Synthesis and characterization of phenanthrene derivatives for optoelectronic applications

Article abstract of DOI:10.1016/j.crci.2017.03.004

New phenanthrene derivatives, bearing cyano group at selected positions, have been prepared in good yields through Knoevenagel condensation and classical oxidative photocyclization. The optical properties of the cyanophenanthrenes have been investigated b

Full text of DOI:10.1016/j.crci.2017.03.004

C. R. Chimie xxx (2017) 1e7
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Full paper/Memoire
Synthesis and characterization of phenanthrene derivatives
for optoelectronic applications
,
*
b
a
Sondes Raouafi a, Faouzi Aloui a , Amal Raouafi , Bechir Ben Hassine
ꢀ
a University of Monastir, Laboratory of Asymmetric Organic Synthesis and Homogenous Catalysis (UR11ES56), Faculty of Sciences,
Avenue of Environment, 5019 Monastir, Tunisia
b University of Tunis El-Manar, Laboratory of Analytical Chemistry and Electrochemistry (LR99ES15), Faculty of Sciences, 2092 Tunis
El-Manar, Tunisia
a r t i c l e i n f o
a b s t r a c t
Article history:
New phenanthrene derivatives, bearing cyano group at selected positions, have been
prepared in good yields through Knoevenagel condensation and classical oxidative pho-
tocyclization. The optical properties of the cyanophenanthrenes have been investigated by
UVevis absorption. A cyclic voltammetry analysis showed a relatively high electronic af-
finity, indicating that they may be good candidates for electron-injection hole blocking
layers in organic light-emitting diodes.
Received 21 December 2016
Accepted 6 March 2017
Available online xxxx
Keywords:
Photolysis
© 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Cyclization
Photooxidation
UVevis spectroscopy
Cyclic voltammetry
1. Introduction
well as their promising applications in the field of organic
light emitting diodes (OLEDs) [25e30]. Phenanthrene and
Phenanthrenes belong to an important skeleton of
organic compounds owing to their core structure in natural
products [1e5]. A great number of these alkaloids exhibit
interesting biological activities such as anti-inflammatory
[1,6,7], anticancer [4,8,9], antimicrobial [10e12], or anti-
viral [13e15]. N-(2,3-Methylenedioxy-6-methoxyphenan
its derivatives, as their physical properties, including UV
evis, photoluminescence, thermal, and electrochemistry,
have been extensively studied and have demonstrated that
these compounds could serve as emitters for OLEDs [31
e39].
Among the reported work, Nayak [40] reported the
synthesis of novel class of blue-green fluorescent phenan-
thromidazoles like 2-(1-phenyl-1H-phenanthro[9,10,d]
imidazol-2-yl)aniline 2 and reported on its optical, elec-
trochemical, and thermal properties.
For the last several decades, much attention has been
focused on the development of synthetic methods for the
synthesis of phenanthrene derivatives. The most practical
and widely used route to the synthesis of these compounds
is the photocyclization of stilbenes [41e44], as it is well
suited to the laboratory scale. Our research group has pre-
viously reported the synthesis of 3,6-dibromophenanthrene
3, using a photochemical procedure, and described its use in
the synthesis of a helical optically active phosphine [41].
thr-9-ylmethyl)-40-cyanopiperidine,
1 (Fig. 1), is well
known for its inhibition of the growth of cancer cells [16].
Moreover, phenanthrene is of great interest to organic
chemists because of its important properties either in
materials science based on their photoconducting, photo-
chemical, and electroluminescent properties [17e24].
During the past few years, conjugated polymers and
oligomers based on various aromatic building blocks have
received considerable attention, owing to their intriguing
photoluminescent and electroluminescent properties as
* Corresponding author.
E-mail address: alouifaouzi0@gmail.com (F. Aloui).
http://dx.doi.org/10.1016/j.crci.2017.03.004
1631-0748/© 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: S. Raouafi, et al., Synthesis and characterization of phenanthrene derivatives for optoelectronic
applications, Comptes Rendus Chimie (2017), http://dx.doi.org/10.1016/j.crci.2017.03.004

2
S. Raouafi et al. / C. R. Chimie xxx (2017) 1e7
aromatic aldehydes 7aee in dry methanol, in the presence
of sodium methoxide as a base at room temperature, to
obtain the resulting 1,2-diarylethylenes 8aei in 51e85%
yield (Scheme 1, Table 1).
To prepare a novel and highly valuable polysubstituted
phenanthrenes, we have envisaged to subject the resulting
diarylethylenes for photocyclization. Thus, 500 mg of each
olefin 8 have been dissolved in 1.2 L of toluene, and then
irradiated using a 500 W high-pressure mercury immer-
sion lamp, in the presence of a stoichiometric amount of
iodine as the oxidizing agent and an excess of propylene
oxide as a hydrogen iodide scavenger to produce the cor-
responding phenanthrene. This allowed us to obtain
phenanthrenes P1eP9 in 51e83% yield (Scheme 2, Table 2).
