A study on the fluorescence property of the perylene derivatives with methoxy groups

Article abstract of DOI:10.1016/j.dyepig.2017.08.060

Perylene-based dyes with methoxy groups at various positions were synthesized to understand the effect of the methoxy groups on the fluorescence quenching. Additionally, perylene-based dyes with ethyl groups in place of the methoxy groups were also synthesized to serve as control. Absorption and fluorescence properties of the dyes were measured, and then, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) simulations were conducted. The methoxy groups of terminal-substituents had a lesser effect on fluorescence quenching than the methoxy groups of bay-substituents. Moreover, only the methoxy groups at the para-position of the bay-substituents strongly affected on fluorescence quenching. These results showed that the fluorescence of the dyes are influenced by the electron donating effect of the methoxy groups when the methoxy groups are involved in the main conjugation systems of the dyes.

Full text of DOI:10.1016/j.dyepig.2017.08.060

Accepted Manuscript
A study on the fluorescence property of the perylene derivatives with methoxy groups
Jeong Yun Kim, Sung Wun Woo, Jin Woong Namgoong, Jae Pil Kim
PII:
S0143-7208(17)31519-X
10.1016/j.dyepig.2017.08.060
DYPI 6222
DOI:
Reference:
To appear in: Dyes and Pigments
Received Date: 11 July 2017
Revised Date: 25 August 2017
Accepted Date: 25 August 2017
Please cite this article as: Kim JY, Woo SW, Namgoong JW, Kim JP, A study on the fluorescence
property of the perylene derivatives with methoxy groups, Dyes and Pigments (2017), doi: 10.1016/
j.dyepig.2017.08.060.
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Graphical abstract

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A study on the fluorescence property of the perylene derivatives
with methoxy groups
Jeong Yun Kim a, Sung Wun Woo a, Jin Woong Namgoong a, Jae Pil Kim a,*
a. Lab. of Organic Photo-functional Materials, Department of Materials Science and Engineering, Seoul
National University, Seoul 08826, Republic of Korea
* Corresponding author. Tel.: +82 2 880 7187; fax: +82 2 880 7238
E-mail address: jaepil@snu.ac.kr (J. P. Kim)

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Abstract
Perylene-based dyes with methoxy groups at various positions were synthesized to understand the effect of the
methoxy groups on the fluorescence quenching. Additionally, perylene-based dyes with ethyl groups in place of
the methoxy groups were also synthesized to serve as control. Absorption and fluorescence properties of the
dyes were measured, and then, density functional theory (DFT) and time-dependent density functional theory
(TD-DFT) simulations were conducted. The methoxy groups of terminal-substituents had a lesser effect on
fluorescence quenching than the methoxy groups of bay-substituents. Moreover, only the methoxy groups at the
para-position of the bay-substituents strongly affected on fluorescence quenching. These results showed that the
fluorescence of the dyes are influenced by the electron donating effect of the methoxy groups when the methoxy
groups are involved in the main conjugation systems of the dyes.
Keywords
Perylene, Fluorescence, Fluorescence quenching, Methoxy, Electron donating effect, TD-DFT

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1. Introduction
Perylene-based dyes generally show superior thermal stability and optical properties owing to the planarity
of their molecular structures [1-5]. Because of these advantages, perylene-based dyes are widely used as optical
coloring materials for displays among many other useful applications [5-11]. Moreover, perylene dyes are easily
functionalized through the introduction of substituents at their terminal- and bay-positions, which enables the
modification of characteristics such as their spectral properties and solubilities [12-14]. Perylene diimide
derivatives having two bulky substituents at their terminal-positions are commonly used, and these molecules
are often modified for various purposes by the introduction of 1–4 substituents at their bay-positions.
Previously, we have reported many novel perylene-based dyes for use as the red colorants in LCD color
filters [7,8,12-22]. Since the fluorescence of these dyes can negatively affect the optical performance of the
color filters fabricated with them [21], we have also suggested solutions for this problem, in which the decrease
of contrast ratios of color filters was inhibited by using perylene-based dyes with high solubility and low
fluorescence [22]. Based on our previous reports, the effect of methoxy groups on the fluorescence properties of
perylene-based dyes and the relationships between the fluorescence of the dyes and the position of the
introduced methoxy groups are studied in this paper, both experimentally and theoretically.
In this study, perylene-based dyes which contained methoxy groups in the terminal-, bay-, or both positions
were synthesized. The methoxy groups were sequentially placed at the ortho-, meta-, or para-position of each
substituent. Additionally, the dyes with ethyl substituents instead of methoxy groups were designed and
synthesized, these dyes have similar geometrical molecular structures and conjugation systems with the dyes
containing methoxy groups [22]. The absorption and fluorescence properties of the synthesized dyes were
measured and compared. The geometrical structures of the dyes were analyzed by density functional theory
(DFT) calculations, and excitations from the highest occupied molecular orbitals (HOMOs) to the lowest

