Convenient synthesis and reduction properties of [7]circulene

Sato, Masaaki; Yamamoto, Kazuhiro; Sonobe, Hiroyuki; Yamaguchi, Koji; Matsubara, Hiroshi; Fujita, Hideo; Sugimoto, Toyonari; Yamamoto, Kōji

doi:10.1039/a803306d

Cited by 25 publications

(11 citation statements)

References 23 publications

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“…Thus, for 3, as for 1 and 2, the proposition that [n]circulenes behave magnetically as decoupled annulenes is not tenable. A comparison of the calculated integrated magnetic properties ðd C and d H ; Dn, and NICS values) for 3a and 3b indicates that the best fit to available experimental data [8,13] is obtained by symmetry averaging of the properties of the individual sites of the non-planar form 3b, which is consistent with a picture of 3 as a rapidly inverting extremely floppy species which spends much of its life in out-of-plane geometries.…”

Section: Discussionsupporting

confidence: 55%

“…Whilst 2 has a D 6h structure both in solution and in the solid state [9], 1 is bowl-shaped in the solid state [10] but has a time-averaged planar D 5h structure in solution (as established by temperature-dependent 1 H NMR) due to rapid bowl-to-bowl interconversion [11,12]. In contrast, 3 has a saddle-shaped structure of C 2 symmetry (3b) in the solid state [8] and a time-averaged planar structure of D 7h symmetry (3a) in solution (with one 1 H and three 13 C NMR resonances), which is not frozen out even at À90°C [13] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…In Table 2 the computed CTOCD-PZ2 [19,20] 13 C ðd C Þ and 1 H ðd H Þ NMR chemical shifts for planar 3a and saddle-shaped 3b are presented and compared with available experimental values [8,13]. In agreement with the shallow corrugation potential for 3b ( [14] and see Section 2) and the observation that 3b in solution possesses a timeaveraged planar D 7h structure, even at À90°C, a better fit between theory and experiment is obtained using the symmetry-averaged d C values rather than those computed for the D 7h struc- Fig.…”

Section: Global and Local Magnetic Properties Of 3a And 3bmentioning

confidence: 99%

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A simple model for counter-rotating ring currents in [n]circulenes

Acocella

Havenith

Steiner

et al. 2002

Chemical Physics Letters

100

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Ab initio current density maps for [7]circulene computed using the ipsocentric CTOCD-DZ/6-31G**//RHF/6-31G** method show that in both planar [3a (D 7h Þ] and non-planar, saddle-shaped [3b (C 2 Þ] geometries this molecule sustains similar counter-rotating rim (diatropic) and hub (strongly paratropic) currents. A survey of the orbital contributions to the current density reveals that 3 like corannulene (1) is a 4d + 4p system with just eight magnetically active and 20 magnetically inactive p electrons. The graph-theoretical H€ u uckel-London model describes the ring-current patterns of [n]circulenes in terms of a coupling strength (the ratio of radial and tangential resonance integrals) that charts the variation from the decoupled con-rotating currents of the [n]annulene-within-an-[m]annulene model to the fully coupled counter-rotating currents of the real [n]circulene. Ó

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Section: Discussionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Section: Global and Local Magnetic Properties Of 3a And 3bmentioning

confidence: 99%

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A simple model for counter-rotating ring currents in [n]circulenes

Acocella

Havenith

Steiner

et al. 2002

Chemical Physics Letters

100

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“…[5,[8][9][10] On proceeding from 3 to 5 the geometry of these hydrocarbons changes from a cuplike structure through a flat arrangement to a saddle-shaped geometry. Although various attempts to prepare the four-membered derivative 2 (see below) and a [7.7]circulene (in which ten contiguous benzene rings are fused around a central bicycloA C H T U N G T R E N N U N G [5.5.0]dodecane Abstract: MP2 and DFT calculations have been carried out for [n]circulenes for n = 3 to 20 in order to predict the strain energy and topology of these cyclically condensed aromatic systems.…”

Section: Introductionmentioning

confidence: 99%

MP2 and DFT Calculations on Circulenes and an Attempt to Prepare the Second Lowest Benzolog, [4]Circulene

Christoph

Grunenberg

Hopf

et al. 2008

Chemistry A European J

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MP2 and DFT calculations have been carried out for [n]circulenes for n=3 to 20 in order to predict the strain energy and topology of these cyclically condensed aromatic systems. To synthesise [4]circulene (2), 1,5,7,8-tetrakis(bromomethyl)biphenylene (14) was prepared from the corresponding tetramethyl derivative (8) and subjected to various dehalogenation reactions; all attempts to obtain [2.2]biphenylenophane (7) as a precursor for 2 by this route failed. Treatment of 14 with sodium sulfide furnished the thiaphanes 16 and 17, thermal and photochemical desulfurization of which also failed to provide 7. In a second approach [2.2]paracyclophane was converted to the pseudo-geminal dithiol 23, which was subsequently bridged to the thiaphanes 22 and 24. On flash vacuum pyrolysis at 800 degrees C these were converted exclusively into phenanthrene (30). An approach to dehydrochlorinate the commercial product PARYLENE C to the tetrahydro[4]circulene 7 led only to polymerisation. The X-ray structures of the intermediates 8, 14, 17, 23, 24, 26, and 35 are reported.

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“…At this point, the only limitation to synthesize these receptors is the preparation of helicenes and corannulenes, since they are not commercially available. But, according to new methods published elsewhere [46][47][48] they can be obtained in suitable amounts in a reasonable short period of time. 1 mmol) of freshly recrystallized N-bromosuccinimide (NBS) and 24 mg (0.07 mmol) of benzoyl peroxide (BPO) (70% wt with 30% of water as stabilizer).…”

Section: -39mentioning

confidence: 99%

Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

Álvarez

Barbero

Ferrero

2016

JoVE

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The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar polyaromatic units, which are two corannulene moieties and a racemic hexahelicene linking them. The compound described in this work is a good host for fullerenes. Several common organic reactions, such as free-radical reactions, C-C coupling or click chemistry, are employed demonstrating the versatility of functionalization that this compound can accept. All of these reactions work for planar aromatic molecules. With subtle modifications, it is possible to achieve similar results for nonplanar polyaromatic compounds.

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Convenient synthesis and reduction properties of [7]circulene

Cited by 25 publications

References 23 publications

A simple model for counter-rotating ring currents in [n]circulenes

A simple model for counter-rotating ring currents in [n]circulenes

MP2 and DFT Calculations on Circulenes and an Attempt to Prepare the Second Lowest Benzolog, [4]Circulene

Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

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