Thienopyrrolo[3,2,1-jk]carbazoles: Building Blocks for Functional Organic Materials

Abstract

The facile preparation of three regioisomeric thienopyrrolo­[3,2,1-jk]­carbazoles applying a convenient C–H activation approach is presented. The incorporation of thiophene into the triarylamine framework significantly impacted the molecular properties in comparison to the analogous indolo­[3,2,1-jk]­carbazole scaffold. Dependent on the exact substitution pattern, the absorption onsets of the new materials are shifted toward slightly higher wavelengths compared to the analogous indolo­[3,2,1-jk]­carbazole, whereas the emission maxima of the sulfur derivatives is shifted from 375 to 410 nm. In analogy, the HOMO–LUMO energy gap of the thienopyrrolo­[3,2,1-jk]­carbazoles is reduced compared to indolo­[3,2,1-jk]­carbazole. Therefore, the developed thienopyrrolo­[3,2,1-jk]­carbazoles enrich the family of triarylamine donors and constitute a novel building block for functional organic materials.

Alkylated Indolo[3,2,1-Jk]carbazoles as New Building Blocks for Solution Processable Organic Electronics

“…While this increase is only weakly pronounced for the tert-butyl substituted materials, the maximum current efficiency (CE) is increased to 10.12 cd/A, the maximum power efficiency (PE) to 3. 13 In summary, employing the hexyl substituted host materials resulted in higher efficiency of the devices, compared to the tert-butyl substituted materials. Notably, employing HexICzPCz in RIV, GIV and BIV, yielded the best performance within each series.…”

“…[8] Besides its weakened donor strength, the versatility of the building block can be seen as itself has bipolar character [8][9][10] and can also be used solely as acceptor building block. [11,12] Furthermore, the electronic properties can be tuned by incorporation of sulfur atoms to increase the donor strength, [13] as well as nitrogen incorporation [14] or substitution with cyano groups [15] to increase the acceptor strength.…”

“…After evaporation of the solvent, the crude product was flashed over silica (light petroleum/CH2Cl2) yielding 2c (5.08 g, 10.40 mmol, 87%) as off-white solid. .32 (m, 12H), 0.91 (t, J = 7.1 Hz, 6H) 13. C NMR (151 MHz, CDCl3) δ 142.6, 137.4, 136.8, 129.3, 127.9 123.1, 122.2, 119.8, 115.5, 111.8, 36.2, 32.2, 31.9, 29.1, 22.8, 14.3.…”

“…The crude product was purified by column chromatography (light petroleum/CH2Cl2, 15% -25%) yielding 3b (1.93 g, 3.59 mmol, 71%) as colorless oil, which crystallized after several days 1. H NMR (600 MHz, CDCl3) δ 8.54 (s, 2H), 7.94 (d, J = 1.3 Hz, 2H), 7.78 (d, J = 8.1 Hz, 2H), 7.36 (dd, J = 8.2, 1.6 Hz, 2H), 2.80 (t, J = 7.7 Hz, 4H), 1.73 (quint, J = 7.5 Hz, 4H), 1.45 (s, 12H), 1.42 -1.32 (m, 12H), 0.90 (t, J = 6.8 Hz, 6H) 13. C NMR (151 MHz, CDCl3) δ 146.6, 137.4, 136.6, 130.1, 127.2, 126.3, 123.1, 118.4, 111.8, 83.9, 36.2, 32.2, 31.9, 29.1, 25.2, 22.8, 14.3 (C-B not detected).…”

“…H and13 C NMR spectra of the materials, as well as external quantum efficiency -luminance curves and photoluminescence spectra of the devices can be found in the supporting information.…”