Photophysical and self-assembly properties of asymmetrical multi-aralkyl and arylaldehyde substituted pyrene derivatives

Article abstract of DOI:10.1016/j.tet.2012.04.089

A series of novel asymmetrical pyrene derivatives with aralkyl and aldehyde groups have been successfully synthesized, and their spectroscopic parameters were investigated detailedly. The effects of aralkyl substituent amounts on the electronic absorption and emission spectra have been explored in evaluation of their potential as optical materials components. Moreover, the electrochemical properties of the new pyrene derivatives have been studied for the molecules' HOMO and LUMO levels by cyclic voltammograms. In particular, titration of anhydrous ethanol into dilute CH₂Cl₂ solution of above compounds, an unusual change of the fluorescence value was observed. The change is believed to correlate strongly to intermolecular charge transfer. The morphological evolution of self-assembled pyrene derivatives with (arylethynyl)aldehyde substituents, from tamen-distinct-like morphologies to vesicular textures, was obtained by increasing aralkyl-substituted fragments. These asymmetrical discotic compounds represent an interesting set of candidates for optoelectronic device components.

Full text of DOI:10.1016/j.tet.2012.04.089

Tetrahedron 68 (2012) 6338e6342
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Photophysical and self-assembly properties of asymmetrical multi-aralkyl and
arylaldehyde substituted pyrene derivatives
Dong Wang, Zhaokui Jin, Jiankai Tang, Pengxia Liang, Yongsheng Mi, Zongcheng Miao, Yongming Zhang,
*
Huai Yang
State Key Laboratory for Advanced Metals and Materials, Department of Materials Physics and Chemistry, School of Materials Science and Engineering,
University of Science and Technology Beijing, Beijing 100083, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel asymmetrical pyrene derivatives with aralkyl and aldehyde groups have been suc-
cessfully synthesized, and their spectroscopic parameters were investigated detailedly. The effects of
aralkyl substituent amounts on the electronic absorption and emission spectra have been explored in
evaluation of their potential as optical materials components. Moreover, the electrochemical properties
of the new pyrene derivatives have been studied for the molecules’ HOMO and LUMO levels by cyclic
voltammograms. In particular, titration of anhydrous ethanol into dilute CH2Cl2 solution of above
compounds, an unusual change of the fluorescence value was observed. The change is believed to cor-
relate strongly to intermolecular charge transfer. The morphological evolution of self-assembled pyrene
derivatives with (arylethynyl)aldehyde substituents, from tamen-distinct-like morphologies to vesicular
textures, was obtained by increasing aralkyl-substituted fragments. These asymmetrical discotic com-
pounds represent an interesting set of candidates for optoelectronic device components.
Ó 2012 Published by Elsevier Ltd.
Received 6 January 2012
Received in revised form 10 April 2012
Accepted 24 April 2012
Available online 30 April 2012
Keywords:
Pyrene
Asymmetrical
Self-assembly
1. Introduction
organic semiconductor for application in materials science and or-
ganic electronics. Modification of the chemical structure by varying
Carbon-rich, highly conjugated organic-based molecules have
been the subject of considerable study in recent years,1,2 resulting
in advanced materials that hold great promise for successful ap-
plications in many optoelectronic devices, such as organic light-
emitting diodes (OLEDs),3 organic field-effect transistors (OFETs),4
and photovoltaic cells.5 The organization of objects at the meso-
scopic scale is a current paradigm of materials science because it
allows the synthesis of structures with novel properties derived
from the cooperative interactions of the individual components.6
Among the different types of assembly components, the use of
disc-like molecules functionalized with special groups is of par-
ticular interest because of the various synthetic routes available to
manipulate their size, shape and conjugation, offering the ability to
tune their physical and chemical properties, such as energy gap,
charge carrier mobility, and electron transfer.7
the substitution at different positions of the pyrene ring allows the
control of the molecular architecture and thus the molecular packing,
which renders the handling of pyrene substitution a key factor in
pyrene-based semiconductors.7 Although pyrene and its derivatives
have been widely and successfully employed in the preparation of
organic materials, the fact that
p aggregates and ordered alignment
(exhibit sensitivity to the charge carrier mobility) constitutes a major
drawback. Recently, great efforts have been made to regulate the
photophysical effect through the incorporation of donoreacceptor
(DeA)-substituted systems9 or asymmetrical groups around the flu-
orophore.10 The presence of electron-rich or electron-poor units is
indeed important and permits the fine-tuning of the optical proper-
ties while also influencing the molecular packing.7 High spatial or-
ganization is also a key strategy to control the order and packing of
organic optoelectronic materials and to suppress defect formation.7,11
Herein, we describe the synthesis of a new series of pyrene
derivatives having an asymmetric structure of a pyrene mesogenic
core and aldehyde group peripherals, and the H-bonded assemblies
nucleated in solution using a solvent evaporation approach that
feature different geometries. Two important factors have been
considered in the rational design of such pyrene-based architec-
tures: (i) the asymmetry and (ii) the binding capabilities of the
substituted fragment. To our knowledge no attempts have been
Pyrene is a prototypical discoid molecule, which has high fluo-
rescence quantum yield in solution and shows efficient excimer
emission.8 In addition to excimer sensing, which propelled pyrene
and its derivatives to the status of the most used fluorescent probe,
there has been a recent increased interest in the use of pyrene as
* Corresponding author. E-mail address: wangdong_ustb@foxmail.com (H. Yang).
