Fused Bis-Benzothiadiazoles as Electron Acceptors - Crystal Growth

Oct 26, 2016 - Experimental and theoretical studies indicated that both compounds give rise to electron-accepting materials. This work thus also contr...
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Fused Bis-Benzothiadiazoles as Electron Acceptors Debin Xia,†,‡ Xiao-Ye Wang,‡ Xin Guo,§ Martin Baumgarten,*,‡ Mengmeng Li,‡ and Klaus Müllen*,‡ †

MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 150001 Harbin, P. R. China ‡ Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany § Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China

Crystal Growth & Design 2016.16:7124-7129. Downloaded from pubs.acs.org by DURHAM UNIV on 08/28/18. For personal use only.

S Supporting Information *

ABSTRACT: Fused bis-benzothiadiazoles with different molecular geometries, namely, linear benzoquinone-fused bis(benzothiadiazole) (Q-BBT) and V-shaped sulfone-fused bis(benzothiadiazole) (S-BBT), were synthesized. Single crystal analysis of Q-BBT and S-BBT revealed profoundly distinct packing modes, which must be ascribed to the different molecular shapes. Experimental and theoretical studies indicated that both compounds give rise to electron-accepting materials. This work thus also contributes to the diversity of electron acceptors based on bis-benzothiadiazole moieties and highlights the important role of molecular shape for the solid-state packing of organic conjugated materials.

1. INTRODUCTION Electron-deficient (hetero)aromatic moieties are key components of n-type organic semiconducting materials.1−3 Various electron acceptor moieties such as dicyanovinylene,4−9 diketopyrrolopyrrole (DPP),10,11 [1,2,5]-thiadia-zolo[3,4-g]quinoxaline (TQ),12−15 benzothiadiazole (BT),16 perylene diimide (PDI),17−19 naphthalene diimide (NDI),20 and isoindigo (IID)21 have already been developed. Among them, BT is a particularly popular case and has been introduced into oligomers and polymers for use in (opto)electronic devices.16,22−34 Moreover, some other BT derivatives, such as thiazole-fused BTs,35,36 thiadiazolopyridine,37,38 and thiadiazoloquinoxaline39 have also been synthesized, which largely enriched the BT-based electron acceptors. To further explore the potential of BT-based electronaccepting materials, several bis-benzothiadiazole (BBT) derivatives (Figure 1) have been developed very recently, considering they should possess higher electron affinities than BT. One approach is to connect two BT units via different linkers, such as a single, a double, and a triple bond.40,41 These BBTs behaved as promising electron acceptor units, but intrinsically the single and double bond connected BBTs still have a rotational flexibility, which is detrimental to molecular ordering. Another approach is to incorporate two BT units into fused aromatic systems, providing more rigid structures and more pronounced π-conjugations.42−44 To the best of our knowledge, the synthesis of such important BBT-based electron-deficient cores has been rarely reported. Herein, we describe the synthesis, single crystal structures, and photophysical and electrochemical properties of linear benzoquinone-fused BBT (Q-BBT) and V-shaped sulfone-fused BBT (S-BBT) (see Scheme 1). The influence on the solid-state © 2016 American Chemical Society

packing mode caused by the varying molecular shapes was also investigated, which is an appealing feature of this study.