To extend the scope of these reactions, a new derivative
of cyclopenta[a]naphthalene has been prepared according
to the same synthetic approach. Our procedure uses 2-(p-
tolyl)acetonitrile 9 and thiophene-2-carbaldehyde 10 as
key building blocks for the synthesis olefin 8j, which is then
converted
to
5-methylnaphtho[2,1-b]thiophene-8-
carbonitrile P10 by photolysis (Scheme 3). The 1H NMR
data of compound P10 showed that proton H9 is manifested
in the form of a desheilded singlet at 8.24 ppm, a doublet at
7.98 ppm is ascribed to H3, and H4 takes the form of a
singlet at 8.14 ppm, which is observed in the most
desheilded aromatic area.
The optical properties of the target cyanophenanthrenes
have been investigated using UVevis absorption spectros-
copy in dilute chloroform solutions (7 ꢀ 10ꢁ5 M) as
depicted in Fig. 2. The UVevis spectrum of these com-
pounds exhibited a strong absorption in the region of 250
Fig. 1. Representative examples of phenanthrene derivatives.
More recently, Mallory et al. [43] prepared 3-methoxy-8-
methylphenanthrene-1-carbonitrile using the same
4
approach. Several nonphotochemical approaches have been
investigated, among them are DielseAlder reaction [45],
FriedeleCrafts reaction [46,47], the photochemical proced-
ure radical cyclizations [48], ring-closing metathesis [49
e52]. In addition, complicated precursors, expensive and
sensitive metallic catalysts, or harsh reaction conditions
were needed for the synthesis of aromatic compounds [53
e55]. Phenanthrene synthesis via photocyclodehydro
genation of stilbene derivatives still represents a simple and
efficient synthetic method.
In this article, we describe the synthesis and charac-
terization of new phenanthrene derivatives with cyano
groups at selected positions on the aromatic rings. Our
synthetic approach relies on the easy preparation of cya-
nodiarylethylenes via Knoevenagel reaction, which are
then converted into phenanthrenes through the classical
photocyclodehydrogenation.
e450 nm. These absorption bands are associated with
e
p
p* and nep* electronic transitions. The gap energy (Eg)
values of the phenanthrenes determined from the ab-
sorption edge of the solution spectra are given in Table 3.
To investigate the redox behavior of phenanthrenes and
to estimate their highest occupied molecular orbital
(HOMO) and lowest unoccupied molecular orbital (LUMO)
energy levels, cyclic voltammetry (CV) was applied to the
materials. Knowledge of the HOMO and LUMO energy
levels is of crucial importance for the selection of the
cathode and anode materials for OLED devices. The use of
CV analysis is of good reliability as the electrochemical
processes probed therein are similar to those involved in
charge injection and transport processes in OLED devices.
The cyanophenanthrenes P1-P10 have been scanned
both positively and negatively, in solutions of tetra-n-
2. Results and discussion
In the first part of our work, we have used the Knoe-
venagel condensation for the synthesis of several func-
tionalized 1,2-diarylethylenes containing the powerful
electron-withdrawing cyano group, using a simple and
efficient route shown in Scheme 1. First, we have carried
the reaction between arylacetonitriles 5e6 and the
Table 1
Chemical yields of 1,2-diarylethylenes 8aei.
1,2-Diarylethylene
R1
R2
R3
Yield (%)a
8a
8b
8c
8d
8e
8f
8g
8h
8i
H
H
H
H
Br
OCH3
CN
OCH3
H
Br
OCH3
CN
OCH3
H
H
H
OCH3
OCH3
H
H
H
85
76
82
75
73
71
75
78
74
H
CH3
CH3
CH3
CH3
OCH3
a
Scheme 1. Synthetic pathway for the synthesis of 1,2-diarylethylenes 8aei.
Isolated yields.
Please cite this article in press as: S. Raouafi, et al., Synthesis and characterization of phenanthrene derivatives for optoelectronic
applications, Comptes Rendus Chimie (2017), http://dx.doi.org/10.1016/j.crci.2017.03.004

S. Raouafi et al. / C. R. Chimie xxx (2017) 1e7
3
Scheme 2. Photocyclization of 1,2-diarylethylenes 8aei into phenanthrenes
P1eP9.
Table 2
Chemical yields of cyanophenanthrenes P1eP9.
Phenanthrene
R1
R2
R3
Yield (%)a
P1
P2
P3
P4
P5
P6
P7
P8
P9
H
H
H
H
Br
OCH3
CN
OCH3
H
Br
OCH3
CN
OCH3
H
H
H
OCH3
OCH3
H
H
H
70
75
84
65
62
83
76
75
72
H
CH3
CH3
CH3
CH3
OCH3
a
Isolated yields.
Fig. 2. UVevis absorption spectrum of cyanophenanthrenes P1eP10 in
dilute chloroform solutions (7 ꢀ 10ꢁ5 M).
