Relative Weights of σ and π Ring Currents in a Few Simple Monocycles

Monaco, Guglielmo; Zanasi, Riccardo; Pelloni, Stefano; Lazzeretti, Paolo

doi:10.1021/ct100442j

Cited by 89 publications

(158 citation statements)

References 40 publications

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“…This situation is quite different from ring current maps 79,80,89 for e.g. Al 4 2-where we do find a much more similar ring current map as in e.g., benzene.…”

Section: Stability Reactivity and Aromaticitycontrasting

confidence: 99%

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

Deb

Duley

Radenković

et al. 2012

Phys. Chem. Chem. Phys.

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“…This situation is quite different from ring current maps 79,80,89 for e.g. Al 4 2-where we do find a much more similar ring current map as in e.g., benzene.…”

Section: Stability Reactivity and Aromaticitycontrasting

confidence: 99%

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

Deb

Duley

Radenković

et al. 2012

Phys. Chem. Chem. Phys.

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“…They noted also that similar calculations on (planar) cyclobutane gave, in contrast, a central paratropic ring current. Recent calculations by Pelloni and co‐workers confirm and expand these results . They constructed a three‐dimensional model of the quantum mechanical current density in cyclopropane induced by a uniform magnetic field and also calculated that 95% of the diatropic ring current in cyclopropane is transported by the σ ( π ‐like) electrons.…”

Section: Introductionmentioning

confidence: 80%

¹H NMR Spectra. Part 28: Proton chemical shifts and couplings in three‐membered rings. A ring current model for cyclopropane and a novel dihedral angle dependence for ³J_HH couplings involving the epoxy proton

Abraham

Leonard

Tormena³

2012

Magnetic Reson in Chemistry

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The (1) H chemical shifts of selected three-membered ring compounds in CDCl(3) solvent were obtained. This allowed the determination of the substituent chemical shifts of the substituents in the three-membered rings and the long-range effect of these rings on the distant protons. The substituent chemical shifts of common substituents in the cyclopropane ring differ considerably from the same substituents in acyclic fragments and in cyclohexane and were modelled in terms of a three-bond (γ)-effect. For long-range protons (more than three bonds removed), the substituent effects of the cyclopropane ring were analysed in terms of the cyclopropane magnetic anisotropy and steric effect. The cyclopropane magnetic anisotropy (ring current) shift was modelled by (a) a single equivalent dipole perpendicular to and at the centre of the cyclopropane ring and (b) by three identical equivalent dipoles perpendicular to the ring placed at each carbon atom. Model (b) gave a more accurate description of the (1) H chemical shifts and was the selected model. After parameterization, the overall root mean square error for the dataset of 289 entries was 0.068 ppm. The anisotropic effects are significant for the cyclopropane protons (ca 1 ppm) but decrease rapidly with distance. The heterocyclic rings of oxirane, thiirane and aziridine do not possess a ring current. (3) J(HH) couplings of the epoxy ring proton with side-chain protons were obtained and shown to be dependent on both the H-C-C-H and H-C-C-O orientations. Both density functional theory calculations and a simple Karplus-type equation gave general agreement with the observed couplings (root mean square error 0.5 Hz over a 10-Hz range).

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“…RCS data were taken from ref. 47. For more details about calculations, we recommend reviewing this work and the references therein.…”

Section: àmentioning

confidence: 99%

Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles

et al. 2018

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The aromaticity of benzene, Al 4 2À cluster, cyclopropane, borazine and planar cyclooctatetraene (COT) was analyzed according to different strategies based on nucleus-independent chemical shift (NICS) computations. The analysis of NICS-components evolution along the main molecular axis seems to be the most adequate and simplest strategy to predict the aromatic or antiaromatic character of the studied systems. Moreover, the analysis of the s-and p-electron contributions to the out-of-plane component of NICS (NICS zz ) leads to the same qualitative and quantitative conclusions previously obtained by the analysis of the magnetically induced ring current densities.

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Relative Weights of σ and π Ring Currents in a Few Simple Monocycles

Cited by 89 publications

References 40 publications

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

¹H NMR Spectra. Part 28: Proton chemical shifts and couplings in three‐membered rings. A ring current model for cyclopropane and a novel dihedral angle dependence for ³J_HH couplings involving the epoxy proton

Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles

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Relative Weights of σ and π Ring Currents in a Few Simple Monocycles

Cited by 89 publications

References 40 publications

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

1H NMR Spectra. Part 28: Proton chemical shifts and couplings in three‐membered rings. A ring current model for cyclopropane and a novel dihedral angle dependence for 3JHH couplings involving the epoxy proton

Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles

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¹H NMR Spectra. Part 28: Proton chemical shifts and couplings in three‐membered rings. A ring current model for cyclopropane and a novel dihedral angle dependence for ³J_HH couplings involving the epoxy proton