DOI: 10.1002/asia.201600753
Communication
Hexabenzocoronenes Derivatives
Derivatizing Tribenzothiophene-Fused Hexa-peri-
hexabenzocoronenes with Tunable Optoelectronic Properties
Yi Liu+,[a] Tomasz Marszalek+,[a] Klaus Mꢀllen,[a] Wojciech Pisula,*[a, b] and Xinliang Feng*[c]
f’’g’’]tris[1]benzothiophene (trisbenzothieno[1,2:7,8:13,14]hexa-
Abstract: A series of trisbenzothieno[1,2:7,8:13,14]hexa-
peri-hexabenzocoronene, TTC Figure 1),[6] in which three ben-
peri-hexabenzocoronenes were synthesized and character-
zothiophene rings are fused to the HBC periphery with a C3
ized by a combination of NMR, 2D NMR, MALDI-TOF MS,
symmetric architecture. Fusion with benzothiophene moieties
UV/Vis absorption spectroscopy, and 2D-WAXS measure-
renders an HBC derivative with extended p-conjugation and
ment. By structural modulation like decoration of electro-
offers the potential for further chemical modification on S
donating alkoxyl chain, and conversion from an electron-
atoms, like oxidation of the thiophene ring into thiophene-S,S-
rich thiophene ring into an electron-poor thiophene-S,S-
dioxide.[7] However, the poor solubility of unsubstituted TTC
dioxide moiety, the highest occupied molecular orbital
has hindered detailed studies of its optoelectronic properties
(HOMO) and lowest unoccupied molecular orbital (LUMO)
and supramolecular behaviors.
levels of the hexabenzocoronenes derivatives can be ef-
Herein, a series of TTC derivatives bearing alkoxy and alkyl
fectively tuned which is further verified by the DFT calcula-
chains were successfully synthesized, and showed good solu-
tions and cyclic voltammetry.
bility in common organic solvents (like dichloromethane (DCM)
and THF). Of particular interest, we developed a new protocol
to modulate the electronic energy level and self-assembly be-
Polycyclic aromatic hydrocarbons (PAHs), such as triphenylenes
and hexa-peri-hexabenzocoronenes (HBCs),[1] have attracted
enormous attention in the fields of synthetic chemistry and or-
ganic semiconducting materials because of their unique optoe-
lectronic properties[2] and supramolecular behavior.[3] For exam-
ple, HBCs bearing long aliphatic side chains can self-organize
into one-dimensional columnar superstructures in the solid
state, which is highly promising for organic field-effect transis-
tors. The fusion of thiophene rings at the periphery of PAHs
offers the opportunity to tune their electronic energy levels,
packing motifs and charge transport properties,[4] which is
widely used in the design of novel organic semiconductors.[5]
Therefore, by combining these two types of fascinating p-con-
jugated structures, we have previously synthesized a triben-
zo[b,b’,b’’]tribenzo[2,3:6,7:10,-11]coroneno[1,12-fg:5,4-f’g’:9,8-
havior of TTC via the oxidation of S atoms into the thiophene-
S,S-dioxide moieties (trisbenzothieno-S,S-dioxide[1,2:7,8:13,14]-
hexa-peri-hexabenzocoronene, TTOC, Figure 1), which are inte-
grated into the p-conjugated skeleton. Both the decoration of
electron-donating alkoxy chains and conversion from the elec-
tron-rich thiophene ring into electron-poor thiophene-S,S-diox-
ide units would be capable of tuning the highest occupied
molecular orbital (HOMO) and lowest unoccupied molecular
orbital (LUMO) levels. Furthermore, unique helical packing in
bulk with a relatively long pitch (3.4 nm) was achieved for alkyl
chain-substituted TTCs.
The synthesis of TTCs 6 bearing linear or branched alkoxy
chains was based on the key building block, 1,3,5-tris-(2’-
bromo-4’-methoxylphenyl)benzene (2),[8] which was readily ob-
tained via acid-catalyzed condensation of 2-bromo-4-methox-
yacetophenone (1, Scheme 1). The synthetic route consisted of
Suzuki coupling of 2 with 4-dibenzothiophenylboronic acid,
BBr3 induced deprotection of the methoxyl group, and then
a substitution reaction with the desired alkyl bromide to afford
the oligophenylene precursor (5a–e) with various alkoxy
chains. An intramolecular oxidative cyclodehydrogenation reac-
tion of 5a–e (MALDI-TOF mass spectrometry of 5a in Fig-
ure S1) was then performed with FeCl3 as the Lewis acid and
oxidant to provide targeted compounds 6a–e substituted with
different alkoxy chains (linear or branched) as orange powder.
The products were well soluble in common organic solvents,
including dichloromethane, toluene, and tetrahydrofuran.
MALDI-TOF mass spectrometry (Figures S2–S6 in the Support-
ing Information) of 6a–e indicated a single species with de-
sired molecular weight and isotopic distributions consistent
[a] Y. Liu,+ Dr. T. Marszalek,+ Prof. Dr. K. Mꢀllen, Prof. Dr. W. Pisula
Max Planck Institute for Polymer Research
Ackermannweg 10, 55128 Mainz (Germany)
[b] Prof. Dr. W. Pisula
Department of Molecular Physics, Faculty of Chemistry
Lodz University of Technology
Zeromskiego 116, 90-924 Lodz (Poland)
[c] Prof. Dr. X. Feng
Center for Advancing Electronics Dresden (cfaed) and
Department of Chemistry and Food Chemistry
Technische Universitꢁt Dresden
01062 Dresden (Germany)
[+] These authors contributed equally to this work.
Supporting information for this article can be found under http://
Chem. Asian J. 2016, 00, 0 – 0
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