Toward electron-deficient pyrene derivatives: Construction of pyrene tetracarboxylic diimide containing five-membered imide rings

Article abstract of DOI:10.1039/c5cc04860e

Electron-deficient pyrene-1,2,6,7-tetracarboxylic diimide (PyrDI) and its cyano derivative (PyrDI-CN) have been designed and synthesized as a new family of aromatic diimides. PyrDI has two unexpected five-membered imide rings and can form excimers facilely in the solid state. These new pyrene derivatives are promising n-type semiconductors for organic electronics.

Full text of DOI:10.1039/c5cc04860e

View Article Online
View Journal
ChemComm
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: J. Pei, L. Zou, X.
Wang, X. Zhang, Y. Dai, Y. Wu and J. Wang, Chem. Commun., 2015, DOI: 10.1039/C5CC04860E.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/chemcomm

Please do not adjust margins
ChemComm
Page 1 of 4
View Article Online
DOI: 10.1039/C5CC04860E
Journal Name
COMMUNICATION
Toward Electron-Deficient Pyrene Derivatives: Construction of
Pyrene Tetracarboxylic Diimide Containing Five-Membered Imide
Rings
Received 00th January 20xx,
Accepted 00th January 20xx
Lin Zou,a Xiao-Ye Wang,a Xiao-Xiao Zhang,b Ya-Zhong Dai,b Yun-Dong Wu,*b Jie-Yu Wang,*a and
Jian Pei*a
DOI: 10.1039/x0xx00000x
www.rsc.org/
Electron-deficient pyrene-1,2,6,7-tetracarboxylic diimide (PyrDI) and its diversify the structures of aromatic imides and further
cyano derivative (PyrDI-CN) have been designed and synthesized as a new broaden the application of pyrene derivatives as n-type
family of aromatic diimides. PyrDI has two unexpected five-membered semiconductors, but none of them has been reported so far.
imide rings and can form excimers facilely in solid state. These new pyrene Compared with those K-region fused pyrene derivatives, fusion
derivatives are promising n-type semiconductors for organic electronics.
at the non-K-region is an alternative strategy to extend π-
framework of pyrene and to obtain unique properties due to
the different conjugation modes.21,22 However, previous works
have shown that fusion at the non-K-region of pyrene is of
challenge because of the low reactivity at C2 and C7 positions
of pyrene.25
Aromatic diimides are among the most promising and versatile
candidates for n-type organic semiconductors.1-3 Many imide
derivatives have been developed, which exhibit excellent
optical and electrical properties.1,4-9 Naphthalene diimides
10-14
)
15
)
(NDI
and perylene diimides (PDI
are the most widely
studied aromatic imides due to their high stability, strong
assembly tendency and unique opto-electronic properties.16
However, new aromatic diimides are still rare. Only few other
types of acenes have been decorated with imide groups to
construct new organic semiconductors recently, such as
anthracene diimide (ADI
pentacene bisimide (PBI
19,20. The difficulty in synthesis as well
)
17,18, tetracene bisimide (TBI), and
)
as lack of structural diversity limit the rapid development of
novel aromatic imides.
Many novel aromatics derived from pyrene have been
developed and widely investigated in organic electronics due
to their unique properties.21-24 However, extending the π-
conjugation plane of pyrene by fusing imide groups is
unknown. Three isomers might be obtained if two imide
groups are fused onto pyrene core centrosymmetrically (Fig.
1). One has five-membered imide rings fused at the non-K-
region of pyrene. Another has five-membered imide rings
fused at the K-region of pyrene. The third kind of isomer has
two six-membered imide rings. These pyrene diimides will
Fig. 1 The structures of some aromatic diimides such as NDI
PDI, and pyrene diimdes.
,
Herein, we report the development of a new type of
aromatic diimide, pyrene-1,2,6,7-tetracarboxylic diimide
(
PyrDI) and its cyano derivative, by a concise synthetic route.
The synthetic route to PyrDI and PyrDI-CN is shown in Scheme
1. A lithium-halogen exchange of commercially available 1,6-
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 2 of 4
View Article Online
DOI: 10.1039/C5CC04860E
COMMUNICATION
Journal Name
dibromopyrene (
1) with n-BuLi and subsequent quenching by spectroscopy and high resolution mass spectrometry (see the
carbon dioxide afforded pyrene-1,6-dicarboxylic acid (
2
) in Supporting Information).
