Synthesis and properties of perylene diimide dyes bearing unsymmetrical and symmetrical phenoxy substituents at bay positions

Article abstract of DOI:10.1016/j.tet.2015.07.032

Perylene diimide dyes bearing symmetrical and unsymmetrical phenoxy substituents at the bay positions (N,N′-diethylhexyl-1-bromo-7-pentafluorophenoxy-substituted perylene diimide and 1,7-diphenoxy-substituted perylene diimide) were prepared. ¹H NMR analysis indicated that these compounds contain a small quantity of the 1,6-regioisomer, and yield intramolecular hydrogen bonds. Furthermore, their photophysical, electrochemical, aggregation, and thermal properties were studied. It was found that their photophysical properties, structure, aggregation, and thermal stability in the solid state depend on the structure of the phenoxy substituent.

Full text of DOI:10.1016/j.tet.2015.07.032

Accepted Manuscript
Synthesis and properties of perylene diimide dyes bearing unsymmetrical and
symmetrical phenoxy substituents at bay positions
Hang Zhao, Ying-ying Zhang, Hai Xu, Ze-min He, Zhen-Lin Zhang, Hai-quan Zhang
PII:
S0040-4020(15)01069-8
10.1016/j.tet.2015.07.032
TET 26977
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 26 May 2015
Revised Date: 9 July 2015
Accepted Date: 11 July 2015
Please cite this article as: Zhao H, Zhang Y-y, Xu H, He Z-m, Zhang Z-L, Zhang H-q, Synthesis and
properties of perylene diimide dyes bearing unsymmetrical and symmetrical phenoxy substituents at bay
positions, Tetrahedron (2015), doi: 10.1016/j.tet.2015.07.032.
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ACCEPTED MANUSCRIPT
Graphical Abstract
Synthesis and properties of perylene
diimide dyes bearing unsymmetrical
and symmetrical phenoxy
substituents at bay positions
Hang Zhaoa, Ying-ying Zhanga, Hai Xub, Ze-min Hea, Zhen-Lin Zhanga and Hai-quan Zhanga*
aState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao
066004, PR China
bCollege of Chemistry, Jilin University, Changchun, 130021, PR China
F
F
F
F
F
F
O
O
C
O
O
O
O
O
C
O
O
N
C
C
N
C
C
N
N
C
O
C
DMF
N
C
K2CO3
N
C
C
O
C
O
O
O
O
O
O
Reflux 7h
O
F
F
F
F
F
Br
Br
F
O
O
BOPDI
PFPDI
C
C
DFPDI
N
C
N
C
O
O
Br
Br
O
Br
O
O
O
O
C
O
C
C
C
C
N
C
N
N
N
DMF
N
C
O
C
N
C
Triethylamine
Reflux 7h
C
C
C
O
O
O
O
O
O
O
O
F
F
F
F
F
F
SFPDI
SPFPDI
SBOPDI