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occupied molecular orbitals (LUMOs) of the dyes were simulated with time-dependent density functional theory
(TD-DFT) [23,24]. Using these methods, the influence of the position of the methoxy groups on the
electrochemical and the fluorescence properties of the dyes were studied.
2. Experimental
2.1. Materials and instrumentation
Perylene-3,4,9,10-tetracarboxylic dianhydride, iodine, sulfuric acid, bromine, and acetic acid were
purchased from Sigma-Aldrich, 2,6-diisopropylaniline, 2-methoxy-6-methylaniline, 4-methoxy-2-methylaniline,
4-methoxyphenol, 4-ethylphenol, 3-methoxyphenol, 3-ethylphenol, 2-methoxyphenol, and 2-ethylphenol were
purchased from TCI. Potassium carbonate anhydrous, methylene chloride, and other chemical solvents were
purchased from Samchun Pure Chemical. All chemicals were used without any additional purification.
Absorption spectra were measured using a Perkin Elmer Lambda 25 UV/Vis spectrophotometer.
Fluorescence spectra and quantum yield data were measured on a Perkin Elmer LS 55 and a PTI Quanta Master
40 fluorescence spectrometer, respectively. Elemental Analysis (EA) was completed on a CE Instruments
1
EA1112 analyzer. H and 13C Nuclear Magnetic Resonance (NMR) spectra were recorded on a Bruker Avance
500 spectrometer running at 500 MHz using chloroform-d as a solvent with TMS as an internal standard. Matrix
Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectra were recorded on an Applied
Biosystems Voyager-DE STR Biospectrometry Workstation using α-cyano-4-hydroxycinnamic acid (CHCA) as
a matrix.

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2.2. Syntheses of the dyes
All synthetic procedures were carried out by following our previous reports [20-22]. The dyes PI-4EP,
PI-4ME, P2M-4EP, and P2M-4ME were already reported in our previous report [22]. The specified
name of the dyes P2M-4EP and P2M-4ME were PM-4EP and PM-4ME in the report, respectively.
The syntheses of these dyes are repeated in this paper.
2.2.1. 1,7-Dibromoperylene-3,4,9,10-tetracarboxydiimide : Bromination
Perylene-3,4,9,10-tetracarboxylic dianhydride (32.00 g, 81.40 mmol), iodine (0.78 g, 3.04 mmol) and
sulfuric acid (98 %, 450 mL) were mixed and stirred for 2 h at room temperature. The temperature of the
mixture was raised to 80 and bromine (8.33 mL, 162.80 mmol) was added dropwise over 1 h. The resulting
mixture allowed to react for 16 h as sealed, upon which time, it was cooled to room temperature and the
remaining bromine gas was displaced by nitrogen gas. The mixture was slowly poured into 3 L of ice water and
the crude precipitate formed was collected by suction filtration followed by washing several times with distilled
water. The crude product was dried at 80
under reduced pressure and used in the next step without further
purification. The crude product containing both mono- and di-bromoperylene derivatives was separated by
column chromatography in next step, after introducing bulky substituents in the terminal-position to increase
their solubilities.
2.2.2. N,N’-bis(R1)-1,7-dibromoperylene-3,4,9,10-tetracarboxydiimide : Terminal-position substitution
Crude 1,7-dibromoperylene-3,4,9,10-tetracarboxydiimide (8.00 g, 14.55 mmol), R1-NH2 (45.00 mmol),
acetic acid (4.60 mL) and N-methyl-2-pyrrolidone (NMP, 100 mL) were mixed and heated to 120
under

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nitrogen atmosphere for 96 h. Water was added to the mixture and the resulting precipitate was collected by
suction filtration. The crude product was washed with water and dried under reduced pressure. The crude
product was purified by column chromatography in silica gel using CH2Cl2 as an eluent. Three bands were
collected. The first band contained a small amount of tribrominated diimide, the second band contained the
dibrominated diimide, and the third contained the monobrominated diimide. Detailed structural analysis was
conducted after the next step. To obtain the PI-series, 2,6-diisopropylaniline was used as R1-NH2, to obtain PM-
series, 2-methoxy-6-methylaniline was used and to obtain P2M-series, and 4-methoxy-2-methylaniline was
used for P4M-series.
2.2.3. N,N’-Bis(R1)-1,7-bis(R2)-perylene-3,4,9,10-tetracarboxydiimide : Bay-position substitution
N,N’-bis(R1)-1,7-dibromoperylene-3,4,9,10-tetracarboxydiimide (0.58 mmol) was mixed with anhydrous
potassium carbonate (0.35 g, 2.54 mmol), R2-OH (1.60 mmol) and NMP (60 mL). The mixture was heated at 40
under nitrogen and was stirred for 1.5 h. Thin layer chromatography (TLC) of the crude was repetitively
performed during the reaction to check the progress. After the reaction, the mixture was cooled to room
temperature, and then poured into HCl aqueous solution (400 mL, 5 %). The precipitate was collected by
suction filtration, washed with water and dried under vacuum at 80 . The crude product was purified by
column chromatography in silica gel using CH2Cl2 as an eluent to obtain the products as red solids.
Yield : PI-3EP (74.4 %), PI-3ME (73.5 %), PI-2EP (67.6 %), PI-2ME (67.0 %), P4M-4EP (65.9 %),
P4M-4ME (62.1 %)
2.3. Geometry optimization of the dyes
Density functional theory (DFT) and Time-dependent density functional theory (TD-DFT) calculations
were carried out with the Gaussian 09 program package. We used the 6-311++G(d,p) Pople basis set for all
elements and the conventional B3LYP exchange-correlation function. The intermolecular interactions were
analyzed by examining the core twist angles and the size of substituents. Dihedral angles of perylene main body