Table 3
Scheme 3. Synthetic pathway for the synthesis of compound P10.
Optical properties of cyanophenanthrenes P1eP10.
abs
max
Compound
l
a (nm)
lonset (nm)
Eg-opb (eV)
butylammonium perchlorate (n-Bu4NClO4) in acetonitrile
(0.10 M) with a scan rate of 50 mV sꢁ1 at room temperature.
The obtained cyclic voltammogram of P1 is shown in Fig. 3
as an example and the electrochemical properties of all
products are summarized in Table 4. We found that the
oxidation and reduction processes of the phenanthrenes
were irreversible. The onset potentials for oxidation were
1.53, 1.48, 2.13, 2.09, 1.71, 1.63, 1.60, 2.19, 2.20, and 2.17 V (vs
saturated calomel electrode [SCE]) for cyanophenanthrenes
P1eP10, respectively, whereas the onset potentials for
reduction were ꢁ1.09, ꢁ1.07, ꢁ0.54, ꢁ0.57, ꢁ0.85, ꢁ0.38,
ꢁ0.83, ꢁ0.60, ꢁ0.56, and ꢁ0.58 V (vs SCE), respectively
(Table 4). From the onset potentials of the oxidation and
reduction processes, the electrochemical band gaps (Eg)
could be calculated as follows [56]:
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
274
261
315
268
264
268
279
325
265
264
441
446
430
441
454
464
441
428
432
446
2.81
2.78
2.88
2.81
2.73
2.67
2.81
2.89
2.87
2.78
a
Absorption maxima measured in
a
chloroform solution
(7 ꢀ 10ꢁ5 mol Lꢁ1) at room temperature.
b
The optical gap (Eg-op) was estimated from the onset point of the
absorption spectra: Eg-op ¼ 1240/lonset
.
Egꢁel ¼ ðELUMO ꢁ EHOMOÞeV
EHOMOðionization potentialÞ ¼ ꢁðVonsetꢁox ꢁ VFOC þ 4:8Þ
where VFOC is the ferrocene half-wave potential (0.53 V),
Vonset-ox and Vonset-red are the onset potentials for the
oxidation and reduction of the phenanthrenes versus the
reference electrode (Ag/AgCl).
ELUMOðelectron affinityÞ ¼ ꢁðVonsetꢁred ꢁ VFOC þ 4:8Þ
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4
S. Raouafi et al. / C. R. Chimie xxx (2017) 1e7
Fig. 4. Comparison of the HOMOeLUMO energy levels of P1eP10 and those
of BCP, indium tin oxide (ITO), and aluminum.
might be suitable candidates for electron-injection hole-
blocking layers. Work is currently under way toward the
application of these materials in multilayer devices.
Fig. 3. Cyclic voltammogram of P1 in 0.1 M (n-Bu)4NClO4/acetonitrile at a
scanning rate of 50 mV sꢁ1
.
Table 4
4. Experimental section
Electrochemical properties of cyanophenanthrenes P1eP10.
a
b
c
4.1. General
Compound Vonset-ox
Vonset-red
EHOMO
ELUMO
Eg-el
(V)
(V)
(eV)
(eV)
(eV)
All reagents and solvents used in this work are available
commercially and used without further purification. The
reactions were monitored by thin-layer chromatography
using commercial silica-gel plate 60F254. Melting points
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
1.53
1.48
2.13
2.09
1.71
1.63
1.60
2.19
2.20
2.17
ꢁ1.09
ꢁ1.07
ꢁ0.54
ꢁ0.57
ꢁ0.85
ꢁ0.38
ꢁ0.83
ꢁ0.60
ꢁ0.56
ꢁ0.58
ꢁ5.65
ꢁ5.60
ꢁ6.25
ꢁ6.21
ꢁ5.83
ꢁ5.75
ꢁ5.72
ꢁ6.31
ꢁ6.32
ꢁ6.29
ꢁ3.03
ꢁ3.05
ꢁ3.58
ꢁ3.55
ꢁ3.27
ꢁ3.20
ꢁ3.29
ꢁ3.52
ꢁ3.56
ꢁ3.54
2.62
2.55
2.67
2.66
2.56
2.55
2.43
2.79
2.76
2.75
were measured on
a Bibby Scientific Stuart Digital,
Advanced, SMP30. The 1H NMR and 13C NMR spectra were
recorded in a Bruker AC-300 and were obtained in CDCl3 as
a solvent with tetramethylsilane as the internal reference.
