Article Cite This: J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Hexacene Diimides Xiaoping Cui,†,§ Chengyi Xiao,∥ Thorsten Winands,# Tobias Koch,# Yan Li,*,‡,⊥ Lei Zhang,∥ Nikos L. Doltsinis,# and Zhaohui Wang*,†,‡,§
J. Am. Chem. Soc. Downloaded from pubs.acs.org by EASTERN KENTUCKY UNIV on 09/01/18. For personal use only.
†
Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China ‡ Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China § Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China ∥ College of Energy, Beijing University of Chemical Technology, Beijing 100029, China # Institute for Solid State Theory and Center for Multiscale Theory & Computation, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany ⊥ School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China S Supporting Information *
ABSTRACT: Acene imides are expected to possess smaller band gaps than homologous acenes while maintaining good solubility and stability. However, the design and synthesis of large acene imides are still a big challenge. Herein, we report a one-pot synthesis of hexacene diimides (HDI) by double aromatic annulation between zirconabenzocyclopentene and tetrabrominated naphthalene diimides. HDIs with branched alkyl chains exhibit very good solubility, stability, and much smaller band gaps than hexacene. Organic fieldeffect transistors (OFETs) based on HDI microribbons exhibit excellent ambipolar transport behavior with the highest electron mobility of 2.17 cm2 V−1 s−1 and hole mobility of 0.30 cm2 V−1 s−1 under ambient conditions.
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INTRODUCTION Acenes, which are composed of linearly fused benzene rings, have attracted much attention of chemists, physicists, and material scientists for more than a century.1 Acenes are considered as the narrowest zigzag graphene nanoribbons, which possess small band gaps that can quickly decrease along with the length of the conjugated π system to make them promising high-conductive materials.2 Among them, pentacene is most widely studied and has been successfully employed in various organic electronics.3 However, the synthesis of longer acenes that are expected to possess smaller band gaps and extraordinary application prospects remains an attractive but challenging target for chemists, although large acenes from heptacene to undecacene have been obtained by introducing bulky groups or detected by matrix-isolation or on-surface techniques.4 Large acenes are susceptible to two problems, namely, poor solubility and high reactivity with the extension of the π system.5 Acene imides that are composed of acenes and one or more dicarboximide groups on the zigzag periphery have gained extensive attention in recent years because they potentially have smaller band gaps than homologous acenes while maintaining good solubility and high stability.2a,6 In addition, introduction of electron-withdrawing imide groups will change © XXXX American Chemical Society
the optical and electronic properties of acenes evidently to obtain n-type and even ambipolar semiconductors. Until now, only a few acene diimides, such as anthracene, tetracene, and pentacene diimides, have been reported due to the synthetic difficulties, and the organic field-effect transistors (OFETs) based on them show much lower electron mobilities (∼10−3 cm2 V−1 s−1).7 Hexacene diimides, especially consummate hexacene diimides composed of an unsubstituted hexacene backbone and two dicarboximides groups linked in the central naphthalene subunit, have not yet been reported. Metallacyclopentadienes and related compounds are versatile intermediates in the construction of large polycyclic aromatic hydrocarbons.8 In our previous work, tetracene diimides (TDIs) were successfully obtained by one step of double cross-coupling reaction of zirconacyclopentadiene with tetrabrominated naphthalene diimides (TBNDIs).7c Furthermore, a cyclohexene-fused TDI was also synthesized when cyclohexene-fused zirconacyclopentadiene reagent coupled with TBNDI, as shown in Figure 1a. Unfortunately, it is difficult to obtain the target product of hexacene diimides by dehydrogenation of cyclohexene-fused TDI. Meanwhile, the Received: July 11, 2018 Published: August 22, 2018 A
DOI: 10.1021/jacs.8b07305 J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Journal of the American Chemical Society Scheme 1. Synthesis of Hexacene Diimides
Figure 1. (a) Previously presented and (b) new design strategies toward the synthesis of hexacene diimides.
