Synthesis and properties of novel 'ethyne-linked' compounds containing carbazole and 1, 8-naphthalimide groups

Article abstract of DOI:10.1071/CH08411

A series of the novel 'ethyne-linked' compounds containing carbazole and 1,8-naphthalimide groups have been synthesized by Pd/Cu-catalyzed Sonogashira reaction. These compounds were fully characterized by means of Fourier-transform IR, ¹H, ¹³C NMR, and high resolution mass spectroscopy. The thermal, optical, and electrochemical properties were also investigated. As we expected, the results indicated that these compounds could improve charge-transport ability and fluorescent quantum yield by introducing the electron-transporting emitting moieties naphthalimide and the alkyne group to carbazole moieties.

Full text of DOI:10.1071/CH08411

Full Paper
CSIRO PUBLISHING
Aust. J. Chem. 2009, 62, 934–940
www.publish.csiro.au/journals/ajc
Synthesis and Properties of Novel ‘Ethyne-Linked’
Compounds Containing Carbazole and
1,8-Naphthalimide Groups
Yu Liu,A Hai-Ying Wang,A Gang Chen,A Xiao-Ping Xu,A and Shun-Jun JiA,B
AKey Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science, Soochow University,
Renai Road, Suzhou Industrial Park, Suzhou 215123, China.
BCorresponding author. Email: chemjsj@suda.edu.cn
A series of the novel ‘ethyne-linked’compounds containing carbazole and 1,8-naphthalimide groups have been synthesized
by Pd/Cu-catalyzed Sonogashira reaction. These compounds were fully characterized by means of Fourier-transform IR,
1H, 13C NMR, and high resolution mass spectroscopy. The thermal, optical, and electrochemical properties were also
investigated. As we expected, the results indicated that these compounds could improve charge-transport ability and
fluorescent quantum yield by introducing the electron-transporting emitting moieties naphthalimide and the alkyne group
to carbazole moieties.
Manuscript received: 27 September 2008.
Final version: 23 March 2009.
Introduction
we further considered introducing electron-transporting emit-
ting units and the alkyne group to the carbazole moiety in
order to enhance the charge injection/transport ability and
fluorescent quantum yield. Here, we wish to report the syn-
thesis and characterization of a series of novel ‘ethyne-linked’
carbazole-naphthalimide compounds, which contain both an
electron-donating segment (carbazole moiety) and an electron-
transporting segment (naphthalimide moiety). As we expected,
these novel compounds (highest occupied molecular orbital
(HOMO) level is 5.80 eV) showed higher blue-green light-
emitting properties and enhanced internal quantum efficiency
from highly π-conjugated systems, and showed no reduction in
their thermal stability.
Organic materials with π-conjugated systems have become
a subject of intense research recently. They can be used as
organic light-emitting diodes (OLEDs), solar cells, field-effect
transistors (FETs), and optical storage devices.[1] In these mate-
rials, carbazole and its derivatives,[2] such as polyvinylcarbazole
(PVK) and N,Nꢀ-dicarbazolyl-4,4ꢀ-biphenyl (CBP), have been
widely used in the fabrication of the organic photoconductors,
non-linearopticalmaterials, andphotorefractivematerialsowing
to their electron-donating capabilities.[3] Moreover, it is also
recognized that the thermal stability or glass-state durability
of organic compounds can be greatly improved by introducing
carbazoles into the core structures.[4] Thus, structural modifica-
tion of carbazole for improving the optoelectronic performance
of materials, such as hole-transport/emitting/electron-transport
(three-in-one) for simplified OLED architecture is feasible,
challengeable, and valuable.[5]
Result and Discussion
N-Substituted-4-bromo-1,8-naphthalimide 2 was synthesized by
the condensation of 1 and primary amine in ethanol in good
yields (2a, 92%; 2b, 86%). Compounds 3 or 4 were synthesized
via a Sonogashira coupling reaction using 3-methyl-1-butyn-
3-ol (route 1, yields: 3a, 89%; 3b, 80%) or trimethylsilyl
acetylene (TMSA) (route 2, yields: 4a, 97%; 4b, 92%), in good
yields. The 4-ethynyl-1,8-naphthalimide segments 5a–b were
obtained by the deprotection of the polar group 1-hydroxy-
1-methylethyl (route 1, yields: 5a, 80%; 5b, 74%) or the
trimethylsilyl protecting group (route 2, yields: 4a, 97%; 4b,
92%) (Scheme 1).[9]
Bromo derivatives 6–9 were synthesized according to our
former work (Scheme 2).[8] 4-Ethynyl-1,8-naphthalimide 5 was
treatedwithbromocarbazolederivatives6–9usingaSonogashira
coupling reaction and gave the desired π-conjugated compounds
10a–h in moderate yields (Scheme 3). The low yield of 10b is
caused by the low reactivity of bromocarbazole derivatives 6.