0040-4020/$ e see front matter Ó 2012 Published by Elsevier Ltd.
doi:10.1016/j.tet.2012.04.089

D. Wang et al. / Tetrahedron 68 (2012) 6338e6342
6339
made to elaborate an ordered architecture by using the effect of
aldehyde group in discoid molecule field. It is expected that the
concept reported here can be expanded to other functional groups
and will impact many optoelectronic applications.
2. Results and discussion
2.1. Synthesis
A strategy was proposed on the design of pyrene-based asym-
metric structures, which consist of three main units: the discoid core,
the multifunctional ketone group and the
p-conjugated phenyl-
ethynyl. The multifunctional ketone group can both engender the
asymmetric structures and influence the intermolecular in-
teractions,12 and the
p-conjugated phenylethynyl can easily extend
intramolecular
p-conjugation, so as to improve the charge mobility
within the material.13 One special design here is that the active al-
dehyde as one side group provides the H-bonding interaction to the
pyrene matrix. Onthe basis of the idea mentioned above, a series of 1-
substituted, 1,6-disubstituted, 1,6,8-trisubstituted pyrene derivatives
have been synthesized thatperipherallyconnected withalkylaryl and
aromatic aldehyde through ethynyl or carbonyl linkers. The synthesis
of the target compounds was accomplished by four-step reactions:
FriedeleCrafts acylation procedure (a), bromination procedure (b)
and HagiharaeSonogashira cross-coupling procedures (c) and (d)14
as showed in Scheme 1. The acceptor terminal alkyne was synthe-
sized in two steps from 4-bromobenzaldehyde (Fig. S1, see the Sup-
plementary data). All of above compounds were obtained in good
yields and high purities. Their molecular structures and purities were
assigned using 1H NMR, 13C NMR, FT-IR, and MALDI-TOF-MS.
Fig. 1. UVevis absorption spectra (a) and fluorescence emission spectra (b) of B1eB4
in CH2Cl2 under room temperature.
provided some insight into the electronic structure of the systems.
All display a characteristic pattern of two broad absorption bands
between 300 and 500 nm except for B1, which has only one obvious
absorption band. All the data were summarized in Table 1. Com-
pared with the monosubstituted compound (B1), the disubstituted
(B2) and trisubstituted (B3) compounds reveal significant red shifts
(w50 nm) of the maxima absorption wavelengths. The red shift in
the onset absorption on moving from B1 to B3 is also observed in
Fig.1 (a). This trend is further illustrated by the energy of the optical
band gap (measured from the absorption onset) of B1 (2.80 eV)
when compared to B2 (2.59 eV) and B3 (2.52 eV). Such bath-
ochromic shifts upon donor/acceptor functionalization are in-
dicative of intramolecular charge transfer.15 On the other hand, the
straightforward ethynyl-substituted compound (B4) exhibited
significant broadening and large (w60 nm) red shifts by compari-
son with B1. A reasonable explanation is that the ketone groups
weaker the conjugation and influence the charge transfer extent
between electron-withdrawing group and the core.