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were calculated by measuring the distortion angle of benzene ring in the center of perylene main body.
Calculated lengths of substituents were indicated by measuring the longest lineal distance of the atoms in the
substituents. The spaces of the substituents away from the plane of perylene back bone were assessed by
measuring the inserted angle between the substituents and the plane.
3. Results and discussion
3.1. Design concept of the synthesized dyes
The synthetic route and molecular structures of the synthesized dyes are shown in Scheme 1 and Fig. 1,
respectively. Seven dyes containing methoxy groups and three without methoxy groups were synthesized. The
methoxy group, a readily available organic substituent and powerful electron donor, usually inhibits
fluorescence when introduced into organic coloring materials [22,25-28]. To observe the effects of methoxy
groups incorporated into bay-substituents, dyes containing methoxy groups in the ortho-, meta-, or para-
position of bay-position benzene rings were designed. For comparison, analogs with ethyl groups introduced in
place of the methoxy groups were also designed. To observe the effects of methoxy groups on the terminal-
substituents, ortho- or para-methoxylated aryl substituents were introduced at the terminal-substituents of the
dyes. Finally, the dyes with the methoxylated terminal-substituents carried only para-methoxy- or para-ethyl-
aryl groups as their bay-substituents.
All the dyes were designed to have similar conjugation lengths and steric bulkiness, to minimize
differences in the spectral properties and intermolecular interactions. As is widely known, the most impactful
principal factor influencing the fluorescence of organic coloring materials is quenching through intermolecular
interactions [29-33]. If H-aggregation intensively occurs, the excited energy is significantly consumed via non-
radiative decay accompanied by intermolecular energy transfer, and as a result, radiative decay processes such

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as emission are inhibited [30,34-36]. Therefore, the dyes used in this study were designed to have similar
geometrical structures and intermolecular interactions so that their fluorescence properties would be primarily
dependent on their electrochemical properties rather than their physical molecular behaviors [22].
3.2. Geometry optimization of the synthesized dyes
The optimized geometries of the synthesized dyes obtained via DFT calculations are shown in Fig. 2. The
images as observed from the normal to the perylene main body plane are presented in Fig. 2. All the designed
dyes have similar molecular morphologies, despite the introduction of the various substituents. The size of a dye
molecule and its substituents majorly influence the distance between molecules [20], which, in turn, affects
intermolecular interactions and fluorescence properties.
The dihedral angle of the perylene main body and the calculated lengths of the introduced substituents are
listed in Table 1. The dihedral angle of the perylene main body was measured on the benzene ring at the center
of perylene backbone [20]. All the introduced substituents are symmetrically oriented at each substitution
position, but the dye molecules are not three-dimensionally symmetric according to the DFT simulations [20].
Therefore, all values were measured for both sides of the molecules and the average values are provided in
Table 1. The synthesized dyes exhibited similar values for the dihedral angle of the perylene main body, which
principally determines its planarity. The difference in the dihedral angles among the dyes is within about 1°,
except for PI-2ME, therefore, it can be assumed that the planarity of the dyes is generally analogous to each
other. As can be observed in Table 1, the dihedral angle data of PI-2ME is slightly out of the tendency. Our
guess is that an unexpected error occurred in the case of PI-2ME, because the molecular structure of PI-2ME
dye is less stable than the other dyes owing to the close proximity of the branches of the bay-substituents and the
perylene backbone. This would increase the interference factor, and as a result, an error would be observed in
the DFT calculations.

