Polymorphism, Fluorescence, and Optoelectronic Properties of a Borazine Derivative

Kervyn, Simon; Fenwick, Oliver; Stasio, Francesco Di; Shin, Yong Sig; Wouters, Johan; Accorsi, Gianluca; Osella, Silvio; Beljonne, David; Cacialli, Franco; Bonifazi, Davide

doi:10.1002/chem.201204598

Cited by 56 publications

(90 citation statements)

References 77 publications

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“…A deviation from orthogonal arrangement of the aryl substituents and the borazine ring is clearly observed with inter˗planar angles of 122.6 between the borazine ring and phenyl groups, and of 108.9 between both phenyl and xylyl groups. As previously observed in the literature, 8,25 the intra˗annular distance values between boron and nitrogen atoms are between 1.43 and 1.46 Å, with the internal angle of the borazine cycle between 122.7 and 117.03 (BNB and NBN, respectively).…”

Section: Resultssupporting

confidence: 76%

Photoactive Boron–Nitrogen–Carbon Hybrids: From Azo-borazines to Polymeric Materials

et al. 2019

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In this paper, we describe the synthetic routes for preparing a novel switchable BNC˗based chromophore, composed of a borazine core peripherally functionalized with azobenzene moieties. Capitalizing on the Pd˗catalyzed Suzuki cross˗coupling reaction between a tris˗triflate borazine and an organoboron azobenzene derivative, a photoswticheable azo˗borazine derivative was successfully prepared. The molecule showed reversible E/Z photoisomerization upon irradiation at the maximum of the intense ˗  absorption feature (360 nm). X˗Ray crystallographic investigations revealed a non˗planar orientation of the three azobenzene moieties and the trans configuration of the ˗N=N˗ bonds. Building on the synthetic versatility of the borazine˗azobenzene derivative, we used this photoactive scaffold to engineer soluble BN˗doped polythiophene polymers. Photophysical characterization performed in solvents of different polarity, suggested that the polymer undergoes intramolecular charge˗transfer (ICT).A c c e p t e d m a n u s c r i p t Stimuli˗responsive molecules and materials capable of undergoing reversible structural changes are of great interest for future technology. 1 A typical example is the E/Z photoisomerization of azobenzenes, which is characterized by an irradiation˗induced ZE isomerization between the thermodynamically favored, stretchedE˗isomer and its Z˗isomer. The photoisomerization is accompanied by a dramatic change in electronic structure, geometric shape, and polarity, resulting into the spatiotemporal control of the conformational and overall structural properties of molecular systems. 2 Notable applications include their integration into architectures expressing functional properties in materials science, 3 biology 4 and molecular recognition. 1c, 5 The replacement of C=C units by more polarized BN couples is a versatile functionalization strategy to tailor the optoelectronic characteristics of organic ˗systems without significant structural alteration of the nanostructure. 6The BN/CC isosterism concept goes back to the seminal discovery of the borazine (H 3 B 3 N 3 H 3 ) by Stock and Pohland in 1926. 7 The borazine core is commonly referred to as the "inorganic benzene", owing to its iso˗electronic and iso˗structural relationships with benzene. 7 Accordingly, borazine and its derivatives are valuable scaffolds to be inserted as doping units in graphitic˗based carbon materials to tailor their optoelectronic characteristics 8 and self˗assembly properties on surfaces. 9, 23 Important examples include dendritic borazine˗doped polyphenylenes, 10 borazine˗doped coronenes 11 and borazino˗based polymers. 10, 12 Not only borazine˗based materials, but also hybrid BNC˗based architectures are attracting increasing consideration due to their thermal stability, mechanical robustness and tunable optoelectronic properties. 13 In this respect, the incorporation of BN units into ˗conjugated polymers is emerging as an evident route to broaden the scope of organic electronic materials. 6d, 13b, 14 For their part, ˗c...

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Section: Resultssupporting

confidence: 76%

Photoactive Boron–Nitrogen–Carbon Hybrids: From Azo-borazines to Polymeric Materials

et al. 2019

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“…The pyridine-bearing borazines have been prepared following the BCl 3 condensation protocol (see Supporting Information for synthesis procedure). [3,4] Startingfrom aniline,which was reacted with BCl 3 under refluxing conditions, the B,B',B"-trichloro-N,N',N"-triphenylb orazine intermediate was obtained. Upon subsequentt reatment with tert-butyldimethylsilyl (TBDMS)-aryllithium (ArLi) 1,T BDMS protected borazine 2 could be prepared in 78 %yield (Scheme 1).…”