2. EXPERIMENTAL SECTION General Methods. 1H NMR and 13C NMR spectra were recorded in deuterated solvents on Bruker DPX 250, 500, or 700 MHz instruments. FD mass spectra were recorded on a VG-Instrument ZAB 2-SE-FDP. Density functional theory (DFT) calculations were performed using the Gaussian 09 program, with the B3LYP hybrid functional and basis set 6-311G(d,p) for the ground-state geometry optimization. X-ray crystallographic data for the molecules were collected on a STOE IPDS 2T diffractometer with Cu−Kα IμS radiation source (Q-BBT), and a STOE IPDS 2T diffractometer using a graphite monochromator with Mo Kα radiation source (S-BBT). The structures were resolved by direct methods (SIR-2004) and refined by SHELXL-2014 (full matrix): 55 refined parameters for Q-BBT and 191 refined parameters for S-BBT. Synthetic Details. All reagents and starting materials were obtained from commercial suppliers and used without further purification. Column chromatography was performed on silica gel 60 (MachereyNagel, Si60). All reported yields are isolated yields. Compound 2 was synthesized according to a reported procedure.45,46 2,3,7,8-Tetrabromodibenzo[b,d]thiophene 5,5-dioxide (4). 3-Bromobenzo[b]thiophene 1,1-dioxide (2.0 g, 5.0 mmol) and 3,4-dibromothiophene 1,1-dioxide (1.64 g, 5.97 mmol) were mixed together and refluxed in acetic acid for 48 h. After being cooled to room temperature, the precipitate was filtered and washed with water and acetone, respectively, to give 4 (300 mg, yield: 20%) 1H NMR (250 MHz, THF-d8): δ 8.52 (s, 2H), 7.38 (s, 2H). The 13C NMR spectrum could not be obtained due to the extremely poor solubility. Received: September 14, 2016 Revised: October 25, 2016 Published: October 26, 2016 7124

DOI: 10.1021/acs.cgd.6b01359 Cryst. Growth Des. 2016, 16, 7124−7129

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Figure 1. Chemical structures of BT unit and BBT derivatives.

Scheme 1. Synthesis of Q-BBT and S-BBT

General Procedure for the Synthesis of 5 and 6. A mixture of tris(dibenzylideneacetone)dipalladium(0) (40 mg, 0.045 mmol), rac-BINAP (56 mg, 0.09 mmol), and toluene (15 mL) was stirred at

FD MS: m/z calcd 527.7, found 528.0. MALDI-ESI: m/z calcd for C12H4NaO2S 550.6558, found 550.6553. Melting point was not observed below 300 °C. 7125

DOI: 10.1021/acs.cgd.6b01359 Cryst. Growth Des. 2016, 16, 7124−7129

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Figure 2. Single crystal structure of Q-BBT: (a) C−H···N hydrogen bonds as shown with dashed red lines; (b) slipped columnar π−π stacking and single crystal structure of S-BBT: (c) C−H···N hydrogen bonds and intermolecular S···O/N interactions as shown with dashed red lines and dashed blue lines, respectively; (d) one-dimensional π−π stacking. 110 °C for 0.5 under argon. After being cooled to room temperature, benzophenone imine (0.19 mL, 1.20 mmol), sodium tert-butoxide (0.12 g, 1.21 mmol), and 2 (0.10 g, 0.19 mmol) or 4 (0.10 g, 0.19 mmol) were added. The reaction mixture was stirred at 110 °C overnight. Then toluene was evaporated under reduced pressure, and the residue was purified by column chromatography on silica gel (neutralized by triethylamine to prevent decomposition of target compounds in an acidic condition) using hexane/AcOEt (4:1) as eluent to give 5 (90 mg, yield: 51%) or 6 (131 mg, yield: 74%) as orange solids. 2,3,6,7-Tetrakis((diphenylmethylene)amino)anthracene9,10-dione (5). 1H NMR (700 MHz, CD2Cl2, 298 K, ppm): δ 7.73 (s, 8H), 7.48 (s, 4H), 7.40−7.33 (m, 20H), 7.25 (s, 4H), 7.17 (s, 4H). 13 C NMR (700 MHz, CD2Cl2, 298 K, ppm): 181.48, 168.84, 147.60, 138.69, 136.10, 131.01, 129.63, 129.53, 129.26, 128.49, 128.49, 128.04, 118.11. HRMS (ESI): m/z calcd for C66H45N4O2 925.3543, found 925.3533. Crystallographic data (CCDC deposition number): CCDC 1410009. Melting point was not observed. The compound decomposed at around 268−270 °C during the melting point measurement. 2,3,7,8-Tetrakis((diphenylmethylene)amino)dibenzo[b,d]thiophene 5,5-Dioxide (6). 1H NMR (700 MHz, CD2Cl2, 298 K, ppm): δ 7.78−7.65 (m, 8 H), 7.54−7.44 (m, 4H), 7.43−7.31 (m, 20H), 7.20 (s, 4H), 7.03 (dd, J = 11.4, 7.2 Hz, 4H), 6.69 (d, J = 7.0 Hz, 2H), 6.62 (d, J = 7.0 Hz, 2H). 13C NMR (700 MHz, CD2Cl2, 298 K, ppm): δ 169.05, 147.99, 142.35, 138.98, 138.85, 136.25, 135.81, 132.49, 131.04, 130.94, 129.50, 129.44, 129.35, 129.24, 128.85, 128.84, 128.11, 128.05, 127.14, 113.51, 112.54. HRMS (ESI): m/z calcd for C64H45N4O2S 933.3263, found 933.3260. Melting point was not observed. The compound decomposed at around 258−260 °C during the melting point measurement. General Procedure for the Synthesis of 7 and 8. To a solution of 5 (0.30 g, 0.32 mmol) or 6 (0.30 g, 0.32 mmol) in 30 mL of THF was added dropwise 3 mL of hydrochloric acid (2 M). The mixture was stirred for 10 h at room temperature. Then THF was evaporated under reduced pressure, and the residue was dried under a freeze drier. The dark solid was washed with hexane to give 7 (80 mg, yield: 60%) or 8 (98 mg, yield: 67%). The crude products were used directly for the next step without further purification.