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The sizes of introduced substituents are similar. Commonly, the bay-substituents with methoxy groups are
smaller than those bearing ethyl groups by ~0.2
Å, and the terminal-substituents with methoxy groups are
smaller than those without methoxy groups by ~1.2
Å. Generally, bulky substituents that contain several alkyl
groups or benzene rings are used to prevent the intermolecular interactions of perylene-based dyes [3,21,22,37-
43]. From this point of view, the difference of the physical morphologies of the dyes used in this study would
not have a significant influence on the molecular interactions or the fluorescence behaviors of them.
3.3. Absorption properties of the synthesized dyes
The absorption properties of the synthesized dyes are shown in Fig. 3 and Table 2. The absorption
properties of the dyes have been reported in our previous study were remeasured and the measured results under
this research are provided [22]. As intended, the overall shapes of the absorption spectra are similar, owing to
the similar conjugation lengths designed for the synthesized dyes.
The dyes with ortho- or para-methoxylated bay-substituents exhibit bathochromic shifts of ~4 nm due to
the electron donating effects of the methoxy groups. In contrast, the dye with meta-methoxylated bay-
substituents shows a hypsochromic shift compared to the analogous dye with ethylated bay-substituents. These
phenomena result from the well-known electron donating ability of the introduced organic substituents [25-
27,44-47]. The same tendency is observed when methoxy groups are introduced in the terminal-substituents.
However, the effects of electron donation by the methoxy groups appear to be more powerful when these groups
are incorporated in the bay-substituents than in the terminal-substituents. The dyes with methoxylated terminal-
substituents exhibited bathochromic shifts of only ~2 nm compared to the dyes without methoxy groups in the
terminal-substituents.

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3.4. Fluorescence properties of the synthesized dyes
The fluorescence properties of the synthesized dyes are presented in Fig. 4 and Table 3. All fluorescence
properties except quantum yield were measured at an excitation wavelength corresponding to the wavelength of
maximum absorption. The quantum yield was measured at an excitation wavelength of 480 nm. Similarly to the
absorption properties, the fluorescence properties of the dyes that were reported in our previous study were
remeasured for comparison with the new dyes in this study [22]. The optical image of the synthesized dyes in
chloroform solutions are shown in Fig. 5. The images were photographed under 365 or 254 nm of UV light.
Among the ten synthesized compounds, dyes PI-4ME, P2M-4ME, and P4M-4ME show quenched
fluorescence, with differences in quantum yield of ~20-fold from the highly fluorescent dyes. The dyes with low
fluorescence all bear methoxy groups at the para-positions of the bay-substituents. Compounds with methoxy
groups at the ortho- or meta-positions of the bay-substituents show no fluorescence quenching. The differences
in the fluorescence of the highly fluorescent dyes appear less significant compared to the obvious influences of
para-methoxy groups in the bay-substituents. As observed above, methoxy groups electronically affect the
absorption properties of perylene-based dyes irrespective of their positions. However, only the methoxy groups
at the para-position of the bay-substituents inhibit fluorescence. Thus, the electrochemical influence of the
introduced substituents on the fluorescence properties is dependent on their positions.
Methoxy groups introduced into terminal-substituents exerted a weaker influence on the fluorescence of
dyes. Ortho-methoxylated terminal-substituents showed no fluorescence quenching effects, and those were
para-methoxylated exhibited limited effects on fluorescence quenching compared to the cases with methoxy-
bearing bay-substituents. It is widely known that the terminal-substituents have no or little influence on the
conjugation systems of perylene-based dyes [41-43,48]. Comprehensively judged with the results of this study,
it would seem that the terminal-substituents exert a very weak influence on the electrochemical properties of the
perylene-based dyes, especially on their spectral properties, and these effects are very minor compared to the

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influences of bay-substituents. However, it is not reasonable to assume that the terminal-substituents have no
relationship with the conjugation systems of the perylene-based dyes.
3.5. Molecular orbital modeling of the synthesized dyes
The TD-DFT simulation results for excitation from the HOMOs to the LUMOs of the synthesized dyes are
presented in Table 4. For each dye, the excitation system with the highest oscillator strength among the
theoretically possible excitation systems is presented [23,24,49]. The maximum theoretical absorption
wavelength changes along with the electron donating effect of the introduced substituents, although the results
are not perfectly correlated with the measured data. Similar to the results of the DFT calculations, the
simulations of dyes with groups at the ortho-positions of the bay-substituents show slight errors due to structural
instability and the increase of interference factors.
The HOMO and LUMO molecular orbital models of the PI-4EP, PI-4ME, PI-3ME, PI-2ME, P2M-4ME,
and P4M-4ME dyes are illustrated in Fig. 6–11, respectively. The HOMO and LUMO states are based on the
results presented in Table 4, with the highest oscillator strength for each dye. For each figure, images of the
HOMO state are presented in the upper three panels, and those of the LUMO state are presented below. The
images as observed from the direction of x (terminal-substituents), y (bay-substituents), or z (normal of perylene
main body plane) axis are sequentially presented for each state. The molecular orbital models of all the dyes are
presented in the supplementary data in larger format.
The PI-4ME, P2M-4ME, and P4M-4ME dyes show inhibited fluorescence and have methoxy groups in
the para-positions of the bay-substituents. Dyes PI-3ME and PI-2ME exhibit strong fluorescence and have
methoxy groups in the meta- and ortho-positions, respectively. In the HOMO states of the fluorescence
quenched dyes, electron density is clearly visible on the methoxy groups at the para-positions of the bay-
substituents. In contrast, electron density is not observed on the methoxy groups in either the HOMO or LUMO

