Tetracyclopropylmethan: ein einzigartiger Kohlenwasserstoff mitS4-Symmetrie

Kozhushkov, Sergei I.; Kostikov, R. R.; Molchanov, A. P.; Boese, Roland; Benet‐Buchholz, Jordi; Schreiner, Peter R.; Rinderspacher, Christopher; Ghiviriga, Ion; Meijere, Armin de

doi:10.1002/1521-3757(20010105)113:1<179::aid-ange179>3.0.co;2-7

“…more highly crowded tetraisopropylmethane. Catalytic hydrogenation of tetracyclopropylmethane over platinum oxide in acetic acid occurred remarkably smoothly and selectively with a quantitative yield of tetraisopropylmethane [36]. In the crystal, tetraisopropylmethane has C 2v symmetry with two pairs of isopropyl groups facing each other (Fig.…”

Section: Conformational Dynamics In Tetracyclopropyl-and Tetraisopropmentioning

confidence: 97%

“…Tetracyclopropylmethane also served as a precursor to the even New structurally interesting cyclopropane derivatives 559 Fig. 9 Structures of tricyclopropylmethane and tetracyclopropylmethane in the crystals [36]. more highly crowded tetraisopropylmethane.…”

Section: Conformational Dynamics In Tetracyclopropyl-and Tetraisopropmentioning

confidence: 99%

New Structurally Interesting Cyclopropane Derivatives: A World of Wonders and Surprises

Meijere

¹

,

Kozhushkov

²

,

Fokin

³

et al. 2003

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The structurally intriguing [4]-and [5]triangulanes have been prepared in enantiomerically pure form. Their surprisingly high specific rotations are well reproduced by DFT/SCI computations and stem from the fact that these hydrocarbons essentially are σ-helicenes (i.e., rigidly held helical arrangements of σ-bonds). Some light is shed on the properties of radical cations derived from [3]-and [4]rotanes. While the former adopts C s or C 2v symmetry, the latter retains the D 4h symmetry of the neutral hydrocarbon, according to highlevel computations. Experimental and computational evidence is also presented that the antiaromatic cyclopentadienyl cation is stabilized as a singlet ground state by five cyclopropyl substituents. Yet, the three cyclopropyl groups in tricyclopropylamine do not favor the formation of its radical cation, because they are not in the proper orientation. When this amine radical cation is generated by cobalt γ-irradiation in a Freon matrix, evidence for a significant conformational change is obtained by EPR spectroscopy. Finally, the conformational dynamics of the newly prepared crowded molecules tetracyclopropyl-and tetraisopropylmethane are discussed.

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“…Indeed, a crystal structure analysis revealed that tricyclopropylmethane has C 3v symmetry in the solid [36], and undoubtedly tricyclopropylmethyl cation would have a trigonal planar coordination around the central carbon with all three cyclopropyl groups in a bisected orientation [15].…”

Section: Conformational Dynamics In Tetracyclopropyl-and Tetraisopropmentioning

confidence: 99%

“…Tetracyclopropylmethane also served as a precursor to the even © 2003 IUPAC, Pure and Applied Chemistry 75, 549-562 New structurally interesting cyclopropane derivatives 559 Fig. 9 Structures of tricyclopropylmethane and tetracyclopropylmethane in the crystals [36]. more highly crowded tetraisopropylmethane.…”

Section: Conformational Dynamics In Tetracyclopropyl-and Tetraisopropmentioning

confidence: 99%

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New structurally interesting cyclopropane derivatives. A world of wonders and surprises

Meijere

¹

,

Kozhushkov

²

,

Fokin

³

et al. 2003

Pure and Applied Chemistry

Self Cite

View full text Add to dashboard Cite

The structurally intriguing [4]-and [5]triangulanes have been prepared in enantiomerically pure form. Their surprisingly high specific rotations are well reproduced by DFT/SCI computations and stem from the fact that these hydrocarbons essentially are σ-helicenes (i.e., rigidly held helical arrangements of σ-bonds). Some light is shed on the properties of radical cations derived from [3]-and [4]rotanes. While the former adopts C s or C 2v symmetry, the latter retains the D 4h symmetry of the neutral hydrocarbon, according to highlevel computations. Experimental and computational evidence is also presented that the antiaromatic cyclopentadienyl cation is stabilized as a singlet ground state by five cyclopropyl substituents. Yet, the three cyclopropyl groups in tricyclopropylamine do not favor the formation of its radical cation, because they are not in the proper orientation. When this amine radical cation is generated by cobalt γ-irradiation in a Freon matrix, evidence for a significant conformational change is obtained by EPR spectroscopy. Finally, the conformational dynamics of the newly prepared crowded molecules tetracyclopropyl-and tetraisopropylmethane are discussed.

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Faszinierende natürliche und synthetische Cyclopropan-Architekturen

Faust

¹

2001

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Es ist erstaunlich, was drei C‐Atome alles fertigbringen! Chemiker in Hochschule und Industrie sind weiterhin damit beschäftigt, unter den verschiedensten Gesichtspunkten die Struktureinheit des Cyclopropanrings zu erforschen, z. B. seine biologische Aktivität, seine Reaktivität und Verfahren zu seiner Synthese. Atemberaubende Ringstrukturen mit mehreren Cyclopropanringen wie 1 und 2 konnten kürzlich synthetisiert werden. Dies sind Meilensteine auf dem Gebiet der Chemie der kleinen Ringe.

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Tetracyclopropylmethan: ein einzigartiger Kohlenwasserstoff mitS4-Symmetrie

Cited by 11 publications

References 45 publications

New Structurally Interesting Cyclopropane Derivatives: A World of Wonders and Surprises

New Structurally Interesting Cyclopropane Derivatives: A World of Wonders and Surprises

New structurally interesting cyclopropane derivatives. A world of wonders and surprises

Faszinierende natürliche und synthetische Cyclopropan-Architekturen

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