Table 1
Scheme 1. Reagents and conditions: (a) 4-iodobenzoyl chloride (1.2 equiv), dichloro-
methane, AlCl3, 55 ꢀC, reflux, 10 h; (b) bromine (1 equiv/2 equiv), nitrobenzene, rt, 2 h,
then 120 ꢀC, reflux, 10 h; (c) 4-ethynylbenzaldehyde, THF, Et3N, [PdCl2(PPh3)2], CuI, rt,
8 h; (d) THF, Et3N, [PdCl2(PPh3)2], CuI, 80 ꢀC, reflux, 8 h.
Summary of the physical properties of the compounds B1eB4
Tm (ꢀC)a
l
abs (nm)
l
(nm)
Stokes shift (cmꢁ1
)
em
Compounds
max
B1
B2
B3
B4
179
174
168
190
326b
498
502
506
482
10,595
5853
3493
5482
328b, 388
325b, 430
308, 380b
2.2. Photophysical properties
a
Tested by DSC at a rate of 10 ꢀC/min.
Excitation wavelength.
The absorption spectra of pyrene derivatives B1eB4 in dilute
CH2Cl2 solution at room temperature, depicted in Fig. 1 (a),
b

6340
D. Wang et al. / Tetrahedron 68 (2012) 6338e6342
With the electronic emission spectra together, the photo-
physical properties of B1eB4 have been further deliberated. The
electronic emission spectra of B1eB4 in CH2Cl2 were shown in
through H-bonding, and varying the fragments on pyrene unit
enables us to fine-tune the optical band gap. Not surprisingly, other
compounds showed the resemble spectra in Fig. S4.
Fig. 1 (b) and summarized in Table 1. Compared with the maximum
em
fluorescence emission wavelength (
l
) of compound B1 at
max
em
2.3. Self-organization behavior in solution
498 nm, the
l
max
of B2, B3 and B4 occurred at 502, 506 and 482 nm,
respectively. The initial fluorescence emission wavelengths of B1,
B2 and B3 were almost identical, but the maxima emission wave-
length showed the bathochromic shift, which indicated some dif-
ferent energy transfer absorption exists. Additionally, the
fluorescence spectra of these compounds systematically varied in
agreement with the electronic absorption spectra, implying that
the energy gap between the ground and excited states decreased in
the order of B1>B2>B3, based on the maximum absorption
wavelength (see Table 1). The fluorescence spectra were in-
dependent of the excitation wavelength. The Stokes shifts de-
creased in the order of B1>B2>B3.
Titration of protic solvent into aldehyde-containing compound
represents a facile method of investigating the intermolecular in-
teraction and the consequent structure-property implications.16 In
order to obtain more insight into the photophysical properties of
these new pyrene-based derivatives, the anhydrous ethanol be-
tween 0.2 and 4 equiv was gradually titrated into the dilute CH2Cl2
To develop organic optoelectronic materials, the hierarchical
self-assembly of multivalent components through the concerted
action of multiple noncovalent interactions turns out to be one of
the most promising approaches, as it allows the simultaneous or-
ganization of discrete molecules, long-range order, and inherently
defect-free structures.17e20 Taking it into account, an activated al-
dehyde group as acceptor was introduced into the discoid pyrene
core so as to enhance multiple noncovalent interactions. The self-
assembly process was performed through
a phase transfer
method with a THF/ethanol binary solvent system (more detailed
process see Supplementary data), and exhibited different mor-
phologies in Fig. 3. For compound B1, the formation of a stamen-
distinct-like morphology was highly ordered. Introduced one
aralkyl substituent into the dish core, the obtained compound B2
was showed as vesicular textures. Connected one more same
fragment into pyrene core, the obtained compound B3 can’t exhibit
the regular morphology. With the increasing of the substituent, the
degree of self-assembling order is likely to get worse for the in-
creasing steric hindrance. For compound B4, without the ketone
linking group comparison with B1, the morphology is dendrite-like.
