Synthesis and properties of a graphene-like macrocycle based on tetraphenylethene

Article abstract of DOI:10.1016/j.tet.2014.06.018

In this work, tetraphenylethene macrocycles are selectively synthesized in one step from McMurry coupling reaction of 1,1-bis(4-phenylcarbonyl)-2,2- diphenylethene in 45% overall yield. A more planar cyclized compound can be obtained by oxidization of tetraphenylethene macrocycles with iron (III) chloride in nitromethane. Their unusual optical properties and electrical properties are explored. The measured mobilities are 0.7022 and 0.0055 cm ² V^-1 s^-1, respectively. The decomposition temperatures are also measured by thermal gravimetric analysis as, respectively 342°C and 455°C, indicating good thermal stabilities. The understanding of the structure and properties will benefit to the chemical synthesis of graphene.

Full text of DOI:10.1016/j.tet.2014.06.018

Accepted Manuscript
Synthesis and properties of a graphene-like macrocycle based on tetraphenylethene
Han Wang , Tingting Lin , Ji Ma , Weizhi Wang
PII:
S0040-4020(14)00864-3
10.1016/j.tet.2014.06.018
TET 25683
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 10 March 2014
Revised Date: 4 May 2014
Accepted Date: 3 June 2014
Please cite this article as: Wang H, Lin T, Ma J, Wang W, Synthesis and properties of a graphene-like
macrocycle based on tetraphenylethene, Tetrahedron (2014), doi: 10.1016/j.tet.2014.06.018.
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Graphical Abstract
Leave this area blank for abstract info.
Synthesis and properties of a graphene-like
macrocycle based on tetraphenylethene
Han Wang, Tingting Lin, Ji Ma, Weizhi Wang*
Physical
grinding
Chemical
oxidation

1
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Tetrahedron
journal homepage: www.elsevier.com
Synthesis and properties of a graphene-like macrocycle based on tetraphenylethene
Han Wang,a Tingting Lin,b Ji Ma,a Weizhi Wang*a
a State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
b Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
In this work, tetraphenylethene macrocycles are selectively synthesized in one step from
McMurry coupling reaction of 1,1-bis(4-phenylcarbonyl)-2,2-diphenylethene in 45% overall
yield. A more planar cyclized compound can be obtained by oxidization of tetraphenylethene
macrocycles with iron (III) chloride in nitromethane. Their unusual optical properties and
Available online
electrical properties are explored. The measured mobilities are 0.7022 and 0.0055 cm2 V − 1 s– 1
,
respectively. The decomposition temperatures are also measured by thermal gravimetric analysis
as respectively 342 °C and 455 °C, indicating good thermal stabilities. The understanding of the
structure and properties will benefit to the chemical synthesis of graphene.
Keywords:
tetraphenylethene
macrocycle
McMurry coupling
mobilities
graphene
2009 Elsevier Ltd. All rights reserved
.
diameter of 3 nm.21 Fasel’s group synthesized graphene nanoribbon
(GNRs) by surface-assisted coupling to yield GNRs of different
topologies with atomic accuracy by controlling the monomers.22 To
our knowledge, the research on graphene macrocycles is rarely
reported. The synthesis of cyclacenes is inspiring for the research of
carbon nanotubes.23,24 Explorations in synthesizing graphene
macrocycles could also provide more information on graphene.
Herein, we introduce McMurry coupling of carbonyl containing
1. Introduction
Since the breakthrough in graphene discovery1, the applications for
desirable properties of graphene have never failed to lose attractions
to scientists. Based on high performances,2-6 graphene and its
derivatives are promising materials for electronic and optical
devices, such as organic field-effect transistors (FETs),7,8 transparent
electrodes,9 and solar cells10 etc.
Preparation of graphene is generally divided into top-down and
bottom-up methods. Top-down method, which is quick and simple,
is limited in some extents. Mechanical exfoliation of highly oriented
pyrolytic graphite (HOPG) can provide a small amount of pure
graphene,1 while it cannot meet the requirement for large scale
production. Chemical exfoliation of expanded graphite oxide can
produce graphene sheets in larger quantity,11 but it is inevitable to
introduce heteroatoms such as oxygen, which are detrimental to the
performances of graphene. The other method, bottom-up synthesis of
graphene is efficient, such as epitaxial growth on SiC or chemical
vapor deposition (CVD), .12-14 Since the requirement of well-defined
structures and supermolecular assembles of graphene materials
began to rise,15,16 syntheses of graphene structures by small organic
molecules become noticeable for its atomic accuracy. Müllen K. and
colleagues developed an efficient method to synthesize polycyclic
aromatic hydrocarbons by Diels – Alder additions or alkyne
trimerizations and further cyclodehydrogenations.17-20 The largest
--------------------
tetraphenylethene (TPE) monomers to produce
a TPE-based
macrocycle (TM, shown in Scheme 1) selectively at a yield of 45%.
Then, the TM molecule was dehydrogenized by FeCl3/CH3NO2 to
give a more planar TMC molecule. MALDI-TOF was used to
monitor the reaction procedure and detect the final product.25 As
TPE is a typical aggregation-induced emission (AIE) luminogens,26
TM should also possess significant AIE properties. In our further
experiments, TM performed different optical properties in its
solution. The photoluminescence peak of TM shift bathochromically
with an increasing of concentration. Optical and electrical tests of
TM and TMC and density functional theory (DFT) calculations were
carried out to help examine their properties. High thermal stabilities
of TM and TMC were also characterized by TGA. It is worthy
investigating the structures and properties of the yielded conjugated
macrocycles to provide knowledge to chemical syntheses of
graphene.
2. Results and discussion
* Corresponding author. Tel.: +86 21-65640293.
E-mail address: weizhiwang@ustc.edu (W.Z. Wang)
2.1 Syntheses of monomers, TM and TMC
graphene molecule acquired previously possesses 222 carbons and a