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states of the highly fluorescent dyes. Thus, the methoxy groups exert an electrochemical influence through
electron donation when they can overlap with the conjugation system of the perylene main body, effectively
resulting in a fluorescence quenching effect.
The structural angles between the methoxy groups introduced in the bay-substituents and the perylene
main body are listed in Table 5. Para-methoxy groups in the bay-substituents are oriented at an angle of 27°
with respect to the perylene backbone, whereas the angle of methoxy groups in the meta-position is ~59° and
that of the ortho-position is ~75°. Since the average observed dihedral angle of the perylene main body is ~13°,
it can be assumed that the structural estranged degrees of the methoxy groups in the para-position of the bay-
substituents are only about 15° when the plane of the perylene main body is assumed as a curved face. Therefore,
the possibility that the methoxy groups at the para-positions of the bay-substituents overlap with the
conjugation system of the perylene main body would be much higher than those of methoxy groups at other
positions [50,51]. As a result, it could be concluded that the methoxy groups differently influence fluorescence
quenching, dependent on their introduced position.
4. Conclusion
In this study, the effects of methoxy groups on the fluorescence of perylene-based dyes were studied with
dyes that contained methoxy groups in various positions. To observe the effects of the methoxy group at the
bay-substituents, dyes bearing ortho-, meta-, or para-methoxybenzene groups as bay-substituents were designed.
To observe the effects of the methoxy groups in the terminal-substituents, dyes with ortho- or para-methoxyaryl
groups as terminal-substituents were designed. Additionally, dyes with ethyl groups introduced instead of
methoxy groups were also designed for comparison.

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The geometries of the dyes were analyzed by the DFT method to assure the similarity of their structural
morphologies. The introduced methoxy groups show a significant relationship with the spectral properties of the
dyes. In particular, methoxy groups incorporated in the bay-substituents exhibited a stronger influence than
those in the terminal-substituents. Dyes with para-methoxylated bay-substituents showed significantly
quenched fluorescence. These para-methoxy groups in the bay-substituents exhibit the smallest structural
dihedral angle with respect to the perylene main body, and therefore, would easily contribute to the conjugation
system and affect the electrochemical properties. According to the TD-DFT calculations, electron density is only
exhibited on the methoxy groups at the para-positions of the bay-substituents in the HOMO states of
fluorescence quenched dyes. In conclusion, the methoxy groups that can overlap with the conjugation plane of
the perylene main body influence the electrochemical and fluorescence properties of the dyes.
Acknowledgements
This work was supported by the Technology Innovation Program (No. 10052798) funded By the Ministry
of Trade, Industry & Energy (MI, Korea).
Reference
[1] Chao CC, Leung Mk. Photophysical and Electrochemical Properties of 1,7-Diaryl-Substituted Perylene
Diimides. J Org Chem 2005;70:4323-31.
[2] Zhao C, Zhang Y, Renjie Li XL, Jiang J. Di(alkoxy)- and Di(alkylthio)-Substituted Perylene-3,4;9,10-
tetracarboxy Diimides with Tunable Electrochemical and Photophysical Properties. J Org Chem 2006;72:2402-
10.
[3] Dincalp H, Askar Z, Zafer C, Icli S. Effect of side chain substituents on the electron injection abilities of
unsymmetrical perylene diimide dyes. Dyes Pigm 2011;91:182-91.
[4] Huang C, Barlow S, Marder SR. Perylene-3,4,9,10-tetracarboxylic acid diimides: synthesis, physical
properties, and use in organic electronics. J Org Chem 2011;76:2386-407.
[5] Reghu RR, Bisoyi HK, Grazulevicius JV, Anjukandi P, Gaidelis V, Jankauskas V. Air stable electron-