1
ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
Synthesis and properties of perylene diimide dyes bearing unsymmetrical and symmetrical
phenoxy substituents at bay positions
Hang Zhaoa, Ying-ying Zhanga, Hai Xub, Ze-min Hea, Zhen-Lin Zhanga and Hai-quan Zhanga*
aState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, PR China
b College of Chemistry, Jilin University, Changchun, 130021, PR China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
Perylene diimide dyes bearing symmetrical and unsymmetrical phenoxy substituents at the bay
positions (N,N′-diethylhexyl-1-bromo-7-pentafluorophenoxy-substituted perylene diimide and
1,7-diphenoxy-substituted perylene diimide) were prepared. 1H NMR analysis indicated that
these compounds contain a small quantity of the 1,6-regioisomer, and yield intramolecular
hydrogen bonds. Furthermore, their photophysical, electrochemical, aggregation, and thermal
properties were studied. It was found that their photophysical properties, structure, aggregation,
and thermal stability in the solid state depend on the structure of the phenoxy substituent.
Available online
Keywords:
1,7-diphenoxy-substituted perylene diimide
unsymmetrical phenoxy perylene diimide
intramolecular hydrogen bond
photophysical properties
2009 Elsevier Ltd. All rights reserved
.
electrochemical properties
aggregated structure
1 Introduction
bay position is important in the design of unsymmetrical PDIs.10
The introduction of an electron withdrawing group on the phenol
moiety can decrease its nucleophilic ability, thus giving
unsymmetrical phenoxy-substituted PDIs.
We, herein, present the synthesis and the characterization of
four PDIs from a range of phenol derivatives (see Scheme 1).
Structural effects of the nucleophile on the resulting products will
be discussed, and their photophysical and electrochemical
Perylene diimide derivatives (PDIs) are promising and
versatile candidates for use in organic photo-electronic
applications due to their commercial availability, low cost, and
electronic, optical, and charge transport properties, which can be
tuned via careful functionalization.1 In particular, PDIs form an
appealing class of n-channel semiconductors for organic field
effect transistors, and as electron-acceptor components in organic
solar cells.2
properties will be investigated
.
To date, two strategies have been exploited for the design of
new functional PDIs: (1) substitution on the imide nitrogen
atoms,3 and (2) substitution at the 1, 6, 7, or 12 positions, known
as the bay positions.4 Substitution on the imide nitrogen atoms
maintains the planarity of the perylene core, which usually
exhibits indistinguishable absorption and emission properties due
to nodes in the HOMO and LUMO levels on the imide nitrogens
reducing coupling between the perylene diimide units.5
Substitution in the bay positions therefore leads to distortion of
the perylene core, thus altering the photo-physical properties of
the PDIs.6
1,7-Diphenoxy-substituted PDIs are among the most widely
utilized PDI scaffolds due to their facile synthesis via
dibromination and nucleophilic displacement.7 However,
synthesis of PDIs bearing a single phenoxy moiety is difficult,
due to the higher nucleophilic ability of the phenol and the
phenol derivatives.8 To date, only 1-bromo-7-alkoxyl perylene
diimides, prepared by the nucleophilic substitution of one 1,7-
dibromo unit with an alkyl alcohol (using K2CO3 as base), have
been discussed.9 However, the presence of a bromine atom at a
2 Results/Discussion
2.1 Preparation of PDIs
A series of phenoxy-substituted PDIs were synthesized from
perylene-3,4,9,10-tetracarboxylic dianhydride 1 in three steps
according to the route depicted in Scheme 1. Dibromo perylene-
3,4,9,10-tetracarboxylic dianhydride was first prepared by the I2-
catalyzed bromination of perylene-3,4,9,10-tetracarboxylic
dianhydride 1 in 96% sulfuric acid. This reaction yielded the
crude product 2, which was a mixture of 1,7- and 1,6-dibromo
perylene dianhydride, along with a trace of 1,6,7-tribromo
perylene dianhydride. The crude product was insoluble in
commercial organic solvents, and so was subjected to imidization
without characterization or further purification. Imidization of 2
with 2-ethylhexylamine in propionic acid at reflux yielded
BrPDI and 3. The resulting product mixture was subjected to
silica gel column chromatography using CH2Cl2 as eluent.
BrPDI was obtained and characterized by 1H NMR spectroscopy
and FTIR spectrophotometry. Two groups of signals with
* Corresponding author. Tel.:+0335-8057047; fax:+0335-8057047; e-mail
address:hqzhang@ysu.edu.cn (haiquan zhang).