2
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planar molecule (C H , Table S3) cannot be obtained by FeCl
40
3
because of its low oxidizing ability and the twisted structure of
TMC. When AlCl3 was used instead of FeCl3, the more planar
molecule (C80H40) can be seen in the MALDI-TOF spectra (not
given). However, as the oxidization proceeds, there was a series of
peaks with intervals of 16 (exactly the molar mass of an oxygen
atom) in MALDI-TOF spectra, indicating that the products were
readily to react with oxygen to yield impurity. The additional by-
products meant the purification became more difficult, even after
careful removal of oxygen. The major oxidation product TMC was
separated from its by-products by column chromatography. Results
of MALDI-TOF-MS and 1H NMR suggested TMC molecule was the
product losing 12 hydrogen atoms from TM. While there might exist
isomers in the final product, the confirmation of the structure of
TMC was based on both experimental results and DFT calculations.
The energy band gaps measured by optical (Fig. 3) and cyclic
voltammetry tests (Table S2) coincided with band gaps of TMC
molecule by DFT calculations (Table S3) than other isomers, which
pointed out that TMC was the most reasonable structure.
Scheme 1. The synthesis of TM and TMC.
The synthesis of two monomers by Friedel – Crafts reaction is based
on our former research.27 It can be inferred that the Friedel – Crafts
benzoylation of tetraphenylethene possess distinct configurational
isomers. After separation, two isomers, which are discriminated by
the positions of benzoyl groups, were obtained. The NMR spectra
and single crystal diffractions have determined the structures of the
two
isomers:
1,1-bis(4-phenylcarbonyl)-2,2-diphenylethene
(monomer 1) and 1,2-bis(4-phenylcarbonyl)-1,2-diphenylethene
(monomer 2) (see Table. S1, ESI†).
Scheme 1 describes the McMurry self-coupling of monomers. In a
typical preparation, monomer 1 was added to a previous prepared
Zn/TiCl4/THF solution and the reaction was kept at 66 °C for 24 h.
The reaction solution was inspected by MALDI-TOF and it showed
two peaks at 510 and 1016 (as shown in Fig. 1). The peak at 1016
belongs to TM. The peak at 510 is a reduction by-product of
monomer 1. After purification, the total yield of TM was 45%. Using
the same coupling process and characterization for monomer 2, no
TM peak at 1016 was detected. The identified peaks were attributed
to non-cycled products of two molecules coupling (as shown in Fig.
S1). From these results, a possible reaction mechanism can be
derived. First, a monomer comes to the surface of zero-valent
titanium [Ti (0)], which has been formed by the reduction of
TiCl4/Zn. Second, two monomers are induced to cross-couple and
form a pinacol dimer by the Ti (0). Finally, the carbonyl-coupling
reaction gives a pinacol deoxygenation to yield the desired alkene.
The results are closely related to the monomer structural
characteristics and the reaction mechanism. The structure of
monomer 1 allows four oxygen atoms of the pinacolate dimer to
approach and bond on a common Ti (0) surface. This step is
important to the formation of the cycled structure. In contrast,
monomer 2 cannot react in this way to give TM. As only one oxygen
atom from each monomer can attach to the same catalyst surface, the
final products are opened structure dimers. The solvent used in the
reaction has two effects on the yield of TM. First, it can affect the
conformation of Ti (0), such as the particle size, surface area, and
physical nature of the surface (edges, corners, holes). The second is
the relative solubility of the monomer and product in a given solvent.
For a solvent to increase the yield of TM, the monomer should be
very soluble in it, but TM should be insoluble. This prevents the
coupling reaction at the dimer stage. The McMurry coupling of the
two monomers was incipiently designed to synthesize different
polymerized chain consisted of TPE blocks. However, there is a very
small peak of trimer but no peak of higher molecular weight in
MALDI-TOF mass spectra. This is in accordance with the former
explanation that the later coupling is prohibited by both the steric
hindrance of phenyl rings and low solubility of the dimer.
Fig. 1 MALDI-TOF mass spectra of McMurry coupling product TM and its
byproduct for monomer 1.
2.2. Optical properties
Even being same in composition, the optical properties of the two
monomers are different. The two monomers possess different
fluorescence in their solid states and solutions. Monomer 1 is white
under natural light and emits blue fluorescence under UV irradiation.
In comparison, monomer 2 is yellow under natural light and emits
green fluorescence under UV irradiation (Fig. 2a). The bathochromic
shifts in absorption and fluorescence spectra in solid state and
solutions (Fig. 2b) are possibly due to their different configurations
and conformations.
TM performed unusual optical properties observed in our former
syntheses. The solid powder of TM purified from the
recrystallization procedure emitted blue fluorescence, while when
treated with a few solvent, the fluorescence turned evidently to
yellow-green. This phenomenon drew our attention to further
investigation on its optical properties.
The nearly planar TMC can then be prepared by the oxidation of TM
(50 mmol) by FeCl3 (20 mmol) in DCM (100 mL) at room
temperature in 40 min. This method has been used previously in the
synthesis of polycyclic aromatic hydrocarbons.19 The oxidation is a
step-by-step dehydrogenation, and TM can give oxidized product
TMC by losing 6 pairs of hydrogen atoms. The MALDI-TOF and
1H-NMR spectra of TM and TMC are shown in Fig. S2-4. The more

