THE INVESTIGATION ON ELECTRONIC PROPERTIES AND STABILITY OF POLYOXOMETALATES FUNCTIONALIZED BY ORGANOMETALLIC TITANIUM [CpTi · SiW9V3O40]4- BY DENSITY FUNCTIONAL THEORY

2009 ◽  
Vol 08 (04) ◽  
pp. 773-781 ◽  
Author(s):  
YANLING SI ◽  
WEILIN CHEN ◽  
ZHIMING ZHANG ◽  
ENBO WANG
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Molecular Orbitals ◽  
Frontier Molecular Orbitals ◽  
Functional Theory ◽  
Fragment Analysis ◽  
Keggin Type ◽  
System A ◽  
The Stability ◽  
Oxygen Atoms

The electronic structures of [ CpTi · SiW 9 V 3 O 40]4- constructed from Keggin–type polyoxometalates functionalized by CpTi 3+ group have been investigated by Density Functional Theory (DFT) methods. We discuss the relative stability affected by incorporating the CpTi 3+ group into the different sites of the [ SiW 9 V 3 O 40]7- framework on the basis of geometrical parameters, total bonding energies, fragment analysis and frontier molecular orbitals analysis. The calculated results indicated that the structure of the CpTi 3+ group coordinating to one terminal oxygen and two bridging oxygen atoms of the Keggin–type polyoxoanion (system a) is more stable than that to three bridging oxygen atoms (system b). In system a, Ti -Ob1, Ti -Ob2 and Ti - Ot1 are relatively shorter, and as result, it exhibits a more compact and nearly spherical structure of the well-known Keggin–type [ SiW 9 V 3 O 40]7-. Fragment analysis elucidates that there is deviation of ΔE B in systems a and b, which makes a significant contribution to the stability of system a. The stability of different isomeric forms of polyoxoanions appears to be a balance between the stabilizing ΔE O and ΔE E terms and the destabilizing ΔE P term. The relatively small energy differences (ΔE B = 4.26 eV ) between systems a and b arise directly from this balance. Frontier molecular orbitals analysis further confirms the stability order of systems a > b by the difference of the HOMO-LUMO energy gap.

Molecular Structures, Rotational Barriers, and Density Functional Theory Studies on 3,5-Diamino-6-(2,3-Dichlorophenyl)-1,2,4-Triazine

2019 ◽  
Vol 892 ◽  
pp. 185-192
Author(s):  
Pek Lan Toh ◽  
Suh Miin Wang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Molecular Orbitals ◽  
Geometrical Parameters ◽  
Atomic Charges ◽  
Frontier Molecular Orbitals ◽  
Dft Methods ◽  
Functional Theory ◽  
Rotational Barriers ◽  
Total Energies

In this report, different hybrid Density Functional Theory (DFT) methods were utilized to determine the geometries, total energies, Frontier molecular orbitals, atomic charges, and rotational barriers of 3,5-Diamino-6-(2,3-Dichlorophenyl)-1,2,4-Triazine, C9H7Cl2N5 molecular system. All optimized geometrical parameters (i.e. bond lengths, bond angles, and dihedral angles) were then compared with the experimental data, which reported by Sridhar and Ravikumar in 2009 [5]. Also, the results of electronic structures (i.e. total energies, Frontier molecular orbitals, atomic charges, and others) obtained by different DFT methods were compared and discussed.

scholarly journals The stability and electronic and photocatalytic properties of the ZnWO4 (010) surface determined from first-principles and thermodynamic calculations

RSC Advances ◽  
2021 ◽  
Vol 11 (38) ◽  
pp. 23477-23490
Author(s):  
Yonggang Wu ◽  
Jihua Zhang ◽  
Bingwei Long ◽  
Hong Zhang
Keyword(s):  
Phase Diagram ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Thermodynamic Calculations ◽  
Photocatalytic Properties ◽  
Thermodynamic Approach ◽  
Functional Theory ◽  
Stability Phase Diagram ◽  
The Stability

The ZnWO4 (010) surface termination stability is studied using a density functional theory-based thermodynamic approach. The stability phase diagram shows that O-Zn, DL-W, and DL-Zn terminations of ZnWO4 (010) can be stabilized.