2
Tetrahedron
different intensities were observed in the aromatic region of the
presence of additional fluorine atoms can result in a decrease in
ACCEPTED MANUSCRIPT
1H NMR spectrum indicating the presence of 1,7- and 1,6-
regioisomers in the product (Figure 1, BrPDI). Two well-
resolved doublets and a singlet were observed in the region
between 8.6 ppm and 9.4 ppm. Integration of the doublets at 9.50
and 9.43 ppm revealed that the 1,7- and 1,6-regioisomers were
present in a 97:3 ratio in the product. The mixture was
subsequently treated with p-fluorophenol (PF), p-tert-butylphenol
(BO), and pentafluorophenol (DF) in the presence of a K2CO3
catalyst to afford symmetrical PDIs. In addition, 1H NMR
spectroscopic data indicated that the 1,7- and 1,6-regioisomers
were also present in PFPDI, DFPDI, and BOPDI, respectively
(Figure 1).
interactions between the PDIs and silica gel, resulting in facile
purification by silica gel column chromatography.
The presence of C-HꢀꢀꢀO hydrogen bonds between the 1,7-
oxygen and the 6,12-hydrogen atoms in BOPDI, PFPDI, and
DFPDI molecules was supported by analysis of the proton
chemical shifts of bay protons 6 and 12 (Figure 1 and Table 1).
The shifts of the 6, 12-bay protons were observed between 9.44
and 9.61 ppm for BOPDI, PFPDI, and DFPDI, while those of
the parent Br-substituted PDI (BrPDI) were observed at
9.48 ppm. Figure 1 shows how the chemical shifts corresponding
to the aromatic protons of PDIs shift downfield with an increase
in the electronegativity of the oxygen atom of the phenoxy
groups (DFPDI→PFPDI→BOPDI), suggesting the presence of
C–HꢀꢀꢀO hydrogen bonds.11 Concomitant to the involvement of
the H6 and H12 protons in hydrogen bonding, the H2 and H8
protons located in direct proximity to the respective phenoxy
substituents shifted to higher fields. Further evidence was found
in the shifts of bay protons 6 and 12 adjacent to the
pentafluorophenol and Br moieties in SFPDI, respectively. The
chemical shifts corresponding to the H6 aromatic protons
(9.65 ppm) move downfield compared to that of H12 (9.26 ppm),
suggesting the formation of an intramolecular C6–H6ꢀꢀꢀO
hydrogen bond in SFPDI. The H8 protons (8.08 ppm), located in
close proximity to the phenoxy substituents, were also displaced
to higher fields. It was therefore clear that the substituent-induced
distortion of the perylene core may be restrained through the
presence of such hydrogen bonds, especially for the 1,7-
diphenoxy-substituted PDIs.
Br
Br
O
O
O
O
C
C
C
C
N
O
C
O
N
O
C
C
O
C
O
O
Br
BrPDI
Br
Br
Br
Br
O
O
O
O
H2SO4
85oC, 24h
Br2
O
C
C
O
C
C
C
2-ethylhexylamine
C2H5CO2H,
O
O
O
O
C
C
C
I2
N
C
C
N
O
O
Reflux , 48h
O
C
O
C
O
O
Br
1
Br Br
O
O
Br Br
O
C
C
O
O
O
C
C
C
N
C
O
N
O
C
C
Br
O
O
Br
2
3
F
F
F
F
O
12
8
2
F
F
O
O
O
C
C
12
8
7
2
O
O
N
O
N
12
8
O
2
O
C
N
C
C
C
O
N
C
C
O
K2CO3
DMF
6
7
5
N
C
C
O
N
O
C
O
C
O
O
Reflux 7h
5
6
O
7
F
5
6
O
F
F
F
F
F
PFPDI
BOPDI
DFPDI
Br
Br
O
Br
8
O
12
2
O
O
C
O
C
O
C
C
C
C
N
N
N
Triethylamine
Reflux 7h
DMF
N
N
C
O
C
N
C
C
C
C
O
O
O
O
O
O
7
O
6
5
O
F
F
F
1
F
F
Table 1. H NMR (400 MHz) chemical shifts for perylene core
F
SBOPDI
SPFPDI
SFPDI
protons (CDCl3, 298 K)
Scheme 1. Synthetic pathway to PDI derivatives.
dye
H6, H12/ppm
(doublet)
H5, H11/ppm
(doublet)
H2, H8/ppm
(singlet)
BOPDI 9.61 (d, J=8 Hz)
857 (d, J=8 Hz)
8.60 (d, J=8 Hz)
8.68 (d, J=8 Hz)
8.34
8.27
8.15
PFPDI
DFPDI
SFPDI
9.54 (d, J=8 Hz)
9.44 (d, J=8 Hz)
H6: 9. 65 (d,
H5: 8.71 (d,
J=4 Hz); H11: 8.69
(d, J=4 Hz)
H2: 8.99;
H8: 8.09
J=8 Hz); H12: 9.26
(d, J=8 Hz)
BrPDI
9.48 (d, J=8 Hz)
8.69 (d, J=8 Hz)
8.93
The presence of intramolecular C-HꢀꢀꢀO hydrogen bonds in
these molecules was further confirmed by computer simulations.
Optimized molecule structures of the PDIs are shown in Figure 2.
A weak hydrogen bond was observed between the phenoxy
oxygen (O1, O2) atom and two hydrogen atoms (H1, H2) of the
perylene core. The H1ꢀꢀꢀO1 distances between the 1,7-oxygen and
1,2-hydrogen atoms are 2.05 Å, 2.05 Å, 2.05 Å, and 2.11 Å for
PFPDI, BOPDI, DFPDI, and SFPDI, respectively, and the C5-
H1ꢀꢀꢀO1 angles are 119.8°, 119.8°, 116.4°, and 115.7° for PFPDI,
BOPDI, DFPDI, and SFPDI, respectively. These distances and
angles are consistent with weak hydrogen bonding according to a
previously reported study.12 Furthermore, the C1-C2-C3-C4
dihedral angles 13.56°, 13.65°, 15.79°, and 16.57° for PFPDI,
BOPDI, DFPDI, and SFPDI, respectively are almost equal,
indicating that their photophysical properties primary depend on
the substituent structures.
1
Figure 1. H NMR (400 MHz, CDCl3) spectra of PFPDI (R =
86:14); BOPDI (R = 80:20); DFPDI (R = 90:10); SFPDI (R =
88:12); and BrPDI (R = 97:3). R = ratio of 1,7- to 1,6-
regioisomers.
Nucleophilic substitution of a single 1,7-dibromo unit was
attempted to prepare the monophenoxy PDIs (SFPDI, SPFPDI,
and SBOPDI) using either a K2CO3 or triethylamine catalyst, but
only 1-bromo-7-pentafluorophenol perylene diimide (SFPDI)
was obtained. This is likely due to the p-tert-butylphenol being
easily converted into a p-tert-butylphenol ion when treated with
either K2CO3 or triethylamine, as the resulting oxide anion (O−) is
a much stronger nucleophile than neutral oxygen itself (O). As a
result, reaction of p-tert-butylphenol with 1,7-dibromo-PDI
produced diphenoxy PDIs. The introduction of a fluorine atom to
the phenol moiety can destabilize the oxide anion (O−), which
aids in forming only the monophenoxy PDI. In addition, the

