Locally dense basis sets for chemical shift calculations

1989 ◽  
Vol 10 (5) ◽  
pp. 648-659 ◽  
Author(s):  
D. B. Chesnut ◽  
K. D. Moore
Keyword(s):  
Chemical Shift ◽  
Basis Sets ◽  
Dense Basis ◽  
Chemical Shift Calculations

scholarly journals 1 H/ 13 C chemical shift calculations for biaryls: DFT approaches to geometry optimization

2021 ◽  
Vol 8 (9) ◽  
Author(s):  
Thien T. Nguyen
Keyword(s):  
Chemical Shift ◽  
Density Functional ◽  
Geometry Optimization ◽  
Optimization Methods ◽  
High Accuracy ◽  
Basis Set ◽  
Basis Sets ◽  
Functional Methods ◽  
Chemical Shift Calculations ◽  
Optimized Geometries

Twelve common density functional methods and seven basis sets for geometry optimization were evaluated on the accuracy of 1 H/ 13 C NMR chemical shift calculations for biaryls. For these functionals, 1 H shifts calculations for gas phase optimized geometries were significantly less accurate than those for in-solution optimized structures, while 13 C results were not strongly influenced by geometry optimization methods and solvent effects. B3LYP, B3PW91, mPW1PW91 and ω B97XD were the best-performing functionals with lowest errors; among seven basis sets, DGDZVP2 and 6-31G(d,p) outperformed the others. The combination of these functionals and basis sets resulted in high accuracy with CMAE min = 0.0327 ppm (0.76%) and 0.888 ppm (0.58%) for 1 H and 13 C, respectively. The selected functionals and basis set were validated when consistently producing optimized structures with high accuracy results for 1 H and 13 C chemical shift calculations of two other biaryls. This study highly recommends the IEFPCM/B3LYP, B3PW91, mPW1PW91 or ω B97XD/DGDZVP2 or 6-31G(d,p) level of theory for the geometry optimization step, especially the solvent incorporation, which would lead to high accuracy 1 H/ 13 C calculation. This work would assist in the fully structural assignments of biaryls and provide insights into in-solution biaryl conformations.

scholarly journals 1,3,5-Triaza-7-Phosphaadamantane (PTA) as a 31P NMR Probe for Organometallic Transition Metal Complexes in Solution

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1390 ◽  
Author(s):  
Ilya G. Shenderovich
Keyword(s):  
Chemical Shift ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.

Ab Initio NMR Chemical Shift Calculations Using Fragment Molecular Orbitals

2009 ◽  
Author(s):  
Satoshi Yokojima ◽  
Qi Gao ◽  
Shinichiro Nakamura ◽  
Dong-Qing Wei ◽  
Xi-Jun Wang
Keyword(s):  
Chemical Shift ◽  
Ab Initio ◽  
Molecular Orbitals ◽  
Nmr Chemical Shift ◽  
Chemical Shift Calculations

Organic Peracids: A Structural Puzzle for 17O NMR and Ab Initio Chemical Shift Calculations

2012 ◽  
Vol 116 (7) ◽  
pp. 1814-1819 ◽  
Author(s):  
Franca Castiglione ◽  
Alberto Baggioli ◽  
Attilio Citterio ◽  
Andrea Mele ◽  
Guido Raos
Keyword(s):  
Chemical Shift ◽  
Ab Initio ◽  
17O Nmr ◽  
Chemical Shift Calculations

scholarly journals An automated framework for NMR chemical shift calculations of small organic molecules

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Yasemin Yesiltepe ◽  
Jamie R. Nuñez ◽  
Sean M. Colby ◽  
Dennis G. Thomas ◽  
Mark I. Borkum ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Organic Molecules ◽  
Nmr Chemical Shift ◽  
Small Organic Molecules ◽  
Chemical Shift Calculations
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