UVevis spectra were recorded on a spectrophotometer UV-
1600PC. CV measurements have been conducted using a
standard one-compartment, three-electrode electro-
chemical cell using a CH-660B potentiostat. Investigations
have been carried out in millimolar anhydrous 1,2-
dichlorobenzene solutions containing tetra-n-butylammo-
nium perchlorate (0.5 M) as a supporting electrolyte. A
platinum wire has been used as the counter electrode. An
ALS Co. Ltd Agþ/Ag electrode ([Agþ] ¼ 10ꢁ2 M in CH3CN)
has been used as a reference. This reference electrode was
calibrated with respect to the formal potential of the fer-
rocenium/ferrocene (Fcþ/Fc) couple in CH3CN. All poten-
tials values have been converted toward SCE using E versus
SCE ¼ E versus Ag/Agþ (10ꢁ2) þ 298 mV. Yields refer to
quantities obtained after chromatography.
a
Calculated from the oxidation potential.
Calculated from the reduction potential.
Band gap was calculated from the difference between HOMO and
b
c
LUMO.
The estimated EHOMO and ELUMO values of products P1
eP10 are given in Table 4. The slight difference between the
optical and electrochemical band gap (0.03e0.38 eV) is
attributed to the interface barrier between the electrode
and the helicene, and the exciton binding energy [57,58].
A comparison of these compounds revealed that the
HOMO energy levels were slightly different (Fig. 4). How-
ever, a higher electron affinity was observed for compound
P7. The LUMO levels of these
p-conjugated tricyclic sys-
tems were comparable with that of bathocuproine (BCP).
BCP is widely used as an electron-injection hole-blocking
layer in OLEDs [59,60]. It prohibits excitons diffusing to-
ward the Al electrode where they would otherwise be
quenched. However, it is known that BCP crystallizes
quickly, which results in degradation of the device perfor-
mance [61,62]. For this reason, it is desirable to replace BCP
by other materials in such devices. In fact, the fused tricy-
clic systems P1eP10 might be good replacements for BCP
and for the elaboration of multilayer devices.
4.2. General procedure for the preparation of the a,b-
unsaturated nitriles (8aei)
A mixture of arylacetonitrile 5 or 6 (12.9 mmol, 1 equiv)
and aldehyde 7 (12.9 mmol, 1 equiv) in dry methanol
(30 mL) was stirred at 0 ꢂC for 5 min. Then, sodium
methoxide (1.2 g, 25.9 mmol) was added in small portions,
and the mixture was stirred for 30 min at 0 ꢂC and then for
12 h at room temperature. The precipitate was collected
using a sintered glass filter, washed with MeOH and then
with water, and dried.
3. Conclusion
We have described a straightforward method for the
preparation of new cyanophenanthrenes in good yields
under mild conditions. The photophysical and electro-
chemical behaviors of these compounds indicated that they
4.2.1. (Z)-3-(p-Bromophenyl)-2-phenylacrylonitrile (8a)
White solid, 85%, mp ¼ 99e101 C; 1H NMR (300 MHz,
ꢂ
CDCl3):
d
(ppm): 7.38e7.48 (m, 4H); 7.59 (d, J ¼ 8.4 Hz, 2H);
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S. Raouafi et al. / C. R. Chimie xxx (2017) 1e7
5
7.66 (d, J ¼ 7.2 Hz, 2H); 7.74 (d, J ¼ 8.1 Hz, 2H); 13C NMR
108.42 (C); 113.89 (2CeH); 117.98 (CN); 125.17 (2CeH);
126.26 (C); 129.14 (2CeH); 130.50 (2CeH); 131.65 (C);
138.33 (C); 140.31 (CeH); 160.82 (CeO).
(75 MHz, CDCl3):
d (ppm): 112.14 (C); 117.08 (CN); 124.31
(CeBr); 125.52 (2CeH); 128.60 (2CeH); 128.91 (CeH);
130.08 (2CeH); 131.71 (2CeH); 132.15 (C); 133.75 (C);
140.10 (CeH).
4.2.8. (Z)-3-(p-Cyanophenyl)-2-(p-tolyl)acrylonitrile (8h)
White solid, 78%, mp ¼ 190e192 ꢂC; 1H NMR (300 MHz,
4.2.2. (Z)-3-(p-Methoxyphenyl)-2-phenylacrylonitrile (8b)
White solid, 76%, mp ¼ 93e95 ꢂC; 1H NMR (300 MHz,
CDCl3):
d
(ppm): 2.37 (s, 3H, CH3); 7.30 (d, J ¼ 8.7 Hz, 2H);
7.50 (s, 1H, Hvinyl); 7.61 (d, J ¼ 8.1 Hz, 2H); 7.76 (d, J ¼ 8.4 Hz,
CDCl3):
d
(ppm): 3.89 (s, 3H, OCH3); 6.99 (d, J ¼ 8.7 Hz, 2H);
2H); 7.97 (d, J ¼ 8.1 Hz, 2H); 13C NMR (75 MHz, CDCl3):
7.38e7.48 (m, 4H); 7.66 (d, J ¼ 8.7 Hz, 2H); 7.89 (d,
d (ppm): 21.17 (CH3); 113.41 (C); 115.48 (C); 117.13 (CN);
J ¼ 8.7 Hz, 2H); 13C NMR (75 MHz, CDCl3):
d
(ppm): 54.88
118.12 (CN); 126.11 (2CeH); 129.46 (2CeH); 129.91
(2CeH); 130.88 (C); 132.53 (2CeH); 138.05 (CeH); 138.17
(C); 140.51 (C).