In addition, the desired products 11a–b (11a, 81%; 11b, 67%)
1,8-Naphthalimide derivatives usually exhibit strong fluo-
rescent emission on irradiation, and are well known to act as
supermolecular moieties for the study of photo-induced elec-
trontransfer, fluorescenceswitchers, orliquidcrystaldisplays.[6]
The fluorescence emission can be widely tuned (from blue to
yellow, green, and even red) with amino and alkoxy groups
at the 4-position of naphthalimide. It implies that naphthalim-
ide derivatives are a new type of electron-transporting emit-
ting materials for full colour with high performance, such as
good photo-stability, high fluorescent quantum yield, and high
electron affinity (∼3.1 eV).[7]
In our previous work, the starburst carbazoles based on a 9-
phenylcarbazole core and star-shaped carbazole-functionalized
triazatruxenes were synthesized.[8] Those compounds may serve
as excellent blue-light-emitting materials, which are also found
to show high thermal and electrochemical stability. Therefore,
© CSIRO 2009
10.1071/CH08411
0004-9425/09/080934

Novel ‘Ethyne-Linked’ Compounds
935
R
N
R
N
O
O
O
O
(c)
(b)
Route 1
R
N
O
O
O
O
O
3
5
(a)
OH
R
N
R
N
Route 2
Br
Br
O
O
O
O
(d)
1
2
(e)
R
5a
5b
n-Bu
p-MeO-Ph
4
5
TMS
Scheme 1. Reagents and conditions: (a) RNH2/EtOH/reflux; (b) 3-methyl-1-butyn-3-ol, Pd(PPh3)2Cl2, CuI,
TEA, under argon, 80◦C, 24 h; (c) NaOH, toluene, under argon, 130◦C; (d) TMSA, Pd(PPh3)2Cl2, CuI, under
argon, 80◦C, 24 h; (e) K2CO3/methanol/THF.
backbone. Compound 10b exhibited a maximum absorption
peak at 399 nm, and compound 10d exhibited a maximum
absorption peak at 435 nm, which was red-shifted by 36 nm
with respect to the C9-position and C3-position of the carbazole
moieties. From Table 1, we can conclude that there are slight
differences if we change the substituent on the C3-position of
the carbazole moieties. The π–π* energy gaps (Eg) of these
compounds were calculated from the UV-visible absorption
threshold.[11] The Eg of compounds 10a–h could be increased
by changing the carbazole moieties from the C3-position to the
C9-position. The Eg of the homo-coupling products 11a–b were
higher than those of compounds 10a–h, which might be due to
the symmetry of 11a and 11b.
Br
N
6
(a)
60%
C4H9
N
C4H9
N
(e)
(b)
94%
7
8
97%
Br
Br
N
H
C6H13
N
CH13
N
(c)
95%
(e)
Carbazole
96%
Fig. 2 displays the photoluminescence (PL) emission spec-
tra of compounds 10a–h excited at room temperature in dilute
CH2Cl2 solution (10−6 mol L−1). These compounds showed
a green PL emission, with the maximum emission peaks
varying from 544 to 560 nm. The compounds of 10a, 10c,
10e, and 10g showed a main emission peak at 556, 555,
557, and 544 nm, respectively. In comparison with the emis-
sionspectrumof4-phenylacetylene-N-alkyl-1,8-naphthalimides
(PNA)[6h] and triphenylamine-naphthalimide derivatives (TPA-
NA),[6j] 10a, 10c, 10e, 10g showedaredshiftinCH2Cl2 solution.