Section: Synthesis Of Bnppy and Bnapymentioning

confidence: 99%

“…The pyridine‐bearing borazines have been prepared following the BCl 3 condensation protocol (see Supporting Information for synthesis procedure) . Starting from aniline, which was reacted with BCl 3 under refluxing conditions, the B , B ′, B “‐trichloro‐ N , N ′, N ”‐triphenyl borazine intermediate was obtained.…”

Section: Introductionmentioning

confidence: 99%

“…Borazine derivatives have recently attracted increasing interest as molecular building blocks, [1] due to their high potentialf or applicationsi nt he fields of electronics, [2, [3][4][5] and non-linear optics. [6] In particular hybrid h-BNC nanostructures, where carbon-carbon bonds are replaced by isoelectronic and isostructural BN couples are emerging as anew route to functionalize polycyclic aromatic hydrocarbons without as ignificant structural perturbation of the molecular periphery and of its skeleton.…”

Section: Introductionmentioning

confidence: 99%

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BN‐Patterning of Metallic Substrates through Metal Coordination of Decoupled Borazines

Schwarz

Garnica

Fasano

et al. 2018

Chemistry A European J

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We report on the synthesis of pyridine-terminated borazine derivatives, their molecular self-assembly as well as the electronic properties investigated on silver and copper surfaces by means of scanning tunneling microscopy and X-ray photoelectron spectroscopy. The introduction of pyridine functionalities allows us to achieve distinct supramolecular architectures with control of the interdigitation of the molecules by surface templating. On silver surfaces, the borazine derivatives arrange in a dense-packed hexagonal structure through van der Waals and H-bonding interactions, whereas on Cu(111), the molecules undergo metal coordination. The porosity and coordination symmetry of the reticulated structure depends on the stoichiometric ratio between copper adatoms and the borazine ligands, permitting an unusual three-fold coordinated Cu-pyridyl network. Finally, spectroscopy measurements indicate that the borazine core is electronically decoupled from the metallic substrate. We thus demonstrate that BNC-containing molecular units can be integrated into stable metal-coordination architectures on surfaces, opening pathways to patterned, BN-doped sheets with specific functionalities, for example, regarding the adsorption of polar guest gases.

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“…Amongt he different functionalisation approaches, the replacement (i.e.,d oping) of one or more carbon atoms with electron-deficient or -rich heteroatoms is emerging as av ersatile strategyt ot une optoelectronic properties. [9] The insertion of third-group elements, such as borono ra luminium, introduces electronicv acancies (or holes), [10][11][12][13][14][15] whereas the insertion of fifth-and sixth-group elementse lectronicallye nriches carbonbased substrates to generate non-bonding states. [16][17][18][19] Phosphorescence is aforbidden radiativerelaxationo fanexcited state with spin symmetry different from that of the ground state.F or organic species, it mostly involves the decay from at riplet to as inglet state.…”

Section: Introductionmentioning

confidence: 99%

Walking Down the Chalcogenic Group of the Periodic Table: From Singlet to Triplet Organic Emitters

Kremer

Aurisicchio

Leo

et al. 2015

Chemistry A European J

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The synthesis, X-ray crystal structures, ground- and excited-state UV/Vis absorption spectra, and luminescence properties of chalcogen-doped organic emitters equipped on both extremities with benzoxa-, benzothia-, benzoselena- and benzotellurazole (1X and 2X ) moieties have been reported for the first time. The insertion of the four different chalcogen atoms within the same molecular skeleton enables the investigation of only the chalcogenic effect on the organisation and photophysical properties of the material. Detailed crystal-structure analyses provide evidence of similar packing for 2O -2Se , in which the benzoazoles are engaged in π-π stacking and, for the heavier atoms, in secondary X⋅⋅⋅X and X⋅⋅⋅N bonding interactions. Detailed computational analysis shows that the arrangement is essentially governed by the interplay of van der Waals and secondary bonding interactions. Progressive quenching of the fluorescence and concomitant onset of phosphorescence features with gradually shorter lifetimes are detected as the atomic weight of the chalcogen heteroatom increases, with the tellurium-doped derivatives exhibiting only emission from the lowest triplet excited state. Notably, the phosphorescence spectra of the selenium and tellurium derivatives can be recorded even at room temperature; this is a very rare finding for fully organic emitters.

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Polymorphism, Fluorescence, and Optoelectronic Properties of a Borazine Derivative

Cited by 56 publications

References 77 publications

Photoactive Boron–Nitrogen–Carbon Hybrids: From Azo-borazines to Polymeric Materials

Photoactive Boron–Nitrogen–Carbon Hybrids: From Azo-borazines to Polymeric Materials

BN‐Patterning of Metallic Substrates through Metal Coordination of Decoupled Borazines

Walking Down the Chalcogenic Group of the Periodic Table: From Singlet to Triplet Organic Emitters

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