These self-recognition behaviors should be attributed to the acti-
(spectrum pure) solutions of the compound B4 solution (w15 mM),
and the change in the electronic emission spectra was observed
(see Fig. 2). Upon addition of the anhydrous ethanol, the fluores-
cence signal was further decreased until fluorescence quenching,
whereas bathochromic shifts were manifested in the fluorescence
lmax. During the initial stage of the titration, the substantial de-
crease in the fluorescence intensity (w50%, Fig. 2) suggested that
a large majority of hydrogen bonding were formed between the
pyrene derivatives and the anhydrous ethanol. However, a new
phenomenon was observed in this paper that a series of new
fluorescence peaks were tracked and the intensity increased with
the addition of anhydrous alcohol. The phenomenon revealed that
there is an unusual energy transfer from B4 to anhydrous ethanol
through hydrogen bonding. For corroborate indirectly the infection
between the aldehyde group and the protic solvent, 1H NMR
spectra were used to monitor the infection, and the change of
chemical shifts as observed in Fig. S3. After replacing the aldehyde
group of B4 with pentyl group, which is quoted from a publishing
article in our laboratory,25 there was no evident signal of the
fluorescence data. Overall, these results support the hypothesis that
introducing the aldehyde group may give a possible self-assembly
vated aldehyde group so as to form H-bonding and
pep* in-
teractions around the dish cores. Meanwhile, the ketone group is
hindered by a restriction of the access of potential binding partners
to the hydrogen atoms and increasing aryne conjugation impairs
the
pep* interactions between the layers. As a consequence,
compounds B2 and B3 do not assemble into much highly ordered
texture, but instead form aggregation through hydrogen bonding
even lose the self-organization behavior. By comparing the be-
havior to that of compound B4, which nearly forms flat structures,
it may be explained that without steric hindrance by an additional
ketone, the dipoleedipole interaction is energetically less favored
than the formation through hydrogen bonding. This is in agreement
with a calculation by Okuno21 et al. and was also observed for
a different molecular structure with similar substituent. On the
basis of morphological observations, speculation was made that the
Fig. 2. Emission spectra of anhydrous ethanol titration of B4 into CH2Cl2 at approxi-
mately 15
(380 nm).
mM concentration. Excitation at wavelength of most intense absorption band
Fig. 3. SEM micrographs of compounds (a) B1, (b) B2, (c) B4.

D. Wang et al. / Tetrahedron 68 (2012) 6338e6342
6341
self-assembly is driven by hydrogen bonding intermolecular in-
teractions and amplified by * interactions leading to different
continuous development of the discoid molecular for application in
optoelectronic materials.
pep
aggregation so as to stabilize the morphology, whereas the car-
bonyl moieties create the activity to form the stamen-distinct-like
morphology.
4. Experimental
4.1. General
2.4. Electrochemical properties
Chemicals and solvents were purchased from commercial
sources (Aldrich) and used without further purification. Triethyl-
amine (TEA) and tetrahydrofuran (THF) were distilled and purged
with argon before use. A Bruker DMS-400 spectrometer was used
to record the 1H NMR and 13C NMR spectra at 298 K. CDCl3 was the
solvent for NMR and chemical shifts relative to tetramethyl silane
(TMS) at 0.00 ppm are reported in parts per million (ppm) on the
As is well known, the levels of HOMO and LUMO are sensitive to
organic materials structure properties. Further characterization
with electrochemical method is discussed as followed. The detailed
investigation of the electrochemical reaction of the compounds
B1eB4 carried out by cyclic voltammetry (CV) was showed in Fig. 4
and Table S1 (see the Supplementary data). These pyrene de-
rivatives showed tiny reversible single-electron oxidation peaks
between 0.1 and 0.2 V (Fig. S2), possibly for the formation of rigid
structure. Their HOMO levels were estimated from the onset of
oxidation potentials to be between ꢁ4.95 and ꢁ4.98 eV.22 HOMO
levels of good p-type organic semiconductors are known typically
to be in the range of ꢁ4.9 to ꢁ5.5 eV.23 Low HOMO levels and large
energy gaps, in addition to the highly ordered arrangement prop-
erty, suggest that the above compounds are promising hole trans-
porting organic materials. In addition, the electrochemical data
support the idea that the increasing fragment as the band gap
corresponds to decreasing is feasible for fine-tuning the band
structure.
d
scale. All UVevisible spectra were recorded on a JASCO V-570
spectrophotometer, and all fluorescence spectra were recorded on
a HITACHI F-4500 fluorescence spectrophotometer. FT-IR spec-
troscopy was recorded on a Perkin Elmer LR-64912C spectropho-
tometer. Differential scanning calorimetry (DSC) analyses were
performed on a Perkin Elmer Pyris 6 instrument. MALDI-TOF-MS
spectra were determined on a Shimadzu AXIMA-CFR mass spec-
trometer. Cyclic voltammetric measurements were carried out in
a conventional three-electrode cell using Glassy Carbon working
electrodes of 2 mm diameter, a platinum wire counter electrode,
and a Ag/AgCl reference electrode on a computer-controlled CHI
660C instrument at room temperature.
