Response to ‘‘Comment on ‘Density functional calculation of nuclear chemical shifts’ ’’ [J. Chem. Phys. 104, 1163 (1996)]

1996 ◽  
Vol 104 (3) ◽  
pp. 1165-1165 ◽  
Author(s):  
Christoph van Wüllen
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Chem Phys ◽  
Density Functional Calculation

scholarly journals Correction: Fragment density functional theory calculation of NMR chemical shifts for proteins with implicit solvation

2015 ◽  
Vol 17 (18) ◽  
pp. 12367-12367
Author(s):  
Tong Zhu ◽  
Xiao He ◽  
John Z. H. Zhang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Shifts ◽  
Density Functional Theory Calculation ◽  
Chem Phys ◽  
Implicit Solvation ◽  
Functional Theory ◽  
Nmr Chemical Shifts ◽  
Theory Calculation ◽  
Phys Chem Chem Phys

Correction for ‘Fragment density functional theory calculation of NMR chemical shifts for proteins with implicit solvation’ by Tong Zhu et al., Phys. Chem. Chem. Phys., 2012, 14, 7837–7845.

Density-Functional Calculation of the183W and17O NMR Chemical Shifts for Large Polyoxotungstates

ChemInform ◽  
2006 ◽  
Vol 37 (20) ◽  
Author(s):  
Jose Gracia ◽  
Josep M. Poblet ◽  
Jochen Autschbach ◽  
Leonid P. Kazansky
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Density Functional Calculation ◽  
Nmr Chemical Shifts

scholarly journals Ellipticity, PDI and FLU, Evaluation of Aromaticity Indexes During Substituting B &N Atoms in Poly-Annulene

2020 ◽  
Vol 11 (1) ◽  
pp. 8298-8317
Keyword(s):  
Density Functional ◽  
Ring Current ◽  
Chemical Shifts ◽  
Density Functional Calculation ◽  
Close Relationship ◽  
Whole Space ◽  
Homo And Lumo ◽  
Localized Orbital ◽  
Derivatives Of ◽  
Homo Lumo

A close relationship between chemical shift and magnetic criteria for aromaticity arouses a deeper view for probing and modeling of induced current density in π systems through external magnetic fields. The (4n+2)π systems aromatic are studied on variants of Azabora Derivatives of [8] Annulene (BnNnC(8-2n)H8) via the localized orbital localization (LOL) and electron localized function (ELF) by considering the density functional calculation. By this work, it has been predicted a four-electron dia-tropic (aromatic) ring current for (4n+2) π variants of Bn NnC(8-2n) H8 and a two-electron para-tropic (anti-aromatic) current for (4n) π. With the HOMO and LUMO energies and also HOMO/LUMO overlapping in whole space, it is possible to predict the transition states from delocalized to-localized currents in all variant mentioned compounds in the viewpoint of aromaticity and anti-aromaticity. In addition, the nucleus independent chemical shifts (NICS), HOMA, Ellipticity, Aromatic Fluctuation index (FLU), and para delocalization index (PDI) values confirm the amounts of aromaticity and anti-aromaticity in those rings.

Density-Functional Calculation of the183W and17O NMR Chemical Shifts for Large Polyoxotungstates

2006 ◽  
Vol 2006 (6) ◽  
pp. 1139-1148 ◽  
Author(s):  
Jose Gracia ◽  
Josep M. Poblet ◽  
Jochen Autschbach ◽  
Leonid P. Kazansky
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Density Functional Calculation ◽  
Nmr Chemical Shifts

Computational Investigation of the Asymmetry in Photosynthetic Reaction Center Models from First Principles

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer
Keyword(s):  
Spin Density ◽  
Reaction Center ◽  
Density Functional ◽  
Photosynthetic Reaction Center ◽  
Chem Phys ◽  
Molecular Structures ◽  
Error Characteristic ◽  
Molecular Systems ◽  
Density Distributions ◽  
The Asymmetry

We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from <i>Synechococcus elongatus</i>, <i>Thermococcus vulcanus</i>, and <i>Rhodobacter sphaeroides</i>, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.

`Diet GMKTN55' Offers Accelerated Benchmarking Through a Representative Subset Approach

2018 ◽  
Author(s):  
Tim Gould
Keyword(s):  
Density Functional ◽  
Chem Phys ◽  
Comprehensive Analysis ◽  
Genetic Approach ◽  
Representative Subset ◽  
Phys Chem Chem Phys

The GMTKN55 benchmarking protocol introduced by [Goerigk et al., Phys. Chem. Chem. Phys., 2017, 19, 32184] allows comprehensive analysis and ranking of density functional approximations with diverse chemical behaviours. But this comprehensiveness comes at a cost: GMTKN55's 1500 benchmarking values require energies for around 2500 systems to be calculated, making it a costly exercise. This manuscript introduces three subsets of GMTKN55, consisting of 30, 100 and 150 systems, as `diet' substitutes for the full database. The subsets are chosen via a stochastic genetic approach, and consequently can reproduce key results of the full GMTKN55 database, including ranking of approximations.

Synthesis, Conformational Analysis and Crystal Structure of New Thioxo, Oxo, Seleno Diastereomeric Cyclophosphamides Containing 1,3,2-dioxaphosphorinane

2019 ◽  
Vol 23 (2) ◽  
pp. 205-213
Author(s):  
Dorra Kanzari-Mnallah ◽  
Med L. Efrit ◽  
Jiří Pavlíček ◽  
Frédéric Vellieux ◽  
Habib Boughzala ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Density Functional ◽  
Chemical Shifts ◽  
Structural Determination ◽  
Conformational Study ◽  
Functional Theory ◽  
One Step ◽  
High Resolution Mass Spectroscopy ◽  
Resolution Mass

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.

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