ACCEPTED MANUSCRIPT
transporting and ambipolar bay substituted perylene bisimides. J Mater Chem 2011;21:7811.
[6] Lee SK, Zu Y, Herrmann A, Geerts Y, Müllen K, Bard AJ. Electrochemistry, Spectroscopy and
Electrogenerated Chemiluminescence of Perylene, Terrylene, and Quaterrylene Diimides in Aprotic Solution. J
Am Chem Soc 1999;121:3513-20.
[7] Kim YD, Kim JP, Kwon OS, Cho IH. The synthesis and application of thermally stable dyes for ink-jet
printed LCD color filters. Dyes Pigm 2009;81:45-52.
[8] Choi J, Kim SH, Lee W, Chang JB, Namgoong JW, Kim YH, et al. The influence of aggregation behavior of
novel quinophthalone dyes on optical and thermal properties of LCD color filters. Dyes Pigm 2014;101:186-95.
[9] Biedermann F, Elmalem E, Ghosh I, Nau WM, Scherman OA. Strongly fluorescent, switchable perylene
bis(diimide) host-guest complexes with cucurbit[8]uril in water. Angew Chem Int Ed 2012;51:7739-43.
[10] Stolarski R, Fiksinski KJ. Fluorescent perylene dyes for liquid crystal displays. Dyes Pigm 1994;24:295-
303.
[11] Qiao Y, Chen J, Yi X, Duan W, Gao B, Wu Y. Highly fluorescent perylene dyes with large stokes shifts:
synthesis, photophysical properties, and live cell imaging. Tetrahedron Lett 2015;56:2749-53.
[12] Choi J, Sakong C, Choi JH, Yoon C, Kim JP. Synthesis and characterization of some perylene dyes for dye-
based LCD color filters. Dyes Pigm 2011;90:82-8.
[13] Kim YD, Cho JH, Park CR, Choi JH, Yoon C, Kim JP. Synthesis, application and investigation of
structure–thermal stability relationships of thermally stable water-soluble azo naphthalene dyes for LCD red
color filters. Dyes Pigm 2011;89:1-8.
[14] Sakong C, Kim YD, Choi JH, Yoon C, Kim JP. The synthesis of thermally-stable red dyes for LCD color
filters and analysis of their aggregation and spectral properties. Dyes Pigm 2011;88:166-73.
[15] Choi J, Lee W, Sakong C, Yuk SB, Park JS, Kim JP. Facile synthesis and characterization of novel coronene
chromophores and their application to LCD color filters. Dyes Pigm 2012;94:34-9.
[16] Choi J, Lee W, Namgoong JW, Kim TM, Kim JP. Synthesis and characterization of novel
triazatetrabenzcorrole dyes for LCD color filter and black matrix. Dyes Pigm 2013;99:357-65.
[17] Kim SH, Choi J, Sakong C, Namgoong JW, Lee W, Kim DH, et al. The effect of the number, position, and
shape of methoxy groups in triphenylamine donors on the performance of dye-sensitized solar cells. Dyes Pigm
2015;113:390-401.
[18] Kim SH, Namgoong JW, Yuk SB, Kim JY, Lee W, Yoon C, et al. Synthesis and characteristics of metal-
phthalocyanines tetra-substituted at non-peripheral (α) or peripheral (β) positions, and their applications in LCD
color filters. J Inclusion Phenom Macrocyclic Chem 2015;82:195-202.
[19] Yuk SB, Lee W, Namgoong JW, Choi J, Chang JB, Kim SH, et al. Synthesis and characterization of bay-
substituted perylene dyes for LCD black matrix of low dielectric constant. J Inclusion Phenom Macrocyclic
Chem 2015;82:187-94.
[20] Kim JY, Choi J, Namgoong JW, Kim SH, Sakong C, Yuk SB, et al. Synthesis and characterization of novel
perylene dyes with new substituents at terminal-position as colorants for LCD color filter. J Inclusion Phenom
Macrocyclic Chem 2015;82:203-12.
[21] Kim JY, Sakong C, Choi S, Jang H, Kim SH, Chang KS, et al. The Effect of Fluorescence of Perylene Red
Dyes on the Contrast Ratio of LCD Color Filters. Dyes Pigm 2016;131:293-300.
[22] Kim JY, Hwang TG, Kim SH, Namgoong JW, Kim JE, Sakong C, et al. Synthesis of high-soluble and non-