3
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Fig. 2 (a) The appearance of monomer 1 and 2 in natural light and UV
irradiation. (b) The absorption and photoluminescence (PL) spectra of
monomer 1 and 2 solutions. The absorption peaks of monomer 1 are 250 nm,
342 nm and of monomer 2 are 252 nm, 342 nm, respectively. The PL peak of
monomer 2 is 15 nm red-shifted (at 476 nm) to monomer 1 (at 451 nm).
TM is a white powder under natural light. When irradiated at 365
nm, it has a bright blue emission (Fig. 3a) at 446 nm. The UV
absorption curve has a broad, shapeless peak at 365 nm with a small
shoulder at 275 nm. This indicates that TM adopts varied
conformations in the solid state. On the other hand, TM is composed
of four AIE active TPE units and should also exhibit the AIE effect.
The emission intensity of pure TM in DCM solution (3.0 µM)
increases fourfold after adding 20 wt% of petroleum ether (shown in
Fig. S5). This elevation in PL intensity was attributed to the
aggregation-induced enhanced emission (AIEE) effect of TM in the
petroleum ether. THF is a relatively good solvent for TM, while TM
is insoluble in petroleum ether. Adding proportion poor solvent
(petroleum ether) to the THF solution of TM induces TM molecules
to aggregate. This aggregation leads to the restrictions of phenyl
rings intramolecular rotations and thus decreases the non-radiative
deactivation process, which finally enhance the emission intensity.28
Furthermore, we found the TM emission dependent on the
concentration. When the concentration of TM in DCM increasing
from 0.1 to 3 µM (Fig. 3c), the emission changes from 453 nm (blue)
to 530 nm (yellow green). At high concentrations, TM forms
aggregates that are very crowded and have little free volume. This
induces the TM molecule to adopt a less twisted conformation. These
structures tend to be more conjugated, especially for the inner TM
molecules of the aggregates, and cause a red shift in the emission. In
diluted solutions, on the other hand, TM has a deep blue emission
due to the larger free volumes and a more twisted structure.
However, in the solid state where the structure should be the most
rigorously confined, the emission comes at 446 nm. This is smaller
than in both the diluted solution and as an aggregate.
To determine the cause of this unusual result, we first examined the
emissive properties of TMC. The emission of TMC is also dependent
on the concentration. Fig. 3d shows the emission of TMC in DCM
with increasing concentration (inset, from left to right). The emission
peak moves from 510 nm to 539 nm as the concentration increases
from 0.2 to 10 µM. Furthermore, the intensity also increases with the
increasing concentration. The TMC molecule, with its less twisted
structure, should readily form aggregates by π-π interaction. As the
concentration increases, the molecules are more likely to aggregate,
which lowers the energy band-gap and leads to the red-shift of
emission peak. This interaction becomes even stronger in a solid
film. Compared with the solution sample, the emission of a solid
TMC film consequently peaks at 600 nm (Fig. 3b). This is a large red
shift of 61 nm.
Fig. 3 The optical properties of TM and TMC at room temperature. (a) A solid
film of TM, (b) A solid film of TMC, (c) TM in DCM, from 0.1 to 3 µM, (d) TMC
in DCM, from 0.2 to 10 µM. For samples c and d, the concentration increases
from left to right, irradiated at 365 nm.
These results show how the morphology and structure of molecule
have a dramatic effect on its emission properties. Blue, green, yellow
and red emissions can be obtained. To understand the relationship
between structure and emission, we used molecular calculations. TM
acts like a big cyclohexane molecule and adopts different conformers
such as “boat”, “chair” or planar depending on the environment. In a
solid film, the TM molecule adopts the most twisted structure and
the shortest conjugated unit. The calculated occupied volume of each
molecule is 969.57 Å3, and surface area is 978.32 Å2. The compact
structure easily forms crystals as proved by the XRD data of TM
(Fig. 4). Once dissolved, TM adopts a more extended structure. The
calculated solvent volume and area increase to 2690.12 Å3 and
1279.42 Å2, respectively. TMC is the oxidized product of TM and
has the less twisted conformation, which gives it
a longer
conjugation and improves the formation of aggregates. It also has
smaller calculated occupied volume (893.12 Å3), and surface area
(842.86 Å2). The decrease in area and volume continues for the more
planar molecule (C80H40, Table S3) although we were not successful
in obtaining experimental data for this molecule. This suggests that
this molecule would have the largest red shift in the emission.

