1,4,7-Triazacycl[3.3.3]azine:  basicity, photoelectron spectrum, photophysical properties

Leupin, Werner; Magde, Douglas; Persy, Gabriele; Wirz, Jakob

doi:10.1021/ja00261a004

Cited by 66 publications

(60 citation statements)

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“…It may suggest the weak BÀ N bond in 5APÀ B because of the weak basicity of the nitrogen atom of 5AP. [16] It should be noted that the formation of the BÀ N dative bond involving the four-coordinated boron atom was also confirmed by the chemical shift of 11 B{ 1 H} NMR spectrum (4.69 ppm). [34] Another important point in the synthesis of 5APÀ B is potential generation of a structural isomer which has a BÀ N dative bond with the 1-nitrogen atom.…”

Section: Resultsmentioning

confidence: 74%

“…The B−N bond length determined by SCXRD was 1.697(4) Å, which was longer compared to B−N bond lengths of other boron complexes; 1.550(2) Å (BODIPY without any substituent, CCDC 1408453) or 1.656(2) Å (the boron complex containing 5‐membered C−B‐N coordination structure, CCDC 1880835). It may suggest the weak B−N bond in 5AP−B because of the weak basicity of the nitrogen atom of 5AP . It should be noted that the formation of the B−N dative bond involving the four‐coordinated boron atom was also confirmed by the chemical shift of 11 B{ 1 H} NMR spectrum (4.69 ppm) .…”

Section: Resultsmentioning

confidence: 85%

“…In this research, as a new potential π‐conjugated element‐block, azaphenalene (AP) has been focused because of its unique electronic properties originating from the triangular structure . Leupin and Wirz thoroughly investigated electronic properties of the series of AP derivatives, and they revealed that APs have a symmetry‐forbidden transition from the first singlet (S 1 ) excited state to the ground (S 0 ) state .…”

Section: Introductionmentioning

confidence: 99%

“…In this research, as a new potential π-conjugated elementblock, azaphenalene (AP) has been focused [10][11][12][13] because of its unique electronic properties originating from the triangular structure. [11][12][13][14][15][16] Leupin and Wirz thoroughly investigated electronic properties of the series of AP derivatives, and they revealed that APs have a symmetry-forbidden transition from the first singlet (S 1 ) excited state to the ground (S 0 ) state. [14] As a consequence, the slow radiative process was observed due to the symmetry-forbidden nature of the S 0 À S 1 transition, and indeed poor luminescent properties are commonly obtained from the AP derivatives.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Enhancing Light‐Absorption and Luminescent Properties of Non‐Emissive 1,3,4,6,9b‐Pentaazaphenalene through Perturbation of Forbidden Electronic Transition by Boron Complexation

et al. 2020

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We report an improvement of optical properties of the non‐emissive molecule through shuffling the molecular orbitals by boron complexation. The 1,3,4,6,9b‐pentaazaphenelene (5AP) derivative having a 2‐(dimesitylboryl)phenyl group was synthesized through a substitution reaction from a 2‐bromophenyl compound. The formation of the B−N dative bond was confirmed by 11B{1H} NMR spectroscopy and a single‐crystal X‐ray structure analysis. Most of the conventional 5AP derivatives hardly showed emission despite their planar and rigid molecular structures. The previous reports on 5AP derivatives ascribed the non‐luminescent behavior to the forbidden transition between frontier orbitals. On the other hand, the 5AP‐based boron complex in this work showed enhanced light absorption and luminescence from the HOMO−LUMO transition. Theoretical calculations suggested that the boron complexation should play a critical role in perturbing the forbidden character of the HOMO−LUMO transition. Because the nitrogen atom on the 5AP moiety formed the Lewis acid−base pair with the boron atom, the energy level of the HOMO of 5AP was downshifted. The character of the HOMO−LUMO transition of the boron complex was changed to afford the improved optical properties of the boron complex.

