optical bandgap and the vibron frequency show that Ar(H2)2 retains 2-eV bandgap and H2 molecular units up to 358 GPa. This is attributed to reduced intermolecular interactions between H2 molecules in Ar(H2)2 compared with that in solid H2. A splitting of the molecular vibron mode above 216 GPa suggests an orientational ordering transition, which is not accompanied by a change in lattice symmetry. The experimental and theoretical equations of state of Ar(H2)2 provide direct insight into the structure and bonding of this hydrogen-rich system, suggesting a negative chemical pressure on H2 molecules brought about by doping of Ar.

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