4
Tetrahedron
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Fig. 4 (a) XRD results of crystal, amorphous TM and TMC powder. Crystal (b)
and amorphous (c) TM powder under 365 nm irradiation. The amorphous
TM powder was obtained after physical grinding by pestle and mortar.
Fig. 5 Molecular orbital amplitude plots of the HOMO and LUMO energy
levels of TM and TMC.
Fig. 4 shows the powder X-ray diffraction experiments of TM and
TMC. The highest peak for TM comes at 2θ = 12°, which gives a
distance of 0.34 nm. The less twisted molecule, TMC, has the
highest peak at 2θ = 22° and a distance of 0.19 nm These XRD data
confirm the computed results for TM and TMC. The aggregates from
the most concentrated sample in Fig. 4b were also investigated,
which were prepared by filtering the solution prepared as in the UV
experiment. The XRD curve showed the sample has an amorphous
phase structure with one broad peak at 16°.
Table 1. Electrochemical Properties of the Macrocycles TM and TMC
a
Determined from the cyclic voltammetry in acetonitrile for the oxidation
potentials, and in THF for the reduction potentials (0.1 M n-Bu4N+PF6 as the
-
supporting electrolyte) using Ag/Ag+ (0.01 M) as a reference electrode at a scan
rate of 100 mV/s.
b
With the large free volume in crystal state, TM molecule is expected
to be compressible, and TM should possess the piezochromical
behavior. According to Tang’s restriction of intramolecular rotations
(RIR) mechanism29 of AIE molecules, void volumes exist between
the TM molecules in its crystal state to admit that they to adopt a
state in which the phenyl rings are quite staggered placed, which
reduces the intramolecular interaction. The restriction of phenyl
rotations by the molecular interaction limits both the planarization
and the π-conjugation. Emission of the crystal state is blue. While
exerting external force to the crystal powder (physical grinding), the
pressurization reacts against the intramolecular interaction, thus
decreases the void volumes and densifies the molecular packing,
causing the angles between phenyl rings planes decrease. The
molecules become more planar. Therefore it increases the electron
delocalizations and lowers the energy band gap of TM molecule,
leading to a bathochromical shift in fluorescence emission to a
green-yellow light (shown in Fig. 4c). A similar transformation has
been observed in another of our former experiment. When
amorphous TM treated with DCM steam, the fluorescence
hypochromatically shifts from yellow-green to blue. The amorphous
solid can be infiltrated with solvent molecules, enlarging the
intermolecular space and activate the rotation of phenyl rings,
ultimately reducing the molecular conjugation length and increasing
the band gap. Thus the emission of steam treated samples turns back
to a short wavelength of blue.
The HOMO and LUMO levels were determined using the following equations:
HOMO/LUMO = - e (Eonset - 0.0468 V) - 4.8 eV, where 0.0468 V corresponds to
FOC vs Ag/Ag+.
To obtain a direct structure/property relationship for TM and TMC,
we used the space-charge limited-current (SCLC) method suggested
by Wu’s group30 to determine the charge carrier mobility. The device
is a sandwich structure composed of ITO/PEDOT:PSS/(TM or
TMC)/Au. The ITO acted as one electrode and the other was gold,
cast by thermal evaporation to 200 nm. The TM or TMC film was
made by drop casting from a DCM solution to a thickness of 2 µm.
The charge carrier mobility is based on the following formula:
µ=8Jd3 / 9ε0εrV2
Where J is the measured current density, ꢀ the charge mobility, ε0 the
permittivity of free space, εr the dielectric constant of the material (a
value of εr = 3 is assumed here), V the applied voltage, and d the
thickness of the device. The measured mobilities for TMC and TM
2
−
1
– 1
were 0.7022 and 0.0055 cm
V
s
(shown in Fig. 6),
respectively. The augmentation of mobility from TM to TMC
(increased by ~ 102) is suggested by the significantly stronger π-π
interaction in the less twisted molecule TMC than in TM.
2.3. Electrical properties
The fluorescent mechanism discussed above is also supported by the
electrochemical tests and DFT calculations. CV measurements and
DFT calculations on TM and TMC are summarized in Table 1and
Fig.5. The HOMO of TM and TMC come at –6.51 and –5.35 eV,
respectively, and the LUMO energy levels that come at –1.94 and –
3.55 eV with respect to ferrocene can be deducted from the onset
potential of the oxidation and reduction, respectively. The band gaps
of TM and TMC are 4.22 eV and 1.80 eV, respectively. In
comparison, the DFT calculations gave 1.987 eV and 1.275 eV.
Although, there is poor agreement between experiment and
calculation, the trend is conserved. This implies that for TM and
TMC, the band gap is narrowed by enlarging the delocalization in
the less twisted molecule.
Fig. 6 Plot of the current density (J) versus applied voltage (V) measured
across a 2.0 µm thick sample of TM and TMC at room temperature.

