共查询到20条相似文献,搜索用时 0 毫秒
1.
Dr. Max M. Martin Dr. Frank Hampel Prof. Dr. Norbert Jux 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(45):10210-10212
A synthetic route towards a novel hexabenzocoronene-based helical nanographene motif was developed. A hexaphenylbenzene precursor was therefore designed, which cannot undergo, due to steric restrictions, a complete planarization reaction. This precursor was transformed under oxidative cyclodehydrogenation conditions to a π-extended [5]helicene, which was fully characterized including X-ray diffraction analysis. 相似文献
2.
Luka
orevi Cataldo Valentini Nicola Demitri Ccile Mzire Magali Allain Marc Sall Andrea Folli Damien Murphy Samuel Maas‐Valero Eugenio Coronado Davide Bonifazi 《Angewandte Chemie (International ed. in English)》2020,59(10):4106-4114
Herein we report an efficient synthesis to prepare O‐doped nanographenes derived from the π‐extension of pyrene. The derivatives are highly fluorescent and feature low oxidation potentials. Using electrooxidation, crystals of cationic mixed‐valence (MV) complexes were grown in which the organic salts organize into face‐to‐face π‐stacks, a favorable solid‐state arrangement for organic electronics. Variable‐temperature electron paramagnetic resonance (EPR) measurements and relaxation studies suggest a strong electron delocalization along the longitudinal axis of the columnar π‐stacking architectures. Electric measurements of single crystals of the MV salts show a semiconducting behavior with a remarkably high conductivity at room temperature. These findings support the notion that π‐extension of heteroatom‐doped polycyclic aromatic hydrocarbons is an attractive approach to fabricate nanographenes with a broad spectrum of semiconducting properties and high charge mobilities. 相似文献
3.
Giacomo Biagiotti Ilaria Perini Barbara Richichi Stefano Cicchi 《Molecules (Basel, Switzerland)》2021,26(20)
The success of the rational bottom-up approach to nanostructured carbon materials and the discovery of the importance of their doping with heteroatoms puts under the spotlight all synthetic organic approaches to polycyclic aromatic hydrocarbons. The construction of atomically precise heteroatom doped nanographenes has evidenced the importance of controlling its geometry and the position of the doping heteroatoms, since these parameters influence their chemical–physical properties and their applications. The growing interest towards this research topic is testified by the large number of works published in this area, which have transformed a once “fundamental research” into applied research at the cutting edge of technology. This review analyzes the most recent synthetic approaches to this class of compounds. 相似文献
4.
Synthesis of Nitrogen‐Doped ZigZag‐Edge Peripheries: Dibenzo‐9a‐azaphenalene as Repeating Unit
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Reinhard Berger Angelos Giannakopoulos Prince Ravat Dr. Manfred Wagner Dr. David Beljonne Prof. Dr. Xinliang Feng Prof. Dr. Klaus Müllen 《Angewandte Chemie (International ed. in English)》2014,53(39):10520-10524
A bottom‐up approach toward stable and monodisperse segments of graphenes with a nitrogen‐doped zigzag edge is introduced. Exemplified by the so far unprecedented dibenzo‐9a‐azaphenalene (DBAPhen) as the core unit, a versatile synthetic concept is introduced that leads to nitrogen‐doped zigzag nanographenes and graphene nanoribbons. 相似文献
5.
Dr. Diego Cortizo‐Lacalle Juan P. Mora‐Fuentes Dr. Karol Strutyński Prof. Dr. Akinori Saeki Prof. Dr. Manuel Melle‐Franco Prof. Dr. Aurelio Mateo‐Alonso 《Angewandte Chemie (International ed. in English)》2018,57(3):703-708
The properties of graphene nanoribbons are highly dependent on structural variables such as width, length, edge structure, and heteroatom doping. Therefore, atomic precision over all these variables is necessary for establishing their fundamental properties and exploring their potential applications. An iterative approach is presented that assembles a small and carefully designed molecular building block into monodisperse N‐doped graphene nanoribbons with different lengths. To showcase this approach, the synthesis and characterisation of a series of nanoribbons constituted of 10, 20 and 30 conjugated linearly‐fused rings (2.9, 5.3, and 7.7 nm in length, respectively) is presented. 相似文献
6.
