Synthesis of Large Polycyclic Aromatic Hydrocarbons:  Variation of Size and Periphery

Dötz, Florian; Brand, J. D.; Ito, Shunji; Gherghel, Lileta; Müllen, Kläus

doi:10.1021/ja000832x

Cited by 184 publications

(104 citation statements)

References 30 publications

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“…Polycyclic Aromatic Hydrocarbons and Circumcoronene Series of Benzenoid are two families of hydrocarbon molecules, such that their structure is consisting of Benzene C 6 H 6 or cycles with length six C 6 by defferent componds. In a series of papers, some properties and more historical details of hydrocarbon molecules are studed [44][45][46][47][48][49][50][51][52][53][54][55][56][57] and some applications of Benzenoid system are presented in many papers [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74].…”

Section: Resultsmentioning

confidence: 99%

Schultz and Modified Schultz Polynomials of Coronene Polycyclic Aromatic Hydrocarbons

Farahani

2014

ILCPA

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Let G = (V;E) be a simple connected graph. The sets of vertices and edges of G are denoted by V = V(G) and E = E(G), respectively. In such a simple molecular graph, vertices represent atoms and edges represent bonds. The distance between the vertices u and v in V(G) of graph G is the number of edges in a shortest path connecting them, we denote by d (u,v). In graph theory, we have many invariant polynomials for a graph G. In this research, we computing the Schultz polynomial, Modified Schultz polynomial, Hosoya polynomial and their topological indices of a Hydrocarbon molecule, that we call "Coronene Polycyclic Aromatic Hydrocarbons".

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Section: Resultsmentioning

confidence: 99%

Schultz and Modified Schultz Polynomials of Coronene Polycyclic Aromatic Hydrocarbons

Farahani

2014

ILCPA

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“…Bottom-up approaches reported to date include organic synthesis in solution via crosscoupling of the appropriate organic building-blocks followed by the dehydrogenation of the resulting oligomers, 37,38,[40][41][42][43][44][45][46][47] the conversion of precursors inside CNTs, 48,49 and surface-assisted polymerization with subsequent dehydrogenation in an ultra-high vacuum environment. 39,50,51 Although these bottom-up methods provide GNRs with a defined edge structure, they so far suffer from the inability to afford GNRs having variable widths at large scales, owing to the low solubility of the synthesized GNRs, and/or the need for highly-specialized instrumentation.…”

Section: Methodsmentioning

confidence: 99%

“…In 2013, Bronner and co-workers 51 expanded the work of Cai 50 by preparing analogous, nitrogen-doped GNRs via the polymerization of specially-designed monomers on an Au(111) surface. Moreover, they studied the band gap of these nitrogen-doped GNRs with surfacesensitive electron spectroscopies.…”

Section: Gnrs Synthesis Through Surface-assisted Polymerizationmentioning

confidence: 99%

Chemical synthesis of graphene nanoribbons

Pefkianakis¹,

Σακελλαρίου²,

Vougioukalakis³

2015

Arkivoc

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Dedicated to Professor Michael AbstractGraphene is a two-dimensional atom-thick sheet of graphite composed of an sp 2 -hybridized carbon atom network. Its isolation in 2004 and the extensive research that followed have led, amongst others, to graphene nanoribbons (GNRs), a graphene-based structure having nano-scale dimensions and semiconducting or metallic electronic properties that depend on its geometry and dimensions. These characteristics of GNRs are in stark contrast to those of graphene, which is a carbon sheet with semimetal, zero band gap characteristics. In the present article, we discuss the progress that has been reported towards producing GNRs with predefined dimensions, by using bottom-up chemical synthesis approaches.

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“…In order to get access to substances with a defined substitution pattern it is therefore mandatory to introduce the desired functional groups into smaller building blocks and use these precursors to establish the synthesis of the p-quaterphenylene scaffold. In the past this was achieved by cyclotrimerisations of acetylenes [93][94][95][96][97], Diels-Alder reactions of cyclopentadienones and subsequent aromatisation [98][99][100][101][102][103][104], Wittig reactions of cinnamaldehydes followed by Diels-Alder reactions with acetylenic dicarboxylates and subsequent aromatisation [105], addition of Grignard reagents to arines [106][107][108][109], Grignard reactions with p-quinones and subsequent dehydratisation [110,111], or Ullmann-type coupling reactions [112]. Modern transition metal catalysed homo-and cross-coupling reactions have become more and more popular over the last 30 years [113][114][115][116].…”

Section: Fig 12mentioning

confidence: 99%

Organic Molecular Nanotechnology

Schiek

Balzer

Al‐Shamery

et al. 2008

Small

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Zur Homepage der Dissertation AbstractFormation of needle-like crystals from inorganic as well as from organic semiconductors such as para-phenylenes, α-thiophenes and phenyl-thiophene co-oligomers on dielectric surfaces has attracted increasing interest within the last years. The para-hexaphenylene has proven to be a versatile building block for generating long, parallely aligned organic nanofibers by a self-assembly process on a muscovite mica substrate via sublimation in high vacuum. These nanofibers possess outstanding optical properties like strong, polarised blue fluorescence in high quantum yields after unpolarised excitation with UV light, waveguiding and lasing features. Furthermore, they are chemically and thermically stable and can be easily detached from the growth substrate to serve as key elements in next generation optoelectronic and nanophotonic devices. Owing to their typical height and width on a nanometer scale and length up to one millimeter, the fibers bridge the gap between microscopic and macroscopic dimensions. The morphology of the nanofibers (length, height, width, aspect ratio, bending into rings) is susceptable to process parameters and pretreatment of the substrate. But chemically functionalisation of the molecular building block as key step of this thesis widens the scope of possibilities: Nanoaggregates with tailored morphology and optical properties are generated from designed functionalised molecular building blocks. Functional groups have been implemented at the 1,4´´´-para-positions of p-quaterphenylenes using a non-trivial Suzuki cross-coupling strategy. Symmetrically as well as non-symmetrically functionalised oligomers have been achieved in excellent yields and high purity. Additionally, the synthesis of phenyl-thiophene cooligomers and their acceptability for the nanofiber growth on muscovite mica via organic molecule deposition in high vacuum are presented. The fluorescence peak emission frequency of the nanostructures from the substituted p-quaterphenylenes shifts within the blue depending on the functionalisation. While dimensions are still influenced by the growth parameters, the overall shape (i.e. cross-section) of the aggregates alters significantly with the functional group. Even new properties like nonlinear optical activity are accessible. Due to intrinsic nonzero hyperpolarisability of push-pull functionalised oligomers, the respective nanofibers act as frequency doublers and emit strong second harmonic light after excitation with near infrared femtosecond laser pulses. Note that this design approach is possible while conserving the concept of highly crystalline nanofibers. Thus, a new route of bottom-up nanotechnology is presented starting from organic molecular synthesis towards generating of tailormade organic nanofibers opening new prospects for future nanotechnology. 3 ZusammenfassungDie Bildung von nadelförmigen Kristallen aus anorganischen und organischen Halbleitermolekülen wie zum Beispiel para-Phenylenen, α-Thiophenen und Phenylthiophen Co-oligomeren fa...

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Synthesis of Large Polycyclic Aromatic Hydrocarbons: Variation of Size and Periphery

Cited by 184 publications

References 30 publications

Schultz and Modified Schultz Polynomials of Coronene Polycyclic Aromatic Hydrocarbons

Schultz and Modified Schultz Polynomials of Coronene Polycyclic Aromatic Hydrocarbons

Chemical synthesis of graphene nanoribbons

Organic Molecular Nanotechnology

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