3
shifts of 35 nm and 34 nm. These data indicate that the Stokes
ACCEPTED MANUSCRIPT
shift decreased with the introduction of additional fluorine atoms
into the phenoxy groups. The powder/solid state emission spectra
of DFPDI, SFPDI, PFPDI, and BOPDI were largely red-shifted
and broadened compared to the solution spectra. Corresponding
maxima appeared at 661 nm, 638 nm, 661 nm, and 669 nm,
respectively. In contrast with its solution behavior, SFPDI
powder exhibited a redshift of 81 nm, which is lowest redshift of
all PDIs. This suggests that weak molecular interactions exist in
solid SFPDI, as confirmed by X-ray diffraction (XRD) analysis
(see Section 2.4).
Figure 2. Optimized molecular structures of the PDIs.
PFPDI
a
BOPDI
DFPDI
PFPDI
SFPDI
BOPDI
SFPDI
DFPDI
b
2.2 Steady-State Absorption and Fluorescence Studies
UV-Vis absorption spectra of the PDIs in CH2Cl2 allow
important information regarding the molecular structures of the
PDIs to be derived (Figure 3). DFPDI contains two
pentafluorophenol groups, BOPDI two p-tert-butylphenol
groups, and PFPDI two p-fluorophenoxyl groups at the 1,7-
positions, while the 1,7-positions in SFPDI are occupied by one
pentafluorophenol group and a Br atom, respectively. Such
structural differences result in different optical properties,
reflected in the S0/S1 and S0/S2 absorption bands.
600
650
700
750
800
850
500
550
600
650
700
Wavelength(nm)
Wavelength (nm)
Figure 4. Fluorescence spectra of PDIs (a) in CH2Cl2,
concentration = 10-5 M; and (b) as a solid powder. Excitation
wavelength: 530 nm.
For example, the S0→S1 absorption band is red shifted from
SFPDI to DFPDI, PFPDI, and BOPDI with λmax moving from
528 nm to 529 nm, 539 nm, and 543 nm, respectively. Such a
change in absorption spectra can be caused either by increased
conjugation between the substituents and the PDI core,13 or by
substituent-induced distortion of perylene core.14 The latter can
be ignored in the case of BOPDI, PFPDI, and DFPDI due to the
presence of two CHꢀꢀꢀO hydrogen bonds and almost unanimously
dihedral angles. Hence, the spectral changes between BOPDI,
DFPDI, and PFPDI are dependent only on the electronic
coupling between the electron-rich phenoxy substituents, and the
electron-deficient perylene core.15 In addition, the low energy
absorption onset provides the value for optical gap (OG).16 The
2.3 Electrochemical properties
The electrochemical properties of DFPDI in CH2Cl2 at room
temperature were investigated by cyclic voltammetry (CV). The
CV curve was recorded vs. the Ag/AgCl electrode as reference
electrode(Ag/AgCl), using ferrocene as an internal standard
(Figure. 5). As expected, DFPDI exhibited two typical reversible
reduction waves due to the first and second one-electron stepwise
reductive process from the perylene core to the corresponding
radical anions and dianions (for the DFPDI molecule these are
DFPDI− and DFPDI2−).17
The onset reduction potential (Eonset) for DFPDI is −0.32 eV.
According to the empirical formulae ELUMO = −([Eonset]red
+
optical gap and the wavelength maxima (λabs0-0) and onsets (λabs
)
4.8 eV)18 and EHOMO = Eg + ELUMO, the HOMO and LUMO
energy levels of DFPDI were calculated as −6.73 eV and
−4.48 eV. The calculated values for the HOMO and LUMO of
PFPDI, SFPDI, and BOPDI are summarized in ST2. The first
reduction potentials appeared to vary with the introduction of
substituted groups. So the HOMO and LUMO energy levels also
changed, with the LUMO levels being calculated as −4.32 eV,
−4.48 eV, −4.54 eV, and −4.35eV for PFPDI, DFPDI, BOPDI,
and SFPDI, respectively. The HOMO and LUMO energy levels
for P3HT were previously reported in the literature to be 5.1 eV
and 3.2 eV,19 and so it is clear that the HOMO and LUMO
energy levels of our PDIs are suitable to efficiently drive exciton
dissociation at the P3HT/PDIs heterojunction interfaces. Thus,
PFPDI, DFPDI, BOPDI, and SFPDI may be candidates for use
as an electron-acceptor component in P3HT/PDIs systems.
opt
of the 0-0 transitions are summarized in ST1.
In contrast with the solution spectra, the casting film spectra
for DFPDI, SFPDI, PFPDI, and BOPDI exhibited a slight red-
shift and were significantly broader. The 0-0 transitions of the
DFPDI, SFPDI, PFPDI, and BOPDI occur at shifts of 11, 13,
17 and 16 nm, respectively.
BOPDI
SFPDI
PFPDI
DFPDI
DFPDI
SFPDI
PFPDI
BOPDI
a
b
450
500
550
400
450
500
550
600
650
Wavelength (nm)
Wavelength (nm)
Figure 3. UV-Vis absorption spectra of the PDIs (a) in CH2Cl2,
concentration = 10-5 M; and (b) in casting films.
PFPDI
The fluorescence spectra of the PDIs recorded in both solution
(CH2Cl2) and solid/powder form are shown in Figure 4. As
expected from the absorption results, DFPDI and SFPDI
exhibited comparable emission characteristics once again. The
emission bands of both DFPDI and SFPDI were approximate
mirror images of their S0-S1 absorption bands, with a Stokes shift
of approximately 29 nm. Both compounds show maximum
emission peak at ~556 nm, with a shoulder peak at 590 nm. The
maximum emissions of PFPDI and BOPDI were observed at
574 nm and 577 nm, respectively, with corresponding Stokes
SFPDI
DFPDI
BFPDI
-1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2 1.5 1.8
Potential/V (vs. Ag/AgCl)
Figure 5. Cyclic voltammograms of DFPDI and BOPDI
recorded in CH2Cl2 containing 0.1 M n-Bu4NPF6 at 0.1 Vs-1.
* Corresponding author. Tel.:+0335-8057047; fax:+0335-8057047; e-mail
address:hqzhang@ysu.edu.cn (haiquan zhang).

