Angular BN-Heteroacenes with <i>syn</i>-Structure-Induced Promising Properties as Host Materials of Blue Organic Light-Emitting Diodes

A series of novel angular BN-heteroacenes were successfully synthesized. Associated with the intrinsic <i>syn</i>-structures, they exhibit unique molecular alignments in a solid state and promising electronic properties, and are thus suitable as efficient nondoped emitters for the fabrication of blue organic light-emitting diodes with improved performance

Triple Boron-Cored Chromophores Bearing Discotic 5,11,17-Triazatrinaphthylene-Based Ligands

A series of novel chromophores fused with multiple boron cores have been successfully synthesized by the complexation of three difluoroboryl or diphenylboryl at the periphery of 5,11,17-triazatrinaphthylene derivative ligands. Their sterically congested molecular scaffolds with expanded π-conjugated discotic backbones render them with unique electronic properties including large Stokes shifts, tunable electrochemical behaviors, and low-lying LUMO energy levels up to −3.18 eV

Angular BN-Heteroacenes with <i>syn</i>-Structure-Induced Promising Properties as Host Materials of Blue Organic Light-Emitting Diodes

A series of novel angular BN-heteroacenes were successfully synthesized. Associated with the intrinsic <i>syn</i>-structures, they exhibit unique molecular alignments in a solid state and promising electronic properties, and are thus suitable as efficient nondoped emitters for the fabrication of blue organic light-emitting diodes with improved performance

Synthesis and Properties of <i>C</i>_<i>2h</i>-Symmetric BN-Heteroacenes Tailored through Aromatic Central Cores

The 2-fold successive electrophilic borylation on one aromatic central core led to a series of <i>C</i>_<i>2h</i>-symmetric BN-heteroacenes in excellent yields. For the first time, we introduced trimethylsilyl (TMS) as either leaving group or oriented group for efficiently improving the preparation of BN-embedded polycyclic aromatic hydrocarbons (PAHs). The physical properties of the as-synthesized BN-heteroacenes in either solid state or solution can be finely tuned through the position isomerization or the fused ring numbers of the aromatic central core

Synthesis and Properties of <i>C</i>_<i>2h</i>-Symmetric BN-Heteroacenes Tailored through Aromatic Central Cores

The 2-fold successive electrophilic borylation on one aromatic central core led to a series of <i>C</i>_<i>2h</i>-symmetric BN-heteroacenes in excellent yields. For the first time, we introduced trimethylsilyl (TMS) as either leaving group or oriented group for efficiently improving the preparation of BN-embedded polycyclic aromatic hydrocarbons (PAHs). The physical properties of the as-synthesized BN-heteroacenes in either solid state or solution can be finely tuned through the position isomerization or the fused ring numbers of the aromatic central core

Ladder-Type BN-Embedded Heteroacenes with Blue Emission

Using a concise synthetic strategy, a series of novel ladder-type BN-embedded heteroacenes were successfully synthesized. Their molecular skeletons render the versatile modification which is desirable for achieving unique physical properties. Organic light-emitting diode devices based on BN-embedded heteroacenes were subsequently fabricated, demonstrating their promising application as blue emitters

Efficient Approach to Electron-Deficient 1,2,7,8-Tetraazaperylene Derivatives

Using an efficient synthetic strategy, a novel class of 1,2-diazine-embedded perylenes, namely 1,2,7,8-tetraazaperylene derivatives, have been successfully synthesized. These molecules were fully characterized by X-ray diffraction analysis, optical spectroscopy, and electrochemistry. The low-lying lowest unoccupied molecular orbital (LUMO) level of these molecules suggests their potential as good electronic acceptors

Nonplanar Ladder-Type Polycyclic Conjugated Molecules: Structures and Solid-State Properties

Using an efficient intramolecular carbon–carbon cross-coupling reaction, a series of new ladder-type conjugated molecules have been prepared successfully in high yields. Such a pyran-fused polycylic structure possesses an extended π-conjugated backbone with flexible conformation, which gives these molecules interesting properties, including high solubility in common organic solvents, excellent thin film-forming abilities, blue fluorescent emission with good quantum yields, and aggregate formation in a binary solvent. The self-assembly behaviors of these molecules as well as various nanostructures can be finely tailored by varying the substituted group on the molecular periphery. The powder and single-crystal X-ray diffraction analyses revealed that the synergetic effect of π–π stacking and van der Waals interactions play a key role in controlling the morphologies of these aggregates. More importantly, self-assembled molecules exhibit good fluorescent performance, due to their twist backbone conformation

Synthesis of NBN-Type Zigzag-Edged Polycyclic Aromatic Hydrocarbons: 1,9-Diaza-9a-boraphenalene as a Structural Motif

A novel class of dibenzo-fused 1,9-diaza-9a-boraphenalenes featuring zigzag edges with a nitrogen–boron–nitrogen bonding pattern named NBN-dibenzophenalenes (NBN-DBPs) has been synthesized. Alternating nitrogen and boron atoms impart high chemical stability to these zigzag-edged polycyclic aromatic hydrocarbons (PAHs), and this motif even allows for postsynthetic modifications, as demonstrated here through electrophilic bromination and subsequent palladium-catalyzed cross-coupling reactions. Upon oxidation, as a typical example, NBN-DBP <b>5a</b> was nearly quantitatively converted to σ-dimer <b>5a-2</b> through an open-shell intermediate, as indicated by UV–vis–NIR absorption spectroscopy and electron paramagnetic resonance spectroscopy corroborated by spectroscopic calculations, as well as 2D NMR spectra analyses. In situ spectroelectrochemistry was used to confirm the formation process of the dimer radical cation <b>5a-2</b>^•+. Finally, the developed new synthetic strategy could also be applied to obtain π-extended NBN-dibenzoheptazethrene (NBN-DBHZ), representing an efficient pathway toward NBN-doped zigzag-edged graphene nanoribbons

Synthesis of NBN-Type Zigzag-Edged Polycyclic Aromatic Hydrocarbons: 1,9-Diaza-9a-boraphenalene as a Structural Motif

A novel class of dibenzo-fused 1,9-diaza-9a-boraphenalenes featuring zigzag edges with a nitrogen–boron–nitrogen bonding pattern named NBN-dibenzophenalenes (NBN-DBPs) has been synthesized. Alternating nitrogen and boron atoms impart high chemical stability to these zigzag-edged polycyclic aromatic hydrocarbons (PAHs), and this motif even allows for postsynthetic modifications, as demonstrated here through electrophilic bromination and subsequent palladium-catalyzed cross-coupling reactions. Upon oxidation, as a typical example, NBN-DBP <b>5a</b> was nearly quantitatively converted to σ-dimer <b>5a-2</b> through an open-shell intermediate, as indicated by UV–vis–NIR absorption spectroscopy and electron paramagnetic resonance spectroscopy corroborated by spectroscopic calculations, as well as 2D NMR spectra analyses. In situ spectroelectrochemistry was used to confirm the formation process of the dimer radical cation <b>5a-2</b>^•+. Finally, the developed new synthetic strategy could also be applied to obtain π-extended NBN-dibenzoheptazethrene (NBN-DBHZ), representing an efficient pathway toward NBN-doped zigzag-edged graphene nanoribbons