ACCEPTED MANUSCRIPT
fluorescent perylene derivatives and their effect on the contrast ratio of LCD color filters. Dyes Pigm
2017;136:836-45.
[23] Tretiak S. Triplet State Absorption in Carbon Nanotubes: A TD-DFT Study. Nano Lett 2007;7:2201-6.
[24] Li GY, Chu T. TD-DFT study on fluoride-sensing mechanism of 2-(2'-phenylureaphenyl)benzoxazole: the
way to inhibit the ESIPT process. Phys Chem Chem Phys 2011;13:20766-71.
[25] Pu S, Fan C, Miao W, Liu G. The effect of substituent position upon unsymmetrical isomeric diarylethenes
bearing a methoxy group. Dyes Pigm 2010;84:25-35.
[26] Saeed A, Shabir G. New fluorescent symmetrically substituted perylene-3,4,9,10-dianhydride-azohybrid
dyes: Synthesis and spectroscopic studies. Spectrochim Acta A 2014;133:7-12.
[27] Suzuki R, Tada R, Miura Y, Yoshioka N. Synthesis and physicochemical properties of methoxy-substituted
diphenyldihydroacridine and its Si and Ge bridged analogues and corresponding nitroxide radical derivatives. J
Mol Struct 2016;1106:399-406.
[28] Korzdorfer T, Tretiak S, Kummel S. Fluorescence quenching in an organic donor-acceptor dyad: a first
principles study. J Chem Phys 2009;131:034310.
[29] Andreussi O, Corni S, Mennucci B, Tomasi J. Radiative and nonradiative decay rates of a molecule close to
a metal particle of complex shape. J Chem Phys 2004;121:10190-202.
[30] Kang J, Jung J, Kim SK. Flexibility of single-stranded DNA measured by single-molecule FRET. Biophys
Chem 2014;195:49-52.
[31] Kim M, Park WB, Bang B, Kim CH, Sohn KS. Radiative and non-radiative decay rate of
K2SiF6:Mn4+phosphors. J Mater Chem C 2015;3:5484-9.
[32] Kwon J, Hwang J, Park J, Han GR, Han KY, Kim SK. RESOLFT nanoscopy with photoswitchable organic
fluorophores. Sci Rep 2015;5:17804.
[33] Mazurak Z, Wanic A, Karolczak J, Czaja M. The fluorescence decay times and quantum efficiencies of
1,4,5,8-naphthalisoimides. J Lumin 2015;158:103-9.
[34] Bae S, Lim E, Hwang D, Huh H, Kim SK. Torsion-dependent fluorescence switching of amyloid-binding
dye NIAD-4. Chem Phys Lett 2015;633:109-13.
[35] Karolin J, Johansson LBA, Ring U, Langhals H. Aggregation of perylene dyes in lipid vesicles: The effect
of optically active substituents. Spectrochim Acta A 1996;52:747-53.
[36] Wurthner F, Thalacker C, Diele S, Tschierske C. Fluorescent J-type Aggregates and Thermotropic
Columnar Mesophases of Perylene Bisimide Dyes. Chem Eur J 2001;7:2245-53.
[37] Turkmen G, Erten-Ela S, Icli S. Highly soluble perylene dyes: Synthesis, photophysical and
electrochemical characterizations. Dyes Pigm 2009;83:297-303.
[38] Gao B, Li H, Liu H, Zhang L, Bai Q, Ba X. Water-soluble and fluorescent dendritic perylene bisimides for
live-cell imaging. Chem Commun 2011;47:3894-96.
[39] Osswald P, Wurthner F. Conformational Effects of Bay Substituents on Optical, Electrochemical and
Dynamic Properties of Perylene Bisimides: Macrocyclic Derivatives as Effective Probes. Chem Eur J
2007;13:7395-409.
[40] Zhang X, Wu Y, Li J, Li F, Li M. Synthesis and characterization of perylene tetracarboxylic bisester
monoimide derivatives. Dyes Pigm 2008;76:810-6.
[41] Georgiev NI, Sakr AR, Bojinov VB. Design and synthesis of novel fluorescence sensing perylene diimides

ACCEPTED MANUSCRIPT
based on photoinduced electron transfer. Dyes Pigm 2011;91:332-9.
[42] Lee IL, Li SR, Chen KF, Ku PJ, Singh AS, Kuo HT, et al. Synthesis, Photophysical Properties, and Field-
Effect Characteristics of (Ethynylphenyl)benzimidazole-Decorated Anthracene and Perylene Bisimide
Derivatives. Eur J Org Chem 2012;15:2906-15.
[43] Tsai HY, Chen KY. Synthesis and optical properties of novel asymmetric perylene bisimides. J Lumin
2014;149:103-11.
[44] Hutchings MG. Unexpected Bathochromic Shifts in the Visible Absorption Spectra of Arylazo Dyes
Containing the orfho-N-pyridinium-nitro Substituent Combination. Dyes Pigm 1991;17:227-40.
[45] Durbeej B, Eriksson LA. On the bathochromic shift of the absorption by astaxanthin in crustacyanin: a
quantum chemical study. Chem Phys Lett 2003;375:30-8.
[46] Lakshmi Praveen P, Ojha DP. Effect of molecular interactions and end chain length on ultraviolet
absorption behavior and photo stability of alkoxycinnamic acids: Theoretical models of liquid crystal. J Mol Liq
2014;197:106-13.
[47] Outlaw VK, Zhou J, Bragg AE, Townsend CA. Unusual blue-shifted acid-responsive photoluminescence
behavior in 6-amino-8-cyanobenzo[1,2-b]indolizines. RSC Adv 2016;6:61249.
[48] Erdogmus A, Nyokong T. Novel, soluble, FluXoro functional substituted zinc phthalocyanines; synthesis,
characterization and photophysicochemical properties. Dyes Pigm 2010;86:174-81.
[49] Zhou J, Outlaw VK, Townsend CA, Bragg AE. Quenching of pH-Responsive Luminescence of a
Benzoindolizine Sensor by an Ultrafast Hydrogen Shift. Chem Eur J 2016;22:15212-5.
[50] Chen J, Shi MM, Hu XL, Wang M, Chen HZ. Conjugated polymers based on benzodithiophene and arylene
imides: Extended absorptions and tunable electrochemical properties. Polymer 2010;51:2897-902.
[51] Dincalp H, Kizilok S, Icli S. Fluorescent macromolecular perylene diimides containing pyrene or indole
units in bay positions. Dyes Pigm 2010;86:32-41.

