Computational 19F NMR. 1. General features

Saielli, Giacomo; Bini, Riccardo; Bagno, Alessandro

doi:10.1007/s00214-012-1140-z

Cited by 19 publications

(31 citation statements)

References 110 publications

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“…18,22,[30][31][32][33] The problem of predicting 19 F chemical shis has recently been tested in detail on the large body of experimental data. 33,34 On the other hand, the rst test calculations of the indirect spin-spin coupling constants in such compounds yielded denitely poor values of 1 J(F,C) parameter. 35 It has also been noticed that the same problem concerns two-bond indirect spin-spin coupling constants between geminal uorines.…”

Section: Introductionmentioning

confidence: 99%

An efficient DFT method of predicting the one-, two- and three-bond indirect spin–spin coupling constants involving a fluorine nucleus in fluoroalkanes

Gryff‐Keller

Szczeciński

2016

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

An efficient DFT method of predicting the one-, two- and three-bond indirect spin–spin coupling constants involving a fluorine nucleus in fluoroalkanes

Gryff‐Keller

Szczeciński

2016

RSC Adv.

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“…The fluorine chemical shifts of compounds 1b and 1c were also calculated by means of a published method, 17 namely, gauge including atomic orbitals (GIAO) combined with B3LYP DFT using the cc-pVTZ basis set. The calculated fluorine chemical shifts of compounds 1b (δ F = −101.9 ppm) and 1c (δ F = −101.0 ppm) are upfield-shifted by 10.9 and 8.4 ppm compared with the observed values (Table S10 in the Supporting Information).…”

mentioning

confidence: 99%

The Synthesis of Rigid Polycyclic Structures for the Study of Diatropic or Steric Effects of a Phenyl Ring on CF Bond

Chang

et al. 2013

J. Org. Chem.

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Polycyclic compounds 1a−c were synthesized to study the diatropic effects of a flanking phenyl ring on nearby CH and CF bonds. 19 F NMR spectra of 1b and 1c were strongly deshielded compared with those of the ring-opened compounds 3b, 7b, and 7c. DMol3 calculations on 1a−c provided quantitative bond lengths and torsional angles to support the conclusion that the downfield shifts in the 19 F NMR spectra are mainly due to steric interactions between the CF bonds and the π clouds of the phenyl ring(s).I nter-and intramolecular CH−π and CF−π interactions play important roles in host−guest chemistry, molecular assembly, and the folding of proteins and polynucleotides. 1 The CH−π interaction is a weak force (0.5−2.5 kcal/mol) 2a that is usually difficult to measure directly using molecules with flexible conformations. Therefore, the measurement of this weak interaction in molecules with intramolecular folding and unfolding has intrigued chemists for decades. 2 Recently, Tsuzuki 3a reported an excellent review that summarizes recently reported gas-phase measurements and high-level ab initio calculations of the CH−π interactions. Ab initio calculations show that the major source of attraction in the CH−π interactions is the dispersion interaction, while the contribution from electrostatic interactions is small. On the other hand, Nishio et al. 3b surveyed and analyzed literature results relevant to the CH−π interactions in crystal packing and conformations based on data reported in crystallographic databases (CSD and PDB). Moreover, as the organofluoride compounds are getting more popular in medicinal chemistry, the need to study CF−π interactions in organic and biological molecules has markedly increased. In order to study such CF−π interactions efficiently, one needs to have a special molecular design in which the CF bond is pointing toward conformationally rigid π bonds or aromatic rings. 4 In previous literature, the typical CF−π interactions between fluoromethane and benzene/hexafluorobenzene were only theoretically studied. For example, the very weak attractive interaction between the fluorine of HF and hexafluorobenzene was measured on the basis of theoretical calculations. 5a Kawahara also indicated that a weak interaction between fluoromethane and hexafluorobenzene was observed; furthermore, it is worth noting that this was an attractive force. 5b Nowak, however, studied CF−π interactions by measuring the effect of fluorine on the reactivity of a proximal double bond using a polyfluorinated indacene system. 6 The through-space interactions between the CF bond and the π electrons of alkenes were explained by Lectka 7 to be due to steric hindrance, anchimeric assistance, and the repulsive interactions from overlap of lone-pair electrons on fluorine with the π electrons on the olefin. Furthermore, they reported that the fluorine was little perturbed by anisotropic effects from the π electrons of the alkene, and only a slight upfield shift relative to theoretical values of fluorine chemical shifts...

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“…Rather we update with recent developments in exchange correlation functionals (since the Wilson review in vol. 49,2003) and in relativistic computations (since the Autschbach review in vol. 67,2009).…”

Section: Overview Of This Reviewmentioning

confidence: 99%

“…Since the Wilson review of this topic in this series (vol 49,2003), research on improvements on the currently available exchange correlation functionals remains an important and active area of theoretical research. Despite the great success of global hybrid functionals, for example, B3LYP and PBE0, in predicting various molecular properties, they turned out not to be sufficiently flexible: It is usually not possible to find a unique constant for the amount of exact exchange admixture that provides consistently high accuracy for different properties as well as for different classes of systems.…”

Section: Density Functional Calculationsmentioning

confidence: 99%