existence of R2 groups from a zirconacyclopentadiene reagent9 will make the hexacene backbone highly twisted owing to the steric hindrance between R2 and carboxide groups, which is detrimental to intermolecular charge transport. Inspired by previous work, herein, we present a new design strategy for consummate hexacene diimides (HDIs) based on one step of double aromatic annulation of TBNDI as shown in Figure 1b. Metallabenzocyclopentene reagents which have much higher thermal stability than the di-Grignard reagent were reported in 1984.10 However, their application in aromatic annulation coupling with dihalo aromatic compounds has never been reported. The coupling reaction of zirconabenzocyclopentene and TBNDI proceeds well in tetrahydrofuran (THF) in the presence of cuprous chloride, which contains four C(sp2)−C(sp2) bond formation. The structures of HDIs with three different lengths of branched alkyl chains are unambiguously identified and exhibit very good thermal and light stability together with excellent solubility. OFETs based on microribbons of three HDIs all exhibit excellent ambipolar transport behavior with electron mobilities of 0.91−2.17 cm2 V−1 s−1 and hole mobilities of 0.11−0.30 cm2 V−1 s−1 under ambient conditions.
Figure 2. (a) 1H−1H COSY and (b) 1D NOE spectra of HDI (3b).
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RESULTS AND DISCUSSION The synthetic route to hexacene diimides is shown in Scheme 1. Zirconabenzocyclopentene reagent 1 was prepared by the reaction of the di-Grignard reagent o-C6H4(CH2MgCl)2 in THF with bis(cyclopentadienyl)zirconium dichloride.10a TBNDI 2 was obtained according to known procedures.11 Hexacene diimides were synthesized in ∼15% yields via one step of double aromatic annulation between zirconabenzocyclopentene reagent and TBNDI in the presence of CuCl at 50 °C for 48 h. HDIs with three different lengths of branched alkyl chains 3a, 3b, and 3c were fully characterized by 1H and
Figure 3. Optimized geometry of HDI with methyl groups calculated by the DFT (PBE0-D3BJ/6-31G*) method.
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DOI: 10.1021/jacs.8b07305 J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Figure 5. Cyclic voltammograms of NDI (black), TDI (red), and HDI (3b, blue) in dichloromethane (V vs Ag/AgCl). Wave at ca. 0.5 V is the internal Fc/Fc+ reference.
Figure 4. UV−vis−NIR absorption spectrum of HDI (3b) in chloroform (1 × 10−5 M) and in film (inset). 13
diimides.7b The relatively large hexacene backbone and relatively planar molecular geometry of HDI will be favorable for intermolecular π-stacking. The optical properties of HDIs were investigated by UV− vis−NIR absorption spectroscopy. As shown in Figure 4, HDI 3b exhibits three absorption bands in the range 300−1100 nm with three maxima at 335, 498, and 950 nm in dilute chloroform solution. According to the TDDFT eigenvectors (Figure S5 and Tables S3−S5), the lowest energy peak arises from the lowest excited singlet state S1 with a 98.3% HOMO− LUMO contribution. The modest energy peak (498 nm) is due to the S3 state predominantly containing a transition from HOMO−2 to LUMO with a 92.5% weight. The highest energy peak (335 nm) can be assigned to the S14 and S16 excited states. The former primarily involves transitions from the HOMO−1 to the LUMO+1 with a weight of 54.2% and from the HOMO to the LUMO+2 with a weight of 36.0%, while the latter has a 92.1% contribution from the HOMO to LUMO+3 transition. HDIs 3a, 