(OCH3); 108.41 (C); 113.93 (2CeH); 117.89 (CN); 125.29
(2CeH); 126.11(C); 128.19 (CeH); 128.45 (2CeH); 130.63
(2CeH); 134.47 (C); 141.29 (CeH); 160.99 (C).
4.2.9. (Z)-3-(30,40-Dimethoxyphenyl)-2-(p-tolyl)acrylonitrile
(8i)
4.2.3. (Z)-3-(p-Cyanophenyl)-2-phenyl)acrylonitrile (8c)
White solid, 82%, mp ¼ 66e68 ꢂC; 1H NMR (300 MHz,
Yellow solid, 74%, mp ¼ 95e97 ꢂC; 1H NMR (300 MHz,
CDCl3):
d
(ppm): 7.46e7.50 (m, 3H); 7.53 (s, 1H, Hvinyl); 7.69
CDCl3): d (ppm): 2.41 (s, 3H, CH3); 3.96 (s, 3H, OCH3); 3.99
e7.76 (m, 4H); 7.95 (d, J ¼ 8.1 Hz, 2H); 13C NMR (75 MHz;
(s, 3H, OCH3); 6.94 (d, J ¼ 8.1 Hz, 1H); 7.26 (d, J ¼ 7.8 Hz,
2H); 7.37 (d, J ¼ 8.4 Hz, 1H); 7.42 (s, 1H, Hvinyl); 7.57 (d,
J ¼ 7.8 Hz, 2H); 7.72 (s, 1H); 13C NMR (75 MHz, CDCl3):
CDCl3):
d (ppm): 113.14 (C); 115.04 (C); 116.53 (CN); 117.57
(CN) 125.73 (2CeH); 128.74 (2CeH); 129.05 (2CeH);
129.56 (CeH); 132.08 (2CeH); 133.16 (C); 137.37 (C); 138.78
(CeH).
d
(ppm): 21.05 (CH3); 55.97 (OCH3); 56.05 (OCH3); 108.94
(C); 111.21 (CeH); 111.24 (CeH); 118.60 (CN); 124.11 (CeH);
125.67 (2CeH); 127.03 (C); 129.65 (2CeH); 132.11 (C);
138.88 (C); 141.03 (CeH); 149.27 (C); 151.19 (C).
4.2.4. (Z)-3-(30,40-Dimethoxyphenyl)-2-phenylacrylonitrile
(8d)
Yellow solid, 75%, mp ¼ 91e93 ꢂC; 1H NMR (300 MHz,
4.2.10. (Z)-3-(Thiophen-2-yl)-2-(p-tolyl)acrylonitrile (8j)
Orange solid, 71%, mp ¼ 125e127 ꢂC; 1H NMR (300 MHz,
CDCl3): d (ppm): 3.97 (s, 3H, OCH3); 4.00 (s, 3H, OCH3); 6.94
(d, J ¼ 8.4 Hz, 1H); 7.36e7.48 (m, 5H); 7.66 (d, J ¼ 7.2 Hz,
CDCl3): d (ppm): 2.39 (s, 3H, CH3); 7.12e7.15 (m, 1H); 7.22 (d,
2H); 7.74 (d, J ¼ 1.8 Hz, 1H); 13C NMR (75 MHz, CDCl3):
J ¼ 8.1 Hz, 2H); 7.51e7.55 (m, 3H); 7.60 (s,1H, Hvinyl); 7.65 (d,
d
(ppm): 55.52 (2 OCH3); 108.02 (C); 110.26 (CeH); 110.45
J ¼ 3.6 Hz, 1H); 13C NMR (75 MHz; CDCl3):
d (ppm): 20.60
(CeH); 118.19 (CN); 123.92 (CeH); 125.30 (2CeH); 126.26
(C); 128.29 (CeH); 128.53 (2CeH); 134.33 (C); 141.64
(CeH); 148.57 (CeO); 150.67 (CeO).
(CH3); 108.08 (C); 117.62 (CN); 125.10 (2CeH); 127.63 (CeH);
129.01 (CeH); 129.25 (2CeH); 130.71 (C); 131.21 (CeH);
132.59 (CeH); 137.65 (C); 138.65 (C).