General Procedure for the Synthesis of Q-BBT and S-BBT. To a solution of 7 (25 mg, 0.06 mmol) or 8 (45 mg, 0.10 mmol) in 10 mL of pyridine were added N-sulfinylaniline (0.04 mL, 0.38 mmol) and chlorotrimethylsilane (0.05 mL, 0.41 mmol). The mixture was stirred under argon at 80 °C overnight. After cooling to room temperature, the precipitate was filtrated and washed with acetone to give Q-BBT (18 mg, yield: 92%) or S-BBT (26 mg, yield: 80%) 1H NMR (250 MHz, D2SO4, 298 K, ppm): δ 9.22 (s, 4H). 13C NMR (250 MHz, D2SO4, 298 K, ppm): δ 182.13, 150.64, 136.73, 123.78. HRMS (ESI): m/z calcd for C14H4N4O2S2 323.9776, found 324.9847. Crystallographic data (CCDC deposition number): CCDC 1400306. Melting point has not been observed below 300 °C. S-BBT. 1H NMR (500 MHz, D2SO4, 298 K, ppm): δ 8.87 (s, 2H), δ 8.84 (s, 2H). 13C NMR (500 MHz, D2SO4, 298 K, ppm): δ 144.79, 143.13, 135.93, 129.01, 113.16, 109.07. HRMS (ESI): m/z calcd for C12H4N4O2S3 331.9496, found 332.2009. Crystallographic data (CCDC deposition number): CCDC 1400305. Melting point has not been observed below 300 °C. Cyclic Voltammetry Measurements. Electrochemistry was carried out on a computer-controlled GSTAT12 in a three-electrode cell in anhydrous NMP solution of Bu4NPF6 (0.1 M) with a scan rate of 100 mV/s at room temperature. A platinum wire, a silver wire, and a glassy carbon electrode were used as counter electrode, the reference electrode, and the working electrode, respectively. The lowestunoccupied molecular orbital (LUMO) energy levels were estimated from the onsets of the first reduction peak through the equation ELUMO = −[Eredonset − E(Fc+/Fc) + 4.8] eV, using ferrocene as an external standard. Fluorescence Quantum Yield Measurements. Spectroscopic measurements of Q-BBT and S-BBT were carried out in tetrahydrofuran using a cuvette with a 1 cm path length at room temperature. Fluorescence quantum yield measurements were performed on UV−vis absorption and fluorescence spectroscopies. The absorbance spectra were measured within a maximum absorbance between 0.05 and 0.10. Tetrahydrofuran solutions of Q-BBT and S-BBT were excited at 331 nm. Quantum yields were estimated by using the relative method with quinine sulfate (1 M H2SO4, Φem = 0.55 at 331 nm). Relative quantum efficiency was obtained according to the following equation: Φfl,sample = Φfl,ref (ODref /ODsample)(Asample/Aref)(ηsample/ηref)2 wherein Φ represents 7126