3b, and 3c, with three different branched alkyl chains, have almost the same absorption spectra as shown in Figure S2, and there is no aggregation observed in dilute chloroform. We also investigated the absorption spectra of NDI, TDI, and HDI in chloroform (Figure S3), and the data are summarized in Table 1. NDI has the same branched alkyl chain as that of HDI 3b for comparison. TDI is the structure that was obtained by double aromatic annulation of zirconacyclopentadiene with TBNDI.7c The absorbance maximum of HDI at long wavelength is significantly redshifted by 195 and 568 nm relative to TDI and NDI due to the large π-conjugation of the hexacene backbone and the donor− acceptor interaction between two imide groups and the
C NMR spectra and high-resolution mass spectra attributed to their good solubility in common organic solvents such as dichloromethane, toluene, tetrahydrofuran, ortho-dichlorobenzene, and chloroform at room temperature. Meanwhile, there are no changes in the absorption spectra when the chloroform solution of HDIs is exposed to sunlight or continuous 365 nm ultraviolet light in air for more than 24 h, confirming that HDIs have good light and oxygen stability under ambient conditions. The thermal properties of HDIs were also evaluated by thermal gravimetric analysis (TGA) performed under nitrogen with the decomposition temperature of 5% weight loss over 380 °C as shown in Figure S1. The assignments of Ha, Hb, and Hc in the hexacene backbone of HDIs were determined by 1H−1H COSY and selective 1D NOE spectra, as shown in Figure 2. The 1H−1H COSY spectrum revealed the correlation between Hb and Hc and assigned Ha to the proton closest to carboxide group according to its lowest field position (large δ value) and no correlation with others. 1D NOE spectrum assigned Hb to the proton closest to Ha in space according to the correlative peak between Ha and Hb. In order to gain insight into the molecular configuration of HDIs, density functional theory (DFT) calculations using the PBE0-D3BJ/6-31G* level were carried out, where the branched alkyl chains were replaced by methyl groups to reduce the computational expense. Figure 3 shows the optimized geometry of HDI in which the hexacene backbone possesses a planar geometry as expected. However, instead of the absolute planar geometry of the HDI molecule, two dicarboximide rings are tilted slightly (∼9° for calculation) from the plane of the central naphthalene subunit due to steric hindrance between hydrogen and the carboxide group, which is very similar to the single-crystal structure of tetracene
Table 1. Summary of Optical and Electronic Properties of NDI, TDI, and HDI in Solution f
NDI TDIg HDIh
λmaxa [nm]
εa [M−1 cm−1]
E1rb [V]
E2rb [V]
ELUMOc [eV]
EHOMOd [eV]
Ege [eV]
382 755 950
24108 5500 5100
−1.14 −0.95 −0.53
−1.60 −1.25 −0.83
−3.82 −4.06 −4.41
−6.98 −5.54 −5.56
3.16 1.48 1.15
a In CHCl3 solution (1.0 × 10−5 M). bHalf-wave reductive potentials (in V vs Fc/Fc+) measured in CH2Cl2 at a scan rate of 0.1 V/s with ferrocene as an internal potential mark. cEstimated from the onset potential of the first reduction wave and calculated according to ELUMO = −(4.8 + Eonsetre) eV. dCalculated according to EHOMO = (ELUMO − Eg) eV. eObtained from the edge of the absorption spectra in CHCl3 according to Eg = 1240/ λonset. fHaving the same branched alkyl chain to that of 3b for comparison. gObtained by double aromatic annulation of zirconacyclopentadiene and TBNDI.7c hHere based on 3b.