4
Tetrahedron
ACCEPTED MANUSCRIPT
diphenoxy-substituted PDIs depend on the identity of the
To gain insight into the geometrical and electronic structures
phenoxy substituents, where the 5% weight loss temperatures for
PFPDI, BOPDI, DFPDI, and SFPDI were 436 °C, 422 °C, 405 °C,
and 373 °C, respectively. In contrast to the other PDIs, SFPDI
exhibited a lower thermal stability due to its structural asymmetry.
of the perylene diimide derivatives, we performed density
functional theory (DFT) calculations on DFPDI using the
Gaussian03 package.20 The orbital spatial distributions of the
HOMO and LUMO for DFPDI are shown in Figure 6, where it is
clear that the HOMO and LUMO of DFPDI both localize at the
central pyrelene core. The theoretical estimation of the HOMO-
LUMO gaps for DFPDI in vacuo (2.62 eV, B3LYP/6-31G*) are
in good agreement with the measured optical bandgaps.
Theoretical estimations of other samples are shown in the
Supplementary Material (Fig. SF1).––
–
Figure 7. X-ray diffraction patterns of the PDI powders: (a)
BOPDI, (b) DFPDI, (c) PFPDI, and (d) SFPDI,
100
BOPDI
DFPDI
PFPDI
SFPDI
90
80
70
60
50
40
30
Figure 6. Molecular orbital distributions and energy levels for
DFPDI estimated by density functional theory (DFT)
calculations.
100
200
300
400
500
600
Temperature(oC)
2.4 Powder X-ray diffraction studies
The structures of the PDI powders were investigated by X-ray
diffraction (XRD) analysis. As shown in Figure 7, in the low
angle range, the XRD pattern of BOPDI shows two clear
diffraction peaks at 2θ = 4.32° (2.04 nm) and 5.56° (1.58 nm),
which correspond to the diffractions from the (100) and (010)
planes, respectively.21 The peak at 24.80° corresponding to a
distance of 3.50 Å can be attributed to the π-π stacking distance
of the adjacent perylene diimide.22 In contrast with BOPDI, the
XRD data of DFPDI displays a greater number of sharp
diffraction peaks between 3-30°, with the diffraction peaks from
the (100) planes appearing at 2θ = 5.00° (1.76 nm). In addition,
diffraction peaks can be seen at 24.39° (0.331 nm), which can be
attributed to the π-π stacking distance of PDI rings between the
adjacent molecules. The d value of the (001) planes and the
distance between the adjacent PFPDI molecules are comparable
with those of DFPDI. This indicates that the solid state structure
of 1,7-diphenoxy-substituted PDIs is dependent on the
substituent group at the para-position of the phenoxy group. This
is supported by comparing DFPDI and PFPDI, because where
the same atom is present on the para position of the phenoxy
group, a similar structure is observed. In the case of BOPDI, the
presence of a large para substituent results in the distances of the
(100) plane and π-π stacking increasing. The XRD diagram of
SFDPI shows two wide diffraction peaks at 2θ = 4.61° (1.93 nm)
and 23.80° (3.70 Å). The former may be related to the (100)
planes, while the latter may be related to the π-π stacking
distance of the adjacent perylene diimide. The wider diffraction
peaks in SFPDI powder indicate that the molecular order degree
in the solid decreased compared with other symmetrical PDIs,
such as BOPDI, DFPDI, and PFPDI.
Figure 8. TG curves of PFPDI, BOPDI, DFPDI, and SFPDI
3 Conclusion
We successfully synthesized a series of 1,7-diphenoxy-PDIs
(perylene diimide derivatives) equipped with different
substituents on one or more positions of their phenoxy moiety,
and investigate the impact of structure on their photophysical,
electrochemical,
aggregation,
and
thermal
properties.
Intramolecular hydrogen bonds were found to restrain rotation of
the PDI core. The photophysical and electrochemical properties
of these species therefore depended on the quantity, position, and
characteristics of the phenoxy substituents. In addition, the 1-
bromo-7-pentafluorophenoxy PDIs were obtained successfully
via optimized reaction conditions. It is expected that our study
will be useful for the development of new PDIs for use in organic
photo-electronic applications.
3 Experimental Section
3.1 Materials and instrument
1HNMR and 13C NMR were recorded on Bruker 400 MHz
spectrometer with CDCl3 as the solvent and tetramethylsilane
(TMS) as an internal reference. Infrared measurement with the
KBr pellet technique was performed within the 400 to 4000 cm−1
on a Perkin-Elmer spectrum 100 spectrophotometer. MS analysis
was performed using an LTQ-Orbitrap XL mass spectrometer
(Thermo Fisher Scientific, San Jose, CA, USA) equipped with an
APCI ion source in the positive ion mode (scan range 150-2000
m/z). Electronic absorption spectra is performed with a Perkine
Elmer Lambda 35 spectrophotometer in dichloromethane
Finally, thermogravimetric (TGA) analysis was carried out on all
four PDIs under a nitrogen atmosphere, and the thermograms are
shown in Figure 8. It is clear that the thermal stability of the 1,7-

