Millisecond Time-scale Photoluminescence of B–N-doped Tetrathienonaphthalene with Borane/Amine Substituents

Abstract

BN-doped polycyclic aromatic hydrocarbons (PAHs) have attracted numerous attentions because of their fascinating optical and electronic properties. In this work, a series of electron-donor (amine)- and -acceptor (borane)-functionalized BN-doped polycyclic aromatic hydrocarbons were prepared to study the substituents’ effect on the photophysical properties. As a result, the compound with both donor and acceptor, BN, exhibits both local emission (LE) and charge-transfer emission (CT) in polar solvents. Especially, the CT emission with a longer wavelength revealed a lifetime as long as millisecond time scale at room temperature, indicating typical phosphorescence characteristics. Low-temperature photoluminescent (PL) spectroscopy and a theoretical study were conducted to help to interpret this phenomenon, and it turned out to be the lowering of the S1 energy level of BN which makes the intersystem crossing favorable. Furthermore, fluoride anion titration experiments exhibit the application potential of the dual-emission phenomenon of BN for ratiometric sensory materials.

Dipole Effect of BN-Doped Tetrathienonaphthalene on Photo-Physical Properties and Lewis Acidity of the D-π-A Derivatives

“…The phosphorescence spectra of these two compounds were recorded at 77 K in 2-methyltetrahydrofuran with 1 ms delay, as shown in Figure c,d. The maximum wavelengths of phosphorescence are located at 633.5 nm for B-BN-N and 669.5 nm for N-BN-B with the lifetime at 17.5 and 7.0 ms (see Figure S1), respectively, which is similar to that of other BN-TTN derivatives reported previously …”

“…As shown in Figure , the maximum absorption peaks of B-BN-N and N-BN-B in CH 2 Cl 2 are located at ca. 454 nm (ε max = 40,000 M –1 cm –1 ) and 447 nm (ε max = 22,081 M –1 cm –1 ), respectively, which are obviously red-shifted compared to that of the BN-TTN-BN compound in our previous work, indicating the more efficient π-conjugation of the BN-TTN skeleton in these two compounds. In the case of fluorescence spectra, the B-BN-N gives rise to maximum emission (λ Fl = 514 nm in CH 2 Cl 2 ) at a shorter wavelengths than that of N-BN-B (λ Fl = 548 nm in CH 2 Cl 2 ).…”

“…The full synthetic approach of the compound HBN was designed according to the literature , and is shown in Scheme S1. The B-BN-N and N-BN-B have been designed and synthesized via different synthetic routes (Schemes and S2).…”

Novel NBN-Embedded Polymers and Their Application as Fluorescent Probes in Fe3+ and Cr3+ Detection

“…Boron-containing π systems have attracted considerable research attention due to their desirable optical, electronic and sensory properties [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Organic π-conjugated compounds with novel BN bonds usually have obvious optoelectronic properties/advantages due to the empty p-orbital in the boron center [ 27 , 28 , 29 , 30 ]. Pioneering researchers such as White, Dewar, Ashe, Liu, Schäfer, Braunschweig, and Jäkle have made considerable progress in the synthesis of BNB-doped π systems with outstanding photophysical properties [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

Synthesis, Characterization, and Photophysical Properties of Triptycene-Based Chiral Organoboranes

“…Triarylboranes have been frequently investigated as electron acceptors because of the empty p orbital of boron atoms . Various compounds containing triarylborane moieties showed intriguing photophysical properties and thermal responses. − Recently, a few examples of chiral triarylborane compounds have also been reported. − Most of them were obtained via a simple coupling of the triarylborane units with chiral frameworks such as axially chiral and planar chiral structures, and they exhibited CPL performance. However, reports on carbon chiral triarylboranes are relatively rare to date.…”