General bromination procedures (b): compound 125(1 equiv) or
pyrene was (1 equiv) dissolved in nitrobenzene. Under vigorous
stirring, bromine (1 equiv or 2 equiv per transformation) was added
slowly. After complete addition, stirred 2 h under room tempera-
ture, then the temperature was increased to 120 ꢀC and maintained
for 10 h. The cooled reaction suspension was poured in to acetone
and the precipitate filtered off. Further drying of the precipitate in
high vacuum gave the crude product, which was used without
further purification because it is insoluble in common organic
solvents.
General HagiharaeSonogashira cross-coupling procedures (c): to
a degassed solution of dry Et3N/THF (1:1, 0.05 M), compound 2 or
3 (1 equiv) were added and the mixture degassed a second time
under Ar. Catalytic agents Pd(PPh3)2Cl2 (0.02 equiv per trans-
formation) and CuI (0.04 equiv per transformation) were then
added, and the reaction mixture was stirred overnight at room
temperature under Ar. The solvent was then concentrated under
vacuum and the conclusive purified by column chromatography.
General HagiharaeSonogashira cross-coupling procedures (d):
compound 4 or 5 or 626(1 equiv) was dissolved in dry Et3N/THF (1:1,
0.05 M) and the solution degassed for 45 min with bubbling Ar.
Catalytic agents Pd(PPh3)2Cl2 (0.02 equiv per transformation), CuI
(0.04 equiv per transformation), and PPh3 (0.04 equiv per trans-
formation) were then added, and the solution was purged another
20 min. 4-ethynylbenzaldehyde (1 equiv or 2 equiv per trans-
formation) was added and the solution was stirred at 80 ꢀC for 10 h
under an Ar atmosphere. Upon completion, the mixture was diluted
with CH2Cl2 and extracted with water. The organic phase was dried
over MgSO4, and the solvent was removed under reduced pressure.
Fig. 4. Energy level diagram of compounds B1eB4 and PCBM.24 The data was derived
from electrochemical experiments.
3. Conclusions
The asymmetrical pyrene-based (arylethynyl)benzaldehyde
with monosubstituted and disubstituted aralkyl were synthesized
and a combination of spectrum and electrochemical analysis
demonstrated that increasing substituent provide access to a wide
adjust of optical band gaps for customized optical materials appli-
cations. Data of anhydrous ethanol titration for B4 imply encour-
aging potential for energy transfer through H-bonding, which is
unusual phenomenon in conjugated system. The most striking
feature of these compounds exhibited distinct behavior for self-
assembly so as to create different self-assembled morphologies
including stamen-distinct-like morphologies, dendrons, and ve-
sicular textures. Herein, it can provide a supramolecular pathway
applicable for electronics organic materials owing to the columnar
morphology and the dynamic nature of the H-bonding. These
findings and suggestions are of paramount importance for the
4.1.1. (4-Iodophenyl)(pyren-3-yl)methanone (1). Pyrene (8.5 g,
42.0 mmol) and 4-iodobenzoyl chloride (11.5 g, 43.2 mmol) were
dissolved in carbon disulfide (50 mL), the mixture was cooled to
0 ꢀC. After the portionwise addition of AlCl3 (7.2 g, 54.0 mmol), the
mixture was heated under reflux overnight, then poured into ice-
water and the resulting mixture was stirred until the color of the
organic phase turned from black to yellow. The layers were then
separated, the aqueous phase was extracted with dichloromethane,
the combined organic phases were dried with MgSO4, and the

6342
D. Wang et al. / Tetrahedron 68 (2012) 6338e6342
solvent was evaporated. The residue was purified by column
chromatography, and compound 1 was obtained (11.6 g, 64%).
2721, 2201, 1699, 1603, 1302, 1207, 1155, 849, 815, 780, 717 cmꢁ1
.
MALDI-TOF-MS (dithranol): m/z: calcd for C25H14O: 330.10 g molꢁ1
,
found: 332.1 g molꢁ1 [MH]þ.
