0000000000017767
AUTHOR
David Beljonne
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 …
Dynamics of guest molecules in PHTP inclusion compounds as probed by solid-state NMR and fluorescence spectroscopy.
Partially deuterated 1,4-distyrylbenzene () is included into the pseudohexagonal nanochannels of perhydrotriphenylene (PHTP). The overall and intramolecular mobility of is investigated over a wide temperature range by (13)C, (2)H NMR as well as fluorescence spectroscopy. Simulations of the (2)H NMR spectral shapes reveal an overall wobble motion of in the channels with an amplitude of about 4 degrees at T = 220 K and 10 degrees at T = 410 K. Above T = 320 K the wobble motion is superimposed by localized 180 degrees flips of the terminal phenyl rings with a frequency of 10(6) Hz at T = 340 K. The activation energies of both types of motions are around 40 kJ mol(-1) which imply a strong steri…
Superexchange-mediated electronic energy transfer in a model dyad
On the basis of time-dependent density functional theory (TD-DFT) calculations coupled to the polarizable continuum model (PCM) and single molecule spectroscopic studies, we provide a detailed investigation of excitation energy transfer within a model bi-chromophoric system where a perylene monoimide (PMI) donor is bridged to a terrylene diimide (TDI) acceptor through a ladder-type pentaphenylene (pPh) spacer. We find that the electronic excitation on the PMI donor significantly extends over the bridge giving rise to a partial charge transfer character and inducing a approximately 3-fold increase in the electronic interaction between the chromophores, which explains the failure of the Först…
Oligophenylenevinylenes in Spatially Confined Nanochannels: Monitoring Intermolecular Interactions by UV/Vis and Raman Spectroscopy
Perhydrotriphenylene-based channel-forming inclusion compounds (ICs) and thin films made of polyphenylenevinylene (PPV)-type oligomers with terminal alkoxy groups are investigated and compared in a combined experimental and theoretical approach. Interchromophore interactions and host-guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum-chemical calculations. In stark contrast to thin films where preferential side-by-side orientation leads to quenching of photoluminescence (PL) via non-emissive traps, the ICs are found to be attractive materials f…
Ab Initio Modeling of Donor–Acceptor Interactions and Charge-Transfer Excitations in Molecular Complexes: The Case of Terthiophene–Tetracyanoquinodimethane
This work presents a thorough quantum chemical study of the terthiophene-tetracyanoquinodimethane complex as a model for π-π donor-acceptor systems. Dispersion-corrected hybrid (B3LYP-D) and double hybrid (B2PLYP-D), hybrid meta (M06-2X and M06-HF), and recently proposed long-range corrected (LC-wPBE, CAM-B3LYP, and wB97X-D) functionals have been chosen to deal with π-π intermolecular interactions and charge-transfer excitations in a balanced way. These properties are exhaustively compared to those computed with high-level ab initio SCS-MP2 and CASPT2 methods. The wB97X-D functional exhibits the best performance. It provides reliable intermolecular distances and interaction energies and pre…
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 …
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
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 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