M. Erdog˘an
Journal of Molecular Structure 1232 (2021) 130056
coefficient, good flexibility of molecular tailoring, tunable spectral
properties, relatively high efficiency, and low cost [13,14,16]. So far,
power conversion efficiencies (PCEs) of 14% have been reached for
those based on metal-free organic dyes [17]. Therefore, the D-A-π-
A photosensitizers have been observed as promising candidates to
increase the cell efficiency [18].
2H), 7.28 (d, B part of AB system, J = 8.2 Hz, 2H), 5.70 (s, 2H).
13C NMR (100 MHz, CDCl3): δ = 189.0, 138.6, 135.9, 135.6, 134.5,
132.6, 124.0, 51.4.
However such studies are scarce in the literature, and it is im-
portant to discover novel D-A-π-A based dyes. To the best of our
knowledge, the dibenzosuberenone-based dyes with different aro-
matic linkers have not been reported. In this study, we report for
the first time novel dibenzosuberenon-based dye 10 (Scheme 3), in
which dibenzosuberenone is used as an additional acceptor, triph-
enylamine is used as donor, benzene is a π-spacer, and aldehyde
is an acceptor/anchor.
2.2.3. 3,7-Dibromo-5H-dibenzo[a,d][7]annulen-5-one (4)
3,7-Dibromo-5H-dibenzo[a,d][7]annulen-5-one (4): white solid,
mp 266-268 °C (lit [22] mp 267 °C). 1H NMR (400 MHz, CDCl3):
δ=8.35 (d, J = 2.0 Hz, 2H), 7.74 (dd, A part of AB system, J = 8.3
Hz, 2.0 Hz, 2H), 7.42 (d, B part of AB system, J = 8.3 Hz, 2H), 7.01
(s, 2H). 13C NMR (100 MHz, CDCl3): δ = 203.2, 139.6, 135.5, 133.9,
133.4, 132.9, 131.4, 123.7.
2. Experimental Section
2.2.4. Synthesis of dicoupling products via Suzuki coupling reaction
of dibromobenzosuberenone 4 with arylboronic acids 5 and 8
Dibromobenzosuberenone 4 (1.49 g, 4.09 mmol) and Pd(PPh3)4
(142 mg, 0.122 mmol) was added into a 100 mL two-necked flask,
followed by addition of 40 mL of dry DME. A solution of (4-
(diphenylamino)phenyl)boronic acid (8) (1.42 g, 4.91 mmol), (4-
formylphenyl)boronic acid (5) (0.736 g, 4.91 mmol) ve Na2CO3
(1.30 g, 12.28 mmol) in degassed water (20 mL) was added and, all
the solution was refluxed for 18 h under nitrogen atmosphere. The
mixture was added to 100 mL of ice-water, and the DME was then
evaporated. The aqueous layer was extracted with CH2Cl2 (3 × 75
mL). The combined organic layers were washed with water, dried
with MgSO4, filtered, and then concentrated. The crude product
was purified by column chromatography on silica gel eluted with
the mixture of solvents (25% EtOAc/n-hexane).
2.1. General
All reactions were carried out under nitrogen and monitored by
TLC thin layer chromatography (TLC) method and spots were visu-
alized by UV irradiation. All solvents were dried and distilled be-
fore use. Melting points are uncorrected. IR spectra were recorded
on Perkin Elmer FT-IR spectrometer. 1H and 13C NMR spectra were
recorded with a Nuclear magnetic resonance spectrometer (Bruker-
400 spectrometer) using CDCl3 as solvent. Tetramethylsilane (TMS)
was used as an internal standard. All spectra were recorded at
25 °C and coupling constants (J values) are given in Hz. Chemical
shifts are given in parts per million (ppm) relative to the resid-
ual solvent peak (CHCl3: 7.26 ppm for 1H and 77.36 ppm for 13C-
NMR). Mass spectra were determined on an Agilent Technologies
6530 Accurate-Mass Q-TOF-LC/MS. TLC was performed on silica gel
60 HF254 aluminium plates (Fluka). Fluorescence analyses were
carried out on a Shimadzu RF-5301PC spectrofluorometer. Fluores-
cence quantum yield (QY) of the dye 10 was performed through
the Parker-Rees equation [19]. J-V measurements were carried out
according to the method reported in our previous study [15]. The
geometry and electronic properties of the compound 9 and the
dye 10 were performed with the Gaussian09 W program package.
The quantum-chemical calculations were performed with Gaus-
sian09 W software by using density functional theory (DFT) and
time-dependent density functional theory (TDDFT) methods with
B3LYP/6-311++G(2d, 2p) basis set [20].
1.