5
2.4. Thermal stabilities
correction based on redundant reflections. The structures were
ACCEPTED MANUSCRIPT
solved by using the direct-methods procedure in the Bruker
SHELXL program library and refined by full-matrix least-squares
methods on F2. All non-hydrogen atoms were refined using
anisotropic thermal parameters, and hydrogen atoms were added as
fixed contributors at calculated positions, with isotropic thermal
parameters based on the carbon atom to which they are bonded.
Synthesis and characterization of 1,1-bis(4-phenylcarbonyl)-2,2-
The thermal stability of TM and TMC were evaluated by TGA under
nitrogen at a heating rate of 10 °C min− 1. The compounds are
thermally stable, losing 5% of their weight at 342 °C and 455 °C for
TM and TMC, respectively (Fig. S6, ESI†). Both TM and TMC
consist of only carbon and hydrogen atoms, and rich in carbon
proportions. The strong carbon-carbon bonds and carbon-hydrogen
bonds are relatively inert chemically, contributing to their high
thermal stabilities. In addition, TMC molecule has a more planar
structure, and it is observable that the peripheral phenyl rings form
new carbon-carbon bonds by cyclodehydrogenation and are
restricted and stabilized from free rotations, resulting in a relatively
higher decomposition temperature of more than 100 °C than TM.
The good thermal stabilities of TM and TMC are advantageous for
their applications in optoelectronic devices. The results also suggest
a viable way to increase thermal stability by cyclodehydrogenation.
diphenylethene
(1)
and
1,2-bis(4-phenylcarbonyl)-1,2-
diphenylethene (2). A stirred slurry of 2.66 g (0.02 mol) of
aluminum chloride and 3.32 g of TPE (0.01 mol) in 15 mL of CS2
was added dropwise with a solution of 1.41 g (0.01 mol) of
benzoylchloride in 5 mL of CS2 in room temperature. After that,
water was cautiously added to the mixture on an ice bath. The
reaction mixture was extracted by dichloromethane. The organic
layer was washed with sodium hydroxide, dried with magnesium
sulfate. The solvent was removed by rotary evaporation to yield a
yellow green solid (3.1 g, 57%).
Two types of diketone of 1 and 2 in the crude product were separated
by a silica column, giving a white solid of 1 and a yellow green
crystal of 2 (petroleum ether : dichloromethane = 7 : 3; the Rf values
are 0.60 for 1 and 0.67 for 2).
3. Conclusion
We have synthesized a tetraphenylethene macrocycle (TM) from 1,1-
bis(4-phenylcarbonyl)-2,2-diphenylethene by the McMurry coupling
reaction in 45% yield. After chemical oxidation, a less twisted
compound TMC was also obtained. These two derivatives clearly
show the relationships between the conformations and the emission
properties. TM has a twisted form and a short conjugated length. Its
solid film luminescence is blue shifted compared with its solution
emission. On the other hand, TMC has a less twisted conformation
and hence is more conjugated, which induces the aggregation and a
red shift in the emission. The different conformations also cause
variations in the electrical properties. The CV characterization,
charge mobility test and computer calculation prove the less twisted
space-structured TMC has higher charge mobility than TM. The
characterization results indicate that the macrocycles are qualified
for potential materials in applications as field-effect transistors, light-
emitting diodes etc. Similar approaches in molecular modification
could also be efficient in adjusting molecular optical and electrical
properties.
1
(1). H NMR (CDCl3, 400 MHz): δ 7.72 - 7.77 (m, 4H), 7.52 - 7.62
(m, 6H), 7.42 - 7.48 (m, 4H), 7.08 - 7.18 (m, 10H), 7.02 - 7.08 (m,
4H). 13C NMR (CDCl3, 100 MHz): δ 127.5, 128.1, 128.4, 130.1,
131.5, 132.5, 135.7, 137.8, 139.1, 142.9, 144.4, 147.9, 196.5. m.p.
209 – 210 oC. Anal. Calcd for C40H28O2 (540.65): C, 88.86; H, 5.22.
Found: C, 88.80; H, 5.41. HRMS (MALDI-TOF): m/z 539.8 (M+,
100%) , 562.8 ([M +Na]+, 55%). Crystal data for 1: crystals were
grown from CH2Cl2; the structure was solved on a Bruker SMART
CCD diffractometer using Mo Kα radiation. C40H28O2 (Mr = 540.62);
monoclinic, space group C2/c, Dc=1.233 g cm-3, a =16.698(3) Å, b =
10.5516(19) Å, c = 16.706 (3) Å, α= 90°, β= 98.437(2)°, γ= 90°, V =
2911.6(9) Å3, Z = 4, λ = 0.710 73 Å, ꢀ = 0.075 mm-1, T = 296(2) K,
R = 0.0264 for 11 361 observed reflections [I > 2σI] and Rw = 0.0939
for all 3138 unique reflections.
1
(2). H NMR (CDCl3, 400 MHz): δ 7.73 - 7.75 (m, 4H), 7.48 - 7.58
(m, 6H), 7.42 - 7.48 (m, 4H), 7.09 - 7.17 (m, 10H), 7.02 - 7.08 (m,
4H). 13C NMR (CDCl3, 100 MHz): δ 127.3, 128.1.5, 128.2, 129.7,
129.9, 131.2, 131.3, 132.3, 135.6, 137.8, 141.6, 142.6, 147.8, 196.2.
4. Experimental sections
Chemicals. Chemicals and reagents were purchased from Aldrich
and Acros Chemical Co. unless otherwise stated and used without
further purification. All of the solvents were used after purification
according to conventional methods when required.
o
m.p. 207-208 C. Anal. Calcd for C40H28O2 (540.65): C, 88.86; H,
5.22. Found: C, 87.71; H, 5.30. HRMS (MALDI-TOF): m/z 539.8
(M+, 100%), 562.8 ([M +Na]+, 47%). Crystal data for 2: crystals
were grown from CH2Cl2; the structure was solved on a Bruker
SMART CCD diffractometer using Mo Kα radiation. C40H28O2 (Mr =
540.62); monoclinic, space group C2/c, Dc=1.219 g cm-3, a =
17.821(7) Å, b = 12.088(5) Å, c = 28.577(12) Å, α= 90°, β=
106.795(7)°, γ= 90°, V = 5894(4) Å3, Z = 8, λ = 0.71073 Å, ꢀ = 0.074
mm-1, T = 296(2) K, R = 0.0461 for 15904 observed reflections [I >
2σI] and Rw = 0.0684 for all 3013 unique reflections.
Measurements and characterizations. H and 13C NMR spectra
1
were recorded with Varian Mercury Plus 400 spectrometers, and
chemical shifts were reported in ppm units with tetramethylsilane as
an internal standard. The UV-visible absorption spectra were
obtained in chloroform on a Shimadzu UV-3150 spectrophotometer.
The photoluminescence spectra were recorded on a Shimadzu RF-
5301 PC fluorometer at room temperature. The samples were
analyzed by Voyager DE-STR matrix assisted laser desorption-time-
of-flight mass spectrometry (MALDI-TOF). Cyclic voltammetry
(CV) measurements of the oligomer films coated on a glassy carbon
electrode (0.08 cm2) were performed in an electrolyte of 0.1 M
tetrabutylammonium hexafluorophosphate (TBAPF6) in acetonitrile
using ferrocene (4.8 eV under vacuum) as the internal standard at a
scan rate of 100 mV s-1 at room temperature under the protection of
argon. A Pt wire was used as the counter electrode and an
Ag/AgNO3 electrode was used as the reference electrode. X-ray
crystallographic data were collected on a P4 Bruker diffractometer
equipped with a Bruker SMART 1K CCD area detector (employing
the program SMART) and a rotating anode utilizing graphite-
monochromated Mo KR radiation (λ ) 0.710 73 Å). Data processing
was carried out by use of the program SAINT, while the program
SADABS was utilized for the scaling of diffraction data, the
application of a decay correction and an empirical absorption
Synthesis of TM(3). A slurry of zinc (3.0 g) and tetrahydrofuran (30
mL) was stirred under a nitrogen atmosphere on an ice bath, and 5
mL of titanium tetrachloride was slowly dropped in. When finished,
the ice bath was withdrawn. The mixture was heated by oil bath and
refluxed for 30 min. Then, a solution of 1 (0.30g, 5.5 mmol) in
tetrahydrofuran (30 mL) was added to the mixture. The reaction
mixture was refluxed overnight. When cooled, the reaction was
stopped by adding 10% potassium carbonate aqueous. The organic
layer was extracted by dichloromethane and was dried by
magnesium sulfate for 30 min. Dried organic layer was concentrated
by rotary evaporation and was poured to a mixture of petroleum
ether and ethyl acetate (9:1) to precipitate a single product of 3. A
white solid (0.13 g, 45%) was obtained by further filtration. 1H NMR
(CD2Cl2, 400 MHz): δ 7.07 - 7.06 (m, 24H), 6.96 - 6.71 (m, 16H),

