The Cyclodecapentaene System

Vogel, E.; Roth, Heinz D.

doi:10.1002/anie.196402282

Cited by 140 publications

(94 citation statements)

References 7 publications

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“…Historical landmarks in the chemistry of these molecules are the synthesis of monocycles up to [30]annulene [163,164] and of the first bridged [10]annulene [165,166]. Due to angle strain and/or steric interactions between hydrogen atoms higher annulenes are characterized by a rich variety of non planar conformational and configurational isomers and of interconversion processes between them [6].…”

Section: Higher Annulenesmentioning

confidence: 99%

“…Spectroscopic measurements on 1,6-methano [10]annulene, including absorption, fluorescence and magnetic circular dichroism [200][201][202], were reported since the synthesis [165] and discussed in relation to the transannular interaction. The molecule was viewed as an example of "arrested transition state" along the electrocyclic path of the ring closure [201].…”

Section: Bridged [10] Annulenesmentioning

confidence: 99%

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Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Gellini

Salvi

2010

Symmetry

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The paper introduces general considerations on structural properties of aromatic, antiaromatic and non-aromatic conjugated systems in terms of potential energy along bond length alternation and distortion coordinates, taking as examples benzene, cyclobutadiene and cyclooctatetraene. Pentalene, formally derived from cyclooctatetraene by cross linking, is also considered as a typical antiaromatic system. The main interest is concerned with [n]annulenes and model [n]annulene molecular systems, n ranging from 10 to 18. The rich variety of conformational and configurational isomers and of dynamical processes among them is described. Specific attention is devoted to bridged [10]-and [14]annulenes in the ground and lowest excited states as well as to s-indacene and biphenylene. Experimental data obtained from vibrational and electronic spectroscopies are discussed and compared with ab initio calculation results. Finally, porphyrin, tetraoxaporphyrin dication and diprotonated porphyrin are presented as annulene structures adopting planar/non-planar geometries depending on the steric hindrance in the inner macrocycle ring. Radiative and non-radiative relaxation processes from excited state levels have been observed by means of time-resolved fluorescence and femtosecond transient absorption spectroscopy. A short account is also given of porphycene, the structural isomer of porphyrin, and of porphycene properties.

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Section: Higher Annulenesmentioning

confidence: 99%

Section: Bridged [10] Annulenesmentioning

confidence: 99%

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Gellini

Salvi

2010

Symmetry

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“…The proton spectrum of aromatic electron delocalization (2). The remarkable aromaticity of 3 might be partially caused by the possibility of some 1,6-bonding overlap; this interaction must be invoked in order to explain the u.v.…”

mentioning

confidence: 99%

¹³C Nuclear Magnetic Resonance Spectra of Bridged 10π-Electron Systems. The Extent of Electron Delocalization

Kemp-Jones¹,

Jones²,

Sakai³

et al. 1973

Can. J. Chem.

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The 13C n.m.r. spectruin of the cation 4 suggests the presence of considerable 1.7-bonding. indicating that it should be described as a substituted homotropylium cation rather than a monocyclic lor-electron system. The intra-annular ca-rbon atoms of 3 and 4 do not show a significant upfield shift due to the ring current. Explanations are offered. [Traduit par le journaljOur recent demonstration that both cis-and tive to changes in the geometry of the molecule trans-[l Olannulenes (1 and 2) are non-planar (5); we have used bicyclo [5.4.1 ldodecapentaolefinic hydrocarbons (1) contrasts with the be-2,5,7,9,11-ene (5) (6)

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“…The synthesis of 1,6-methano [10]annulene has been described elsewhere. 9 The nph from Aldrich was used as received. Solutions of 1a were prepared in spectroscopic-grade cyclohexane and an isopentane−diethyl ether mixture in the concentration range of 10 −4 − 10 −2 M and were irradiated in quartz cells at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Photochemical Reactivity of 1,6-Methano[10]annulene

et al. 2017

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1,6-Methano [10]annulene solutions in cyclohexane have been subjected to continuous and pulsed UV irradiation. Photolysis occurs in both cases, giving naphthalene as a minor and major product, respectively. The wavelength dependence of the reaction in solution indicates that the photochemical process occurs, exciting 1,6-methano[10]annulene in the second and third singlet electronic excited states. The reaction kinetics has been determined under pulsed irradiation. From the time dependence of concentrations, along with support of density functional theory calculations and early published data, two mechanisms are proposed for naphthalene production. Reaction steps such as direct migration of the bridging methylene of 1,6-methano[10]annulene to cyclohexane and 1,6-methano[10]annulene isomerization to benzotropilidene have been identified. The calculated energy diagrams relative to the ground and lowest excited states allow one to relate these steps to processes such as electrocyclic closure and sigmatropic shift. The norcaradienic form of 1,6-methano [10]annulene results in the critical species for methylene migration and the sigmatropic [1,5] shift. The present results and those arising from photolysis in the gas phase are good examples of the photochemical reactivity of 1,6-methano[10]annulene.

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The Cyclodecapentaene System

Cited by 140 publications

References 7 publications

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

¹³C Nuclear Magnetic Resonance Spectra of Bridged 10π-Electron Systems. The Extent of Electron Delocalization

Photochemical Reactivity of 1,6-Methano[10]annulene

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The Cyclodecapentaene System

Cited by 140 publications

References 7 publications

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

13C Nuclear Magnetic Resonance Spectra of Bridged 10π-Electron Systems. The Extent of Electron Delocalization

Photochemical Reactivity of 1,6-Methano[10]annulene

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¹³C Nuclear Magnetic Resonance Spectra of Bridged 10π-Electron Systems. The Extent of Electron Delocalization