David Reger Kilian Schöll Dr. Frank Hampel Dr. Harald Maid Prof. Dr. Norbert Jux 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(6):1984-1989
In this work we present the solution-synthesis of pyridine analogues to hexa-peri-hexabenzocoronene (HBC)—which might be called superpyridines—via a novel precursor design. The key step in our strategy was the pre-formation of the C−C bonds between the 3/3’ positions of the pyridine and the adjacent phenyl rings—bonds that are otherwise unreactive and difficult to close under Scholl-conditions. Apart from the synthesis of the parent compound we show that classical pyridine chemistry, namely oxidation, N-alkylation and metal-coordination is applicable to the π-extended analogue. Furthermore, we present basic physical chemical characterizations of the newly synthesized molecules. With this novel synthetic strategy, we hope to unlock the pyridine chemistry of nanographenes. 相似文献
7.
Computational studies have often been carried out on hydrogen-terminated nanographenes (NGs). These structures are, however, far from those deduced from experimental observations, which have suggested armchair edges with two carboxy groups on the edges as dominant. We conducted computational studies on NGs consisting of C42, C60, C78, C96, C142, and C174 carbon atoms with hydrogen, carboxy, and N-methyl imide-terminated armchair edges. DFT calculations inform distorted basal planes and similar HOMO-LUMO gaps, indicating that the edge oxidation and functionalization do not very influence the electronic structure. Comparison of observed UV-vis spectra of carboxy- and N-octadecyl chain terminated NGs with calculated spectra of model NGs informs the contribution of π-π* transitions on the basal plane to the absorptions in the visible region. A dimeric structure of NG and octadecyl-installed NG demonstrate that both the distorted basal planes and the steric contacts among the functional groups widen the surface-to-surface distance thereby allowing the invasion of solvent molecules between the surfaces. This picture is consistent with the improved solubility of edge-modified NGs. 相似文献
8.
Shusaku Takahashi Prof. Dr. Ryo Sekiya Prof. Dr. Takeharu Haino 《Chemphyschem》2023,24(12):e202300066
Regulation of the physical properties of nanographenes (NGs) by edge functionalization is an active research area. We conducted a computational study of the effects of edge functionalization on the physical properties of NGs. The computed NGs were models of experimentally obtained NGs and composed of a C174 carbon framework with one to four 3,5-dimethylnaphthalene units on the edge. The effects were assessed structurally, magnetically, and electronically by the least square planarity index, harmonic oscillator model of aromaticity, nucleus-independent chemical shift, and HOMO–LUMO (H–L) gaps. Density functional theory calculations indicate that although the structures of the model NGs are not very sensitive to edge functionalization, but the magnetic and electronic properties are. The installed substituents narrowed the H−L gap and induced a redshift of the photoluminescence (PL) band by the π conjugation between NG and the substituent. These results are consistent with the extension of the absorption band and the redshift of the PL bands of the experimentally modified NGs. Furthermore, the calculations confirmed the contribution of the charge transfer character to the absorption spectra. 相似文献
9.
10.
En Route to Stimuli‐Responsive Boron‐, Nitrogen‐, and Sulfur‐Doped Polycyclic Aromatic Hydrocarbons
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Valentin M. Hertz Julian G. Massoth Dr. Michael Bolte Dr. Hans‐Wolfram Lerner Prof. Dr. Matthias Wagner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13181-13188
Replacing both meso carbon atoms of the polycyclic aromatic hydrocarbon (PAH) bisanthene by boron atoms creates an efficient blue fluorophore with a strong electron‐accepting character. The corresponding meso‐B,S‐doped bisanthene exhibits a solvent‐dependent green‐to‐orange photoluminescence and undergoes a reversible reduction at E =?2.06 V (vs. FcH/FcH+). After oxidation of the sulfur atom, the resulting sulfoxide emits in the blue range of the spectrum, shows only negligible solvatochromism, and a reversible redox transition at E =?1.74 V. Several related B, N‐ and B, S‐containing PAHs have been prepared following the same modular synthetic procedure and are also described herein. In order to systematically compare their optoelectronic properties, all products have been investigated by cyclic voltammetry as well as UV/Vis absorption/emission spectroscopy. 相似文献
11.
《Angewandte Chemie (International ed. in English)》2017,56(40):12356-12360
Two saddle‐shaped polycyclic aromatic compounds ( 8 a and 8 b ) bearing an all‐cis‐[5.5.5.5]fenestrane core surrounded by an o,p,o,p,o,p,o,p‐cyclooctaphenylene belt were synthesized and characterized by NMR spectroscopy and mass spectrometry. The key step of this synthesis involves the formation of four cycloheptatriene rings from the corresponding electron‐rich 1,4,9,12‐tetraarylfenestrindane derivatives 7 a and 7 b in Scholl‐type cyclizations. The structural details of the D2d‐symmetric saddle compound 8 a were determined by X‐ray crystallography, and the properties of 8 a and 8 b were studied by UV/Vis and fluorescence spectroscopy and cyclic voltammetry. 相似文献
12.