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Section: Resultsmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enhancing Light‐Absorption and Luminescent Properties of Non‐Emissive 1,3,4,6,9b‐Pentaazaphenalene through Perturbation of Forbidden Electronic Transition by Boron Complexation

et al. 2020

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“…notwithstanding the fact that the HMO model used in [7] assumes an ortho-transmission coefficient of 0.31. A more reliable check of a(&) is provided by a comparison of the PE spectra of cyc1[3.3.3]azine [El, 1,4,6-triazacyc1[3.3.3]azine [9], and of 1,3,4,6,7,9-hexazacyc1[3.3.3]azine [lo], because of the high symmetry of these molecules. The value a ( N ) = -9.2 eV, i.e.…”

Section: The Ionization Energies Of Tetrazinodi(heter0arenes)mentioning

confidence: 99%

The Ionization Energies of Tetrazinodi(heteroarenes)

Lecoultre

Heilbronner

Eichenberger

et al. 1987

Helvetica Chimica Acta

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The ionization energies of four [I ,2,4,5]tetrazinodi(heteroarenes) of C,, symmetry have been measured by PE spectroscopy. It is found that the first ionization energy is very low (6.2 eV to 6.4 eV) and rather independent of the size and/or topology of the molecules. This is explained, by comparison with the results of a simple MO treatment, as being due to the strong localization of the HOMO (of A , symmetry) on the [1,2,4,5]tetrazino moiety of the molecules. The PE-spectroscopic data are shown to be in agreement with the UVjVIS-and electrochemical-oxidation data published previously.Introduction. -Recently, we have reported the synthesis, the electronic spectra [I], and the oxidation potentials [2] of a series of tetrazinodi(heter0arenes). These molecules are of interest as electron donators in charge-transfer complexes and as redox catalysts. In this connection, the ionization energies of these electron donators are important quantities, which now have been determined for four key molecules, using PE spectros-COPY.

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Enhancing Reverse Intersystem Crossing with Extended Inverted Singlet–Triplet (X−INVEST) Systems

Ricci,

Landi,

Sancho‐García

et al. 2024

Advanced Optical Materials

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The discovery of triangular‐shaped molecules displaying an inverted singlet–triplet (INVEST) energy gap between their lowest singlet (S1) and triplet (T1) states opened the way for a new strategy to increase the internal quantum efficiency (IQE) of organic light‐emitting diodes (OLEDs), enhancing the reverse intersystem crossing (RISC) thanks to a downhill process. However, the compounds showing a negative ΔEST suffer from both a vanishing spin–orbit coupling (SOC) between these excited states and high energy differences with higher‐lying singlets and triplets, therefore limiting their involvement in the spin conversion process. Here, we proposed a new design strategy entailing the extension of the triangulene cores by connecting two INVEST triangulene units to form Uthrene‐ and Zethrene‐like systems, doped with N and B. The inspection of the resulting molecular orbitals (MOs) distribution allowed rationalizing the electronic structure properties obtained from wavefunction‐based methods, showing how the Uthrene‐like architecture can lead to the quasi‐resonance between S1 and T1, in some cases provoking their inversion. By feeding a kinetic model with the non‐radiative rate constants, calculated from first principles, we showed how the extended INVEST (X−INVEST) design strategy can open new pathways to boost the spin conversion process and the population of the emissive S1.

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1,4,7-Triazacycl[3.3.3]azine: basicity, photoelectron spectrum, photophysical properties

Cited by 66 publications

References 0 publications

Enhancing Light‐Absorption and Luminescent Properties of Non‐Emissive 1,3,4,6,9b‐Pentaazaphenalene through Perturbation of Forbidden Electronic Transition by Boron Complexation

Enhancing Light‐Absorption and Luminescent Properties of Non‐Emissive 1,3,4,6,9b‐Pentaazaphenalene through Perturbation of Forbidden Electronic Transition by Boron Complexation

The Ionization Energies of Tetrazinodi(heteroarenes)

Enhancing Reverse Intersystem Crossing with Extended Inverted Singlet–Triplet (X−INVEST) Systems

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