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Picometer Detection by Adaptive Holographic Interferometry
Published in Klaus D. Sattler, Fundamentals of PICOSCIENCE, 2013
The continuation of this work in a very recent paper demonstrated that a CO-functionalized tip used in a noncontact AFM can distinguish different bond orders of individual C-C bonds in polycyclic aromatic hydrocarbons and fullerenes. 120 Figure 8.21 a shows the model of hexabenzocoronene, with the i-bonds within the central ring having greater bond order than the j-bonds which connect the central ring to the outside rings. The AFM images for two different z-heights are shown in Figure 8.21b and c, and the i-bonds are imaged as brighter and shorter than the j-bonds. The calculated electron density from DFT in Figure 8.21d corroborates this assignment.
Two-dimensional coronene fractal structures: topological entropy measures, energetics, NMR and ESR spectroscopic patterns and existence of isentropic structures
Published in Molecular Physics, 2022
Micheal Arockiaraj, Joseph Jency, Jessie Abraham, S. Ruth Julie Kavitha, Krishnan Balasubramanian
The family of deterministic benzenoid fractals was studied by Klein et al. [35] by compounding a benzene unit systematically at different stages, the first stage being benzene, the second stage being benzenoid compounds such as kekulene, coronene, singly connected benzene, and so on. The coronoid family of benzenoid fractals, in particular, is obtained by circumscribing benzene to generate coronene, and then fusing six copies of benzo[ghi]perylenes through their bay regions to yield six coronene-shaped frames and a hexabenzocoronene hole, as shown in Figure 1. In general, for , the nth stage fractal of a coronoid family is obtained by merging six copies of th stage fractal structure. Such materials have attracted the attention of synthetic organic chemists and material scientists as they are precursors to novel nanomaterials in nano and biotechnology. The aromaticity of fractal benzenoids was investigated based on Clar structures by Plavsić et al. [36] while El-Basil [37] has demonstrated the characteristic scaling factor of molecular fractals as the golden mean value (τ = 1.618033989). Though the chances of synthesising these fractal molecules were discussed in the early 1990s [35], their synthesis continues to be a challenging problem till date. This in fact signifies the present work in which we present the theoretical characterisation of these coronene-based molecular fractals that would help further understand and grasp the behaviours of these fractal compounds.
Synthesis and properties of 3-fold symmetrical hexabenzocoronene-bridged trinuclear alkynylgold(I) complexes
Published in Journal of Coordination Chemistry, 2021
Ming-Xing Zhang, Xuyang Jin, Xiaofei Yang, Zhiqiang Xu, Sheng Hua Liu
As an important class of polycyclic aromatic hydrocarbons (PAHs) [1–3], hexa-peri-hexabenzocoronene (planar HBC, p-HBC) and hexa-cata-hexabenzocoronene (contorted HBC, c-HBC) which show high stability, good hole transport ability, unique optoelectronic properties and facile supramolecular self-assembly behavior, have attracted enormous attention in synthetic chemistry and organic optoelectronic devices [4–7]. Compared with the hexa-peri-hexabenzocoronene (p-HBC), the aromatic core of hexa-cata-hexabenzocoronene (c-HBC) and its derivatives have doubly concave structures due to the steric hindrance of adjacent C-H bonds. Their properties are affected by the central core and the edge substituents. They have good electronic and self-assembly properties, and can be used as new organic functional materials. Therefore, the synthesis and studies of functional hexa-cata-hexabenzocoronenes are of great significance [8–11].
A short review of nanographenes: structures, properties and applications
Published in Molecular Physics, 2018
Yafei Dai, Yi Liu, Kai Ding, Jinlong Yang
With various synthesis routes mentioned above, numerous NGs are prepared successfully with different size, shape, edges and substituents. Halleux et al. (1958) described for the first time the planar NG C42 composed of 13 benzene rings synthesised successfully applying the Hexa-peri-hexabenzocoronene method and the structure is shown in Figure 1 [29,30,36]. After that Müllen et al. presented the synthesis and characterisation of a series of planar NGs with various geometries and sizes, including C48, C72, C96, C132, C150 and C222 (Figure 1). These NGs were synthesised by a sequence of Diels-Alder and cyclotrimerisation reactions to build up oligophenylene precursor molecule, and then planarised in the final step by oxidative cyclodehydrogenation to the corresponding hexagonal PAH [30,37].