Emission differences between these compounds and PNA and
TPA-NA1 should be ascribed to the ethynylene linkages that
elongate the conjugation length of the molecule and make the
molecule more planar.[5f] The compounds 10b, 10d, 10f, and
10h showed a green fluorescence, with the maximum emission
peaks at 559, 558, 560, and 550 nm, respectively, which is sim-
ilar to the emission spectra of compounds of 10a, 10c, 10e, and
10g. But, to our surprise, 11a showed a significant blue shift
in its fluorescence emission, which may be caused by the pro-
nounced steric crowding in 11a, which leads to less coplanarity
of the molecule.[12] In the solid state, as thin films, the emission
spectra were different from those in solution. Emission spectra
of thin films of compounds 10b and 10f were blue-shifted by
3–55 nm in comparison with their solutions. Compounds 10c,
10d, 10e, and 10g were red-shifted by 13–53 nm from their
solution values, which is mainly due to the solvent effect.[5b]
(d)
87%
(e)
N
N
94%
9
Br
Scheme 2. Reagents and conditions: (a) 1,4-dibromobenzene, CuI,
K2CO3, l-proline, DMSO, 180◦C; (b) 1-bromobutane, KOH, TBAB,
DMSO, 100◦C; (c) 1-bromohexane, KOH, TBAB, DMSO, 100◦C;
(d) 1-iodobenzene, CuI, K2CO3, l-proline, DMSO, 180◦C; (e) NBS, DMF,
darkness, 0◦C.
were also synthesized via a Glaser-type homo-coupling reaction
of the terminal acetylene 5a–b (Scheme 4).[10]
The UV-visible absorption and fluorescence spectra of
the novel compounds were measured in CH2Cl2 solution
(Fig. 1). The solution concentration of all compounds was
∼1.0 × 10−5 mol L−1. The optical properties of all new com-
pounds are summarized in Table 1. Absorption spectra of these
compounds were complex with multiple overlapping broad
bands. The maximum UV-visible absorption wavelengths of the
compounds 10a–h range from 393 to 435 nm, which can be
ascribed to the π–π* transition of the conjugated molecular

936
Y. Liu et al.
R
N
O
O
O
N
O
Carbazole
derivatives
(a)
Carbazole
derivatives
R
Br
ꢁ
Cz
Cz
5a–b
6–9
10a–h
10a R ꢀ n-Bu, Cz ꢀ 6, 61%; 10b R ꢀ p-MeO-Ph, Cz ꢀ 6, 49%;
10c R ꢀ n-Bu, Cz ꢀ 7, 68%; 10d R ꢀ p-MeO-Ph, Cz ꢀ 7, 62%;
10e R ꢀ n-Bu, Cz ꢀ 8, 81%; 10f R ꢀ p-MeO-Ph, Cz ꢀ 8, 74%;
10g R ꢀ n-Bu, Cz ꢀ 9, 65%; 10h R ꢀ p-MeO-Ph, Cz ꢀ 9, 55%.
Scheme 3. Reagents and conditions: (a) Pd(PPh3)2Cl2, CuI, TEA, under argon, 80◦C, 24 h.
R
N
light-emittingmaterialinthefuture.Workonfurtherapplications
is currently under way in our laboratory.
O
O
O
N
O
O
N
O
CuCl, CuCl2
Pyridine
R
R
Experimental
5a–b
11a–b
General Procedures and Requirements
11a R ꢀ n-Bu, 81%
All manipulations were carried out under an inert nitrogen or
argon atmosphere using Schlenk techniques. All solvents were
carefully dried and freshly distilled according to common labo-
ratory techniques. All reactants were purchased from Aldrich,
Acros, or Fluka and used without further purification. Melt-
ing points were recorded on an Electrothermal digital melting
point apparatus and are uncorrected. 1H and 13C NMR spectra
were recorded at 295 K on a Varian INOVA 400 MHz or Varian
NMR System 300 MHz spectrometer using CDCl3 as solvent
andTMS as internal standard. UV-Visible spectra were recorded
on a Shimadzu UV-2501PC spectrometer; fluorescence spectra
were obtained on a Hitachi FL-2500 spectrofluorimeter; Fourier-
transform (FT)-IR spectra were recorded on a Varian FT-1000
spectrometer using KBr pellets in the 4000–400 cm−1 region.