Fraction:
3,7-Bis(4-(diphenylamino)phenyl)-5H-
dibenzo[a,d][7]annulen-5-one (9): yield 39%, 1.10 g, yellow crystals,
mp 239-241 °C (239-241 °C [15]), 1H NMR (400 MHz, CDCl3): δ=
8.49 (d, J = 1.9 Hz, 2H), 7.86 (dd, J = 8.1 Hz, 1.9 Hz, 2H), 7.62-7.58
(m, 6H), 7.32-7.25 (m, 10H), 7.20-7.13 (m, 10H), 7.10 (s, 2H), 7.08-
7.03 (m, 4H). 13C NMR (100 MHz, CDCl3): δ= 193.1, 148.1, 147.7,
141.1, 138.9, 133.9, 133.4, 131.9, 131.3, 130.1, 129.6, 128.2, 128.0,
124.9, 123.8, 123.4. IR (KBr, cm−1): 3065, 3055, 3032, 1737, 1626,
1587, 1515, 1483, 1385, 1331, 1315, 1286, 1269, 1233, 1175, 1073,
1028, 964, 835. HRMS (Q-TOF): m/z [M+H]+ calcd. for C51H37N2O:
693,2906, found: 693,2934.
2.
Fraction:
4-(7-(4-(diphenylamino)phenyl)-5-oxo-5H-
dibenzo[a,d][7]annulen-3-yl)benzaldehyde (10): yield 26%, 589
mg, yellow crystals, mp 216-218 °C, 1H-NMR (400 MHz, CDCl3):
δ = 10.08 (s, 1H), 8.56 (d, J = 1.9 Hz, 1H), 8.49 (d, J = 1.9 Hz, 1H),
8.00 (d, J = 8.2 Hz, 2H), 7.95-7.84 (m, 4H), 7.71-7.56 (m, 4H), 7.32-
7.26 (m, 2H), 7.19-7.11 (m, 8H), 7.09-7.02 (m, 4H). 13C-NMR (100
MHz, CDCl3): δ = 192.52, 191.85, 148.00, 147.47, 145.44, 141.22,
139.66, 138.72, 138.68, 135.57, 135.03, 133.49, 132.87, 132.17,
131.92, 131.88, 130.62, 130.45, 130.41, 130.03, 129.42, 129.24,
127.93, 127.80, 127.67, 124.74, 123.50, 123.32. IR (KBr, cm−1): 3062,
3031, 2992, 2926, 1735, 1689, 1640, 1587, 1518, 1484, 1421, 1397,
1331, 1276, 1267, 1238, 1209, 1195, 1165, 1072, 1045, 027, 1013,
967, 914, 881, 855, 826, 755, 731, 695. HRMS (Q-TOF): m/z [M+H]+
2.2. Synthesis and characterization
The key compounds 2, 3 and 4 were synthesized according to
procedures the literature [21].
2.2.1. 3,7-Dibromo-10,11-dihydro-5H-dibenzo[a,d][7]annulen-5-one
(2)
3,7-Dibromo-10,11-dihydro-5H-dibenzo[a,d][7]annulen-5-one
(2) [21]: white crystals from CH2Cl2/n-hexane (1:3), mp 159-161
°C (lit [22] mp 160 °C). 1H NMR (400 MHz, CDCl3): δ= 8.11 (d,
J = 1.8 Hz, 2H), 7.54 (dd, A part of AB system, J = 8.0 Hz, 1.8,
2H), 7.11 (d, B part of AB system, J = 8.0 Hz, 2H), 3.15 (s, 4H). 13C
NMR (100 MHz, CDCl3): δ= 192.3, 140.7, 139.4, 135.4, 133.4, 131.2,
120.8, 34.2.
calcd. for C40H28NO2: 554,21200; found: 554,21176.
ꢀ
3.
Fraction:
4,4 -(5-oxo-5H-dibenzo[a,d][7]annulene-3,7-
diyl)dibenzaldehyde (7): yield 15%, 250 mg, brown solid, 1H-NMR
(400 MHz, CDCl3): δ = 10.10 (s, 2H), 8.57 (s, 2H), 8.01 (d, J = 7.9
Hz, 4H), 7.96 (d, J = 8.0 Hz, 2H), 7.90 (d, J = 7.9 Hz, 4H), 7.71
(d, J = 8.0 Hz, 2H), 7.19 (s, 2H). ). 13C NMR spectrum could not
be obtained due to strong aggregation even in different polar
solvents. IR (KBr, cm−1): 3006, 2987, 2958, 2919, 2849, 2747, 1691,
1679, 1643, 1603, 1572, 1464, 1419, 1392, 1366, 1336, 1309, 1275,
1260, 1215, 1166, 1048, 821, 764, 750, 694. HRMS (Q-TOF): m/z
[M+H]+ calcd. for C29H19 O3: 415,13342; found: 415,13318.
2.2.2.
3,7,10,11-Tetrabromo-10,11-dihydro-5H-dibenzo[a,d][7]annulen-5-one
(3)
3,7,10,11-Tetrabromo-10,11-dihydro-5H-dibenzo[a,d][7]annulen-
5-one (3): The compound 3 [22] was moved onto the next reaction
without purification. 1H NMR (400 MHz, CDCl3): δ = 8.21 (d, J
= 2.0 Hz, 2H), 7.69 (dd, A part of AB system, J = 8.2 Hz, 2.0 Hz,
2