Analysis of the diamagnetic spin-orbital contribution to indirect nuclear spin-spin coupling constants

Pérez, Jorge Enrique Romero; Fernández, Federico; Contreras, Rubén H.; Giribet, C. G.; Azúa, Martín C. Ruiz de

doi:10.1016/0166-1280(90)80041-l

Cited by 22 publications

(11 citation statements)

References 12 publications

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“…These are in line with the known trends of DSO terms, i.e. when a sphere, whose diameter is given by the internuclear distance of the coupling nuclei, is considered, then the electrons inside that sphere yield a negative contribution and the electrons outside that sphere yield a positive contribution 37…”

Section: Fc Term For Ssccsupporting

confidence: 84%

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

et al. 2010

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Adequate analyses of canonical molecular orbitals (CMOs) can provide rather detailed information on the importance of different σ-Fermi contact (FC) coupling pathways (FC term transmitted through the σ-skeleton). Knowledge of the spatial distribution of CMOs is obtained by expanding them in terms of natural bond orbitals (NBOs). Their relative importance for transmitting the σ-FC contribution to a given spin-spin coupling constants (SSCCs) is estimated by resorting to the expression of the FC term given by the polarisation propagator formalism. In this way, it is possible to classify the effects affecting such couplings in two different ways: delocalisation interactions taking place in the neighbourhood of the coupling nuclei and 'round the ring' effects. The latter, associated with σ-ring currents, are observed to yield significant differences between the FC terms of (2)J(C2H3) and (2)J(C3H2) SSCCs which, consequently, are taken as probes to gauge the differences in σ-ring currents for the five-membered rings (furan, thiophene, selenophene and pyrrol) and also for the six-membered rings (benzene, pyridine, protonated pyridine and N-oxide pyridine) used in the present study.

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Section: Fc Term For Ssccsupporting

confidence: 84%

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

et al. 2010

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“…As shown in Table , for cis conformations, the most significant contributions are the FC, PSO, and DSO terms. The latter follows a well‐known trend [23a], that is, if the space is divided by a sphere whose diameter coincides with the distance between the coupling nuclei, then electrons inside that sphere yield a negative contribution to the DSO term whereas those outside that sphere yield a positive contribution. This trend was experimentally verified by studying the DSO term in several geminal SSCCs [23b].…”

Section: Resultsmentioning

confidence: 72%

^1hJ_FHcoupling in 2‐fluorophenol revisited: Is intramolecular hydrogen bond responsible for this long‐range coupling?

Cormanich

Moreira

Freitas

et al. 2011

Magnetic Reson in Chemistry

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The present study shows that a hydrogen bond between the OH group and the fluorine atom is not involved in the (1h)J(FH) spin-spin coupling transmission either for 4-bromo-2-fluorophenol or 2-fluorophenol. In fact, according to a quantum theory of atoms in molecules analysis, no bond critical point is found between O-H and F moieties. The nature of the transmission mechanism of the Fermi contact term of the (1h)J(FH) spin-spin coupling is studied by analyzing canonical molecular orbitals (see J. Phys. Chem. A 2010, 114, 1044), and it is observed that virtual orbitals play only a quite minor role in its transmission. This is typical of a Fermi contact term transmitted mainly through exchange interactions owing to the overlap of proximate electronic clouds; therefore, it is suggested to identify them as (nTS)J(FH) coupling where n stands for the number of formal bonds separating the coupling nuclei. In the cases studied in this work is n = 4. Results presented in this work could provide an interesting rationalization for different experimental signs known in the current literature for proximate J(FH) couplings.

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“…The DSO term, which in all cases is the smallest of the four, follows the trend described years ago. 16 Substituent effects on the SD term appear to be, in percentage terms, larger than those on the FC and PSO terms; however, total substituent effects are dominated by the FC behavior (Table 1). This trend contrasts with that of substituent effects on 2,3 J(F,F) couplings which can be dominated by non-contact contributions.…”

Section: Resultsmentioning

confidence: 96%

Substituent effects on scalar J(¹³C, ¹³C) couplings in pyrimidines. An experimental and DFT study

Kowalewski¹,

Esteban²,

Barone³

et al. 2004

Magnetic Reson in Chemistry

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One- two- and three 13C, 13C (n = 1, 2, 3) scalar couplings, (n)J(C,C) in a set of pyrimidine derivatives were studied both experimentally at natural abundance and theoretically by their DFT calculation of all four contributions. Trends of non-contact terms are discussed and substituent effects are rationalized, comparing some of them with the corresponding values in benzene and pyridine. Although substituent effects on non-contact terms are relatively important, the whole trend is dominated by the Fermi contact term. According to the current literature, substituent effects on 1J(C,C) couplings in benzene derivatives are dominated by the inductive effect, which, apparently, is also the case in nitrogen heteroaromatic compounds. However, some differences observed in this work for substituent effects on 1J(C,C) couplings in pyrimidine derivatives suggest that in the latter type of compounds substituent effects can be affected by the orientation of the ring nitrogen lone pairs.

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Analysis of the diamagnetic spin-orbital contribution to indirect nuclear spin-spin coupling constants

Cited by 22 publications

References 12 publications

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

^1hJ_FHcoupling in 2‐fluorophenol revisited: Is intramolecular hydrogen bond responsible for this long‐range coupling?

Substituent effects on scalar J(¹³C, ¹³C) couplings in pyrimidines. An experimental and DFT study

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Analysis of the diamagnetic spin-orbital contribution to indirect nuclear spin-spin coupling constants

Cited by 22 publications

References 12 publications

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

Difference between 2JC2H3 and 2JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis

1hJFHcoupling in 2‐fluorophenol revisited: Is intramolecular hydrogen bond responsible for this long‐range coupling?

Substituent effects on scalar J(13C, 13C) couplings in pyrimidines. An experimental and DFT study

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^1hJ_FHcoupling in 2‐fluorophenol revisited: Is intramolecular hydrogen bond responsible for this long‐range coupling?

Substituent effects on scalar J(¹³C, ¹³C) couplings in pyrimidines. An experimental and DFT study