scholarly journals Elucidating the germanium distribution in ITQ-13 zeolites by density functional theory

2021 ◽  
Author(s):  
Michael Fischer ◽  
Carlos Bornes ◽  
Luís Mafra ◽  
João Rocha
Keyword(s):  
Density Functional Theory ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Basal Plane ◽  
Density Functional ◽  
Dynamic Behaviour ◽  
Local Environment ◽  
19F Nmr ◽  
Functional Theory ◽  
Clear Identification

ITQ-13 is a medium-pore zeolite that can be prepared in all-silica form and as silicogermanate with Si/Ge ratios as low as 3. Usually synthesised in the presence of fluoride, ITQ-13 is among the very few systems containing fluoride anions in two distinct cage types, cube-like d4r units and [4·5^6] cages. Here, dispersion-corrected density functional theory (DFT) calculations are used to investigate the energetically most favourable Ge distributions for Si/Ge ratios between 55 and 6. The calculations show Ge atoms are incorporated at both the corners of d4r cages and at the basal plane of the [4·5^6] cages, in accordance with 19F-NMR spectroscopy. Two Ge atoms at adjacent corners of [4·5^6] cages are stable at the highest Ge content. Such a local environment has not yet been considered in the experimental literature. A calculation of the corresponding 19F-NMR resonance points to overlap with other resonances, which might preclude its clear identification. Additional calculations investigate the variation of the dynamic behaviour of the fluoride anions as a function of the local environment as well as the selective defluorination of the [4·5^6] cages.

scholarly journals NMR spectroscopy and ion pairing: Measuring and understanding how ions interact

2009 ◽  
Vol 81 (4) ◽  
pp. 615-633 ◽  
Author(s):  
Paul S. Pregosin
Keyword(s):  
Density Functional Theory ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Density Functional ◽  
Spin Echo ◽  
Ion Pairing ◽  
Functional Theory ◽  
Nmr Data ◽  
Insight Into ◽  
Qualitative Estimation

Pulsed gradient spin-echo (PGSE) diffusion and Overhauser NMR data together with density functional theory (DFT) calculations afford a qualitative estimation of the amount of ion pairing, as well as insight into the structures of a variety of inorganic, organic, and organometallic salts.

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.

Synthesis, characterization, crystal structure and density functional theory (DFT) calculations of dioxomolybdenum (VI) complexes of an ONS donor ligand derived from benzoylacetone and S-benzyl dithiocarbazate

Polyhedron ◽  
2013 ◽  
Vol 50 (1) ◽  
pp. 602-611 ◽  
Author(s):  
Manashi Chakraborty ◽  
Sathi Roychowdhury ◽  
Nikhil Ranjan Pramanik ◽  
Tapas Kumar Raychaudhuri ◽  
Tapan Kumar Mondal ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Functional Theory ◽  
Donor Ligand

The Pivotal Alkyne Group in the Mutual Size-Conversion of Au9 with Au10 Nanoclusters

2021 ◽  
Author(s):  
Xiaohang Wu ◽  
Ying Lv ◽  
Yuyuan Bai ◽  
Haizhu Yu ◽  
Manzhou Zhu
Keyword(s):  
Density Functional Theory ◽  
Theoretical Model ◽  
Dft Calculations ◽  
Density Functional ◽  
Single Atom ◽  
Functional Theory

Herein, density functional theory (DFT) calculations were performed to elucidate the mechanism of the reversible single atom size conversion between [Au10(DMPP)4(C6H11C≡C)]3+ and [Au9(DMPP)4]3+ (DMPP is 2,2’-bis-(dimethylphosphino)-1,1’-biphenyl, the simplified, theoretical model...

scholarly journals Experimental and Computational Studies on N-alkylation Reaction of N-Benzoyl 5-(Aminomethyl)Tetrazole

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 704-713
Author(s):  
Younas Aouine ◽  
Aaziz Jmiai ◽  
Anouar Alami ◽  
Abdallah El Asri ◽  
Souad El Issami ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Nmr Spectroscopy ◽  
Density Functional ◽  
Computational Study ◽  
Benzyl Bromide ◽  
13C Nmr Spectroscopy ◽  
Alkylation Reaction ◽  
Computational Studies ◽  
Functional Theory ◽  
1H And 13C Nmr

The N-alkylation reaction of N-benzoyl 5-(aminomethyl)tetrazole (5-AMT) with benzyl bromide was carried out in the presence of K2CO3 as a base. Two separable regioisomers were obtained, thus their purification led to determine the proportion of each of them, and their structures were attributed essentially based on 1H and 13C NMR spectroscopy in addition to the elemental analysis and MS data. In order to confirm the results obtained at the synthesis level, a computational study was carried out by application of density functional theory (DFT) using the Becke three-parameter hybrid exchange functional and the Lee-Yang-Parr correlation functional (B3LYP).

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