Planarization of the Cyclohexane Ring by Its Incorporation Into a Cyclophane Cage: Hexahydrosuperphane

Dodziuk, Helena; Ostrowski, Maciej

doi:10.1002/ejoc.200600237

Cited by 11 publications

(5 citation statements)

References 21 publications

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“…As a continuation of our study of the hypothetical hexahydrosuperphane 5, [12] the computation of the optimum geometry and the NMR parameters was carried out for cyclophanes 1-4 together with the measurements of these parameters for 3 and 4. The X-ray data have been published for 1 [13] and 2; [14] however, as will be discussed below, it is difficult to compare them with the calculated values.…”

Section: Introductionmentioning

confidence: 99%

Spatial structure and NMR spectra of strained [2.2.2]cyclophanes

Dodziuk

Ostrowski

Ruud

et al. 2009

Magnetic Reson in Chemistry

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The chemical shifts and coupling constants in the NMR spectra of the title compounds are influenced by their strain and the proximity of the aromatic rings. These parameters are studied by density functional theory (DFT) calculations for 1-4 and measured for 3 and 4. We find that, in spite of the strain, the calculations reproduce the experimental values satisfactorily. This finding is of special importance for novel hypothetical molecules like hexahydrosuperphane 5 for their future identification and in searches of hydrocarbons exhibiting unusual NMR parameters. Our results demonstrate the influence of strain on the parameters studied. Most proton and carbon chemical shifts for the molecules under study having nonplanar aromatic rings differ considerably from the corresponding values for the relatively unstrained trimethylbenzenes and ethylbenzene. In addition, the calculated values of the coupling constants through three bonds in most cases do not follow Karplus relation.

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Section: Introductionmentioning

confidence: 99%

Spatial structure and NMR spectra of strained [2.2.2]cyclophanes

Dodziuk

Ostrowski

Ruud

et al. 2009

Magnetic Reson in Chemistry

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“…Highly strained cyclophanes with small bridges such as [2.2]paracyclophane 1 , (1,2,3)-, (1,3,5)-, (1,2,4)-, and (1,2,4;1,2,5)[2.2.2]cyclophanes 2−5 , respectively, and hexahydrosuperphane 6 , which we have recently studied, are interesting objects of basic research for several reasons. − First, as opposed to benzene, they have nonplanar aromatic ring(s). Second, the aromatic rings in 1−5 are closely situated, enabling interaction of π-electrons of the rings.…”

Section: Introductionmentioning

confidence: 99%

Structure and Dynamics of [3.3]Paracyclophane As Studied by Nuclear Magnetic Resonance and Density Functional Theory Calculations

et al. 2010

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Strained cyclophanes with small (-CH(2)-)(n) bridges connecting two benzene rings are interesting objects of basic research, mostly because of the nonplanarity of the rings and of interference of π-electrons of the latter. For title [3.3]paracyclophane, in solutions occurring in two interconverting cis and trans conformers, the published nuclear magnetic resonance (NMR) data are incomplete and involve its partially deuterated isotopomers. In this paper, variable-temperature NMR studies of its perprotio isotopomer combined with DFT quantum chemical calculations provide a complete characterization of the solution structure, NMR parameters, and interconversion of the cis and trans isomers of the title compound. Using advanced methods of spectral analysis, total quantitative interpretation of its proton NMR spectra in both the static and dynamic regimes is conducted. In particular, not only the geminal but also all of the vicinal J(HH) values for the bridge protons are determined, and for the first time, complete Arrhenius data for the interconversion process are reported. The experimental proton and carbon chemical shifts and the (n)J(HH), (1)J(CH), and (1)J(CC) coupling constants are satisfactorily reproduced theoretically by the values obtained from the density functional theory calculations.

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“…NMR and electronic spectra are especially sensitive to such effects. We have previously reported NMR spectra and other properties of several cyclophanes with saturated bridges . In this article, we extend these investigations to a study of the structure and NMR spectra of the molecules 2–4 and 6–12 with one or more unsaturated bridges.…”

Section: Introductionmentioning

confidence: 66%

“…We have previously reported NMR spectra and other properties of several cyclophanes with saturated bridges. [8][9][10] In this article, we extend these investigations to a study of the structure and NMR spectra of the molecules 2-4 and 6-12 with one or more unsaturated bridges. The influence of unsaturated bridges roughly perpendicular to the aromatic rings on the physicochemical properties of cyclophanes is exciting in view of possible, although weak, interactions of p-electrons of the bridge(s) with those of the aromatic rings.…”

Section: Introductionmentioning

confidence: 99%

Structure and NMR spectra of cyclophanes with unsaturated bridges (cyclophenes)

Dodziuk

Demissie

Ruud

et al. 2012

Magnetic Reson in Chemistry

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The calculated structures of several known and hypothetical cyclophanes with ethylene bridges (cyclophenes) are reported together with experimental and calculated values of their NMR parameters. Of the exchange-correlation functionals and basis sets used in this work, only the ωB97X-D/6-311++G(2d,2p) and ωB97X-D/cc-pVQZ yielded values of the C(sp3)-C(sp3) bond length close to the experimental data, although significant differences still remain. As far as the NMR parameters are concerned, except for close-lying signals, chemical shifts and coupling constants calculated at the ωB97X-D/cc-pVQZ level reproduce in most cases the experimental trends. Contrary to the calculations of geometries, an agreement between the values of the NMR parameters obtained at ωB97X-D/cc-pVQZ level and the experimental ones is the poorest compared with that of the ωB97X-D/6-311++G(2d,2p) one. Taking into account that the results of the different calculations show the same qualitative trends in most cases, we believe that they correctly describe the structure and properties of the hypothetical molecules studied here.

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Planarization of the Cyclohexane Ring by Its Incorporation Into a Cyclophane Cage: Hexahydrosuperphane

Cited by 11 publications

References 21 publications

Spatial structure and NMR spectra of strained [2.2.2]cyclophanes

Spatial structure and NMR spectra of strained [2.2.2]cyclophanes

Structure and Dynamics of [3.3]Paracyclophane As Studied by Nuclear Magnetic Resonance and Density Functional Theory Calculations

Structure and NMR spectra of cyclophanes with unsaturated bridges (cyclophenes)

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