DOI: 10.1021/acs.cgd.6b01359 Cryst. Growth Des. 2016, 16, 7124−7129

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the fluorescence quantum yield, OD is the absorption intensity, A is the area under fluorescence intensity, and η is the refractive index of the solvent (tetrahydrofuran, 1.41; 1 M aqueous H2SO4, 1.33). Device Fabrication and Measurements. Bottom-gate bottomcontact architecture was utilized for field-effect transistors. The Au source and drain electrodes with 50 nm in thickness were deposited by thermal evaporation. SiO2 with 300 nm in thickness was used as dielectric layer and modified by hexamethyldisilazane (HMDS) self-assembled monolayers. Q-BBT and S-BBT films with 50 nm in thickness were deposited by vacuum thermal evaporation at a rate of 2 Å/s under a pressure of 1 × 10−6 Torr. A Keithley 4200-SCS was employed for all electrical measurements in a glovebox under nitrogen atmosphere.

distance of 3.42 Å. Such dense molecular packing and close contacts between π-stacks of both Q-BBT and S-BBT hold promise for rapid charge carrier transport. UV−vis absorption and emission spectra (Figure 3) of Q-BBT and S-BBT in THF solutions provide insight into the electronic

3. RESULTS AND DISCUSSION Synthesis and Electronic Properties. A facile synthetic route to the two target molecules is illustrated in Scheme 1. Following a procedure described in the literature,45 2,3,6,7tetrabromo-anthracene-9,10-dione (2) was synthesized in 18% yield, which cannot be further enhanced by altering the ratio of the reagents, prolonging reaction time or using microwave. Also, the major byproduct 3,5,6-tribromobenzo[b]thiophene 1,1- dioxide (3) was formed in 52% yield through homodimerization of 3,4-dibromothiophene 1,1-dioxide (1).45 Surprisingly, a ∼2% yield of 2,3,7,8-tetrabromodibenzo[b,d]-thiophene 5,5- dioxide (4) was also obtained, presumably due to further Diels−Alder reaction of compound 3 with 1. Indeed, an independent Diels−Alder reaction between compound 3 and 1 successfully produced 4 in a yield of 20%. Moreover, compound 4 could also be prepared in 10% yield only using 1 as the reactant in refluxing acetic acid. We assume that this synthesis proceeded in a sequence of Diels−Alder reactions (see Figure S1). The amine-substituted compounds 7 and 8 were synthesized by Buchwald−Hartwig aminations,47,48 followed by hydrolysis in the presence of 2.0 M HCl in THF. Finally, using N-sulfinylaniline as the cyclization reagent, Q-BBT and S-BBT were successfully synthesized in yields of 92% and 80%, respectively. Single crystal analysis of molecules is a vital requirement to understand their electronic properties. Single crystals of Q-BBT and S-BBT were obtained by slow evaporation of their THF solutions at room temperature. All of them were examined from X-ray analysis. The corresponding data are collected in Table S1. Notably, this is the first time for the crystal structure determination of BBT-based conjugated systems. As depicted in Figure 2, the conjugated backbones of Q-BBT and S-BBT are essentially planar while the sulfone oxygen atoms of S-BBT are out of the π-plane with the S−O−S angle of 103.39°. Each Q-BBT is closely surrounded by four neighbors by virtue of eight hydrogen bonds, whose H···N distance is 2.54 Å and C−H···N angle is 163.4° (Figure 2a). Furthermore, Q-BBT exhibits a slipped π-stacking with an average π−π distance of 3.40 Å (Figure 2b). Unlike Q-BBT and other BT containing molecules,49,50 S-BBT shows a unique crystal packing structure due to its special geometry (V-shaped backbone with out-of-plane oxygen atoms). First, close contacts between the heteroatoms [N···S (2.89 Å) and O···S (3.20 Å)] together with C−H···N hydrogen bonding were observed. Second, S-BBT forms face-toface stacked dimers with a short intermolecular π−π distance (3.35 Å), which corresponds to that occurring in graphite and also suggests it has strong π−π interaction. Moreover, the dimers of S-BBT show an offset of 0.11 Å due to a solid state effect of the π-stacking (Figure S2). Third, the stacked dimers interact with each other in a one-dimensional arrangement with a π−π