4.1.2. 4-((4-(Pyrene-1-carbonyl)phenyl)ethynyl)benzaldehyde
(B1). Compound 1 (0.360 g, 0.833 mmol) was reacted with 4-
ethynylbenzaldehyde (0.110 g, 0.850 mmol) using general pro-
cedure (c). The crude product was purified by column chromatog-
raphy to afford B1 (0.212 g, 0.489 mmol, 59%). 1H NMR (400 MHz,
Acknowledgements
This work was supported by National Natural Science Fund for
Distinguished Young Scholar (Grant No. 51025313), National Nat-
ural Science Foundation (Grant No. 51103010, 50973010, 51173003),
Specialized Research Fund For Doctoral Program of Higher Educa-
tion of China (Grant No. 20110006120002).
CDCl3):
d
10.01 (1H, s), 8.33 (1H, d, J¼9.2 Hz), 8.22 (4H, m), 8.12 (d,
J¼8.8 Hz, 2H), 8.07 (d, J¼8.0 Hz, 1H), 8.06 (t, 1H), 7.87 (4H, m), 7.69
(2H, d, J¼8.0 Hz), 7.63 (2H, d, J¼8.4 Hz) ppm. 13C NMR (100 MHz,
CDCl3):
d 197.6, 191.4, 138.6, 135.9, 133.4, 133.2, 132.6, 132.4, 131.9,
131.2, 130.7,129.9,129.7,129.4,129.2,128.9,127.4,127.3,127.1,126.6,
126.3, 126.2, 124.9, 124.7, 124.5, 123.9, 92.5, 91.8 ppm. FT-IR (KBr):
2212, 1697, 1639, 1596, 1391, 1254, 1137, 936, 835 cmꢁ1. MALDI-TOF-
MS (dithranol): m/z: calcd for C32H18O2: 434.13 g molꢁ1, found:
435.5 g molꢁ1 [MH]þ.
Supplementary data
Experimental details of the acceptor terminal alkyne; CV curves
of compounds B1eB4; Summary of optical and redox data for
compounds B1eB4; The self-assembly process of the compounds;
1H NMR spectra of the compound B1 recorded with different
CD3OD contents; Emission spectra of anhydrous ethanol titration of
compounds B1eB3. Supplementary data related to this article can
be found online at doi:10.1016/j.tet.2012.04.089.
4.1.3. 4-((4-(6-((4-Pentylphenyl)ethynyl)pyrene-1-carbonyl)phenyl)
ethynyl)benzaldehyde (B2). Compound 4 (0.462 g, 0.900 mmol) was
reacted with 1-ethynyl-4-pentylbenzene (0.155 g, 0.900 mmol)
using general procedure (d). The crude product was purified by
column chromatography to afford B2 (0.337 g, 0.558 mmol, 62%). 1H
NMR (400 MHz, CDCl3):
d 9.97 (1H, s), 8.66 (1H, m), 8.38 (1H, d,
References and notes
J¼9.2 Hz), 8.29 (1H, d, J¼9.2 Hz), 8.20 (1H, m), 8.05 (2H, m), 7.90
(2H, d, J¼8.4 Hz), 7.87 (2H, d, J¼8.4 Hz), 7.80 (2H, d, J¼8.0 Hz), 7.61
(6H, m), 7.20 (2H, m), 2.62 (2H, m), 1.62 (2H, m), 1.33 (4H, m), 0.91
1. Carbon-Rich Compounds: From Molecules to Materials; Haley, M. M., Tykwinski,
R. R., Eds.; Wiley-VCH: Weinheim, 2006.
2. Hoeben, F. J. M.; Jonkheijm, P.; Meijer, E. W.; Schenning, A. Chem. Rev. 2005, 105,
1491e1546.
(3H, m) ppm. 13C NMR (100 MHz, CDCl3):
d 197.3, 191.6, 144.4, 138.7,
136.2, 132.6, 132.2, 132.0, 130.9, 130.4, 129.9, 129.5, 129.4, 129.3,
129.0, 127.8, 127.5, 127.1, 126.8, 125.0, 124.7, 121.5, 117.7, 96.6, 92.8,
92.3, 87.6, 36.3, 31.8, 31.3, 22.9, 14.4 ppm. FT-IR (KBr): n 3436, 3032,
2928, 2855, 2729, 2306, 1698, 1656, 1602, 1384, 1431, 1255, 1204,
1157, 934, 828 cmꢁ1. MALDI-TOF-MS (dithranol): m/z: calcd for
C45H3O2: 604.24 g molꢁ1, found: 606.4 g molꢁ1 [MH]þ.