Trefoil‐Shaped Porous Nanographenes Bearing a Tribenzotriquinacene Core by Three‐fold Scholl Macrocyclization
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Lisi He Dr. Chun‐Fai Ng Yuke Li Prof. Zhifeng Liu Prof. Dietmar Kuck Prof. Hak‐Fun Chow 《Angewandte Chemie (International ed. in English)》2018,57(41):13635-13639
Porous curved polycyclic aromatic compounds 6 and 14 bearing a tribenzotriquinacene (TBTQ) core encircled by an m,p,p,m,m,p,p,m,m,p,p,m‐cyclododecaphenylene belt were synthesized and characterized by NMR spectroscopy and mass spectrometry. These trefoil hydrocarbon macrocycles were constructed in high yield using an intramolecular three‐fold Scholl macrocyclization. X‐ray crystal analysis of 14 demonstrated a large wizard‐hat‐shaped structure with three pores (radii 2.9–3.0 Å). The π‐stacking aggregation of the hexa‐n‐dodecyloxy derivative 6 a and the chloride anion binding properties of 14 were studied by NMR spectroscopy. Such stacking and anion binding properties were much weaker in the singly 11 and doubly macrocyclized products 12 . 相似文献
13.
14.
Dr. Uwe Hahn Prof. Emmanuel Maisonhaute Dr. Jean‐François Nierengarten 《Angewandte Chemie (International ed. in English)》2018,57(33):10635-10639
Two diastereoisomeric N‐doped nanographene derivatives have been efficiently prepared in two synthetic steps starting from an ethynylated hexaazatriphenylene building block. The first derivative adopts a D3‐symmetrical propeller‐shaped structure with three equivalent nanographene foils. The structure of the second diastereoisomer is C2‐symmetrical and differs from the first one by the way two peripheral nanographene foils overlap. Owing to their intertwined structures, the two N‐doped nanographenes are soluble in organic solvents and could be characterized by a combination of several analytical tools. Resolution of the D3‐symmetrical derivative has been achieved and CD measurements revealed extremely strong Cotton effects. 相似文献
15.
Juan P. Mora‐Fuentes Alberto Riao Diego Cortizo‐Lacalle Akinori Saeki Manuel Melle‐Franco Aurelio Mateo‐Alonso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(2):562-566
Star‐shaped nanographenes (SNGs) are large monodisperse polycyclic aromatic hydrocarbons that are larger than a nanometer and have shown a lot of promise in a wide range of applications including electronics, energy conversion, and sensing. Herein, we report a new family of giant star‐shaped N‐doped nanographenes with diameters up to 6.5 nm. Furthermore, the high solubility of this SNG family in neutral organic solvents at room temperature allowed a complete structural, optoelectronic, and electrochemical characterisation, which together with charge transport studies illustrate their n‐type semiconducting character. 相似文献
16.
Jacopo Dosso Tommaso Battisti Dr. Benjamin D. Ward Dr. Nicola Demitri Dr. Colan E. Hughes Dr. P. Andrew Williams Prof. Dr. Kenneth D. M. Harris Prof. Dr. Davide Bonifazi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6608-6621
In this work, a comprehensive account of the authors’ synthetic efforts to prepare borazino-doped hexabenzocoronenes by using the Friedel–Crafts-type electrophilic aromatic substitution is reported. Hexafluoro-functionalized aryl borazines, bearing an ortho fluoride leaving group on each of the N- and B-aryl rings, was shown to lead to cascade-type electrophilic aromatic substitution events in the stepwise C−C bond formation, giving higher yields of borazinocoronenes than those obtained with borazine precursors bearing fluoride leaving groups at the ortho positions of the B-aryl substituents. By using this pathway, an unprecedented boroxadizine-doped PAH featuring a gulf-type periphery could be isolated, and its structure proven by single-crystal X-ray diffraction analysis. Mechanistic studies on the stepwise Friedel–Crafts-type cyclization suggest that the mechanism of the planarization reaction proceeds through extension of the π system. To appraise the doping effect of the boroxadizine unit on the optoelectronic properties of topology-equivalent molecular graphenes, the all-carbon and pyrylium PAH analogues, all featuring a gulf-type periphery, were also prepared. As already shown for the borazino-doped hexabenzocoronene, the replacement of the central benzene ring by its B3N2O congener widens the HOMO–LUMO gap and dramatically enhances the fluorescence quantum yield. 相似文献
17.