6
Tetrahedron
13. Reina, A.; Jia, X. T.; Ho, J.; Nezich, D.; Son, H. B.; Bulovic, V.;
6.70-6.68 (s, 16H). HRMS (MALDI-TOF): 1016.51. The solubility
ACCEPTED MANUSCRIPT
Dresselhaus, M. S.; Kong, J. Nano. Lett. 2009, 9, 30-35.
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Ruoff, R. S. Science 2009, 324, 1312-1314.
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dichloromethane and other d-solvents) is low and cannot get the 13C
NMR.
Synthesis of TMC(4). 100 mg of pure TM was dissolved in 100 mL
DCM. The solution was deoxygenized by purging N2. Ferric
trichloride (2 g) was solved in 20 mL CH3NO2 and added to the
solution with a continued purge of nitrogen. After stirring for 30 min
at room temperature, 40 mL of methanol was added to quench the
reaction. The precipitated product was filtered and washed with EA,
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1
ethanol and methanol to afford a red solid (0.85mg, yield 85%). H
NMR (CD2Cl2, 400 MHz): δ 7.77 -7.10 (m, 33H), 8.22 -10.24 (m,
11H). HRMS (MALDI-TOF): 1004.20. The solubility of TMC in
common d-solvents (like d-chloroform, d2-dichloromethane and
other d-solvents) is low and cannot get the 13C NMR.
Acknowledgements
This work was financially supported by the National Natural Science
Foundation of China (21274027 and 20974022). Wang Han thanks
the FDUROP (Fudan's Undergraduate Research Opportunities
Program) for support.
References and notes
1. Novoselov, K.S.; Geim, A.K.; Morozov, S.V.; Jiang, D.; Zhang, Y.;
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H.; Wu, J. S. J. Org. Chem. 2010, 75, 8069-77.
Supplementary Material
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Supplementary information (NMR spectra and single crystal structures of
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7. Avouris, P.; Chen Z. H.; Perebeinos, V. Nature Nanotechnology 2007, 2,
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4, 611-622.
monomer 1 and 2; MALDI-TOF for McMurry coupling of monomer 2;
MALDI-TOF and H NMR spectra of TM and TMC; PL spectra of TM in
varied proportion of DCM/PE solutions; CV experiments of TM and TMC;
TGA of TM and TMC; DFT calculations of TPE, TM, TMC and C80H40. ) can
be found at
1
11. Schniepp, H. C.; Li, J. L.; McAllister, M. J.; Sai, H.; Herrera-Alonso, M.;
Adamson, D. H.; Prud'Homme, ; Car, R.; Saville, D. A. Aksay, I. A. J.
Phys. Chem. B 2006, 110, 8535-8539.
Click here to remove instruction text...
12. Berger, C.; Song, Z. M.; Li, T. B.; Li, X. B.; Ogbazghi, A. Y.; Feng, R.;
Dai, Z. T.; Marchenkov, A. N.; Conrad, E. H.; First, P. N.; de Heer, W.
A. J. Phys. Chem. B 2004, 108, 19912-19916.

