Unexpected Scholl Reaction of 6,7,13,14-Tetraarylbenzo[k]tetraphene: Selective Formation of Five-Membered Rings in Polycyclic Aromatic Hydrocarbons
Cyclodehydrogenation is a versatile reaction that has enabled the syntheses of numerous polycyclic aromatic hydrocarbons (PAHs). We now describe a unique Scholl reaction of 6,7,13,14-tetraarylbenzo[k]tetraphene, which "unexpectedly" forms five-membered rings accompanying highly selective 1,2-shift of aryl groups. The geometric and optoelectronic nature of the resulting bistetracene analogue with five-membered rings is comprehensively investigated by single-crystal X-ray, NMR, UV-vis absorption, and cyclic voltammetry analyses. Furthermore, a possible mechanism is proposed to account for the selective five-membered-ring formation with the rearrangement of the aryl groups, which can be ration…
Fused Dibenzo[ a , m ]rubicene: A New Bowl-Shaped Subunit of C 70 Containing Two Pentagons
Total synthetic approaches of fullerenes are the holy grail for organic chemistry. So far, the main attempts have focused on the synthesis of the buckminsterfullerene C60. In contrast, access to subunits of the homologue C70 remains challenging. Here, we demonstrate an efficient bottom-up strategy toward a novel bowl-shaped polycyclic aromatic hydrocarbons (PAH) C34 with two pentagons. This PAH represents a subunit for C70 and of other higher fullerenes. The bowl-shaped structure was unambiguously determined by X-ray crystallography. A bowl-to-bowl inversion for a C70 fragment in solution was investigated by dynamic NMR analysis, showing a bowl-to-bowl inversion energy (ΔG(⧧)) of 16.7 kcal …
Experimental Observation of Strong Exciton Effects in Graphene Nanoribbons
Graphene nanoribbons (GNRs) with atomically precise width and edge structures are a promising class of nanomaterials for optoelectronics, thanks to their semiconducting nature and high mobility of charge carriers. Understanding the fundamental static optical properties and ultrafast dynamics of charge carrier generation in GNRs is essential for optoelectronic applications. Combining THz spectroscopy and theoretical calculations, we report a strong exciton effect with binding energy up to 700 meV in liquid-phase-dispersed GNRs with a width of 1.7 nm and an optical bandgap of 1.6 eV, illustrating the intrinsically strong Coulomb interactions between photogenerated electrons and holes. By trac…
Synthesis of Nonplanar Graphene Nanoribbon with Fjord Edges
As a new family of semiconductors, graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have appeared as promising candidates for next-generation nanoelectronics. Out-of-plane deformation of π-frames in GNRs brings further opportunities for optical and electronic property tuning. Here we demonstrate a novel fjord-edged GNR (FGNR) with a nonplanar geometry obtained by regioselective cyclodehydrogenation. Triphenanthro-fused teropyrene 1 and pentaphenanthro-fused quateropyrene 2 were synthesized as model compounds, and single-crystal X-ray analysis revealed their helically twisted conformations arising from the [5]helicene substructures. The structures and photophysical properties …
Perylene Derivatives As Useful SERRS Reporters, Including Multiplexing Analysis
Five perylene bisimide (PBI) derivatives were designed and synthesized, on the basis of quantum-chemical calculations. The influence of halogen substituents on the shape and energy of the frontier orbitals and the Raman spectra were calculated, in the prospect use in surface-enhanced resonance Raman scattering (SERRS) studies. The corresponding experiments confirmed a very strong SERRS response in the presence of pristine (i.e., uncoated) gold nanoparticles. These spectra can be used for multiplexing measurements, namely measurements in which, by using a single laser excitation, one can recognize the simultaneous presence of several analytes.
CCDC 1428696: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Akimitsu Narita, Silvio Osella, Wen Zhang, Dieter Schollmeyer, David Beljonne, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|2602|doi:10.1021/jacs.5b10399
CCDC 1472204: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Silvio Osella, Ji Ma, Reinhard Berger, David Beljonne, Dieter Schollmeyer, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|8364|doi:10.1021/jacs.6b04426
CCDC 2058017: Experimental Crystal Structure Determination
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CCDC 1428694: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Akimitsu Narita, Silvio Osella, Wen Zhang, Dieter Schollmeyer, David Beljonne, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|2602|doi:10.1021/jacs.5b10399
CCDC 1427947: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Akimitsu Narita, Silvio Osella, Wen Zhang, Dieter Schollmeyer, David Beljonne, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|2602|doi:10.1021/jacs.5b10399
CCDC 2058018: Experimental Crystal Structure Determination
Related Article: Xuelin Yao, Wenhao Zheng, Silvio Osella, Zijie Qiu, Shuai Fu, Dieter Schollmeyer, Beate Müller, David Beljonne, Mischa Bonn, Hai I. Wang, Klaus Müllen, Akimitsu Narita|2021|J.Am.Chem.Soc.|143|5654|doi:10.1021/jacs.1c01882
CCDC 1428695: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Akimitsu Narita, Silvio Osella, Wen Zhang, Dieter Schollmeyer, David Beljonne, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|2602|doi:10.1021/jacs.5b10399
CCDC 1472205: Experimental Crystal Structure Determination
Related Article: Junzhi Liu, Silvio Osella, Ji Ma, Reinhard Berger, David Beljonne, Dieter Schollmeyer, Xinliang Feng, and Klaus Müllen|2016|J.Am.Chem.Soc.|138|8364|doi:10.1021/jacs.6b04426