5
solution and cast films. Fluorescence spectra were measured on
PE LS-55 system in dichloromethane solutions and solid powder.
The X-ray powder diffraction data was carried out on powered
samples via Rigaku D/max-2500/PC diffraction using
monochromator Cu Kα (λ=1.54 Å) over the 2θ range of 2 to
50o.TGA was done with TA thermal analysisystem at heating
rate 10oC/min under a N2 environment.
Cyclic voltammetry measurements were performed in
solution, under argon atmosphere with a computer controlled
CHI600E electrochemical workstation in a three electrode single-
compartment cell using platinum electrodes and Ag/AgCl
electrode as reference electrode, with Fc/Fc* redox couple as
internal standard23, with a tetrabutyl-ammonium hexafluoro-
phosphate (Bu4NPF6) solution (0.1 M) in dichloromethane at a
scan rate of 0.1V/s.
N-CH2-CH-), 1.92-1.97 (m, 2H, -N-CH2-CH-), 1.28-1.40 (m,
ACCEPTED MANUSCRIPT
16H, alkyl--CH2-), 0.93-0.96 (t, 6H, alkyl-CH3), 0.88-0.91 (t, 6H,
alkyl-CH3). 13C NMR (100.6 MHz, CDCl3), δ 163.5, 155.4, 133.2,
129.1, 128.8, 125.0, 123.8, 123.6, 123.3, 122.3, 121.2, 117.4,
44.3, 37.9, 30.7, 28.7, 24.1, 23.1, 14.1, 10.7. FI-IR (KBr), ʋ:
2958 cm-1, 2929 cm-1, 2858 cm-1, 1669 cm-1, 1656 cm-1, 1595 cm-
1, 1504 cm-1, 1406 cm-1, 1330 cm-1, 1263 cm-1, 1215 cm-1, 1175
cm-1, 1014 cm-1, 852 cm-1, 810 cm-1, 557 cm-1. HRMS (EI) calcd
for C60H66N2O6 : M+, 911. 50 Fount: m/z 911.5009.
3.2.4 N,N’-diethylhexyl-1,7-di(pentafluorophenoxyl) pery-
lenete diimide (DFPDI)
DFPDI was prepared from N,N’-diethylhexyl-1,7-dibromo
perylene diimide and pentafluorophenol as described for the
synthesis of PFPDI. DFPDI shows the red solid with yield of
86%. 1H NMR (400 MHz, CDCl3) δ 9.44 (d, 2H, J=8 Hz, Per-H),
8.69 (d, 2H, J=8 Hz, Per-H), 8.15 (s, 2H, Per-H), 4.10-4.17 (m,
4H, N-CH2-CH- ), 1.93-1.98 (m, 2H, -CH-), 1.31-1.43 (m, 16H,
alkyl-CH2-CH3), 0.95-0.98 (t, 6H, alkyl-CH3), 0.89-0.92 (t, 6H,
alkyl-CH3). 13C NMR (100.6 MHz, CDCl3) δ 163.3, 162.7, 154.4,
138.3, 133.3, 131.8, 131.2, 129.3, 127.3, 125.1, 124.3, 123.1,
122.7, 121.8, 120.6, 118.5, 44.5, 38.0, 30.7, 28.7, 24.0, 23.0, 14.1,
10.6. FI-IR (KBr), ʋ: 2958 cm-1, 2929 cm-1, 2864 cm-1, 1703 cm-1,
1665 cm-1, 1598 cm-1, 1517 cm-1, 1406 cm-1, 1332 cm-1, 1259 cm-
1, 1207 cm-1, 1178 cm-1, 1055 cm-1, 993 cm-1, 810 cm-1. HRMS
(EI) calcd for C52H40F10N2O6 : M+, 979. 28 Fount: m/z 979.2802.
3.2 Synthesis of materials
3.2.1 N,N’-diethylhexyl-1,7-dibromo perylene diimide
(BrPDI)
Synthesis of N,N’-diethylhexyl-1,7-dibromo perylene diimide
1
is reported earlier 24. Yield: 80% ; H NMR (400 MHz, CDCl3, )
δ 9.48 (d, 2H, J=8 Hz, Per-H), 8.93 (s, 2H, Per-H ), 8.69 (d, 2H,
J=8 Hz, Per-H), 4.10-4.20 (m, 4H, N-CH2), 1.92-1.99 (m, 2H, -
CH-), 1.32-1.41 (m, 16H, alkyl-CH2), 0.93-0.97 (t, 6H, alkyl-
CH3), 0.88-0.91 (t, 6H, alkyl-CH3), FI-IR (KBr), ʋ: 2960 cm-1,
2927 cm-1, 2858 cm-1, 1703 cm-1, 1658 cm-1, 1591 cm-1, 1434 cm-
1, 1392 cm-1, 1328 cm-1, 1236 cm-1, 808 cm-1, 744 cm-1, 684 cm-1.
2.2.5 N,N’-diethylhexyl-1-bromo-7-Pentafluorophenoxyl pery
lene diimide (SFPDI)
3.2.2 N,N’-diethylhexyl-1,7-di(p-fluorphenoxyl) perylene
diimide (PFPDI)
SFPDI was synthesised using reaction between N,N’-diethyl