Predicting the stability of ternary intermetallics with density functional theory and machine learning

2018 ◽  
Vol 148 (24) ◽  
pp. 241728 ◽  
Author(s):  
Jonathan Schmidt ◽  
Liming Chen ◽  
Silvana Botti ◽  
Miguel A. L. Marques
Keyword(s):  
Machine Learning ◽  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
The Stability

Computational analyses of Fe-Chelation by thiofavipiravir

2021 ◽  
pp. 1-9
Author(s):  
Halimeh Rajabzadeh ◽  
Maryam Abbasi ◽  
Mostafa Tohoidian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Living Systems ◽  
Functional Theory ◽  
Challenging Issue ◽  
The Density Functional Theory ◽  
Novel Coronavirus ◽  
Computational Analyses ◽  
Oxygen Atoms

Existence of iron (Fe) is important for cells of living systems; however, its level of magnitude for those patients infected by novel coronavirus disease (COVID-19) is still a challenging issue. Therefore, such mechanism of function was investigated in this work by assistance of thiofavipiravir (TFav) compounds generated by the well-known favipiravir (Fav) drug used for medication of COVID-19 patents. To this aim, sulfur-substitutions of oxygen atoms of Fav were done and the obtained parent structures were prepared for participating in Fe-chelation function. The results indicated that the modes were suitable for running such Fe-chelation processes, in which favorability and strength the models were ranged in this order: 1O2S-Fe >  1S2S-Fe >  1O2O-Fe >  1S2O-Fe. As a consequence, such idea of sulfur-substitution of Fav drug for more appropriate favorability of participating in Fe-chelation process was sensed by results of this work proposing 1O2S compound as the most favorable one for doing the function. Hence, information about capability of TFav compounds for participating in Fe-chelation processes were provided in this work regarding the challenging issue of Fe-chelation in medication of COVID-19 patients. All results of this work were obtained by performing computations using the density functional theory (DFT) approach

Targeting complex plutonium oxides by combining crystal chemical reasoning with density-functional theory calculations: the quaternary plutonium oxide Cs2PuSi6O15

2020 ◽  
Vol 56 (66) ◽  
pp. 9501-9504
Author(s):  
Kristen A. Pace ◽  
Vladislav V. Klepov ◽  
Matthew S. Christian ◽  
Gregory Morrison ◽  
Travis K. Deason ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Crystal Growth ◽  
Dft Calculations ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Crystal Chemical ◽  
The Novel ◽  
Functional Theory ◽  
The Stability ◽  
Chemical Reasoning

The stability of the novel Pu(iv) silicate, Cs2PuSi6O15, was predicted from a combination of crystal chemical reasoning and DFT calculations and confirmed by its synthesis via flux crystal growth.

Density Functional Theory Study on the Absorption of CO2 by the Ionic Liquid of 1-butyl-3-methylimidazolium Acetate

2013 ◽  
Vol 807-809 ◽  
pp. 543-548 ◽  
Author(s):  
Yan Fei Chen ◽  
Yan Hong Cui ◽  
Dong Shun Deng ◽  
Ning Ai
Keyword(s):  
Density Functional Theory ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Density Functional ◽  
Ion Pairs ◽  
Ion Pair ◽  
Frontier Molecular Orbitals ◽  
Density Functional Theory Study ◽  
Electronic Density ◽  
Functional Theory

The absorptions of CO2on the 1-butyl-3-methylimidazolium acetate ([Bmi [Ac]) with different substituents are calculated systematically at GGA/PW91 level. Three hydrogen bonds are formed between [A and cations of 1-n-[Bmi [A ([NBmi+) and 1-tert-[Bmi [A ([TBmi+). The interaction between CO2and the [NBmi [A by a C-O bond is much weaker than that with the [TBmi [A by forming a O...O...C...C four member-ring. The chemisorption of CO2on the ion pairs of [NBmi [A is much weaker than that on the [TBmi [A, resulted from the absorption energies analysis. The frontier molecular orbitals shows the electronic density overlap between absorbed CO2and the [A in CO2-[NBmi [A is much weaker than that in [TBmi [A. Therefore, the chemisorption of CO2on the ion pair of [NBmi [A is much weaker than that on the [TBmi [A. The ionic liquids based [NBmi+can be used repetitively, and the adsorbed CO2would be easier desorbed.

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