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Supporting Information
Synthesis and properties of a graphene-like macrocycle based on
tetraphenylethene
Han Wang,a Tingting Lin,b Ji Ma,a Weizhi Wang*a
aState Key Laboratory of Molecular Engineering of Polymers, Department of
Macromolecular Science, Fudan University, Shanghai 200433, China
bInstitute of Materials Research and Engineering, A*STAR (Agency for Science,
Technology and Research), 3 Research Link, Singapore 117602.

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Table S1. The NMR data and crystal structures for monomer 1 and 2.
Monomer 1
Monomer 2
2000
1500
1000
500
0
8.0
7.5
7.0
6.5
ppm
8.00
7.75
7.50
7.25
7.00
ppm (f1)
5000
4000
3000
2000
1000
0
220 210 200 190 180 170 160 150 140 130 120 110 100 90 80
ppm
200
ppm (f1)
150
100

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Fig. S1 MALDI-TOF of McMurry coupling for monomer 2. Isomers may exist in the
coupling products.

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400
300
200
100
0
8.0
ppm (f1)
7.0
6.0
5.0
4.0
4000
3000
2000
1000
0
1016.50743
C80H56
Exact Mass:
Mol. Wt.:
1
016.44
1
017.3
m/e: 1016.44 (100.0%), 1017.44 (87.2%), 1018.44 (37.0%), 1019.45 (10.6%), 1020.45 (2.2%)
C, 94.45; H, 5.55
990 1000 1010 1020 1030 1040 1050
Mass (m/z)
700 800 900 1000 1100 1200 1300 1400 1500
Mass (m/z)
Fig. S2 The 1H-NMR and MALDI-TOF of TM.