-hexyl-1,7-dibromo perylene diimide and pentafluorophenol by
using triethylamine instead of K2CO3 as the base. SFPDI exhibits
A mixture of p-fluorophenol (89.6 mg, 0.8 mmol), K2CO3
(137 mg, 1.00 mmol) in dry dimethylformamide (50 mL), was
stirred for 20 min under argon and subsequently N,N’-diethyl-
hexyl-1,7-dibromo perylene diimide (144.4 mg, 0.20 mmol) was
1
brow solid with yield of 65%. H NMR (400 MHz, CDCl3) δ
9.65 (d, 1H, J=8 Hz, Per-H), 9.26 (d, 1H, J=8 Hz, Per-H) 8.99 (s,
1H, Per-H), 8.71(d, 1H, J=4 Hz, Per-H), 8.71(d, 1H, J=4 Hz, Per-
H), 8.09 (s, 1H, Per-H), 4.07-4.18 (m, 4H, N-CH2), 1.88-1.98 (m,
2H, -CH-), 1.30-1.41 (m, 16H, alkyl-CH2), 0.93-0.97 (t, 6H, -
CH2-CH3), 0.87-0.90 (t, 6H, -CH2-CH3). 13C NMR (100.6 MHz,
CDCl3) δ 163.3, 154.3, 132.6, 130.6, 129.3, 125.4, 124.2, 122.6,
118.8, 44.5, 38.1, 30.7, 28.7, 24.1, 23.1, 14.1, 10.6. FI-IR (KBr),
ʋ: 2956 cm-1, 2929 cm-1, 2860 cm-1, 1701 cm-1, 1658 cm-1, 1593
cm-1, 1517 cm-1, 1450 cm-1, 1334 cm-1, 1257 cm-1, 1184 cm-1,
1041 cm-1, 995 cm-1, 810 cm-1, 748 cm-1, 696 cm-1, 611 cm-1.
HRMS (EI) calcd for C46H40BrF5N2O6 : M+, 876.20 Fount: m/z
876.2002.
o
added. The reaction mixture was stirred for 7 h at 80 C under
argon atmosphere. After being cooled to room temperature, the
solvent was removed by rotary evaporation. The solid residue
was thoroughly washed with several portions of water and dried.
The crude product was dissolved in dichloromethane and purified
by column chromatography on silica 200-300 using dichloro-
methane as eluent to afford the regioisomeric mixture of product
(PFPDI) (113 mg, 72%). 1H NMR (400 MHz, CDCl3) δ 9.54 (d,
2H, J=8 Hz, Per-H), 8.60 (d, 2H, J=8 Hz, Per-H), 8.27 (s, 2H, Per-
H), 7.15 (d, 8H, J=8 Hz, Ar-H), 4.02-4.13 (m, 4H, N-CH2-CH-),
1.86-1.95 (m, 2H, -N-CH2-CH-), 1.25-1.38 (m, 16H, alkyl-CH2-
CH3), 0.89-0.93 (t, 6H, alkyl-CH3), 0.85-0.88 (t, 6H, alkyl-CH3).
13C NMR (100.6 MHz, CDCl3) δ 163.4, 155.5, 152.6, 148.1,
133.3, 130.1, 129.2, 128.7, 127.4, 124.2, 123.2, 119.1, 54.0, 34.5,
31.4, 29.1, 26.5, 25.4. FI-IR (KBr), 2958 cm-1, 2929 cm-1, 2858
cm-1, 1699 cm-1, 1664 cm-1, 1596 cm-1, 1502 cm-1, 1458 cm-1,
1434cm-1,1407 cm-1, 1330 cm-1, 1261 cm-1, 1186 cm-1, 856 cm-1,
810 cm-1,775 cm-1. HRMS (EI) calcd for C52H48F2N2O6 : M+,
835.35 Fount: m/z 835.3561.
Acknowledgments
This work has been supported by the National Natural
Science Foundation of China (No: 51173155, 51472214), the
Natural Science Foundation of Hebei Province (No:
E2014203200) and Colleges and Universities Science and
Technology Research Project of Hebei Province No:
QN20131070ꢀ
3.2.3 N,N’-diethylhexyl-1,7-di(p-tertbutylphenoxyl) perylene
diimide (BOPDI)
References
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BOPDI was prepared from N,N’-diethylhexyl-1,7-dibromo
perylene diimide and 4-tertbutylphenol as described for the
synthesis of PFPDI. BOPDI shows the brown solid with yield of
80%. 1H NMR (400 MHz, CDCl3) δ 9.61 (d, 2H, J=8 Hz, Per-H),
8.57 (d, 2H, J=8 Hz, Per-H), 8.34 (s, 2H, Per-H), 7.46 (d, J=12
Hz, 4H, Ar-H), 7.10 (d, 4H, J=12 Hz, Ar-H), 4.08-4.16 (m, 4H,
* Corresponding author. Tel.:+0335-8057047; fax:+0335-8057047; e-mail
address:hqzhang@ysu.edu.cn (haiquan zhang).