High resolution mass spectroscopy data were obtained using a
Microma GCT-TOF instrument. Cyclic voltammetry measure-
ments were carried out under an inert nitrogen atmosphere with
an Autolab potentiostat PGSTAT 10 using a three-electrode
cell (platinum was used as the working electrode and as a
counter electrode, and scanning calomel electrode as a reference
electrode). The rate scan was 100 mV s−1 and the supporting
electrolyte was a Bu4NPF6 (0.1 mol L−1) solution in CH2Cl2.
TGA and DSC measurements were carried out on PE-1 DSC,
TGA-7, TMA-7 instruments. The thermal analyses were carried
11b R ꢀ p-MeO-Ph, 67%
Scheme 4. Glaser-type homo-coupling reaction of compounds 5a–b.
The electronic properties of these compounds were inves-
tigated by cyclic voltammetry at room temperature and the
results are listed in the Table 1. Fig. 3 shows cyclic voltam-
mograms (CVs) of compound 10a as an example. The anodic
peak potential (Epa) of these compounds was determined in a
range of 0.73–1.26V, and the cathodic peak potentials (Epc)
were in the range of 0.66–1.19V, but we could not observe
the Epc value of compounds 10b, 10c, 10d, and we found that
there were no differences between the homo-coupling products
11a–b and the usual Sonogashira coupling reaction products
10a–h. The HOMO and lowest unoccupied molecular orbital
(LUMO) energy levels of the compounds were determined by
Epa and Eg (Table 1). HOMO levels were in the range of
−5.13 to −5.66 eV, which is near the most widely used hole-
transport material 4,4ꢀ-bis(1-naphthylphenylamino)biphenyl
(NPB) (HOMO = −5.5 eV, LUMO = −2.4 eV) and therefore,
these compounds might be able to be used as hole-transporting
materials in OLEDs.
Thermal stabilities of these compounds were examined by
thermogravimetric analysis (TGA) and differential scanning
calorimetry (DSC) in N2 at a heating rate of 10◦C min−1, and the
results are listed in Table 1. The TGA revealed that compounds
10a–h and 11a–b are highly stable materials, which decompose
at temperatures higher than 340◦C. From the DSC measurement,
the glass transition temperature (Tg) of these compounds were
not observed. All the results indicated that these synthesized
compounds were of high morphological and thermal stabilities,
which is a critical issue for device stability and lifetime.
out under a nitrogen flow and with a heating rate of 10◦C min−1
.
ThesynthesisofN-substituted-4-bromo-1,8-naphthalimide2,
and bromocarbazole derivatives 6–9 were carried out by follow-
ing or slightly adapting literature procedures.
General Procedure for the Synthesis of Novel
‘Ethyne-Linked’ Compounds Containing Carbazole
and 1,8-Naphthalimide Groups 10a–h
N-Substituted-4-ethynyl-1,8-naphthalimide5(0.6 mmol), bromo
derivatives 6–9 (0.5 mmol), copper(i) iodide (4.760 mg,
0.025 mmol), bis(triphenylphosphine) dichloropalladium(ii)
(17.55 mg, 0.025 mmol) and triethylamine (15 mL) in dry
toluene (15 mL) were placed in a sealed flask under an argon
atmosphere. The mixture was stirred at room temperature for
0.5 h and than heated at 80◦C. After stirring for 24 h, the mix-
ture was filtered and the filtrate was concentrated under reduced
pressure. The residue was purified by column chromatography
(silica gel, light petroleum/ethyl acetate as eluent).
Conclusions
In conclusion, a series of novel ‘ethyne-linked’ compounds,
which contain a carbazole moiety and 1,8-naphthalimide group
were synthesized by a stepwise route involving a Pd/Cu-
catalyzed Sonogashira coupling reaction. These compounds
were fully characterized, and their optical, thermal, and elec-
trochemical properties were also investigated. These properties
implied that these compounds might be used as a blue-green

Novel ‘Ethyne-Linked’ Compounds
937
(a)
8.0, 1H). δC (75 MHz, CDCl3) 14.35, 20.89, 30.69, 40.84, 87.60,
98.66, 110.15, 120.93, 121.46, 122.79, 123.53, 124.15, 126.62,
127.44, 127.67, 127.99, 128.53, 130.81, 131.34, 132.09, 132.68,
133.94, 139.16, 140.83, 164.19, 164.44. m/z (HRMS) 518.1992
(M+), calc. for C36H26N2O2: 518.1994.