Figure 3. Absorption (solid) and photoluminescence (hollow) spectra of Q-BBT and S-BBT in THF (λExc = 390 nm).

structure of the molecules. The UV−vis absorption spectrum of Q-BBT displays a broad absorption peaking at 304, 343, and 390 nm. The optical gap calculated from the onset of the absorption is ∼3.08 eV. S-BBT exhibits a significant vibronic structure (λmax = 390 nm) and a similar optical gap (3.05 eV). The different absorption intensities of the molecules in the region of 360−390 nm are supported by time-dependent density functional theory calculations (Figure S3). The normalized fluorescence spectra of Q-BBT and S-BBT reveal almost the same profile with the maximum emission wavelength at 420 nm. The Stokes shifts are small, which is in line with their structural rigidity. Fluorescence quantum yields of Q-BBT and S-BBT are 0.04 and 0.08, respectively (see the Experimental Section). The electron-accepting properties of Q-BBT and S-BBT were studied by electrochemical measurements. Cyclic voltammograms of Q-BBT and S-BBT in NMP exhibited two reversible reduction waves but no oxidation (Figure 4). The onset potentials

Figure 4. Cyclic voltammograms of Q-BBT and S-BBT in N-methyl-2pyrrolidone (NMP).

(vs Fc/Fc+) of Q-BBT and S-BBT are −1.03 V and −0.99 V, respectively. The LUMO energy levels estimated from the equation ELUMO = −[Ered(onset) − EFc1/2 + 4.8] eV are −3.77 eV for Q-BBT and −3.81 eV for S-BBT. Both compounds thus possess a lower LUMO level than the recently reported structurally related acceptors pentacenobis(thiadizaole)dione44 and octafluoropentacenequinone,51 which indicates the potential role of Q-BBT and S-BBT as n-type organic semiconductors. These 7127

DOI: 10.1021/acs.cgd.6b01359 Cryst. Growth Des. 2016, 16, 7124−7129

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results partially suggest that by changing molecular geometries the electron deficient nature of the BT-based molecules cannot be easily tuned. To gain more insights into the electronic properties of Q-BBT and S-BBT, we performed density functional theory (DFT) calculations at the B3LYP/6-311G(d,p) level. The optimized geometries of two molecules reveal highly planar backbones without intramolecular torsions. As depicted in Figure 5,

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.cgd.6b01359. DFT calculations, crystal data, output curves of OFET 1H, 13 C NMR, and HRMS spectra (PDF) Accession Codes

CCDC 1400305−1400306 and 1410009 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/ cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.



AUTHOR INFORMATION

Corresponding Authors

*(M.B.) E-mail: [email protected]. *(K.M.) E-mail: [email protected]. Notes

The authors declare no competing financial interest.



ACKNOWLEDGMENTS We acknowledge Wen Zhang for high-resolution MALDI-TOF MS measurements and Dr. Dieter Schollmeyer (Johannes Gutenberg-University Mainz) for single-crystal X-ray structural analysis. This work was financially supported by the Transregio TR49 and Natural Science Foundation of China (No. 51603055).

Figure 5. Frontier molecular orbitals (FMOs) and their energies (in eV) for Q-BBT and S-BBT.

the frontier molecular orbitals are delocalized over the whole molecules, indicating effective π-conjugation in the fused systems. Moreover, the LUMOs of Q-BBT and S-BBT demonstrate almost the same orbital distributions, as well as similar energy levels, which is in accordance with the CV results. In contrast, the highest-occupied molecular orbital (HOMO) energy levels of Q-BBT and S-BBT exhibit different energy levels. Furthermore, the HOMO−LUMO gaps of Q-BBT and S-BBT are reduced relative to those of their isoelectronic analogue pentacene-6,13-dione and dinaphthothiophene 6,6-dioxide, respectively (Figure S4). This finding can be attributed to the peripheral thiadiazole rings, which stabilize the LUMO levels. The charge carrier transport properties of Q-BBT and S-BBT were investigated by fabricating field-effect transistors (FETs). An electron mobility of 1.1 × 10−3 cm2 V−1 s−1 was observed for Q-BBT (Figure S5), whereas the inhomogeneous film morphology of S-BBT remarkably hindered the electron transport, resulting in negligible transistor performance.



REFERENCES

(1) Shi, X.; Chang, J.; Chi, C. Chem. Commun. 2013, 49, 7135−7137. (2) Kohl, B.; Over, L. C.; Lohr, T.; Vasylyeva, M.; Rominger, F.; Mastalerz, M. Org. Lett. 2014, 16, 5596−5599. (3) Black, H. T.; Perepichka, D. F. Angew. Chem., Int. Ed. 2014, 53, 2138−2142. (4) Fitzner, R.; Reinold, E.; Mishra, A.; Mena-Osteritz, E.; Ziehlke, H.; Körner, C.; Leo, K.; Riede, M.; Weil, M.; Tsaryova, O.; Weiß, A.; Uhrich, C.; Pfeiffer, M.; Bäuerle, P. Adv. Funct. Mater. 2011, 21, 897−910. (5) Haid, S.; Mishra, A.; Weil, M.; Uhrich, C.; Pfeiffer, M.; Bäuerle, P. Adv. Funct. Mater. 2012, 22, 4322−4333. (6) Fitzner, R.; Mena-Osteritz, E.; Walzer, K.; Pfeiffer, M.; Bäuerle, P. Adv. Funct. Mater. 2015, 25, 1845−1856. (7) Ie, Y.; Nishida, K.; Karakawa, M.; Tada, H.; Aso, Y. J. Org. Chem. 2011, 76, 6604−6610. (8) Takahashi, T.; Matsuoka, K.-i.; Takimiya, K.; Otsubo, T.; Aso, Y. J. Am. Chem. Soc. 2005, 127, 8928−8929. (9) Ie, Y.; Karakawa, M.; Jinnai, S.; Yoshida, H.; Saeki, A.; Seki, S.; Yamamoto, S.; Ohkita, H.; Aso, Y. Chem. Commun. 2014, 50, 4123− 4125. (10) Lin, Y.; Cheng, P.; Li, Y.; Zhan, X. Chem. Commun. 2012, 48, 4773−4775. (11) Nielsen, C. B.; Turbiez, M.; McCulloch, I. Adv. Mater. 2013, 25, 1859−1880. (12) Dexter Tam, T. L.; Salim, T.; Li, H.; Zhou, F.; Mhaisalkar, S. G.; Su, H.; Lam, Y. M.; Grimsdale, A. C. J. Mater. Chem. 2012, 22, 18528− 18534. (13) Li, H.; Tam, T. L.; Lam, Y. M.; Mhaisalkar, S. G.; Grimsdale, A. C. Org. Lett. 2011, 13, 46−49. (14) Li, M.; An, C.; Marszalek, T.; Guo, X.; Long, Y.-Z.; Yin, H.; Gu, C.; Baumgarten, M.; Pisula, W.; Müllen, K. Chem. Mater. 2015, 27, 2218− 2223. (15) An, C.; Li, M.; Marszalek, T.; Li, D.; Berger, R.; Pisula, W.; Baumgarten, M. Chem. Mater. 2014, 26, 5923−5929.

4. CONCLUSIONS We have prepared two novel bis-benzothiadiazole-based compounds with fused rings, namely, linear Q-BBT and V-shaped S-BBT. The different molecular geometries significantly influence the mode of crystal packing, giving a hint for the design of desired molecules. Also, it has to be emphasized that the key intermediate 4 was obtained in a sequence of Diels−Alder reactions, which is promising for the synthesis of V-shaped long acene. Moreover, a combination of experimental and theoretical studies reveals that both Q-BBT and S-BBT are strong electronwithdrawing systems. FET devices based on Q-BBT showed an electron mobility of 1.1 × 10−3 cm2 V−1 s−1, indicating that fused bis-benzothiadiazoles are potential frameworks for n-type organic semiconductors. 7128

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(16) Chen, L.; Li, P.; Cheng, Y.; Xie, Z.; Wang, L.; Jing, X.; Wang, F. Adv. Mater. 2011, 23, 2986−2990. (17) Zhang, X.; Lu, Z.; Ye, L.; Zhan, C.; Hou, J.; Zhang, S.; Jiang, B.; Zhao, Y.; Huang, J.; Zhang, S.; Liu, Y.; Shi, Q.; Liu, Y.; Yao, J. Adv. Mater. 2013, 25, 5791−5797. (18) Zang, Y.; Li, C.-Z.; Chueh, C.-C.; Williams, S. T.; Jiang, W.; Wang, Z.-H.; Yu, J.-S.; Jen, A. K. Y. Adv. Mater. 2014, 26, 5708−5714. (19) Lin, Y.; Wang, Y.; Wang, J.; Hou, J.; Li, Y.; Zhu, D.; Zhan, X. Adv. Mater. 2014, 26, 5137−5142. (20) Lu, R.-Q.; Zheng, Y.-Q.; Zhou, Y.-N.; Yan, X.-Y.; Lei, T.; Shi, K.; Zhou, Y.; Pei, J.; Zoppi, L.; Baldridge, K. K.; Siegel, J. S.; Cao, X.-Y. J. Mater. Chem. A 2014, 2, 20515−20519. (21) Lei, T.; Wang, J.-Y.; Pei, J. Acc. Chem. Res. 2014, 47, 1117−1126. (22) Chen, L.; Zhang, B.; Cheng, Y.; Xie, Z.; Wang, L.; Jing, X.; Wang, F. Adv. Funct. Mater. 2010, 20, 3143−3153. (23) Chen, L.; Tong, H.; Xie, Z.; Wang, L.; Jing, X.; Wang, F. J. Mater. Chem. 2011, 21, 15773−15779. (24) Chen, L.; Wang, L.; Jing, X.; Wang, F. J. Mater. Chem. 2011, 21, 10265−10267. (25) Peng, Q.; Liu, X.; Su, D.; Fu, G.; Xu, J.; Dai, L. Adv. Mater. 2011, 23, 4554−4558. (26) Sonar, P.; Singh, S. P.; Li, Y.; Soh, M. S.; Dodabalapur, A. Adv. Mater. 2010, 22, 5409−5413. (27) Zhou, H.; Yang, L.; Stuart, A. C.; Price, S. C.; Liu, S.; You, W. Angew. Chem., Int. Ed. 2011, 50, 2995−2998. (28) Wang, N.; Chen, Z.; Wei, W.; Jiang, Z. J. Am. Chem. Soc. 2013, 135, 17060−17068. (29) Mishra, A.; Bäuerle, P. Angew. Chem., Int. Ed. 2012, 51, 2020− 2067. (30) Lin, Y.; Wang, H.; Li, Y.; Zhu, D.; Zhan, X. J. Mater. Chem. A 2013, 1, 14627−14632. (31) Zhang, M.; Wang, Y.; Xu, M.; Ma, W.; Li, R.; Wang, P. Energy Environ. Sci. 2013, 6, 2944−2949. (32) Yang, G.; Di, C.