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DOI: 10.1021/jacs.8b07305 J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Figure 6. AFM images, TEM images and their corresponding SAED patterns, and XRD patterns of 3a (a, d, g), 3b (b, e, h), and 3c (c, f, i). Representative transfer characteristics of the ambipolar OFETs based on 3a (j), 3b (k), and 3c (l). Insets are the OM images of the corresponding macroribbon devices. D
DOI: 10.1021/jacs.8b07305 J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Journal of the American Chemical Society hexacene backbone. There is no fluorescence for HDI in chloroform solution. The absorption spectrum of an HDI film is shown in Figure 4 as an inset. It has been known that the absorbance maximum at long wavelength of a hexacene film is at 850 nm.12 The absorbance maximum of HDI at long wavelength is at 1060 nm in a thin film, which is red-shifted by 210 nm in comparison to homologous hexacene and by 110 nm compared to HDI in chloroform solution. The large redshifted absorption implies that HDI has a much smaller band gap than homologous hexacene. The cyclic voltammograms (CVs) of HDIs 3a, 3b, and 3c show two reversible reduction waves with the first and second half-wave potentials at almost the same position, and there are no oxidation waves observed as shown in Figure S4. For comparison, the CVs of NDI, TDI, and HDI in dichloromethane with ferrocene as an internal potential mark are shown in Figure 5, and the data are summarized in Table 1. Three different lengths of acene diimides, NDI, TDI, and HDI, all exhibit two reversible reduction waves with the first and second half-wave potentials vs Fc/Fc+ at −1.14 and −1.60 V for NDI, −0.95 and −1.25 V for TDI, and −0.53 and −0.83 V for HDI, indicating the stronger electron-withdrawing abilities of acene diimides with the extension of π-conjugation. The LUMO levels were determined to be −3.82 eV for NDI, −4.06 eV for TDI, and −4.41 eV for HDI, from the onset potentials of the first reduction peaks, implying the stable electron-transport ability of HDIs in air conditions.13 The energy gap Eg of HDIs estimated from the edge of the absorption spectra is 1.15 eV in CHCl3 solution and 0.92 eV in film, much smaller than that of NDI and TDI (3.16 and 1.48 eV in solution). The HOMO levels of NDI, TDI, and HDI are calculated to be −6.98, −5.54, and −5.56 eV, respectively, as shown in Table 1. The decrease in the energy gap with an increase in the delocalized π-system is in line with the DFT results (Figure S7 and Table S1). OFETs based on single-crystal microribbons of HDIs 3a, 3b, and 3c were fabricated by an “organic ribbon mask” technique on the octadecyltrichlorosilane (OTS)-treated substrate (OTSSiO2/Si) with silver as electrodes.14 Single-crystalline microribbons of three HDIs were prepared by a typical drop casting method from a toluene solution in sealed jars.15 The optical microscopy (OM) images in Figure S12 show that ribbon-like crystals of three HDIs exhibit excellent long-range regularity with a length of 50−300 μm and width of several micrometers. Atomic force microscopy (AFM) images in Figure 6(a−c) reveal that the microribbons of three HDIs have a very smooth surface ensuring good interface contact in OFET devices. The sharp interlayer Bragg diffractions of X-ray diffraction (XRD) in Figure 6(g−i) show highly ordered lamellar structure of HDI microribbons with the thickness of each layer about 20.3 Å for 3a, 24.9 Å for 3b, and 28.1 Å for 3c, suggesting that the lamellar structures could be along the alkyl chain direction according to the optimized structure. The transmission electron microscopy (TEM) image of an individual microribbon and its corresponding selected area electron diffraction (SAED) pattern in Figure 6(d−f) show ordered and bright diffractions indicating the single-crystal nature of these HDI ribbons. The SAED diffraction patterns are equal to a repeating period of 7.1−7.5 Å along the crystal growth direction, which is far less than the molecular length or width. Thus, we speculate that the molecular stacking direction of HDIs is likely along the crystal growth direction. Figure 6(j−l) and Figure S13 show the transfer and output characteristics of 3a, 3b, and
3c microribbons tested under ambient conditions. OFETs based on microribbons of three HDIs all exhibit excellent ambipolar transport behavior in air. The maximum electron mobility for 3a is 0.91 cm2 V−1 s−1 with a hole mobility of 0.30 cm2 V−1 s−1, the maximum electron mobility for 3b is 2.17 cm2 V−1 s−1 with a hole mobility of 0.30 cm2 V−1 s−1, and the maximum electron mobility for 3c is 1.43 cm2 V−1 s−1 with a hole mobility of 0.11 cm2 V−1 s−1. The average electron and hole mobilities of three HDIs and corresponding important characteristics including on/off ratio (Ion/off) and threshold voltage (Vth) are summarized in Table S6.