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Figure Captions
Fig. 1. Structure of the synthesized dyes.
Fig. 2. Geometry-optimized structure of the synthesized dyes.
Fig. 3. Absorption spectra of the synthesized dyes in chloroform (10-5 mol/L).
Fig. 4. Fluorescence spectra of the synthesized dyes in chloroform (10-8 mol/L).
Fig. 5. Optical image of the synthesized dyes in chloroform solutions (10-4 mol/L) under UV light of (a) 365 nm
and (b) 254 nm.
Fig. 6. Molecular orbital model of PI-4EP at HOMO and LUMO.
Fig. 7. Molecular orbital model of PI-4ME at HOMO and LUMO.
Fig. 8. Molecular orbital model of PI-3ME at HOMO and LUMO.
Fig. 9. Molecular orbital model of PI-2ME at HOMO and LUMO.
Fig. 10. Molecular orbital model of P2M-4ME at HOMO and LUMO.
Fig. 11. Molecular orbital model of P4M-4ME at HOMO and LUMO.

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Table 1 Dihedral angles of the perylene main body and calculated lengths of the substituents. a
Calculated lengths of substituents (Å)
Dihedral angle of the
Dye
perylene main body (°)
Bay-substituent
Terminal-substituent
8.91653
13.66954
13.65821
12.70249
12.90190
12.82097
13.89031
13.58233
13.65405
13.18395
13.57888
7.61265
7.39409
7.22121
7.10929
7.23594
7.11218
7.61336
7.39385
7.50709
7.39411
PI-4EP
PI-4ME
PI-3EP
8.91467
8.83280
8.90940
PI-3ME
PI-2EP
8.82305
8.90961
PI-2ME
P2M-4EP
P2M-4ME
P4M-4EP
P4M-4ME
7.76763
7.76759
7.56291
7.56386
a
dihedral angle and calculated lengths are not symmetric for each side of perylene main body, therefore, the
average values are listed.

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Table 2 Spectral properties of the synthesized dyes.
a
b
Dye
λabs
εabs
546
550
544
540
550
554
548
552
548
552
62,050
56,650
59,880
54,940
61,520
70,520
56,510
60,000
55,040
51,940
PI-4EP
PI-4ME
PI-3EP
PI-3ME
PI-2EP
PI-2ME
P2M-4EP
P2M-4ME
P4M-4EP
P4M-4ME
a λabs : maximum absorption wavelength (nm).
b εabs : molar extinction coefficient (L/mol·cm).

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Table 3 Fluorescence properties of the synthesized dyes.
Maximum emission
intensity (a.u.)
a
b
Dye
λem
Qy
581
586
578
576
579
582
580
582
580
584
241.82
7.08
0.976
0.054
0.938
0.926
0.947
0.961
0.985
0.080
0.880
0.040
PI-4EP
PI-4ME
PI-3EP
241.62
227.61
256.49
242.51
226.75
10.20
PI-3ME
PI-2EP
PI-2ME
P2M-4EP
P2M-4ME
P4M-4EP
P4M-4ME
215.44
6.38
a λem : maximum emission wavelength (nm).
b Qy : quantum yield (10-5 mol/L in chloroform, excited at 480 nm).

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Table 4 Calculated result of TD-DFT for the excitation from HOMO to LUMO of the synthesized dyes.
Excitation
energy (eV)
Theoritical
λabs (nm)
Oscillator
strength
Transition
Dye
Definition
252 → 253
252 → 253
252 → 253
252 → 253
252 → 253
252 → 253
228 → 229
228 → 229
228 → 229
228 → 229
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
S0 → S1
2.2911
2.2661
2.2710
2.2861
1.8731
2.2541
2.3215
2.2951
2.2817
2.2846
541.15
547.13
545.95
542.34
661.91
550.04
534.06
540.20
543.38
542.69
0.7918
0.7547
0.7629
0.7632
0.7067
0.7775
0.7583
0.7268
0.7525
0.7405
PI-4EP
PI-4ME
PI-3EP
PI-3ME
PI-2EP
PI-2ME
P2M-4EP
P2M-4ME
P4M-4EP
P4M-4ME

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Table 5 Structural angle between the methoxy group at bay-substituents and the plane of perylene main body.
PI-3ME
Dye
PI-4ME
PI-2ME
P2M-4ME
P4M-4ME
26.287
58.863
74.911
28.109
27.657
Angle (°)

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Fig. 1. Structure of the synthesized dyes.

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Fig. 10. Molecular orbital model of P2M-4ME at HOMO and LUMO.

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Fig. 11. Molecular orbital model of P4M-4ME at HOMO and LUMO.

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Fig. 2. Geometry-optimized structure of the synthesized dyes.

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Fig. 3. Absorption spectra of the synthesized dyes in chloroform (10-5 mol/L).

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Fig. 4. Fluorescence spectra of the synthesized dyes in chloroform (10-8 mol/L).