6
Tetrahedron
ACCEPTED MANUSCRIPT
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2855.

ACCEPTED MANUSCRIPT
Supplementary Material
Synthesis and properties of perylene diimide dyes bearing unsymmetrical and symmetrical phenoxy substituents at bay
positions
Hang Zhaoa, Ying-ying Zhanga, Hai Xub, Ze-min Hea, Zhen-Lin Zhanga and Hai-quan Zhanga*
aState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, PR China
b College of Chemistry, Jilin University, Changchun, 130021, PR China

ACCEPTED MANUSCRIPT
SF1 Molecular orbital distributions and energy levels for PDIs estimated by density functional theory (DFT) calculations.
Molecular structure
HOMO（eV）
LUMO（eV）
HOMOꢀLUMO
2.3308 eV
DFPDI
531.94 nm
f=0.7436
-6.73
-4.48
HOMOꢀLUMO
2.3280 eV
532.57 nm
f=0.7315
PFPDI
-6.78
-4.32

ACCEPTED MANUSCRIPT
HOMOꢀLUMO
2.3070 eV
537.42 nm
f=0.7276
BOPDI
HOMO-1ꢀLU
MO
2.8615 eV
433.28 nm
f=0.1807
-6.99
-4.54
HOMOꢀLUMO
2.3403 eV
SFPDI
529.79 nm
f=0.6705
-6.84
-6.15
-4.35
-3.60
Br
O
O
C
C
HOMOꢀLUMO
2.3618 eV
N
N
C
C
O
O
BrPDI
Br
524.95 nm
f=0.6140

ACCEPTED MANUSCRIPT
ST 1 UV-Vis absorption and fluorescence properties of PDIs in dichloromethane at 298 K
opt
PDI
Ɛ
Stoks shift
Eg
λabs
(nm)
543
539
529
528
λPL
λgap
0-0
(M-1cm-1) (nm)
(nm)
34
(ev)
(nm)
BOPDI
PFPDI
DFPDI
SFPDI
65 600
92 000
101 300
78 100
577
574
557
557
572 2.14
567 2.16
552 2.25
552 2.25
35
28
29

ACCEPTED MANUSCRIPT
1/2
ST 2 Fist half-wave reduction and oxidation potentials Ered
as well as ELUMO and EHOMO values derived for the PDIs from CV
measurements in CH2Cl2 solution
.
1/2
1/2
dye
Ered
Eox
ELUMO (ev)
EHOMO (ev)
DFPDI -0.69
0.93
-4.48
-6.73
PFPDI -0.76
SFPDI -0.61
1.58
1.88
-4.32
-4.35
-4.54
-6.78
-6.84
-6.99
BOPDI -0.66 a 1.48
1/2
a Calculated from Eox1/2, and the optical gap Egopt : Ered1/2 =-( Egopt - Eox
)