Synthesis and optical and electrochemical properties of polycyclic aromatic compounds with S,S-dioxide benzothiophene fused seven rings

Abstract

ARTICLE This journal isA series of novel linearly-fused polycyclic aromatic compounds, N-(2-decyltetradecyl)carbazole bis [2,3b;6,7-b]benzo [d] thiophene-S,S-dioxide (CzBTO) and 9,9-dioctylfluorene bis[2,3-b;6,7b]benzo[d]thiophene-S,S-dioxide (FBTO), incorporating with S,S-dioxide benzothiophene unit were efficiently synthetized and detailedly characterized. The key step of preparing CzBTO and FBTO was related to the triflic acid induced intramolecular electrophilic cyclizing reaction where the corresponding methyl sulfoxides in activated aromatic building blocks may enable the regioselective ring cyclization. From the photoluminescence (PL) spectra, the CzBTO and FBTO showed very deep blue emission with the emission peaks at 426 and 407 nm, respectively. Through the photoluminescence quantum yield (PLQY) characterization, the FBTO gave a high PLQY value of 77% in tetrahydrofuran solution. The DFT and electrochemical studies showed that the CzBTO and FBTO had large band gaps and very low highest occupied molecular orbital (HOMO) energy levels, which indicated that these two compounds existed the high stability both thermally and optically. From the electrochemical measurement, the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels were -6.04, -6.20 and -2.74, -2.80 eV, with the band gaps of 3.3 and 3.4 eV for CzBTO and FBTO, respectively. ARTICLEThis journal is

Nine-ring angular fused biscarbazoloanthracene displaying a solid state based excimer emission suitable for OLED application

“…This quite low value of the LUMO level is similar to the values reported for extended carbazoles 28 , indenofluorenes 29 , triarylamine capped polyaromatic hydrocarbons 30 or others. 31 The consequence for such LUMO level, lying clearly below --2 eV, should be an easier electron injection from the cathode during the device operation.…”

π-Bridge Effect on Symmetric Carbazole-Based Small Molecules for Realizing Ultraviolet Fluorescent Emission

“…All of the desired compounds were readily obtained by one-pot Suzuki coupling reaction via using the commercially available N -phenyl-3-carbazolylboronic acid and 1,4-dibromo benzene derivatives directly. To promote the reaction yields and simplify the procedures of obtaining target compounds, the previous reaction systems of tetrabutylammonium bromide (TBAB), PdCl 2 , and the solvent of acetone were replaced by Pd(pph 3 ) 4 and toluene, respectively [ 29 , 30 ]. These improvements could successfully control the reaction to get the target products with high yields (>70%).…”

“…The ferrocene was used as a standard internal reference in this study, and the ferrocene/ferrocenium (Fc/Fc + ) redox shows a half-wave potential ( E 1/2 ) at 0.47 V. The CV curves are presented in Figure 4 , and the relative data are concluded in Table 3 . The highest occupied molecular orbital (HOMO) energy levels were calculated according to the empirical formula E HOMO = −e( E ox + 4.8 − E 1/2,(Fc/Fc + ) ) [ 30 ], where E ox is the onset of the oxidation potential. From Figure 4 , the E ox s are 0.97 eV, 1.31 eV, 1.13 eV and 0.91 eV for CzP-H, CzP-CN, CzP-Me and CzP-OMe, respectively.…”

“…However, the new series of carbazole-based ultraviolet emitters in terms of larger band gaps, high quantum efficiency and high color purity remain to be explored [ 30 , 31 , 32 , 33 ]. Carbazole-based small molecules exhibit excellent performance in ultraviolet/deep-blue OLEDs; for example, they demonstrate large conjugation stability, high hole mobility and high thermal properties.…”

Indole‐Based Aza[n]helicenes (n=5, 6) with Violet‐Blue Fluorescence and Two‐Photon Absorption (TPA)

“…These results indicated that heteroatoms such as sulfur and nitrogen of HBTNI might avail to increase thermal stability and fluorescence quantum yield. [32] TPA and TPEF Coumarin 307 of 1 × 10 À 4 M in MeOH was selected as reference for δ calculations. [33] Both the SPEF parameters and the TPEF properties of compounds HTPI, HBTNI, HIPD, HPI, Fluorescein and Coumarin 307 were displayed in Table 1.…”