scholarly journals Metastable cubic and tetragonal phases of transition metals predicted by density-functional theory

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69680-69689 ◽  
Author(s):  
Stephan Schönecker ◽  
Xiaoqing Li ◽  
Klaus Koepernik ◽  
Börje Johansson ◽  
Levente Vitos ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Transition Metals ◽  
Dft Calculations ◽  
Crystal Structures ◽  
Density Functional ◽  
Functional Theory

DFT calculations for 24 transition metals predict eleven metastable allotropes in fcc or bct phase and support a relation between nonequilibrium crystal structures observable in nanostructures and corresponding metastable isostructural bulk phases.

scholarly journals Substituent Effects in 3,3’ Bipyrazole Derivatives. X-ray Crystal Structures, Molecular Properties and DFT Analysis

2021 ◽  
Vol 68 (3) ◽  
pp. 718-727
Author(s):  
Ibrahim Bouabdallah ◽  
Tarik Harit ◽  
Mahmoud Rahal ◽  
Fouad Malek ◽  
Monique Tillard ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Solid State ◽  
Dft Calculations ◽  
Single Crystal ◽  
Crystal Structures ◽  
Density Functional ◽  
Substituent Effects ◽  
Functional Theory ◽  
X Ray

The single crystal X-ray structure of new 1,1’-bis(2-nitrophenyl)-5,5’-diisopropyl-3,3’-bipyrazole, 1, is triclinic P I–, a = 7.7113(8), b = 12.3926(14), c = 12.9886(12) Å, α = 92.008(8), β = 102.251(8), γ = 99.655(9)°. The structural arrangement is compared to that of 5,5’-diisopropyl-3,3’-bipyrazole, 5, whose single crystal structure is found tetragonal I41/a, a = b = 11.684(1), c = 19.158(1) Å. The comparison is also extended to the structures previously determined for 1,1’-bis(2-nitrophenyl)-5,5’-propyl-3,3’-bipyrazole, 2, 1,1’-bis(4-nitrophenyl)-5,5’-diisopropyl-3,3’-bipyrazole, 3, and 1,1’-bis(benzyl)-5,5’-diisopropyl-3,3’-bipyrazole, 4. Density Functional Theory (DFT) calculations are used to investigate the molecular geometries and to determine the global reactivity parameters. The geometry of isolated molecules and the molecular arrangements in the solid state are analyzed according to the nature of the groups connected to the bipyrazole core.

Syntheses, crystal structures and density functional theory investigations of copper(ii) complexes bearing tridentate Schiff base ligands derived from 8-aminoquinoline

CrystEngComm ◽  
2015 ◽  
Vol 17 (30) ◽  
pp. 5664-5671 ◽  
Author(s):  
Prasanta Kumar Bhaumik ◽  
Antonio Bauzá ◽  
Michael G. B. Drew ◽  
Antonio Frontera ◽  
Shouvik Chattopadhyay
Keyword(s):  
Density Functional Theory ◽  
Schiff Base ◽  
Solid State ◽  
Dft Calculations ◽  
Crystal Structures ◽  
Density Functional ◽  
Schiff Base Complexes ◽  
Schiff Base Ligands ◽  
Functional Theory ◽  
Tridentate Schiff Base

Three copper(ii) Schiff base complexes have been synthesized and characterized. Supramolecular assemblies in the solid state are analyzed by DFT calculations.

Impact of Dopant-induced Ensemble Structure of Hetero Double Atom Catalysts in Electrochemical NH3 Production

2022 ◽  
Author(s):  
Seung-hoon Kim ◽  
Ho Chang Song ◽  
Sung Jong Yoo ◽  
Jonghee Han ◽  
Kwan-Young Lee ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Transition Metals ◽  
Dft Calculations ◽  
Density Functional ◽  
Functional Theory ◽  
Spin Polarized ◽  
Ensemble Structure

Using the spin-polarized density functional theory (DFT) calculations, we examined the electrochemical N2 reduction (N2RR) toward NH3 production on the hetero RuM (M = 3d transition metals) double atom catalysts...

scholarly journals Polarization properties and crystal structures of ferroelectric (Ba,Ca)TiO3 single crystals