10a
10c
10e
10g
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
6-((4-(9H-Carbazol-9-yl)phenyl)ethynyl)-2-(4-
methoxyphenyl)-1H-benzo[de]isoquinoline-
1,3(2H)-dione 10b
49% yield; yellow solid. Mp >300◦C. νmax(KBr)/cm−1 3067,
2961, 2932, 2839, 2202, 1701, 1663, 1585, 1512. δH (400 MHz,
CDCl3) 3.89 (s, 3H), 7.07 (s, 1 H), 7.10 (s, 1H), 7.25 (s, 1H), 7.27
(s, 1H), 7.32–7.36 (m, 2H), 7.44–7.52 (m, 4H), 7.70 (d, J 8.4,
2H), 7.89–7.94 (m, 2H), 7.94–7.95 (m, 1H), 8.06 (d, J 7.6, 1H),
8.17 (d, J 7.6, 2H), 8.65 (d, J 7.6, 1H), 8.72 (d, J 7.6, 1H), 8.86
(d, J 8.4, 1H). δC (75 MHz, CDCl3) 55.96, 86.70, 99.78, 110.17,
115.22, 120.94, 122.67, 122.87, 124.17, 124.22, 126.63, 126.91,
127.07, 127.45, 127.99, 128.10, 128.20, 128.42, 128.90, 129.06,
129.15, 129.25, 129.98, 131.27, 131.40, 132.22, 132.42, 132.49,
132.62, 133.09, 133.19, 133.97, 134.23, 134.37, 140.61, 140.82,
160.05, 164.59, 164.86. m/z (HRMS) 568.1785 (M+), calc. for
C39H24N2O3: 568.1787.
250
300
350
400
450
500
550
Wavelength [nm]
(b)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
10b
10d
10f
10h
2-Butyl-6-((9-butyl-9H-carbazol-3-yl)ethynyl)-1H-
benzo[de]isoquinoline-1,3(2H)-dione 10c
68%yield;orangesolid. Mp185–186◦C. νmax(KBr)/cm−1 3053,
2958, 2927, 2858, 2192, 1692, 1652, 1586, 1509. δH (400 MHz,
CDCl3) 0.95–1.01 (m, 6H), 1.36–1.51 (m, 4H), 1.69–1.77 (m,
2H), 1.82–1.91 (m, 2H), 4.17 (t, J 8.0, 2H), 4.30 (t, J 7.2, 2H),
7.27(t, J6.8, 1H), 7.41(t, J7.0, 2H), 7.48–7.56(m, 1H), 7.74(d, J
8.4, 1H), 7.81 (t, J 7.8, 1H), 7.90 (t, J 7.2, 1H), 8.09 (d, J 7.6, 1H),
8.37 (s, 1H), 8.50 (d, J 7.6, 1H), 8.60 (d, J 7.2, 1H), 8.78 (d, J 8.4,
1H). δC (100 MHz, CDCl3) 14.34, 20.90, 21.02, 30.72, 31.57,
40.76, 43.50, 85.56, 101.94, 109.43, 109.55, 110.25, 112.50,
120.14, 121.02, 121.85, 122.78, 123.40, 123.50, 125.03, 126.87,
127.60, 128.56, 128.90, 129.93, 130.60, 130.88, 131.88, 131.96,
132.98, 141.14, 141.33, 164.27, 164.54. m/z (HRMS) 498.2320
(M+), calc. for C34H30N2O2: 498.2307.