4.2.5. (Z)-3-(30-Methoxyphenyl)-2-phenylacrylonitrile (8e)
Yellow solid, 73%, mp ¼ 40e42 ꢂC; 1H NMR (300 MHz,
4.3. General procedure for the photocyclization of
insaturated nitriles into phenanthrenes
a,b-
CDCl3):
d
(ppm): 3.88 (s, 3H, OCH3); 7.00 (dd, J1 ¼ 2.1 Hz,
J2 ¼ 7.8 Hz, 1H); 7.36 (d, J ¼ 7.8 Hz, 1H); 7.40e7.51 (m, 6H);
To a solution of olefin 8 (2 mmol) in toluene (1.2 L) was
added iodine (558 mg, 1.1 equiv). The solution was
degassed for 15e30 min and then propylene oxide
(50 equiv) was added. Irradiation was performed using a
falling-film photoreactor and a high-pressure Hg-vapor
lamp (500 W, Hanovia). A flow of argon was maintained
throughout the irradiation. The reaction was monitored by
thin-layer chromatography. After completion, the solvent
was removed under reduced pressure and the crude res-
idue was purified by silica gel column chromatography
with cyclohexane/EtOAc (80:20) as the eluent. Spectro-
scopic data for the phenanthrene derivatives are given
subsequently.
7.68 (d, J ¼ 7.8 Hz, 1H); 7.69 (d, J ¼ 8.4 Hz, 1H); 13C NMR
(75 MHz, CDCl3):
d (ppm): 54.91 (OCH3); 111.37 (C); 113.00
(CeH); 116.52 (CeH); 117.56 (CN); 121.71 (CeH); 125.54
(2CeH); 128.57 (2CeH); 128.74 (CeH); 129.44 (CeH);
133.98 (C); 134.47 (C); 141.69 (CeH); 159.37 (CeO).
4.2.6. (Z)-3-(p-Bromophenyl)-2-(p-methylphenyl)acrylonitrile
(8f)
White solid, 71%, mp ¼ 107e109 ꢂC; 1H NMR (300 MHz,
CDCl3):
d
(ppm): 2.40 (s, 3H, CH3); 7.23 (d, J ¼ 8.1 Hz, 2H);
7.41 (s, 1H, Hvinyl); 7.54e7.60 (m, 4H); 7.72 (d, J ¼ 8.7 Hz,
2H); 13C NMR (75 MHz, CDCl3):
d
(ppm): 20.61 (CH3); 112.11
(C); 117.17 (CN); 124.04 (C); 125.39 (2CeH); 129.28 (2CeH);
130.00 (2CeH); 130.96 (C); 131.65 (2CeH); 132.32 (C);
139.02 (CeH); 139.19 (C).
4.3.1. 3-Bromophenanthrene-9-carbonitrile (P1)
Yellow solid, 70%, mp ¼ 176e178 ꢂC; 13C NMR (300 MHz,
CDCl3):d(ppm):7.73e7.79(m,4H);8.14(s,1H,H10);8.25e8.28
4.2.7. (Z)-3-(p-Methoxyphenyl)-2-(p-tolyl)acrylonitrile (8g)
Yellow solid, 75%, mp ¼ 95e97 ꢂC; 1H NMR (300 MHz,
(m,1H); 8.54e8.57 (m,1H); 8.74 (s,1H, H5); 13C NMR(75 MHz,
CDCl3): (ppm): 109.44 (C); 117.04 (CN); 122.60(CeH); 124.15
d
CDCl3):
d
(ppm): 2.39 (s, 3H, CH3); 3.87 (s, 3H, OCH3); 6.97
(C); 125.36 (CeH); 125.68 (CeH); 127.78 (C); 128.04 (CeH);
128.28 (CeH); 128.38 (C); 128.62 (C); 130.25 (CeH); 130.45
(CeH); 132.49 (C); 134.26 (CeH); HRMS (MALDI-TOF) Calcd
for C15H8BrN [M]þ, 280.9840; found, 280.9836.
(d, J ¼ 8.7 Hz, 2H); 7.23 (d, J ¼ 8.1 Hz, 2H); 7.42 (s,1H, Hvinyl);
7.54 (d, J ¼ 8.1 Hz, 2H); 7.86 (d, J ¼ 8.7 Hz, 2H); 13C NMR
(75 MHz, CDCl3):
d (ppm): 20.56 (CH3); 54.86 (OCH3);
Please cite this article in press as: S. Raouafi, et al., Synthesis and characterization of phenanthrene derivatives for optoelectronic
applications, Comptes Rendus Chimie (2017), http://dx.doi.org/10.1016/j.crci.2017.03.004

6
S. Raouafi et al. / C. R. Chimie xxx (2017) 1e7
4.3.2. 3-Methoxyphenanthrene-9-carbonitrile (P2)
1H); 8.06 (s, 1H, H10); 8.11 (d, J ¼ 8.1 Hz, 1H, H4); 8.32 (s, 1H,
H5); 13C NMR (75 MHz, CDCl3):
(ppm): 21.55 (CH3); 55.11
White solid, 75%, mp ¼ 120e122 ꢂC [63]; 1H NMR
d
(300 MHz, CDCl3):
d
(ppm): 4.04 (s, 3H, OCH3); 7.29 (dd,
(OCH3); 103.46 (CeH); 105.83 (C); 117.19 (CeH); 117.98
(CN); 122.23 (CeH); 124.10 (C); 125.38 (CeH); 126.72 (C);
128.87 (C); 129.35 (CeH); 130.50 (CeH); 132.75 (C); 133.76
(CeH); 137.17 (C); 160.23 (C-3); HRMS (MALDI-TOF) Calcd
for C17H13NO [M]þ, 247.0997; found, 247.0991.
