Highly emissive organic solids with remarkably broad color tunability based on N,C-chelate, four-coordinate organoborons

Abstract

Molecular fluorophores based on N,C-chelate, four-coordinate organoborons exhibit tunable solid-state emission colors that cover the whole visible region from blue to red. The emission color can be tuned through the substituents on either quinolines or the boron center.

Controlling the Optoelectronic Properties of Pyrene by Regioselective Lewis Base‐Directed Electrophilic Aromatic Borylation

“…However, variable‐temperature (VT) NMR experiments in [D 8 ]toluene did not reveal any change in chemical shift up to a temperature of 85 °C, suggesting that the LP formation remains favorable under these conditions. The electrophilic borylation of L1 resulted in formation of two five‐membered BN heterocycles, consistent with the earlier results on the borylation of 1‐(quinoline‐2‐yl)pyrene by Patil and co‐workers. Signals corresponding to a single isomer due to borylation in the 2,7‐positions were observed in the 1 H NMR spectrum of isolated 5‐Ph and 5‐Et (Supporting Information).…”

“…In related work, Pischel, Ros et al. introduced quinolinylanthracenes ( G ) with high photostability for fluorescence imaging, as well as molecular switching behavior in the case of derivatives with OR substituents on boron . Circularly polarized luminescence (CPL) was also realized for borylated helicenes…”

“…The B←N LP functionalization of pyrene has thus far not been studied comprehensively. In a single report, Patil and co‐workers described that the electrophilic aromatic borylation of 1‐(quinolin‐2‐yl)pyrene leads to formation of a five‐membered BN heterocycle by activation at the 2‐position (non‐K region) of pyrene ( H ) . However, the effects of borylation in different positions and of multiple borylations on the electronic structure have not been explored.…”

Direct Dimesitylborylation of Benzofuran Derivatives by an Iridium‐Catalyzed C−H Activation with Silyldimesitylborane

“…lectivity.T herefore, the directi ntroduction of BMes 2 into aromatic compounds by iridium-catalyzed CÀHb orylations may potentially provide an ew method for the synthesis of boroncontaining organic compounds with at riarylborons tructure (Scheme 1b). This method thus allows alate-stage introduction of the BMes 2 group, [12] which would be advantageouse specially for the compilation of compound libraries with complicated structures for screening purposes. However,p reviouse xamples of the synthesis of triarylboranes with this strategy have not yet been reported.M oste xamples of CÀHb orylations introduce boronate groups [B(OR) 2 ]s uch as B(pin), and only one example for the introduction of 9-BBN (9-borabicyclo[3.3.1]nonan) has been reported.…”

“…Using monodentate (10 mol %) or bidentate (5.0 mol %) phosphines such as triphenylphosphine (PPh 3 ), tri-tert-butylphosphine (PtBu 3 )a nd 1,2-bis(dicyclohexylphosphino)ethane (dcpe) did not generate 3a efficiently (entries 4-6;0 -13 %). These results suggest that the presence of NHC ligands is crucial to promote the dimesitylborylation of 2a efficiently.T herefore, we further examined various Ir I precursorsa nd NHC ligands( [12][13][14]. Compound 3a wasn ot obtained in the absence of IMes (entry 15).…”