Electrogenerated Chemiluminescence of Cationic Triangulene Dyes: Crucial Influence of the Core Heteroatoms

Adam, Catherine; Wallabregue, Antoine; Li, Haidong; Gouin, Jérôme; Vanel, Rémi; Grass, Stéphane; Bosson, Johann; Bouffier, Laurent; Lacour, Jérôme; Šojić, Nešo

doi:10.1002/chem.201501738

Cited by 23 publications

(30 citation statements)

References 57 publications

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“…It is noteworthy that a similar structure–activity relationship was previously observed on cationic triangulene dyes. [ 14 ] Not surprisingly, the reduction behavior of 2 stands in-between compounds 1 and 3 as a one-to-one comparison reveals cathodic shift of 0.33 V and 0.27 V respectively. As evidenced through the measurement of the p K R+ values of compounds 1 - 3 ( vide supra ) or observed in the case of other cationic helicenes the introduction of amino groups in place of the O atoms in the core structures clearly stabilizes the carbocations [ 2k,12b,12d ] Overall, the CV investigation reveals for all three cationic [6]helicenes a reversible monoelectronic reduction whereas the oxidation could be either reversible (diaza 3 ) or irreversible (dioxa 1 and azaoxa 2 ).…”

Section: Electrochemical Propertiesmentioning

confidence: 97%

Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence

Bosson

Labrador

Pascal

et al. 2016

Chemistry A European J

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Physicochemical properties of cationic dioxa 1, azaoxa 2 and diaza 3 [6]helicenes demonstrate a much higher chemical stability of diaza adduct 3 (pKR+ 20.4, E1false/2red −0.72 V) compared to azaoxa 2 (pKR+ 15.2, E1false/2red −0.45 V) and dioxa 1 (pKR+ 8.8, E1false/2red −0.12 V) analogues. The fluorescence of these cationic chromophores was established and ranges from the orange to the far-red regions. From 1 to 3, a bathochromic shift of the lowest energy transitions (up to 614 nm in acetonitrile) and an enhancement of the fluorescence quantum yields and lifetimes (up to 31% and 9.8 ns at 658 nm) are observed. The triplet quantum yields and the circularly polarized luminescence are also reported. Finally, fine tuning of the optical properties of the diaza [6]helicene core was achieved through selective and orthogonal post-functionalization reactions (12 examples, compounds 4-15). The electronic absorption is modulated from the orange to far-red spectral range (560-731 nm) while fluorescence is observed from 591 to 755 nm with enhanced quantum efficiency up to 70% (619 nm). The influence of the peripheral auxochrome substituents is rationalized by first-principles calculations.

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Section: Electrochemical Propertiesmentioning

confidence: 97%

Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence

Bosson

Labrador

Pascal

et al. 2016

Chemistry A European J

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“…The series of [4], [6]helicenes and triangulene 1–11 was investigated by recording cyclic voltammetry in acetonitrile containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF 6 ) as supporting electrolyte. The electrochemical behavior of some of the compounds was previously described in several independent contributions and they were gathered here with new voltammetric characterizations in order to draw a full structure/activity relationship. Briefly, the 1‐electron reduction of the cation forms a neutral species and the electron transfer reaction is reversible at a scan rate of 0.1 V s −1 .…”

Section: Resultsmentioning

confidence: 99%

Efficient Annihilation Electrochemiluminescence of Cationic Helicene Luminophores

Voci

Wallabregue

et al. 2017

ChemElectroChem

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The electrochemistry and annihilation electrochemiluminescence (ECL) of a series of chiral cationic helicene luminophores containing various substituents were investigated in acetonitrile solvent. The electrochemical characterization evidenced a systematic reversible reduction of cationic derivatives, whereas the oxidation could be reversible or not, depending on the nature of the core heteroatoms within the structure as well as the functional-group appendages. One of the key parameters governing the ECL intensity is, indeed, the formal redox potentials for the electrogeneration of the neutral radical and dication radical species, which will undergo the annihilation reaction. On that basis, a thermodynamic wall of efficiency was proposed in the case of ECL annihilation pathway to predict the formation efficiency of the emitting excited state and, eventually, the light emission's strength. This very simple wall is constructed by plotting the difference of formal potentials in function of the fluorescence wavelength, thus delimiting two domains where ECL is thermodynamically possible or unfavorable.

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“…They are formed by a double nucleophilic aromatic substitution of ortho methoxy groups of tris(2,6‐dimethoxyphenyl)methylium ions with primary amines, gaining mono‐nitrogen, double‐nitrogen, and triple‐nitrogen bridged salts depending on the reaction conditions . The interest in those cations is sparked by their high symmetry, electronic and optical properties, in particular including their electrogenerated chemiluminescence emission, redox behavior, light absorption, and fluorescence …”

Section: Introductionmentioning

confidence: 99%

Influence of electronic and molecular structure on the fragmentation dynamic of even-electron carbocationic triangulenes and helicenes in the gas phase

et al. 2017

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Stable, long-lived organic cations are directly transferred by electrospray ionization (ESI) from solution into the gas phase where their collision-induced dissociations (CID) are studied by tandem mass spectrometry. Three related types of triphenyl carbenium ions are investigated, in which the meta positions are either substituted by methoxy groups or tertiary nitrogen bridges, including tetramethoxyphenylacridinium (TMPA ), dimethoxyquinacridinium (DMQA ), and triazatriangulenium (TATA ) cations. These ions are triangular in shape with increasing degrees of planarity. Fragmentation occurs at the periphery of the triangular molecule, involving the methoxy groups and the substituent of the nitrogen bridge. Each initial precursor cation is an even electron (EE) system and shows competing dissociations into both even (EE) and odd electron (OE) fragment ions. The latter reaction is a breach of the classic 'even-electron rule' in mass spectrometry. While the EE fragment dissociates similar to the precursor, the OE fragment ion shows a rich radical-induced fragmentation pattern. Two driving forces direct the fragmentation of the EE precursor ion toward OE fragment ions, including the release of stabilized radicals and the extension of the π-system by increasing planarization of the triangulene core. Copyright © 2017 John Wiley & Sons, Ltd.

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Electrogenerated Chemiluminescence of Cationic Triangulene Dyes: Crucial Influence of the Core Heteroatoms

Cited by 23 publications

References 57 publications

Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence

Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence

Efficient Annihilation Electrochemiluminescence of Cationic Helicene Luminophores

Influence of electronic and molecular structure on the fragmentation dynamic of even-electron carbocationic triangulenes and helicenes in the gas phase

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