J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, 1H); 7.71e7.75 (m, 2H); 7.82 (d,
J ¼ 9 Hz, 1H); 8.01 (s, 1H, H4); 8.16 (s, 1H, H10); 8.26e8.29
(m, 1H); 8.59e8.62 (m, 1H); 13C NMR (75 MHz, CDCl3):
d
(ppm): 55.56 (OCH3); 104.35 (CeH); 106.72 (C); 117.74
(CeH); 118.15 (CN); 123.05 (CeH); 124.57 (C); 126.12
(CeH); 127.62 (CeH); 128.13 (CeH); 129.41 (C); 129.45 (C);
131.05 (CeH); 133.65 (C); 135.17 (CeH); 161.03 (C-3).
4.3.8. 6-Methylphenanthrene-3,9-dicarbonitrile (P8)
Yellow solid, 75%, mp ¼ 193e195 ꢂC; 1H NMR (300 MHz,
CDCl3):
d
(ppm): 2.69 (s, 3H, CH3); 7.67 (d, J ¼ 8.1 Hz, 1H,
4.3.3. Phenanthrene-3,9-dicarbonitrile (P3)
H7); 7.83 (d, J ¼ 8.1 Hz, 1H); 7.80 (d, J ¼ 8.4 Hz, 1H); 8.16 (s,
1H, H10); 8.23 (d, J ¼ 8.1 Hz, 1H, H2); 8.45 (s, 1H, H5); 8.98 (s,
Yellow solid, 84%, mp > 260 ꢂC [64]; 1H NMR (300 MHz,
CDCl3):
8.27 (s, 1H, H10); 8.36e8.39 (m, 1H); 8.68e8.71 (m, 1H, H5);
9.02 (s, 1H, H4); 13C NMR (75 MHz, CDCl3):
(ppm): 112.89
d
(ppm): 7.86e7.88 (m, 3H); 8.03 (d, J ¼ 8.4 Hz, 1H);
1H, H4); 13C NMR (75 MHz, CDCl3):
d (ppm): 21.53 (CH3);
104.68 (C); 112.29 (C); 112.41 (C); 116.52 (CN); 118.01 (CN);
122.29 (CeH); 125.81 (CeH); 126.74 (C); 127.66 (CeH);
128.22 (CeH); 128.79 (C); 129.77 (CeH); 130.58 (CeH);
131.50 (C); 132.52 (CeH); 139.34 (C); HRMS (MALDI-TOF)
Calcd for C17H10N2 [M]þ, 242.0843; found, 242.0837.
d
(C); 113.10 (C); 117.03 (CN); 118.63 (CN); 123.12 (CeH);
126.53 (CeH); 128.28 (CeH); 129.00 (CeH); 129.17 (C);
129.44 (CeH); 129.47 (CeH); 130.47 (CeH); 131.45 (C);
131.84 (C); 134.27 (CeH).
4.3.9. 2,3-Dimethoxy-6-methylphenanthrene-9-carbonitrile
(P9)
4.3.4. 2,3-Dimethoxyphenanthrene-9-carbonitrile (P4)
White solid, 65%, mp ¼ 150e152 ꢂC [65]; 1H NMR
Yellow solid, 72%, mp ¼ 194e196 ꢂC; 1H NMR (300 MHz,
(300 MHz, CDCl3):
d
(ppm): 4.05 (s, 3H, OCH3); 4.13 (s, 3H,
CDCl3): d (ppm): 2.66 (s, 3H, CH3); 4.06 (s, 3H, OCH3); 4.16
OCH3); 7.22 (s, 1H, H1); 7.68e7.72 (m, 2H); 7.95 (s, 1H, H4);
8.10 (s, 1H, H10); 8.26 (d, J ¼ 8.7 Hz, 1H); 8.51 (d, J ¼ 8.7 Hz,
(s, 3H, OCH3); 7.20 (s,1H, H1); 7.52 (d, J ¼ 8.1 Hz,1H); 7.91 (s,
1H, H10); 8.04 (s, 1H, H4); 8.15 (d, J ¼ 8.4 Hz, 1H, H8); 8.27 (s,
1H); 13C NMR (75 MHz, CDCl3):
d
(ppm): 56.06 (OCH3);
1H, H5); 13C NMR (75 MHz, CDCl3):
d (ppm): 21.57 (CH3);
56.11 (OCH3); 103.29 (CeH); 107.21 (C); 108.82 (CeH);
118.20 (CN); 122.53 (CeH); 125.11 (C); 126.12 (CeH); 127.09
(CeH); 127.21 (C); 127.61 (CeH); 128.58 (C); 129.40 (C);
134.16 (CeH); 150.20 (CeO); 152.02 (CeO).
