Subscriber access provided by MPI FUR POLYMERFORSCHUNG Communication Persulfurated Coronene: A New Generation of “Sulflower” Renhao Dong, Martin Pfeffermann, Dmitry Skidin, Faxing Wang, Yubin Fu, Akimitsu Narita, Matteo Tommasini, Francesca Moresco, Gianaurelio Cuniberti, Reinhard Berger, Klaus Müllen, and Xinliang Feng J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.6b12630 • Publication Date (Web): 27 Jan 2017 Downloaded from http://pubs.acs.org on January 30, 2017 Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. 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Page 1 of 5 Journal of the American Chemical Society 1 2 3 4 5 6 7 Persulfurated Coronene: A New Generation of “Sulflower” 8 † § ‡ † † § 9 Renhao Dong, Martin Pfeffermann, Dmitry Skidin, Faxing Wang, Yubin Fu, Akimitsu Narita, 10 Matteo Tommasini,‖ Francesca Moresco,‡ Gianaurelio Cuniberti,‡ Reinhard Berger,† Klaus Müllen,*,§ 11 Xinliang Feng*,† 12 13 †Department of Chemistry and Food Chemistry, Center for Advancing Electronics Dresden, Technische Universität Dresden, 14 01062 Dresden, Germany 15 § Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany 16 ‡ 17 Institute for Materials Science, Max Bergmann Center of Biomaterials, and Center for Advancing Electronics Dresden, TU 18 Dresden, 01069 Dresden, Germany 19 ‖Dipartimento di Chimica, Materiali ed Ingegneria Chimica ‘G. Natta’, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20 20133 Milano, Italy 21 22 23 Supporting Information Placeholder 24 25 ABSTRACT: We report the first synthesis of a persulfurated pol- 1,2,3,4,5,6,7,8,9,10,11,12-dodecachlorocoronene (2, C24Cl12) was 26 ycyclic aromatic hydrocarbon (PAH) as a next-generation “sul- prepared according to our previous report.9 Nucleophilic replace- 27 flower.” In this novel PAH, disulfide units establish an all-sulfur ment of all peripheral chloro substituents was achieved using lith- 28 periphery around a coronene core. The structure, electronic proper- ium benzylthiolate at room temperature, which afforded 29 ties, and redox behavior were investigated by microscopic, spectro- 1,2,3,4,5,6,7,8,9,10,11,12-dodecakis(benzylthio)coronene (3) as a scopic and electrochemical methods and supported by density func- red powder in 62% yield. After reductive cleavage of the protective 30 benzyl groups under Birch conditions using lithium in anhydrous 31 tional theory (DFT). The sulfur-rich character of persulfurated cor- onene renders it a promising cathode material for lithium-sulfur liquid ammonia at -78 °C, the dodecalithio coronene- 32 batteries, displaying a high capacity of 520 mAh g-1 after 120 cy- 1,2,3,4,5,6,7,8,9,10,11,12-dodecathiolate (4) was obtained. The 33 cles at 0.6 C with a high-capacity retention of 90%. subsequent direct treatment of compound 4 with aqueous hydrogen 34 chloride and hydrogen peroxide afforded the desired product 5 in 35 61% isolated yield over two steps as a dark-red solid after washing 36 in refluxing toluene. 37 Over the last few decades, great efforts have been dedicated to the 38 synthesis of sulfur-rich polycyclic aromatic hydrocarbons (PAHs) 1 2 3 39 , such as acene sulfide, hexathiotriphenylene, hexathienocoro- nene,4 sulfur-annelated hexa-peri-hexabenzocoronenes (HBCs),5 40 and sym-tribenzotetrathienocoronenes.6 They exhibit unique redox 41 behavior and promising charge transport properties for organic 42 field effect transistors (OFETs) and organic photovoltaics (OPVs). 43 However, fully sulfur-substituted PAHs carrying fused disulfide 44 bonds at the periphery have not yet been achieved. Persulfur-sub- 45 stituted benzene (C6S6) was reported by Sü1zle et al. in 1989 but 46 was only detected as charged fragment during the mass spectromet- 47 ric investigation of benzo[1,2-d: 3,4-d’: 5,6-d”]-tri(1,3-dithiol-2- one) after the extrusion of three CO molecules (Figure 1 left).7 In 48 Figure 1. “Sulflower” molecules: (left) persulfurated benzene 2006, the appealing structure of octathio[8]circulene (C16S8), also (C6S6); (middle) fully sulfur-substituted circulene (C16S8); (right) 49 known as "sulflower" (Figure 1 middle), was reported by Nenaj- persulfurated coronene (C24S12). 