Benzimidazole-Based N,O Boron Complexes as Deep Blue Solid-State Fluorophores

Vaz, Patrícia A. A. M.; Rocha, João; Silva, Artur M. S.; Guieu, Samuel

doi:10.3390/ma14154298

Cited by 9 publications

(3 citation statements)

References 50 publications

(80 reference statements)

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“…For example, the formation of a boron complex in benzimidazoles considerably changes the emission spectrum, with the complete disappearance of the band at 470 nm, and the appearance of a new emission band around 380 nm (Figure 14a). [76] The absorption spectrum does not change significantly. This observation is characteristic of a total ESPT, where all the excited molecules undergo a proton transfer before emitting light, resulting in a substantial Stokes′ shift.…”

Section: Structural Modificationsmentioning

confidence: 96%

Excited‐State Proton Transfer in Luminescent Dyes: From Theoretical Insight to Experimental Evidence

Fontes

Rocha

Silva

et al. 2023

Chemistry A European J

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To ESPT, or not to ESPT. The effective utilization of luminescent dyes often relies on a comprehensive understanding of their excitation and relaxation pathways. One such pathway, Excited‐State Proton Transfer (ESPT), involves the tautomerization of the dye in its excited state, resulting in a new structure that exhibits distinct emission properties, such as a very large Stokes' shift or dual‐emission. Although the ESPT phenomenon is well‐explained theoretically, its experimental demonstration can be challenging due to the presence of numerous other phenomena that can yield similar experimental observations. In this review, we propose that an all‐encompassing methodology, integrating experimental findings, computational analyses, and a thorough evaluation of diverse mechanisms, is essential for verifying the occurrence of ESPT in luminescent dyes. Investigations have offered significant understanding of the elements impacting the ESPT process and the array of approaches that can be used to validate the existence of ESPT. These discoveries hold crucial ramifications for the advancement of molecular probes, sensors, and other applications that depend on ESPT as a detection mechanism.

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Section: Structural Modificationsmentioning

confidence: 96%

Excited‐State Proton Transfer in Luminescent Dyes: From Theoretical Insight to Experimental Evidence

Fontes

Rocha

Silva

et al. 2023

Chemistry A European J

Self Cite

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“…[ 7 ] It promotes intersystem crossing, thus enhances spin–orbit coupling between excited state electrons of a compound and the nucleus of the heavy atom. [ 13 ] Furthermore, halogen atoms are able to form directional interactions with both nucleophilic and electrophilic centers, [ 14 ] which is possible due to an anisotropic distribution of electron density (ED)around the halogen atom, allowing electrophiles to interact laterally with the halogen atom and nucleophiles along the CX bond. [ 15 ] As reported by Ghodbane and co‐workers, [ 7 ] fluorinated and chlorinated compounds seem to be the best suited for fine‐tuning the luminescence properties.…”

Section: Introductionmentioning

confidence: 99%

An investigation of Solid‐State Emission of Halogenated Diphenyl Phosphanyl Anthracenes

Patten

Graw

Friedl

et al. 2023

Advanced Optical Materials

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are hardly predictable. It often happens that the strong emission observed in solution is completely quenched in the solid state. This phenomenon is known as aggregation-caused quenching (ACQ) and is mostly attributed to the strong, unfavorable intermolecular interactions present in the crystalline phase. [5] On the other hand, one may tailor aggregation in such a way that the photoluminescence may not only be observed in a solid state, but in fact can be significantly enhanced. Such an effect is called aggregationinduced emission (AIE) and was first described by Tang et al. in 2001. [6] It is an interesting and important phenomenon especially in view of its technological perspective, as it allows to control, up to a certain extent, the self-assembly of molecules via known intermolecular interactions, leading to introduction of light emission upon aggregation. Since the introduction of this concept, particular focus has been paid to single-component crystals and cocrystals in which the fine-tuned solid-state luminescence is controlled via π-π interactions, hydrogen and halogen bonds. [7,8] By selective reorganization of such synthons, it is possible to alter the molecular structure and thus also control the emission behavior. As a result, one may observe excimer/exciplex formation between two conjugated molecules one being the electron donor and another the electron acceptor building block. These form an intermolecular dimer/complex in the excited state which usually leads to the situation that the energy level of an excited complex is below that of the respective molecules involved, resulting in a red shift of emission compared to the original emission of the individual molecules. [9] Such a behavior was observed in recently published studies on a series of phosphanyl anthracenes and their sulfur oxidized analogues. [10,11,12] The presence of carefully targeted dominant face-to-face interactions between anthracene rings and lack of other strong noncovalent interactions (NCIs) resulted in excimer formation and promoted the solid-state AIE effect. Moreover, it was shown that in order to maximize the solid-state emission, the overlap between anthracene rings should be kept at around 45% and possibly the distance between the rings should be reduced to further shift the emission band.As mentioned above, also halogen bonds may play a major role in solid-state luminescence, in particular the so-called heavy atom effect. [7] It promotes intersystem crossing, thus enhances spin-orbit coupling between excited state electrons In today's world, the development and research of optoelectronic materials and devices based on solid-state luminescence is essential. Due to their versatile application possibilities, e.g. as light-emitting diodes or lasers, they are already indispensable. This work presents three halogenated anthracene derivatives [9-PPh 2 -10-X-(C 14 H 8 )] and their respective photoluminescent behavior in solution and in the solid state. The formation of halogen-π interactions in the solid state leads to unanti...

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“…28,29 Specifically, tetra-coordinated organoboron (TCOB) compounds with extended π-conjugation and structural rigidity exhibit notable Stokes shifts, improved fluorescence emission (both in solid and solution states) and offer a broad range of molecular diversity through chemical synthesis. 30 Hydroxyquinolate, 31,32 pyridylphenolate, 33,34 benzimidazolephenolate, 35 and similar bidentate heterocyclic ligands are often used to prepare TCOB complexes.…”

Section: Introductionmentioning

confidence: 99%

Luminescent hexagonal microtubes prepared through water-induced self-assembly of a polymorphic organoboron compound: formation mechanism and waveguide behaviour

Gaikwad,

Samadder,

Som

et al. 2023

Nanoscale

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Benzimidazole-Based N,O Boron Complexes as Deep Blue Solid-State Fluorophores

Cited by 9 publications

References 50 publications

Excited‐State Proton Transfer in Luminescent Dyes: From Theoretical Insight to Experimental Evidence

Excited‐State Proton Transfer in Luminescent Dyes: From Theoretical Insight to Experimental Evidence

An investigation of Solid‐State Emission of Halogenated Diphenyl Phosphanyl Anthracenes

Luminescent hexagonal microtubes prepared through water-induced self-assembly of a polymorphic organoboron compound: formation mechanism and waveguide behaviour

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