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800
700
600
500
400
300
200
100
0
-100
10.0
9.0
8.0
7.0
6.0
5.0
ppm (f1)
20000
1004.19716
15000
10000
5000
0
990
1000
1010
1020
1030
Mass (m/z)
400 600 800 1000 1200 1400 1600 1800 2000 2200
Mass (m/z)
Fig. S3 The 1H-NMR and MALDI-TOF of TMC.

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Fig. S4 The pictures of TM (colorless) and TMC (red) solutions under natural light
(left) and 365 nm UV irradiation (right).
Fig. S5 (a) PL spectra of TM in DCM and DCM/PE mixtures with different PE
fractions. (b) Change in the relative PL intensity (I/I0) with the composition of the
DCM/PE mixture. I0 = PL intensity in pure DCM solution. Concentration: 3.0 µM ;
excitation wavelength: 360 nm.

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Table S2. The CV experiments of TM and TMC.
TMC
0.000004
0.000003
0.000002
0.000001
0.000000
-0.000001
0.00000
-0.00005
-0.00010
0.0
0.5
E(V vs SCE)
1.0
1.5
-3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0
E (V vs SCE)
TM
0.00008
0.00006
0.00004
0.00002
0.00000
0.0000
-0.0002
-0.0004
-0.0006
-0.0008
0.0
0.5
1.0
1.5
2.0
2.5
-4
-3
-2
-1
0
E (V vs SEC)
E (V vs SEC)
140
120
100
80
TMC
TM
455
342
60
40
20
0
0
200
400
600
800
1000
Temperature ( oC)
Fig. S6 The thermal weight loss curves of TM and TMC.

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Density functional theory (DFT) computations: The molecular models (as listed in
Table S3) were built by using Materials Studio v.5.0 (Accelrys Software Inc.). The
structures were optimized at the level of theory GGA-PW91-dspp/dnp (with a orbital
cutoff of 3.7 Å) by using the DFT module DMol3 (refs: B. Delley, J. Chem. Phys.
1990, 92, 508. B. Delley, J. Chem. Phys. 2000, 113, 7756.) in Materials Studio. The
HOMO, LUMO and other properties were obtained at the DFT optimized geometries.
The geometric properties (torsion angles, bond lengths), HOMO and LUMO are
illustrated in Fig. S7 to S10.
Table S3. A summary of DFT calculations.
Molecule
Mass
HOMO LUMO Gap
vdW surface
(accessible) Solvent
surface @ 1.4
(eV)
(eV)
(eV)
Occupied
Volume (Å)3
Surface
Occupied
Surface
area (Å)2
1279.42
1195.26
area (Å)2 Volume (Å)3
C80H56 (TM) 1017.33 -4.447
-2.460
-3.197
1.987 969.57
1.275 893.12
978.32
842.86
2690.12
2385.44
C80H44
(TMC)
C80H40
1005.23 -4.472
1001.20 -4.672
-2.882
-2.216
1.790 873.73
2.663 326.41
805.63
368.70
2305.58
1006.64
1183.97
592.81
C26H20 (TPE) 332.446 -4.879
C40H28O2
540.662
(monomer 1)
C40H28O2
540.662
(monomer 2)
(a)

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(b)
(c)
(d)
(e)
HOMO: -4.879 eV
LUMO: -2.216 eV
Fig. S7 The DFT optimized structure of TPE (C26H20): (a) and (b) torsion angles (in
degree); (c) bond lengths (in Å); (d) HOMO (e) LUMO. (plotted with isovalue 0.03).

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(a)
(b)
(c)
(d)
HOMO: -4.447 eV
LUMO: -2.460 eV
Fig. S8 The DFT optimized structure of TM (C80H56): (a) torsion angles (in degree);
(b) bond lengths (in Å); (c) HOMO (d) LUMO. (Plotted with isovalue 0.03).

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(a)
(b)
(c)
(d)
HOMO: -4.472 eV
LUMO: -3.197 eV
Fig. S9 The DFT optimized structure of TMC (C80H44): (a) torsion angles (in degree);
(b) bond lengths (in Å); (c) HOMO (d) LUMO. (Plotted with isovalue 0.03). The
torsion angles reduce significantly compared to TPE or TM, however the fused rings
twist.

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(a)
(b)
(d)
(c)
HOMO: -4.672 eV
LUMO: -2.882 eV
Fig. S10 The DFT optimized structure of C80H40: (a) torsion angles (in degree); (b)
bond lengths (in Å); (c) HOMO (d) LUMO. (Plotted with isovalue 0.03).