-a.; Zhang, G.; Zhang, J.; Xiang, J.; Zhang, D.; Zhu, D. Adv. Funct. Mater. 2013, 23, 1671−1676. (33) Zhang, Y.; Kim, C.; Lin, J.; Nguyen, T.-Q. Adv. Funct. Mater. 2012, 22, 97−105. (34) Beaujuge, P. M.; Tsao, H. N.; Hansen, M. R.; Amb, C. M.; Risko, C.; Subbiah, J.; Choudhury, K. R.; Mavrinskiy, A.; Pisula, W.; Brédas, J.L.; So, F.; Müllen, K.; Reynolds, J. R. J. Am. Chem. Soc. 2012, 134, 8944− 8957. (35) Satou, M.; Uchinaga, K.; Wakamiya, A.; Murata, Y. Chem. Lett. 2014, 43, 1386−1388. (36) Satou, M.; Nakamura, T.; Aramaki, Y.; Okazaki, S.; Murata, M.; Wakamiya, A.; Murata, Y. Chem. Lett. 2016, 45, 892−894. (37) Zhou, H.; Yang, L.; Price, S. C.; Knight, K. J.; You, W. Angew. Chem., Int. Ed. 2010, 49, 7992−7995. (38) Blouin, N.; Michaud, A.; Gendron, D.; Wakim, S.; Blair, E.; Neagu-Plesu, R.; Belletête, M.; Durocher, G.; Tao, Y.; Leclerc, M. J. Am. Chem. Soc. 2008, 130, 732−742. (39) Steckler, T. T.; Henriksson, P.; Mollinger, S.; Lundin, A.; Salleo, A.; Andersson, M. R. J. Am. Chem. Soc. 2014, 136, 1190−1193. (40) Lee, J.; Cho, S.; Seo, J. H.; Anant, P.; Jacob, J.; Yang, C. J. Mater. Chem. 2012, 22, 1504−1510. (41) Kim, J.; Han, A. R.; Hong, J.; Kim, G.; Lee, J.; Shin, T. J.; Oh, J. H.; Yang, C. Chem. Mater. 2014, 26, 4933−4942. (42) Osaka, I.; Shimawaki, M.; Mori, H.; Doi, I.; Miyazaki, E.; Koganezawa, T.; Takimiya, K. J. Am. Chem. Soc. 2012, 134, 3498−3507. (43) Wang, M.; Hu, X.; Liu, P.; Li, W.; Gong, X.; Huang, F.; Cao, Y. J. Am. Chem. Soc. 2011, 133, 9638−9641. (44) Shi, Z.-F.; Black, H. T.; Dadvand, A.; Perepichka, D. F. J. Org. Chem. 2014, 79, 5858−5860. (45) Bailey, D.; Williams, V. E. Tetrahedron Lett. 2004, 45, 2511−2513. (46) Xia, D.; Guo, X.; Chen, L.; Baumgarten, M.; Keerthi, A.; Müllen, K. Angew. Chem., Int. Ed. 2016, 55, 941−944. (47) Chen, L.; Kim, J.; Ishizuka, T.; Honsho, Y.; Saeki, A.; Seki, S.; Ihee, H.; Jiang, D. J. Am. Chem. Soc. 2009, 131, 7287−7292. (48) Xia, D.; Guo, X.; Chen, L.; Baumgarten, M.; Keerthi, A.; Müllen, K. Angew. Chem., Int. Ed. 2016, 55, 941.

(49) Appleton, A. L.; Miao, S.; Brombosz, S. M.; Berger, N. J.; Barlow, S.; Marder, S. R.; Lawrence, B. M.; Hardcastle, K. I.; Bunz, U. H. F. Org. Lett. 2009, 11, 5222−5225. (50) Lei, T.; Zhou, Y.; Cheng, C.-Y.; Cao, Y.; Peng, Y.; Bian, J.; Pei, J. Org. Lett. 2011, 13, 2642−2645. (51) Liang, Z.; Tang, Q.; Liu, J.; Li, J.; Yan, F.; Miao, Q. Chem. Mater. 2010, 22, 6438−6443.

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DOI: 10.1021/acs.cgd.6b01359 Cryst. Growth Des. 2016, 16, 7124−7129