Heliphenes and Related Structures

Balaban, Alexandrù T.; Vollhardt, K. Peter C.

doi:10.2174/1874364101105010117

Cited by 27 publications

(18 citation statements)

References 86 publications

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“…Graphenylene is a two dimensional sp 2 -carbon network formed by the fusion of hexatomic rings and tetratomic rings. Concurrently with the present work, the structure of graphenylene was proposed in the literature by Balaban and Vollhardt 15 . Graphenylene can be obtained by substituting each hexagonal ring in graphene with a circular [6] phenylene unit, forming a two dimensional carbon honeycomb network that possesses the same point group D 6h as graphene ( Fig.…”

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confidence: 60%

Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units

et al. 2013

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Over many years chemists have established the general principle that two-dimensional chemical structures constructed with pure sp 2 carbon atoms will definitely form an aromatic system with delocalized electron density. However, based on a recently proposed chemical structure, graphenylene, this rule may finally be broken. Herein, we predict the properties of a new two-dimensional sp 2-carbon network known as graphenylene, which is the first example of non-delocalized sp 2-carbon structure composed of cyclohexatriene units with three quite distinct CC bonds within a C6 ring. In addition, theoretical calculations demonstrate that graphenylene has periodic pores of 3.2 Å in diameter and is a semiconductor with a narrow direct band gap, making it promising for various applications, such as electronic devices and efficient hydrogen separation. This study provides a new perspective on carbon allotropes, leading to a better understanding of [N]phenylene based organic frameworks, as well as clarifying the relationship between benzene and cyclohexatriene. Besides graphite and diamond, which have already been known for thousands years, the family of carbon allotropes has suddenly under gone a rapid expansion in recent decades, particularly with the addition of forms such as fullerenes 1 , carbon nanotubes 2 and graphene 3. With its unique chemical character, carbon can bind with itself or other elements to generate not only countless organic compounds, but also new carbon allotropes. The combination of sp-, sp 2-and sp 3hybridized carbon atoms leads to many possible carbon allotropes 4-6 with different dimensionalities 7-13. Of all of these experimentally obtained or theoretically predicted materials, the family of sp 2-carbon allotropes, which include fullerenes, nanotubes and graphene, is the most fascinating and has recently attracted considerable attention owing to their remarkable properties and potential applications in many emerging technologies. However, it is worth noting that fullerene, nanotubes and graphene all possess delocalized π-conjugated bonding such that they have relatively uniform bond lengths and electron distributions. Graphene can be considered as a building unit that can be wrapped up into fullerenes, rolled into carbon nanotubes or stacked into graphite 14. From a theoretical point of view, all of them are similar carbon networks with the same structural unit. One interesting and scientifically important question is whether sp 2-carbon can form alternative net

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confidence: 60%

Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units

et al. 2013

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“…This same conclusion was drawn in the case of antikekulene (structure 6 of Ref. 14, also known as cyclic [6]phenylene 52 ), examined by the present authors, in the context of the AWA rule, in Refs. 14 and 1.…”

supporting

confidence: 85%

“…Cyclic [6] naphthylene (5) was recently discussed by Balaban and Vollhardt. 52 The current pattern predicted here is dramatically different from that found in the benzenoid [4n]-within-[4m] alternant-hydrocarbons 3 and 4 (whose current maps are illustrated in Figure 5). The two types of symmetrically distinct six-membered rings on the periphery of 5 do all still bear diamagnetic ring-currents (though much smaller ones than those associated with the corresponding six-membered rings in 1-4); however, the six four-membered rings in 5, which each contribute one bond to the outer perimeter, support strongly paramagnetic ring-currents.…”

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confidence: 72%

“…(Antikekulene was also discussed by Balaban and Vollhardt in Ref. 52.) As a consequence, even before the central ring of 5 is considered, it is immediately clear that the AWA rule is violated by cyclic [6]naphthylene (5).…”

mentioning

confidence: 96%

“…Like 5, this structure was also recently discussed by Balaban and Vollhardt. 52 Before turning attention to 7, we first consider two other super-ring structures that have odd-membered perimeters and central-rings and whose compliance, or otherwise, with the AWA rule has already been investigated: 14,20,22,57 these are corannulene (10) and [7]circulene (11), the carbon-atom skeletons of which are shown in Figure 8. Their quantitative topological ringcurrent and bond-current maps are both illustrated (labelled 2 and 3, respectively) in Figure 1 of Ref.…”

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confidence: 99%

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Ring-Current Assessment of the Annulene-Within-an-Annulene Model for some Large Coupled Super-Ring Conjugated-Systems

Dickens¹,

Mallion²

2014

Croat. Chem. Acta

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Abstract. The Annulene-Within-an-Annulene (AWA) model for conjugated super-ring systems, proposed by Barth and Lawton nearly fifty years ago, is further tested on six newly considered 'coupled' structures by means of π-electron ring-currents and bond-currents calculated via the Hückel-London-PopleMcWeeny (HLPM) formalism. Super-ring systems are said to be decoupled when the bonds connecting the central ring to the outer perimeter never appear as anything other than single bonds in any Kekulé structure that can be devised for the system as a whole. The preliminary conclusions of other recent investigations -by the same HLPM method and by ipso-centric ab-initio approaches -are verified. Phenylene-[5]-circulene, a (coupled) alternant isomer of the much-studied (decoupled) non-alternant system [10,5]-coronene, is also considered. It is advised that the AWA model should in future either be used with considerable caution in very specific circumstances, or it should be abandoned altogether.

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Zero to Three Dimension Structure Evolution from Carbon Allotropes to Phosphorus Allotropes

Chen

et al. 2022

Adv Materials Inter

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As the promising and highly‐focused materials after silicon, carbon, and phosphorus promote the development of nanotechnology due to its allotropes with unique structures and properties. The carbon allotropes of 0D fullerene, 1D carbon nanotube, and 2D graphene stimulate the investigation of structures, synthesis, properties, and further applications of carbon nanomaterials. Analogous to carbon, phosphorus is demonstrated to have a rich phase diagram. 0D phosphorus fullerenes, 1D phosphorus nanotubes and fibrous red phosphorus, and recently 2D black phosphorene and violet phosphorene have unique structures analogous to carbon fullerene, carbon nanotube, and graphene, is developed. The photoelectronic properties and further applications of the phosphorus allotropes as semiconductors, energy storage materials, biomaterials, and sensors are also investigated. Great efforts are dedicated to studies of the synthesis, structure, and properties of carbons and phosphorus. However, there is no systematic review of the structure of phosphorus allotropes compared to carbon allotropes. Herein, the structures along with possible future perspective of carbon and phosphorus allotropes review and compare in this work based on the classification of different dimensions.

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Heliphenes and Related Structures

Cited by 27 publications

References 86 publications

Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units

Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units

Ring-Current Assessment of the Annulene-Within-an-Annulene Model for some Large Coupled Super-Ring Conjugated-Systems

Zero to Three Dimension Structure Evolution from Carbon Allotropes to Phosphorus Allotropes

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