50 denko et al.8 This molecule can be considered as the first generation 51 of "sulflowers", featuring a D8h-symmetrical structure with eight The detailed synthetic procedure and characterization data of 52 sulfur atoms at the peripheral positions. However, this compound intermediates are described in Supporting Information (section 53 contains one eight-membered central ring fused with eight thio- 1.2). Due to the low solubility of compound 5 in common organic 54 phene units, which possess a rather small π-delocalized carbon solvents, characterization by NMR spectroscopy or growth of sin- 55 framework. Thereby, the full sulfuration of the periphery of large gle crystals was not possible, even at elevated temperatures. Nev- PAH cores remains a challenge. ertheless, matrix-assisted laser desorption/ionization time-of-flight 56 Herein, we report the synthesis and characterization of an un- mass spectroscopy (MALDI-TOF MS) analysis displayed a clear 57 precedented persulfurated coronene (5, C24S12) with an all-sulfur peak at m/z = 671.6629, consistent with the expected mass calcu- 58 terminated edge structure, which we consider as a next-generation lated for C24S12, i.e., 671.6648 (Figure 2a). The isotopic distribution 59 “sulflower” (Figure 1 right). The synthesis of compound 5 was car- observed for the obtained PSC sample was in perfect agreement 60 ried out as depicted in Scheme 1. Starting from coronene (1), ACS Paragon Plus Environment Journal of the American Chemical Society Page 2 of 5 -1 with the pattern simulated for chemical formula C24S12, corroborat- intensity between 545 and 800 cm remain ambiguous for weak C- 1 ing the complete sulfuration (Figure 2a, inset). S absorptions,12 a more prominent absorption peak occurred at 971 2 cm-1 for the C-S stretching vibration. The band at 509 cm-1 is a typ- Scheme 1. Synthetic Route Towards Persulfurated Coronene 11a -1 3 a ical IR absorption for S-S stretching. A weak band at 930 cm (PSC, 5) and Perthiolated Coronene (PTC, 6) -1 4 (939 cm in DFT-calculated spectrum) reflects the breathing mode 5 of the ring containing the stretching S-S bond. 6 7 8 9 10 11 12 13 14 15 16 a 17 Reagents and conditions: (i) AlCl3, ICl, CCl4, 81 °C, 48 h, 93%; (ii) benzyl mercaptan, NaH, DMI, 0 °C to rt, 16 h, 62%; (iii and iv) 18 Li, THF, methanol, NH3, -78 °C to rt, 4 h; HCl/H2O2/water, rt, 61%; 19 (v) NaBH4. 20 21 22 23 24 Figure 3. Low-temperature STM characterization of single PSC 5 25 molecules on the Au (111) surface. (a) STM image showing two 26 PSC 5 molecules adsorbed on an Au (111) terrace at the kink sites 27 (I = 20 pA, U = 0.7 V); (b) STM image of a PSC 5 molecule (I =20 pA, U = 0.5 V); (c) Line scan taken along the molecule in (b); (d) 28 dI/dV spectra of the molecule in (b): bare Au surface (blue curve), 29 center of the molecule (red curve), edge of the molecule (black 30 curve). 31 32 Scanning tunneling microscopy (STM) is a powerful tool for 33 the characterization of single molecules on metal surfaces, thus we 34 performed low-temperature STM studies to visualize compound 13 35 5. Upon adsorption by thermal sublimation, single molecules 36 were present either at the kink sites of the Au (111) herringbone reconstruction (Figure 3a and Figure S2) or at the step edges. The 37 molecules showed a characteristic hexagonal shape, in accord with 38 the six-fold symmetry formed by the outer disulfide bridges (Figure 39 Figure 2. Spectroscopic structure proof of persulfurated coronene 3b). According to the line scan in Figure 3c, the central core of the 40 (5, PSC). (a) HR-MALDI-TOF MS spectrum. Inset: isotopic distri- molecule was imaged as a depression, and all sulfur atoms formed 41 bution compared with the mass spectrum simulated for C24S12. (b) a homogeneous ring around the core. The observed hexagonal spe- 42 Raman spectrum (blue) compared with results from DFT calcula- cies can be unambiguously assigned to intact 5 (Figure 3 b and Fig- 43 tions (red) over the D and G regions.