€
3. (a) Organic Light Emitting Devices: Synthesis, Properties and Applications; Mullen,
K., Scherf, U., Eds.; Wiley-VCH: Weinheim, 2006; (b) Shirota, Y. J. Mater. Chem.
2000, 10, 1e25; (c) Hughes, G.; Bryce, M. R. J. Mater. Chem. 2005, 15, 94e107.
4. (a) Pisula, W.; Menon, A.; Stepputat, M.; Lieberwirth, I.; Kolb, U.; Tracz, A.;
Sirringhaus, H.; Pakula, T.; Mullen, K. Adv. Mater. (Weinheim, Ger.) 2005, 17,
684e689; (b) Simpson, C. D.; Wu, J.; Watson, M. D.; Mullen, K. J. Mater. Chem.
€
€
2004, 14, 494e504.
5. Kubo, W.; Kambe, S.; Nakade, S.; Kitamura, T.; Hanabusa, K.; Wada, Y.; Yanagida,
S. J. Phys. Chem. B 2003, 107, 4374e4381.
4.1.4. 4-((4-(6,8-Bis((4-pentylphenyl)ethynyl)pyrene-1-carbonyl)
6. Baranov, D.; Manna, L.; Kanaras, A. G. J. Mater. Chem. 2011, 21, 16694e16703.
phenyl)ethynyl)benzaldehyde (B3). Compound
5
(0.266 g,
€
7. Figueira-Duarte, T. M.; Mullen, K. Chem. Rev. 2011, 111, 7261e7263.
0.450 mmol) was reacted with 1-ethynyl-4-pentylbenzene (0.155 g,
0.900 mmol) using general procedure (d). The crude product was
purified by column chromatography to afford B3 (0.234 g,
€
8. Forster, T.; Kasper, K. Z. Elektrochem. 1955, 59, 976e980.
9. (a) Oliva, M. M.; Casado, J.; Raposo, M. M. M.; Fonseca, A. M. C.; Hartmann, H.;
Hernandez, V.; Navarrete, J. T. L. J. Org. Chem. 2006, 71, 7509e7520; (b) Spitler,
E. L.; Monson, J. M.; Haley, M. M. J. Org. Chem. 2008, 73, 2211e2223.
10. (a) Zhang, H. J.; Xu, X. J.; Qiu, W. F.; Qi, T.; Gao, X.; Liu, Y.; Lu, K.; Du, C. Y.; Yu, G.;
Liu, Y. Q. J. Phys. Chem. C 2008, 112, 13258e13263; (b) Hu, J. Y.; Era, M.; Mark, R.;
Elsegood, J.; Yamato, T. Eur. J. Org. Chem. 2010, 72e79.
0.302 mmol, 67%). 1H NMR (400 MHz, CDCl3):
d 10.01 (1H, s), 8.88
(1H, d, J¼9.6 Hz), 8.80 (1H, d, J¼9.6 Hz), 8.17 (1H, d, J¼8.0 Hz), 8.08
(1H, d, J¼9.2 Hz), 7.92 (2H, d, J¼8.4 Hz), 7.87 (2H, d, J¼8.0 Hz), 7.64
(8H, m), 7.24 (4H, m), 2.65 (4H, m), 1.65 (4H,m), 1.34 (4H, m), 0.90
€
€
11. Schimdt-Mende, L.; Fechtenlotter, A.; Mullen, K.; Moons, E.; Friend, H.; MacK-
enzie, J. D. Science 2001, 293, 1119e1122.
(6H, m) ppm. 13C NMR (100 MHz, CDCl3):
d 196.6, 191.4, 144.1, 138.2,
12. Beinhoff, M.; Weilfried, W.; Jurczok, M.; Retting, W.; Modrakowski, C.;
Brudgam, I.; Hartl, H.; Schluter, A. D. Eur. J. Org. Chem. 2001, 3819e3829.
13. Lee, C.; Waterland, R.; Sohlberg, K. J. Chem. Theory Comput. 2011, 7, 2556e2567.
14. Bernhardt, S.; Kastler, M.; Enkelmann, V.; Baumgarten, M.; Mullen, K. Chem.
dEur. J. 2006, 12, 6117e6128.
15. (a) Pak, J. J.; Weakley, T. J. R.; Haley, M. M. J. Am. Chem. Soc. 1999, 121,
8182e8192; (b) Sarkar, A.; Pak, J. J.; Rayfield, G. W.; Haley, M. M. J. Mater. Chem.
2001, 11, 2943e2945.
135.8, 133.5, 132.7, 132.3, 132.0, 130.7, 130.3, 130.1, 129.6, 129.4,
128.84, 128.75, 128.2, 127.6, 126.8, 126.2, 126.1, 125.1, 124.6, 124.0,
120.5, 120.3, 120.1, 117.9, 96.7, 92.5, 91.9, 87.8, 36.1, 31.6, 31.1, 22.7,
14.2 ppm. FT-IR (KBr):
n 3040, 2929, 2855, 2729, 2306, 2202, 1698,
1653, 1602, 1513, 1372, 1245, 1164, 1001, 823 cmꢁ1. MALDI-TOF-MS
(dithranol): m/z: calcd for C58H46O2: 774.35 g molꢁ1, found:
775.8 g molꢁ1 [MH]þ.
16. Spitler, E. L.; Shirtcliff, L. D.; Haley, M. M. J. Org. Chem. 2007, 72, 86e96.
€
17. Bonifazi, D.; Kiebele, A.; Stohr, M.; Cheng, F.; Jung, T.; Diederich, F.; Spillmann,
H. Adv. Funct. Mater. 2007, 17, 1051e1062.
18. Barth, J. V. Annu. Rev. Phys. Chem. 2007, 58, 375e407.
4.1.5. 4-(Pyren-1-ylethynyl)benzaldehyde
(B4). Compound
6
19. Rosei, F.; Schunack, M.; Naitoh, Y.; Jiang, P.; Gourdon, A.; Laegsgaard, E.; Sten-
sgaard, I.; Joachim, C.; Besenbacher, F. Prog. Surf. Sci. 2003, 71, 95e146.
20. Rosei, F. J. Phys.: Condens. Matter 2004, 16, S1373eS1436.
21. Okuno, Y.; Yokoyama, T.; Yokoyama, S.; Kamikado, T.; Mashiko, S. J. Am. Chem.
Soc. 2002, 124, 7218e7225.
(0.234 g, 0.833 mmol) was reacted with 4-ethynylbenzaldehyde
(0.110 g, 0.850 mmol) using general procedure (c). The crude
product was purified by column chromatography to afford B4
(0.182 g, 0.550 mmol, 66%). 1H NMR (400 MHz, CDCl3):
d 10.03 (1H,
22. Wang, D.; Michinobu, T. J. Polym. Sci., Polym. Chem. Ed. 2011, 49, 72e81.
23. (a) Murphy, A. R.; Frechet, J. M. J. Chem. Rev. 2007, 107, 1066e1096; (b) Fichou,
D. Handbook of Oligo- and Polythiophenes; Wiley-VCH: New York, NY, 1998.
s), 8.61 (1H, d, J¼9.2 Hz), 8.23 (1H, d, J¼7.6 Hz), 8.21 (1H, t), 8.20
(1H, d, J¼7.6 Hz), 8.18 (1H, d, J¼5.6 Hz), 8.11 (2H, m), 8.04 (2H, d,
J¼8.4 Hz), 7.92 (2H, d, J¼8.4 Hz), 7.83 (2H, d, J¼8.4 Hz) ppm. 13C
€
24. Scharber, M. C.; Muhlbacher, D.; Koppe, M.; Denk, P.; Waldauf, C.; Heeger, A. J.;
Brabec, C. J. Adv. Mater. (Weinheim, Ger.) 2006, 18, 789e794.
25. Li, Y.; Wang, D.; Wang, L.; Li, Z. Q.; Cui, Q.; Zhang, H. Q.; Yang, H. J. Lumin. 2012,
132, 1010e1014.
26. Maeda, H.; Maeda, T.; Mizuno, K.; Fujimo, K.; Shimizu, H.; Inouye, M. Chem.dEur.
J. 2006, 12, 824e831.
NMR (100 MHz, CDCl3):
d 191.5, 135.4, 132.2, 132.1, 131.8, 131.2,
131.0, 129.8, 129.7, 128.7, 128.6, 127.2, 126.4, 126.0, 125.9, 125.3,
124.6, 124.5, 124.2, 116.9, 94.3, 93.0 ppm. FT-IR (KBr): 3036, 2808,
n