The C–Cl⋯π interactions inside supramolecular nanotubes of hexaethynylhexamethoxy[6]pericyclyne

Шишкин, Олег В.; Zubatyuk, Roman I.; Dyakonenko, Viktoriya V.; Lepetit, Christine; Chauvin, Rémi

doi:10.1039/c0cp02666b

Cited by 24 publications

(11 citation statements)

References 53 publications

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“…The structure of 4 in the co‐crystal 2 p – 4 indicates a trans ‐HC=CCl arrangement with an endocyclic Cl atom in the α position from the hexagon CH vertex, and an exocyclic H atom in the α position from the CPh vertex (confirmed by the corresponding deshielded 1 H NMR signal, see below). The inner orientation of the bulky Cl atom is thermodynamically disfavored for steric reasons, but might be partially stabilized by σ‐hole‐induced dipolar electrostatic interactions with facing formal triple bonds of the macrocycle . If G denotes the centroid of the C 18 ring of 4 , the short G···Cl distance of 0.92 ± 0.02 Å only quantifies a partial filling of the van der Waals hole of the carbo ‐benzene ring; this result is reminiscent of the interlocked carbo ‐benzene rings drawn in the original publication on carbo ‐benzenes (Figure ) …”

Section: Experimental Advances Towards Stripped or Filled Carbo‐benzementioning

confidence: 99%

Carbo‐Benzene's Aromaticity, Before and Beyond: A Tribute to Nozoe

Cocq

Maraval

Saffon‐Merceron

et al. 2015

The Chemical Record

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Beyond rigorous inspection of the literature, selected comments and drawings from the Nozoe Autograph Books show how concepts and targets of the chemistry of today already existed 40 years ago. This is illustrated for the chemistry of carbo-mers, which was actually unknowingly inspired by chemists of the golden age. After a personal travel through time and pages by the last author of this essay, who meets autographs by people who have been important in his career, in particular on the occasions of Nozoe's visits to France or past ISNA events, unpublished results in non-benzenoid chemistry are dedicated to Nozoe's memory. Experimental advances are first disclosed on the comparative chemistry of the three ortho, meta and para isomers of tetraphenyl-carbo-benzene C18 H2 Ph4 , the known ortho isomer serving as a reference. The two CH vertices of these chromophores make their [6]pericyclyne precursors quite sensitive and their yields and purifications challenging to optimize. The meta isomer was, however, isolated in 18% yield, and described by NMR and UV-vis absorption spectroscopy and crystallography. The para isomer was characterized both in pure form and in a 1:1 mixture with a single isomer of its HCl adduct, including by X-ray diffraction analysis of a co-crystal showing that the interior of the C18 ring of the HCl adduct is filled by the Cl atom. Theoretical advances are then offered regarding the "aromatic character" of a triple bond, by showing that the topological acyclic reference of acetylene is the Möbius-twisted cyclobutadiene. Acetylenoids are finally proposed as a novel class of non-benzenoid aromatics.

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Section: Experimental Advances Towards Stripped or Filled Carbo‐benzementioning

confidence: 99%

Carbo‐Benzene's Aromaticity, Before and Beyond: A Tribute to Nozoe

Cocq

Maraval

Saffon‐Merceron

et al. 2015

The Chemical Record

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“…Computational studies of a-graphyne instigated efforts for the synthesis and experimental study of the aggregation and assembly of carbo-benzene rings [15][16][17]. Within this spirit, Oleg Shishkin et al addressed the crystallographic packing mode of generic carbo-benzenes or their [6] pericyclic precursors [18], in particular by using the hedgehog model [19]. To extrapolate charge transport properties of a-graphyne, ''monomeric'' functional carbo-benzenes were studied for their single-molecule conductance (SMC) [20].…”

Section: Introductionmentioning

confidence: 98%

How carbo-benzenes fit molecules in their inner core as do biologic ion carriers?

