Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption-based upconversion and circularly polarized luminescence

Cruz, Carlos M.; Márquez, Irene R.; Mariz, Inês F. A.; Blanco, Víctor Francisco Sampedro; Sánchez‐Sánchez, Carlos; Sobrado, Jesús Manuel; Martín‐Gago, José A.; Cuerva, Juan M.; Maçôas, Ermelinda; Campaña, Araceli G.

doi:10.1039/c8sc00427g

Cited by 138 publications

(94 citation statements)

References 104 publications

(29 reference statements)

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“…Campaña and co‐workers synthesized the superhelicene 207 in 7 % yield by employing DDQ/TfOH as an oxidant (Figure ) . The authors have also reported the synthesis of other large PAH‐helicenes and superhelicenes by oxidative coupling …”

Section: Intramolecular Oxidative Aromatic Couplingmentioning

confidence: 98%

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

et al. 2019

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Oxidative aromatic coupling occupies a fundamental place in the modern chemistry of aromatic compounds. It is a method of choice for the assembly of large and bewildering architectures. Considerable effort was also devoted to applications of the Scholl reaction for the synthesis of chiral biphenols and natural products. The ability to form biaryl linkages without any prefunctionalization provides an efficient pathway to many complex structures. Although the chemistry of this process is only now becoming fully understood, this reaction continues to both fascinate and challenge researchers. This is especially true for heterocoupling, that is, oxidative aromatic coupling with the chemoselective formation of a C−C bond between two different arenes. Analysis of the progress achieved in this field since 2013 reveals that many groups have contributed by pushing the boundary of structural possibilities, expanding into surface‐assisted (cyclo)dehydrogenation, and developing new reagents.

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Section: Intramolecular Oxidative Aromatic Couplingmentioning

confidence: 98%

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

et al. 2019

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“…As occurred in the case of the TTM radical, the DE CD band resulted in opposite Cotton effectst o that of the main feature of the spectrum (i.e.,CECD band). According to literature, the sign of the minor absorption bands at longest wavelengths can play arelevant role, since they usually determine the sign of the CPL spectrum, [32] as occurs for the case of carbo[n]helicenes. [33] Thus, in line with previous results, [17] the (P)-TTBrM radicalw as associated with the second eluted (CSP)HPLC fraction while the first one, with a( À) 567 nm ECD Dband, was related to the (M)-TTBrM radical.U nfortunately,n oe nantiopure monocrystals for X-ray diffraction could be obtained to assign the absolute configuration (i.e.…”

Section: Resolution and Evaluation Of The Racemization Barriermentioning

confidence: 99%

An Enantiopure Propeller‐Like Trityl‐Brominated Radical: Bringing Together a High Racemization Barrier and an Efficient Circularly Polarized Luminescent Magnetic Emitter

Mayorga‐Burrezo

Jiménez

Blasi

et al. 2020

Chemistry A European J

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A new persistent organic free radical has been synthetized with Br atoms occupying the ortho‐ and para‐positions of a trityl core. After the isolation of its two propeller‐like atropisomers, Plus (P) and minus (M), their absolute configurations were assigned by a combination of theoretical and experimental data. Remarkably, no hints of racemization were observed up to 60 °C for more than two hours, due to the higher steric hindrance imposed by the bulky Br atoms. Therefore, when compared to its chlorinated homologue (t1/2=18 s at 60 °C), an outstanding stability against racemization was achieved. A circularly polarized luminescence (CPL) response of both enantiomers was detected. This free radical shows a satisfactory luminescent dissymmetry factor (|glum(592 nm)|≈0.7×10−3) despite its pure organic nature and low luminescence quantum yield (LQY). Improved organic magnetic CPL emitters derived from the reported structure can be envisaged thanks to the wide possibilities that Br atoms at para‐positions offer for further functionalization.

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“…With the idea to further enrich the photophysics of this fascinating platform we have built on their biaryl structure, which provides a means to arrive at dyes with helical chirality and the corresponding observation of interesting chiroptical properties, including the detection of circularly polarized luminescence (CPL) . The phenomenon is well established for supramolecular assemblies or nanostructures . However, the observation of CPL from small organic molecules (SOMs), albeit generally showing smaller dissymmetry factors ( g ), has recently created considerable interest in the dye chemistry community .…”

Section: Introductionmentioning

confidence: 99%

“…[29][30][31][32] The phenomenoni sw ell established for supramolecular assemblies or nanostructures. [29,[33][34][35][36][37][38][39][40] However,t he observation of CPL from small organicm olecules (SOMs), albeit generally showing smaller dissymmetry factors (g), has recently createdc onsiderable interesti nt he dye chemistry community. [30] Potential applications are chiral sensing or the preparation of chiroptical systems with innovative photophysical design.…”

Section: Introductionmentioning

confidence: 99%

Azabora[5]helicene Charge‐Transfer Dyes Show Efficient and Spectrally Variable Circularly Polarized Luminescence

Domínguez

López‐Rodríguez

Álvarez

et al. 2018

Chemistry A European J

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Three helicenes based on a borylated arylisoquinoline skeleton have been prepared in their enantiopure forms and characterized with respect to their photophysical properties, including the use of chiroptical spectroscopies. The dyes show varying charge-transfer characteristics and efficient emission (quantum yields between 0.13 and 0.30, in toluene), which is governed by the electron-donor substitution (p-MeO-phenyl, p-Me N-phenyl) at the helicene. Marked differences in the emission wavelength and Stokes shift are observed, with the dimethylamino-substituted derivative emitting most red-shifted (maximum at ca. 590 nm) and displaying the highest Stokes shift (ca. 6000 cm ) in toluene. The helicenes show electronic circular dichroism (ECD) and significant circularly polarized luminescence (CPL) with dissymmetry factors of up to 3.5×10 . The sign of the ECD band corresponding to the first transition and of the CPL spectrum depend sensibly on the electron-donor substitution.

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Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption-based upconversion and circularly polarized luminescence

Abstract: Including defects in a ribbon-shaped nanographene leads to a new combination of optical properties: TPA-based upconversion and CPL.

Cited by 138 publications

References 104 publications

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

An Enantiopure Propeller‐Like Trityl‐Brominated Radical: Bringing Together a High Racemization Barrier and an Efficient Circularly Polarized Luminescent Magnetic Emitter

Azabora[5]helicene Charge‐Transfer Dyes Show Efficient and Spectrally Variable Circularly Polarized Luminescence

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