60% yield. Treated with oxalyl dichloride, dicarboxylic acid
was then converted to the corresponding acyl chloride
2
3
quantitatively, which was used in the following reaction
without further purification. The cyclization reaction between
3
and isopropyl isocyanate was optimized by screening Lewis
acids, solvents, temperature and reaction time.19,20 Finally,
AlCl3 was employed as an efficient Lewis acid to give the target
PyrDI in high yield. Interestingly, PyrDI has two five-membered
imide rings on pyrene. However, its isomer
5 with six-
membered imide rings was not observed. The unique
selectivity of the five-membered imide rings in PyrDI was
investigated by density functional theory (DFT) calculations,
which reveal that the cyclization at C2 and C7 positions of
pyrene to form five-membered imide rings overcomes a lower
energy barrier than the six-membered ones (Fig. S1).
Fig. 2 (a) Single crystal structure of PyrDI with thermal
ellipsoids shown at the 50% probability. Hydrogen atoms are
omitted for clarity. (b) The structure of the nearest two
molecules, viewed along a axis. (c) The π-stacking structure of
the nearest two molecules. (d) Crystal packing diagram of
PyrDI viewed along b axis.
The single crystals of PyrDI were obtained as light yellow
needles by slow evaporation of the mixed solution of
4 in
chloroform and hexane. As shown in Fig. 2, the aromatic
electrophilic substitution mediated by AlCl3 took place at the
less active C2 and C7 positions of pyrene to form the five-
membered imide rings rather than the expected six-membered
ones resulted from cyclization at the K-region.19 Both five-
membered imide rings are almost coplanar with the pyrene
core. PyrDI belongs to the triclinic space group, in which two
molecules alternately pack on the opposite face to generate a
one dimensional columnar structure with an average π-π
stacking distance of 3.40 Å. The two nearest pyrene cores in
one column stack with only slight slipping, leading to a large
overlap of the conjugated backbones as shown in Fig. 2b and
2c. The close π-π stacking and the large spatial overlap of the
π-conjugated planes in columns indicate strong intermolecular
interactions within PyrDI molecules in the solid state, which is
beneficial to their controllable self-assembly and charge carrier
transport.
Scheme 1 The synthetic route to PyrDI and PyrDI-CN.
To diversify the structure of pyrene-based diimides, further
functionalization of PyrDI was explored. Catalyzed by Ir-
complex in the presence of bis(pinacolato)diboron, PyrDI was
directly borylated at the least sterically hindered C4 and C9
positions to give the diborylated compound PyrDI
-Bpin (6) in
high yield.26 The boryl groups on
6
can be converted to a wide
range of desirable synthons for particular applications.27
Herein, to develop n-type semiconductors, the boryl groups
were transformed into cyano groups to lower the energy
The absorption spectra of PyrDI and PyrDI-CN in chloroform
are shown in Fig. 3. For PyrDI, there are three absorption
bands in visible light region peaking at 445, 420 and 388 nm.
Compared to the absorption maximum of pyrene peaked at
334 nm, the incorporation of two imide groups leads to a large
red shift of 110 nm. This can be attributed to the extension of
the π-conjugation plane and the intramolecular charge
levels, yielding PyrDI-CN (7
) in 41% isolated yield.27,28 All the
structures were fully characterized by 1H and 13C NMR
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 3 of 4
View Article Online
DOI: 10.1039/C5CC04860E
Journal Name
COMMUNICATION
transfer after introduction of imide groups to pyrene core.
When incorporation of another two cyano groups, the long-
wavelength absorption maximum significantly blue shifts to
431 nm. The band gaps (Eg) calculated from absorption onset
are 2.73 eV for PyrDI and 2.83 eV for PyrDI
The electrochemical properties of PyrDI and PyrDI
investigated by cyclic voltammetry (Fig. S6). Two reversible
reduction peaks were observed for PyrDI and PyrDI CN. The
LUMO levels of PyrDI and PyrDI CN were calculated to be -
3.44 and -3.84 eV respectively. The incorporation of cyano
groups greatly decreases the LUMO level of PyrDI CN, which is
favourable to electron injection and transport in PyrDI CN
-CN, respectively.
-CN were
-
-
-
-
.
Fig. 4 Calculated molecular orbitals of pyrene, PyrDI and PyrDI
CN. The calculation was performed at B3LYP/6-311+G(d,p)
-
level.
Pyrene excimer is an important photophysical phenomena
and shows promising application in optoelectronic devices and
biosensors.29-32 We are curious about whether PyrDI also
exhibits similar properties. Therefore, the emission feature of
PyrDI in the solid state was investigated. Polystyrene (PS) was
chosen as a polymer matrix to tune the concentration of PyrDI
.
Fig. 3 Absorption spectra of PyrDI and PyrDI
solution (1.0
10-5 M).