Turias

Poater²,

Chauvin

et al. 2015

Struct Chem

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The present computational study complements experimental efforts to describe and characterize carbo-benzene derivatives as paradigms of aromatic carbo-mers. A long-lasting issue has been the possibility of the π-electron crown of the C18 carbo-benzene ring to fit metals or any chemical agents in its core. A systematic screening of candidate inclusion complexes was carried out by density functional theory calculations. Mayer bond order, aromaticity indices, and energy decomposition analyses complete the understanding of the strength of the host-guest interaction. The change in steric and electronic properties induced by the guest agent is investigated by means of steric maps. Substitution of H atoms at the carbo-benzene periphery by electron-withdrawing or electron-donating groups is shown to have a determining influence on the stability of the inclusion complex ions: while electronegative substituents enhance the recognition of cations, electropositive substituents do the same for anions. The results confirm the experimental failure hitherto to evidence a carbo-benzene complex. Nevertheless, the affinity of carbo-benzene for the potassium cation appears promising for the design of planar hydrocarbon analogues of biologic ion carriersA.P. thanks the Spanish MINECO for a project CTQ2014-59832-JIN and European Commission for a Career Integration Grant (CIG09-GA-2011-293900

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“…[5b, 6d, 11,19] Characterization of 1,10-dianisyldimethoxytetraphenylcarbo-cyclohexadiene (4): The 1 H NMR spectrum of the more polar fraction that corresponds to the most polar green TLC spot (R f % 0.25 and 0.30) displayed two pairs of OCH 3 signals in a 55:45 ratio in the region of the methoxy substituents of the [6]pericyclynic precursor 3, namely, at d = 3.65 and 3.77 ppm, respectively. A partial reduction of 3 was therefore anticipated, and indeed the molecular peak at m/z 800.39 uma of the MALDI-TOF spectrum was compatible with the doubly reduced species 4 A or 4 B, which occur as pairs of diastereoisomers (Scheme 4).…”

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confidence: 99%

From Hexaoxy‐[6]Pericyclynes to Carbo‐Cyclohexadienes, Carbo‐Benzenes, and Dihydro‐Carbo‐Benzenes: Synthesis, Structure, and Chromophoric and Redox Properties

Leroyer

Lepetit

Rives

et al. 2012

Chemistry A European J

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When targeting the quadrupolar p-dianisyltetraphenyl-carbo-benzene by reductive treatment of a hexaoxy-[6]pericyclyne precursor 3 with SnCl(2)/HCl, a strict control of the conditions allowed for the isolation of three C(18)-macrocyclic products: the targeted aromatic carbo-benzene 1, a sub-reduced non-aromatic carbo-cyclohexadiene 4A, and an over-reduced aromatic dihydro-carbo-benzene 5A. Each of them was fully characterized by its absorption and NMR spectra, which were interpreted by comparison with calculated spectra from static structures optimized at the DFT level. According to the nucleus-independent chemical shift (NICS) value (NICS≈-13 ppm), the macrocyclic aromaticity of 5A is indicated to be equivalent to that of 1. This is confirmed by the strong NMR spectroscopic deshielding of the ortho-CH protons of the aryl substituents, but also by the strong shielding of the internal proton of the endocyclic trans-CH=CH double bond that results from the hydrogenation of one of the C≡C bonds of 3. Both the aromatics 1 and 5A exhibit a high crystallinity, revealed by SEM and TEM images, which allowed for a structural determination by using an X-ray microsource. A good agreement with calculated molecular structures was found, and columnar assemblies of the C(18) macrocycles were evidenced in the crystal packing. The non-aromatic carbo-cyclohexadiene 4A is shown to be an intermediate in the formation of 1 from 3. It exhibits a remarkable dichromism in solution, which is related to the occurrence of two intense bands in the visible region of its UV/Vis spectrum. These properties could be attributed to the dibutatrienylacetylene (DBA) unit that occurs in the three chromophores, but which is not involved in a macrocyclic π-delocalization in 4A only. A versatile redox behavior of the carbo-chromophores is evidenced by cyclic voltammetry and was analyzed by calculation of the ionization potential, electron affinity, and frontier molecular orbitals.

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The C–Cl⋯π interactions inside supramolecular nanotubes of hexaethynylhexamethoxy[6]pericyclyne

Cited by 24 publications

References 53 publications

Carbo‐Benzene's Aromaticity, Before and Beyond: A Tribute to Nozoe

Carbo‐Benzene's Aromaticity, Before and Beyond: A Tribute to Nozoe

How carbo-benzenes fit molecules in their inner core as do biologic ion carriers?

From Hexaoxy‐[6]Pericyclynes to Carbo‐Cyclohexadienes, Carbo‐Benzenes, and Dihydro‐Carbo‐Benzenes: Synthesis, Structure, and Chromophoric and Redox Properties

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