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CONCLUSIONS In summary, hexacene diimides composed of an unsubstituted hexacene backbone and two imide groups linked in the central naphthalene subunit were successfully synthesized by one step of double aromatic annulation between zirconabenzocyclopentene and tetrabrominated naphthalene diimides. HDIs with three different lengths of branched alkyl chains are unambiguously identified and exhibit very good solubility, stability, and much smaller band gaps than homologous hexacene. OFETs based on microribbons of them all exhibit excellent ambipolar charge transport behavior with the highest electron mobility of 2.17 cm2 V−1 s−1 and hole mobility of 0.30 cm2 V−1 s−1 under ambient conditions, representing the first example of acene diimide-based ambipolar semiconductors.
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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/jacs.8b07305. Experimental details, characterization, theoretical calculations, OFET device fabrication and characterization, and supporting figures and tables (PDF)
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AUTHOR INFORMATION
Corresponding Authors
*
[email protected] *
[email protected] ORCID
Chengyi Xiao: 0000-0002-7253-7136 Lei Zhang: 0000-0002-0162-7222 Zhaohui Wang: 0000-0001-5786-5660 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS We greatly appreciate the fruitful discussion from Prof. Zhenfeng Xi and Dr. Liang Liu (Peking University) for the synthesis of zirconabenzocyclopentene reagent. This work was financially supported by the National Key R&D Program of China (2017YFA0204700), the National Natural Science Foundation of China (NSFC) (No. 21790361), NSFC-DFG joint project PAK943-TRR61 (21661132006), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB12010100), and the Youth Innovation Promotion Association of Chinese Academy of Sciences.
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REFERENCES
(1) (a) Clar, E. Polycyclic Hydrocarbons; Academic Press: New York, 1964; Vol. 1. (b) Watanabe, M.; Chen, K.-Y.; Chang, Y. J.; Chow, T. E
DOI: 10.1021/jacs.8b07305 J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Journal of the American Chemical Society J. Acc. Chem. Res. 2013, 46, 1606−1615. (c) Bendikov, M.; Wudl, F.; Perepichka, D. F. Chem. Rev. 2004, 104, 4891−4945. (d) Anthony, J. E. Chem. Rev. 2006, 106, 5028−5048. (e) Anthony, J. E. Angew. Chem., Int. Ed. 2008, 47, 452−483. (f) Dai, G.; Chang, J.; Luo, J.; Dong, S.; Aratani, N.; Zheng, B.; Huang, K.-W.; Yamada, H.; Chi, C. Angew. Chem., Int. Ed. 2016, 55, 2693−2696. (g) Zhang, L.; Cao, Y.; Colella, N. S.; Liang, Y.; Brédas, J.-L.; Houk, K. N.; Briseno, A. L. Acc. Chem. Res. 2015, 48, 500−509. (h) Bunz, U. H. F. Acc. Chem. Res. 2015, 48, 1676−1686. (i) Liu, Y.-Y.; Song, C.-L.; Zeng, W.-J.; Zhou, K.-G.; Shi, Z.-F.; Ma, C.-B.; Yang, F.; Zhang, H.-L.; Gong, X. J. Am. Chem. Soc. 2010, 132, 16349−16351. (2) (a) Sun, Z.; Ye, Q.; Chi, C.; Wu, J. Chem. Soc. Rev. 2012, 41, 7857−7889. (b) Hachmann, J.; Dorando, J. J.; Avilés, M.; Chan, G. K.-L. J. Chem. Phys. 2007, 127, 134309. (3) (a) Wilson, M. W. B.; Rao, A.; Ehrler, B.; Friend, R. H. Acc. Chem. Res. 2013, 46, 1330−1338. (b) Ryno, S. M.; Risko, C.; Brédas, J.-L. J. Am. Chem. Soc. 2014, 136, 6421−6427. (c) Sirringhaus, H. Adv. Mater. 2014, 26, 1319−1335. (d) Roncali, J.; Leriche, P.; Blanchard, P. Adv. Mater. 2014, 26, 3821−3838. (e) Poletayev, A. D.; Clark, J.; Wilson, M. W. B.; Rao, A.; Makino, Y.; Hotta, S.; Friend, R. H. Adv. Mater. 2014, 26, 919−924. (4) (a) Payne, M. M.; Parkin, S. R.; Anthony, J. E. J. Am. Chem. Soc. 2005, 127, 8028−8029. (b) Kaur, I.; Jazdzyk, M.; Stein, N. N.; Prusevich, P.; Miller, G. P. J. Am. Chem. Soc. 2010, 132, 1261−1263. (c) Einholz, R.; Fang, T.; Berger, R.; Grüninger, P.; Früh, A.; Chassé, T.; Fink, R. F.; Bettinger, H. F. J. Am. Chem. Soc. 2017, 139, 4435− 4442. (d) Mondal, R.; Tönshoff, C.; Khon, D.; Neckers, D. C.; Bettinger, H. F. J. Am. Chem. Soc. 2009, 131, 14281−14289. (e) Tönshoff, C.; Bettinger, H. F. Angew. Chem., Int. Ed. 2010, 49, 4125−4128. (f) Zuzak, R.; Dorel, R.; Kolmer, M.; Szymonski, M.; Godlewski, S.; Echavarren, A. M. Angew. Chem., Int. Ed. 2018, 57, 10500−10505. (5) (a) Mondal, R.; Adhikari, R. M.; Shah, B. K.; Neckers, D. C. Org. Lett. 2007, 9, 2505−2508. (b) Einholz, R.; Bettinger, H. F. Angew. Chem., Int. Ed. 2013, 52, 9818−9820. (c) Zade, S. S.; Zamoshchik, N.; Reddy, A. R.; Fridman-Marueli, G.; Sheberla, D.; Bendikov, M. J. Am. Chem. Soc. 2011, 133, 10803−10816. (d) Biermann, D.; Schmidt, W. J. Am. Chem. Soc. 1980, 102, 3163−3173. (6) (a) Langhals, H.; Schönmann, G.; Polborn, K. Chem. - Eur. J. 2008, 14, 5290−5303. (b) Gawroński, J.; Gawrońska, K.; Skowronek, P.; Holmén, A. J. Org. Chem. 1999, 64, 234−241. (c) Yin, J.; Zhang, K.; Jiao, C.; Li, J.; Chi, C.; Wu, J. Tetrahedron Lett. 2010, 51, 6313− 6315. (d) Okamoto, T.; Suzuki, T.; Tanaka, H.; Hashizume, D.; Matsuo, Y. Chem. - Asian J. 2012, 7, 105−111. (e) Cui, X.; Xiao, C.; Zhang, L.; Li, Y.; Wang, Z. Chem. Commun. 2016, 52, 13209−13212. (7) (a) Mohebbi, A. R.; Munoz, C.; Wudl, F. Org. Lett. 2011, 13, 2560−2563. (b) Katsuta, S.; Tanaka, K.; Maruya, Y.; Mori, S.; Masuo, S.; Okujima, T.; Uno, H.; Nakayama, K.; Yamada, H. Chem. Commun. 2011, 47, 10112−10114. (c) Yue, W.; Gao, J.; Li, Y.; Jiang, W.; Di Motta, S.; Negri, F.; Wang, Z. J. Am. Chem. Soc. 2011, 133, 18054− 18057. (8) (a) Nagao, I.; Shimizu, M.; Hiyama, T. Angew. Chem., Int. Ed. 2009, 48, 7573−7576. (b) Kiel, G. R.; Patel, S. C.; Smith, P. W.; Levine, D. S.; Tilley, T. D. J. Am. Chem. Soc. 2017, 139, 18456− 18459. (c) Takahashi, T.; Hara, R.; Nishihara, Y.; Kotora, M. J. Am. Chem. Soc. 1996, 118, 5154−5155. (d) Hilton, C. L.; Jamison, C. R.; King, B. T. J. Am. Chem. Soc. 2006, 128, 14824. (e) Takahashi, T.; Kitamura, M.; Shen, B.; Nakajima, K. J. Am. Chem. Soc. 2000, 122, 12876−12877. (f) Kiel, G. R.; Ziegler, M. S.; Tilley, T. D. Angew. Chem., Int. Ed. 2017, 56, 4839−4844. (g) Takahashi, T.; Li, Y.; Stepnicka, P.; Kitamura, M.; Liu, Y.; Nakajima, K.; Kotora, M. J. Am. Chem. Soc. 2002, 124, 576−582. (h) Bouit, P.-A.; Escande, A.; Szű cs, R.; Szieberth, D.; Lescop, C.; Nyulászi, L.; Hissler, M.; Réau, R. J. Am. Chem. Soc. 2012, 134, 6524−6527. (9) (a) Grotjahn, D. B. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: New York, 1995; Vol. 12, Hegedus, L. S., Ed.; pp 741−770 and references therein. (b) Ma, W.; Yu, C.; Chen, T.; Xu, L.; Zhang, W.-
X.; Xi, Z. Chem. Soc. Rev. 2017, 46, 1160−1192. (c) Yan, X.; Xi, C. Acc. Chem. Res. 2015, 48, 935−946. (10) (a) Bristow, G. S.; Lappert, M. F.; Martin, T. R.; Atwood, J. L.; Hunter, W. F. J. Chem. Soc., Dalton Trans. 1984, 399−413. (b) Lappert, M. F.; Raston, C. L.; Rowbottom, G. L.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1984, 883−891. (c) Lappert, M. F.; Leung, W.-P.; Raston, C. L.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1992, 775−785. (d) Lappert, M. F.; Raston, C. L.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1984, 893−902. (11) Gao, X.; Qiu, W.; Yang, X.; Liu, Y.; Wang, Y.; Zhang, H.; Qi, T.; Liu, Y.; Lu, K.; Du, C.; Shuai, Z.; Yu, G.; Zhu, D. Org. Lett. 2007, 9, 3917−3920. (12) Watanabe, M.; Chang, Y. J.; Liu, S.-W.; Chao, T.-H.; Goto, K.; Islam, M. M.; Yuan, C.-H.; Tao, Y.-T.; Shinmyozu, T.; Chow, T. J. Nat. Chem. 2012, 4, 574−578. (13) (a) Zhan, X.; Facchetti, A.; Barlow, S.; Marks, T. J.; Ratner, M. A.; Wasielewski, M. R.; Marder, S. R. Adv. Mater. 2011, 23, 268−284. (b) Dong, H.; Wang, C.; Hu, W. Chem. Commun. 2010, 46, 5211− 5222. (14) Jiang, L.; Gao, J.; Wang, E.; Li, H.; Wang, Z.; Hu, W.; Jiang, L. Adv. Mater. 2008, 20, 2735−2740. (15) He, P.; Tu, Z.; Zhao, G.; Zhen, Y.; Geng, H.; Yi, Y.; Wang, Z.; Zhang, H.; Xu, C.; Liu, J.; Lu, X.; Fu, X.; Zhao, Q.; Zhang, X.; Ji, D.; Jiang, L.; Dong, H.; Hu, W. Adv. Mater. 2015, 27, 825−830.
F
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