-CN in CHCl3
The fluorescence spectra of the casted films of PyrDI in PS
were measured as a function of PyrDI concentration as shown
in Fig. 5. At the low concentration of 0.25 wt% PyrDI, three
structural fluorescence bands peaked at 446, 475, and 507 nm
were observed, which was identical to those of dilute PyrDI
solution. When the concentration was increased to 1.0 wt%,
the intensity of the fluorescence peaks at 475 and 507 nm
increased. Further increasing the concentration to 5 wt%, the
fluorescence intensity of PyrDI gradually decreased, and a new
broad fluorescence band appeared at around 517 nm. The
unstructured intense long-wavelength emission peak at
around 517 nm, accompanied with the disappearance of
monomeric vibrational emission peaks, indicates the formation
of PyrDI excimers.33,34 What’s more, the eximer emission
peaked at 517 nm red-shifted to 550 nm as the concentration
is further increased to 100 wt % (neat film). The change of the
fluorescence peaks from 517 nm to 550 nm was attributed to
the different intermolecular packing, from partially overlapped
excimer to fully overlapped one, which was also observed in
perylene films.35
×
DFT calculations were performed to investigate the
electronic structures of PyrDI and PyrDI CN. As shown in Fig. 4,
both PyrDI and PyrDI CN show rigid and planar π-conjugated
backbones. The HOMO/LUMO energy levels of PyrDI and
PyrDI CN were calculated to be -6.51/-3.28 eV and -7.20/-3.94
-
-
-
eV, respectively. The lowered energy levels as compared to
those of pyrene are attributed to the strong electron-
withdrawing ability of imide and cyano groups. PyrDI and
PyrDI-CN show similar HOMOs distribution, which is mainly
localized on the central pyrene core with a nodal plane passing
through the long axis. However, the distribution of LUMOs for
PyrDI and PyrDI
delocalized over the entire molecular backbone, involving both
imide groups. While for PyrDI CN there is no LUMO
-CN is a little different. For PyrDI, the LUMO is
-
,
distribution on the central two atoms in pyrene backbone. The
incorporation of imide groups and cyano groups not only
decreases the electron density of pyrene but also changes its
orbital distribution.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 4 of 4
View Article Online
DOI: 10.1039/C5CC04860E
COMMUNICATION
Journal Name
8. W. Jiang, Y. Li and Z. Wang, Acc. Chem. Res., 2014, 47, 3135-
3147.
9. Z. Sun, Q. Ye, C. Chi and J. Wu, Chem. Soc. Rev., 2012, 41, 7857-
7889.
10. Y. Hu, X. Gao, C.-a. Di, X. Yang, F. Zhang, Y. Liu, H. Li and D. Zhu,
Chem. Mater., 2011, 23, 1204-1215.
11. Y. Fukutomi, M. Nakano, J.-Y. Hu, I. Osaka and K. Takimiya, J.
Am. Chem. Soc., 2013, 135, 11445-11448.
12. B. A. Jones, A. Facchetti, M. R. Wasielewski and T. J. Marks, J.
Am. Chem. Soc., 2007, 129, 15259-15278.
13. S.-c. Chen, Q. Zhang, Q. Zheng, C. Tang and C.-Z. Lu, Chem.
Commun., 2012, 48, 1254-1256.
14. Z. Zhao, F. Zhang, X. Zhang, X. Yang, H. Li, X. Gao, C.-a. Di and D.
Zhu, Macromolecules, 2013, 46, 7705-7714.
15. Y. Zhao, Y. Guo and Y. Liu, Adv. Mater., 2013, 25, 5372-5391.
16. V. B. Sheshanath, V. B. Sidhanath and K. B. Suresh, Org. Biomol.
Chem., 2012, 10, 6455-6468.
17. A. R. Mohebbi, C. Munoz and F. Wudl, Org. Lett., 2011, 13,
2560-2563.
18. Z. Wang, C. Kim, A. Facchetti and T. J. Marks, J. Am. Chem. Soc.,
2007, 129, 13362-13363.
Fig. 5 PL spectra of PyrDI in PS films upon varying the
concentrations from 0.25 wt % to neat film. The fluorescence
spectra were normalized by the maximum intensity.
19. S. Katsuta, K. Tanaka, Y. Maruya, S. Mori, S. Masuo, T. Okujima,
H. Uno, K.-i. Nakayama and H. Yamada, Chem. Commun., 2011,
47, 10112-10114.
In conclusion, a new type of electron-deficient pyrene
derivative, pyrene-1,2,6,7-tetracarboxylic diimide PyrDI with
five-member imide rings and its cyano derivative PyrDI-CN
,
20. T. Okamoto, T. Suzuki, H. Tanaka, D. Hashizume and Y. Matsuo,
Chem. Asian J., 2012, 7, 105-111.