Ji Ma Yubin Fu Evgenia Dmitrieva Fupin Liu Hartmut Komber Felix Hennersdorf Alexey A. Popov Jan J. Weigand Junzhi Liu Xinliang Feng 《Angewandte Chemie (International ed. in English)》2020,59(14):5637-5642
Three unprecedented helical nanographenes ( 1 , 2 , and 3 ) containing an azulene unit are synthesized. The resultant helical structures are unambiguously confirmed by X‐ray crystallographic analysis. The embedded azulene unit in 2 possesses a record‐high twisting degree (16.1°) as a result of the contiguous steric repulsion at the helical inner rim. Structural analysis in combination with theoretical calculations reveals that these helical nanographenes manifest a global aromatic structure, while the inner azulene unit exhibits weak antiaromatic character. Furthermore, UV/Vis‐spectral measurements reveal that superhelicenes 2 and 3 possess narrow energy gaps ( 2 : 1.88 eV; 3 : 2.03 eV), as corroborated by cyclic voltammetry and supported by density functional theory (DFT) calculations. The stable oxidized and reduced states of 2 and 3 are characterized by in‐situ EPR/Vis–NIR spectroelectrochemistry. Our study provides a novel synthetic strategy for helical nanographenes containing azulene units as well as their associated structures and physical properties. 相似文献
18.
Kairi Yamato Ryo Sekiya Kaho Suzuki Takeharu Haino 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9120-9124
The quantum‐size effect, which enables nanographenes to emit photoluminescence (PL) in the UV to visible region, has inspired intense research. However, the control of the PL properties of nanographenes through manipulation of their π‐system by post‐modifications is not well developed. By utilizing a ring‐closure reaction between an aromatic 1,2‐dicarboxylic acid and a 1,8‐naphthalenediamine derivative, which produces a perimidine framework, nitrogen‐doped nanographenes were realized. Two nanographenes produced by a one‐pot reaction of edge‐oxidized nanographene (GQD‐ 2 ) with 1,8‐naphthalenediamine derivatives (GQD‐ 1 a and GQD‐ 1 b ) displayed an absorption band extending to >1000 nm; furthermore, the PL wavelength of GQD‐ 1 a was significantly red‐shifted into the near‐infrared (NIR) region in which it can be used for bioimaging. Time‐dependent DFT calculations of model nanographenes showed that the functional groups narrow the HOMO–LUMO gap, realizing the NIR‐emitting nanographenes. 相似文献
19.
An Electron‐Poor C64 Nanographene by Palladium‐Catalyzed Cascade C−C Bond Formation: One‐Pot Synthesis and Single‐Crystal Structure Analysis
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sabine Seifert Dr. Kazutaka Shoyama Dr. David Schmidt Prof. Dr. Frank Würthner 《Angewandte Chemie (International ed. in English)》2016,55(22):6390-6395
Herein, we report the one‐pot synthesis of an electron‐poor nanographene containing dicarboximide groups at the corners. We efficiently combined palladium‐catalyzed Suzuki–Miyaura cross‐coupling and dehydrohalogenation to synthesize an extended two‐dimensional π‐scaffold of defined size in a single chemical operation starting from N‐(2,6‐diisopropylphenyl)‐4,5‐dibromo‐1,8‐naphthalimide and a tetrasubstituted pyrene boronic acid ester as readily accessible starting materials. The reaction of these precursors under the conditions commonly used for Suzuki–Miyaura cross‐coupling afforded a C64 nanographene through the formation of ten C?C bonds in a one‐pot process. Single‐crystal X‐ray analysis unequivocally confirmed the structure of this unique extended aromatic molecule with a planar geometry. The optical and electrochemical properties of this largest ever synthesized planar electron‐poor nanographene skeleton were also analyzed. 相似文献
20.
Frontispiece: An Electron‐Poor C64 Nanographene by Palladium‐Catalyzed Cascade C−C Bond Formation: One‐Pot Synthesis and Single‐Crystal Structure Analysis
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sabine Seifert Dr. Kazutaka Shoyama Dr. David Schmidt Prof. Dr. Frank Würthner 《Angewandte Chemie (International ed. in English)》2016,55(22)