55.56 (OCH3); 55.65 (OCH3); 102.52 (CeH); 106.41 (C);
108.11 (CeH); 117.99 (CN); 121.65 (CeH); 124.67 (C); 125.44
(CeH); 126.02 (C); 126.31 (C); 128.43 (CeH); 128.91 (C);
132.76 (CeH); 137.20 (C); 149.39 (CeO); 151.15 (CeO);
HRMS (MALDI-TOF) Calcd for C18H15NO2 [M]þ, 277.1102;
found, 277.1042.
4.3.5. 2-Methoxyphenanthrene-9-carbonitrile (P5)
White solid, 62%, mp ¼ 171e173 ꢂC; 1H NMR (300 MHz,
CDCl3):
d
(ppm): 3.97 (s, 3H, OCH3); 7.24e7.26 (t, J ¼ 2.7 Hz,
4.3.10. 5-Methylnaphtho[2,1-b]thiophene-8-carbonitrile (P10)
Yellow solid, 55%, mp ¼ 143e145 ꢂC; 1H NMR (300 MHz,
1H, H1); 7.38e7.42 (dd, J1 ¼ 2.7 Hz, J2 ¼ 9 Hz, 1H, H3); 7.64
e7.75 (m, 2H); 8.14 (s, 1H, H10); 8.24e8.27 (dd, J1 ¼ 1.2 Hz,
J2 ¼ 7.8 Hz,1H); 8.54e8.59 (m, 2H); 13C NMR (75 MHz, CDCl3)
CDCl3):
d
(ppm): 2.63 (s, 3H, CH3); 7.53 (d, J ¼ 8.4 Hz, 1H);
7.81 (d, J ¼ 5.4 Hz, 1H, H2); 7.99 (d, J ¼ 5.1 Hz, 1H, H3); 8.14
d
(ppm): 55.54 (OCH3); 109.12 (CeH); 109.94 (C); 117.89 (CN);
(s, 1H, H9); 8.20e8.24 (m, 2H); 13C NMR (75 MHz, CDCl3):
120.48 (CeH); 122.54 (CeH); 124.43 (CeH); 126.06 (CeH);
126.16 (C); 127.04 (CeH); 128.02 (C); 128.20 (CeH); 130.20
(C); 131.24 (C); 134.84 (CeH); 158.94 (C); HRMS (MALDI-TOF)
Calcd for C16H11NO [M]þ, 233.0840; found, 233.0836.
d (ppm): 21.30 (CH3); 106.29 (C); 117.64 (CN); 121.68 (CeH);
123.01 (CeH); 125.31 (CeH); 126.48 (CeH); 126.89 (C);
128.52 (C); 128.73 (CeH); 129.81 (CeH); 134.98 (C); 137.66
(C); 138.45 (C); HRMS (MALDI-TOF) Calcd for C14H9NS [M]þ,
223.0455; found, 223.0449.
4.3.6. 3-Bromo-6-methylphenanthrene-9-carbonitrile (P6)
White solid, 83%, mp ¼ 186e188 ꢂC; 1H NMR (300 MHz,
Acknowledgments
CDCl3):
d
(ppm): 2.66 (s, 3H, CH3); 7.58 (dd, J1 ¼ 0.9 Hz,
J2 ¼ 8.1 Hz, 1H); 7.73 (d, J ¼ 0.9 Hz, 2H); 8.07 (s, 1H, H10);
ꢀ ꢀ
The authors are grateful to the “Direction generale de la
8.14 (d, J ¼ 8.1 Hz, 1H); 8.32 (s, 1H, H4); 8.72 (s, 1H, H5); 13
C
recherche scientifique” (DGRS) of the Tunisian Ministry of
Higher Education and Scientific Research for the financial
support of this research.
NMR (75 MHz, CDCl3):
d (ppm): 21.55 (CH3); 109.22 (C);
117.18 (CN); 122.28 (CeH); 123.81 (C); 125.25 (CeH);
125.45 (CeH); 126.57 (C); 127.90 (C); 128.40 (C); 129.95
(CeH); 130.18 (CeH); 130.24 (CeH); 132.18 (C); 133.19
(CeH); 138.28 (C); HRMS (MALDI-TOF) Calcd for C16H10NO
[M]þ, 294.9996; found, 294.9990.
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Please cite this article in press as: S. Raouafi, et al., Synthesis and characterization of phenanthrene derivatives for optoelectronic
applications, Comptes Rendus Chimie (2017), http://dx.doi.org/10.1016/j.crci.2017.03.004

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applications, Comptes Rendus Chimie (2017), http://dx.doi.org/10.1016/j.crci.2017.03.004