21. L. Zou, X.-Y. Wang, K. Shi, J.-Y. Wang and J. Pei, Org. Lett., 2013,
15, 4378-4381.
22. S. Zhang, X. Qiao, Y. Chen, Y. Wang, R. M. Edkins, Z. Liu, H. Li
and Q. Fang, Org. Lett., 2014, 16, 342-345.
23. Y. Sagara, T. Mutai, I. Yoshikawa and K. Araki, J. Am. Chem. Soc.,
2007, 129, 1520-1521.
24. G. Venkataramana, P. Dongare, L. N. Dawe, D. W. Thompson, Y.
Zhao and G. J. Bodwell, Org. Lett., 2011, 13, 2240-2243.
25. T. M. Figueira-Duarte and K. Müllen, Chem. Rev., 2011, 111,
7260-7314.
were developed through an efficient synthetic strategy. The
incorporation of imide and cyano groups not only extends the
π-conjugation plane of pyrene, but also decreases the electron
density of pyrene core dramatically. The formation of excimers
was observed in the solid state of PyrDI. The development of
pyrene diimide expands the field of non-K-region
functionalization of pyrene and provides new candidates for
organic electronics and supramolecular chemistry. In addition,
the low LUMO levels of PyrDI and PyrDI
-CN make them
promising building blocks for n-type semiconducting materials.
This work was supported by the Major State Basic Research 26. D. N. Coventry, A. S. Batsanov, A. E. Goeta, J. A. K. Howard, T. B.
Marder and R. N. Perutz, Chem. Commun., 2005, 41, 2172-2174.
27. H.-X. Dai and J.-Q. Yu, J. Am. Chem. Soc., 2011, 134, 134-137.
28. G. Zhang, L. Zhang, M. Hu and J. Cheng, Adv. Synth. Catal., 2011,
353, 291-294.
29. P. Beyazkilic, A. Yildirim and M. Bayindir, ACS Appl. Mater.
Interfaces, 2014, 6, 4997-5004.
Development
Program
(Nos.
2013CB933501
and
2015CB856505) from the Ministry of Science and Technology,
National Natural Science Foundation of China and Beijing
Natural Science Foundation (2144049).
30. H. S. Jung, M. Park, D. Y. Han, E. Kim, C. Lee, S. Ham and J. S.
Kim, Org. Lett., 2009, 11, 3378-3381.
Notes and references
31. H.-S. Jang, Y. Wang, Y. Lei and M.-P. Nieh, J. Phys. Chem. C,
2013, 117, 1428-1435.
32. P. Conlon, C. J. Yang, Y. Wu, Y. Chen, K. Martinez, Y. Kim, N.
Stevens, A. A. Marti, S. Jockusch, N. J. Turro and W. Tan, J. Am.
Chem. Soc., 2007, 130, 336-342.
33. R. Ferreira, C. Baleizao, J. M. Munoz-Molina, M. N. Berberan-
Santos and U. Pischel, J. Phys. Chem. A, 2011, 115, 1092-1099.
34. T. Shigehiro, S. Yagi, T. Maeda, H. Nakazumi, H. Fujiwara and Y.
Sakurai, J. Phys. Chem. C, 2013, 117, 532-542.
35. F. Ito, Y. Kogasaka and K. Yamamoto, J. Phys. Chem. B, 2013,
117, 3675-3681.
1. X. Zhan, A. Facchetti, S. Barlow, T. J. Marks, M. A. Ratner, M. R.
Wasielewski and S. R. Marder, Adv. Mater., 2011, 23, 268-284.
2. M. Durso, D. Gentili, C. Bettini, A. Zanelli, M. Cavallini, F. De
Angelis, M. Grazia Lobello, V. Biondo, M. Muccini, R. Capelli and
M. Melucci, Chem. Commun., 2013, 49, 4298-4300.
3. W. Yue, J. Gao, Y. Li, W. Jiang, S. Di Motta, F. Negri and Z. Wang,
J. Am. Chem. Soc., 2011, 133, 18054-18057.
4. X. Guo, A. Facchetti and T. J. Marks, Chem. Rev., 2014, 114,
8943-9021.
5. Z. Liu, G. Zhang, Z. Cai, X. Chen, H. Luo, Y. Li, J. Wang and D.
Zhang, Adv. Mater., 2014, 26, 6965-6977.
6. F. Würthner and M. Stolte, Chem. Commun., 2011, 47, 5109-
5115.
7. H. Yan, Z. Chen, Y. Zheng, C. Newman, J. R. Quinn, F. Dotz, M.
Kastler and A. Facchetti, Nature, 2009, 457, 679-686.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins