Accurate prediction of proton chemical shifts. I. Substituted aromatic hydrocarbons

2001 ◽  
Vol 22 (16) ◽  
pp. 1887-1895 ◽  
Author(s):  
Bing Wang ◽  
Ulrich Fleischer ◽  
James F. Hinton ◽  
Peter Pulay
2002 ◽  
Vol 23 (4) ◽  
pp. 492-497 ◽  
Author(s):  
Bing Wang ◽  
James F. Hinton ◽  
Peter Pulay

1969 ◽  
Vol 24 (11) ◽  
pp. 1365-1370 ◽  
Author(s):  
H.-H. Perkampus ◽  
U. Krüger ◽  
W. Krüger

The proton chemical shifts of aromatic compounds are strongly concentration dependent. Moreever, for molecules with a dipole moment a temperature dependence of the proton chemical shifts is observed. For hemellitone, p-methylanisole, o-chlortoluene, p-chlortoluene, pyrrole and N-methyl-pyrrole the enthalpies of a dipole-dipole association between -0,7 and -1,8 Kcal could be estimated by NMR measurements combined with the temperature dependence in the whole range of the molefraction (0 → 1).


2014 ◽  
Vol 43 (14) ◽  
pp. 5409-5426 ◽  
Author(s):  
Athanassios C. Tsipis ◽  
Ioannis N. Karapetsas

Exhaustive benchmark DFT calculations reveal that the non-relativistic GIAO-PBE0/SARC-ZORA(Pt)∪6-31+G(d)(E) computational protocol predicts accurate 195Pt NMR chemical shifts for a wide range of square planar Pt(ii) and octahedral Pt(iv) anticancer agents.


Chemistry ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 532-549
Author(s):  
Felix Plasser

Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.


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