2014 ◽  
Vol 04 (01) ◽  
pp. 1450003 ◽  
Author(s):  
Ryota Imura ◽  
Yuuki Kitanaka ◽  
Takeshi Oguchi ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Single Crystals ◽  
Crystal Structures ◽  
Spontaneous Polarization ◽  
Density Functional ◽  
Solution Growth ◽  
Functional Theory ◽  
Polarization Measurements ◽  
Top Seeded Solution Growth

We have investigated the spontaneous polarization (P s ) of Ba 1-x Ca x TiO 3 (BCT) by polarization hysteresis measurements using single crystals and by density functional theory (DFT) calculations. Single crystals of BCT (x = 0.07) were grown by a top-seeded solution growth (TSSG) method. The polarization measurements show that the crystals (x = 0.07) have a P s of 26.0 μC/cm2, which is slightly small compared with BaTiO 3 (27.3 μC/cm2). Our DFT calculations based on a supercell approach show that Ca atoms are markedly displaced cooperatively with the adjacent Ti atoms along the P s direction. It is suggested that the CaTiO 3-like octahedral rotation is constructed in the BCT supercell around the Ca atoms, which is the origin of the smaller P s observed for the BCT crystals.

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

Mechanistic understanding of the Cu(i)-catalyzed domino reaction constructing 1-aryl-1,2,3-triazole from electron-rich aryl bromide, alkyne, and sodium azide: a DFT study

2021 ◽  
Author(s):  
Hanlin Gan ◽  
Liang Peng ◽  
Feng Long Gu
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Sodium Azide ◽  
Density Functional ◽  
Dft Study ◽  
Domino Reaction ◽  
Aryl Bromide ◽  
Functional Theory ◽  
Mechanistic Understanding

The mechanism of the Cu(i)-catalyzed domino reaction furnishing 1-aryl-1,2,3-triazole assisted by CuI and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is explored with density functional theory (DFT) calculations.

scholarly journals Density functional theory (DFT) calculations of VI/V reduction potentials of uranyl coordination complexes in non-aqueous solutions

2019 ◽  
Vol 21 (6) ◽  
pp. 3227-3241 ◽  
Author(s):  
Krishnamoorthy Arumugam ◽  
Neil A. Burton
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Aqueous Solutions ◽  
Density Functional ◽  
Coordination Complexes ◽  
Dft Study ◽  
Redox Behavior ◽  
Functional Theory ◽  
Reduction Potentials ◽  
Uranium Complexes

Of particular interest within the +6 uranium complexes is the linear uranyl(vi) cation and it forms numerous coordination complexes in solution and exhibits incongruent redox behavior depending on coordinating ligands. This DFT study predicts VI/V reduction potentials of a range of uranyl(vi) complexes in non-aqueous solutions within ∼0.10−0.20 eV of experiment.

scholarly journals Iron(II) complexes of dimethyltriazacyclophane

2018 ◽  
Vol 74 (12) ◽  
pp. 1641-1649
Author(s):  
Wei-Tsung Lee ◽  
Matthias Zeller ◽  
David Upp ◽  
Yuliya Politanska ◽  
Doug Steinman ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Dft Calculations ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Coordination Mode ◽  
Functional Theory ◽  
Metal Centers ◽  
Bonding Interaction

Treatment of the ortho-triazacyclophane 1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-triene [(C6H5)3(NH)(NCH3)2, L1] with Fe[N(SiMe3)2]2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C20H18N3)4] or Fe2(L1)4 (9). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κN 7)bis(tetrahydrofuran-κO)iron(II), [Fe(C20H18N3)2(C4H8O)2] or (L1)2Fe(THF)2 (10). The reaction is reversible and 10 reverts in vacuo to diiron complex 9. In the structures of both 9 and 10, the monoanionic triazacyclophane ligand L1− is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ3-coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1− ligands are bound in either a η2-chelating fashion through the amide and one amine donor (for one of the four ligands of 9), or solely through their amide N atoms in an even simpler monodentate η1-coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long Fe...Fe distance of 2.912 (1) Å observed in the solid state.

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