250
300
350
400
450
500
550
Wavelength [nm]
(c)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
11a
11b
6-((9-Butyl-9H-carbazol-3-yl)ethynyl)-2-(4-
methoxyphenyl)-1H-benzo[de]isoquinoline-
1,3(2H)-dione 10d
62% yield; yellow solid. Mp 227–228◦C. νmax(KBr)/cm−1 3057,
2958, 2930, 2860, 2194, 1705, 1660, 1585, 1513. δH (400 MHz,
CDCl3) 0.98 (t, J 7.0, 3H), 1.41–1.46 (m, 2H), 1.88–1.92 (m,
2H), 3.88 (s, 3H), 4.35 (t, J 7.0, 2H), 7.08 (d, J 8.4, 2H), 7.25 (s,
2H), 7.29–7.32 (m, 1H), 7.46 (d, J 8.0, 2H), 7.51–7.59 (m, 1H),
7.79 (d, J 8.4, 1H), 7.90 (t, J 7.6, 1H), 8.00 (d, J 7.6, 1H), 8.15 (d,
J 7.6, 1H), 8.45 (s, 1H), 8.61 (d, J 7.6, 1H), 8.70 (d, J 7.2, 1H).
δC (75 MHz, CDCl3) 14.35, 21.02, 31.56, 43.50, 55.94, 85.57,
102.30, 109.48, 109.57, 112.39, 115.20, 120.14, 121.04, 121.89,
122.76, 123.49, 125.09, 125.27, 126.89, 127.72, 128.33, 128.92,
129.30, 130.02, 130.67, 131.34, 132.10, 132.36, 133.39, 141.32,
159.99, 160.05, 164.66, 164.95. m/z (HRMS) 548.2102 (M+),
calc. for C37H28N2O3: 548.2100.
250
300
350
400
450
500
550
Wavelength [nm]
Fig. 1. UV-Visible absorption spectra of compounds 10a–h and 11a–b in
CH2Cl2 solution.
6-((4-(9H-Carbazol-9-yl)phenyl)ethynyl)-2-butyl-1H-
benzo[de]isoquinoline-1,3(2H)-dione 10a
61% yield; yellow solid. Mp 227–228◦C. νmax(KBr)/cm−1 3065,
2963, 2926, 2857, 2209, 1701, 1663, 1590, 1516. δH (400 MHz,
CDCl3) 1.00 (t, J 7.2, 3H), 1.43–1.50 (m, 2H), 1.71–1.78 (m,
2H), 4.21 (t, J 7.4, 2H), 7.33 (t, J 7.2, 2H), 7.43–7.50 (m, 4H),
7.69 (d, J 8.0, 2H), 7.86–7.93 (m, 3H), 8.02 (d, J 7.6, 1H), 8.17
(d, J 8.0, 2H), 8.60 (d, J 7.6, 1H), 8.68 (d, J 7.2, 1H), 8.79 (d, J
2-Butyl-6-((9-hexyl-9H-carbazol-3-yl)ethynyl)-
1H-benzo[de]isoquinoline-1,3(2H)-dione 10e
81%yield;orangesolid. Mp166–167◦C. νmax(KBr)/cm−1 3056,
2958, 2927, 2859, 2197, 1689, 1649, 1586, 1512. δH (400 MHz,
CDCl3) 0.88 (t, J 6.6, 3H), 0.99 (t, J 7.4, 3H), 1.26–1.32 (m, 4H),
1.38–1.50 (m, 4H), 1.70–1.78 (m, 2H), 1.87–1.96 (m, 2H), 4.20

938
Y. Liu et al.
Table 1. Optical, thermal, and electrochemical properties of the ethyne-linked 1,8-naphthalimide derivatives
HOMO, highest occupied molecular orbitals; LUMO, lowest unoccupied molecular orbital
C
D
D
F
Compounds
AbsA [nm]
DCM
em [nm]
ꢀB
Eg [eV]
Epa [V]
Epc [V]
HOMO/LUMOE [eV]
Tm/Td [◦C]
DCM
Solid
10a
10b
10c
10d
10e
10f
10g
10h
11a
11b
393
399
425
435
430
435
425
432
424
426
556
559
555
558
557
560
544
550
440
526
556
556
608
583
588
605
557
606
554
556
0.501
0.270
0.424
0.485
0.482
0.438
0.802
0.397
0.890
0.101
2.65
2.67
2.51
2.48
2.53
2.46
2.56
2.47
2.79
2.77
0.94
0.77
0.78
0.79
1.26
1.24
0.92
1.25
0.73
0.93
0.73
Not available
Not available
Not available
1.19
−5.34/−2.69
−5.17/−2.50
−5.18/−2.67
−5.19/−2.71
−5.66/−3.13
−5.64/−3.18
−5.32/−2.76
−5.65/−3.18
−5.13/−2.34
−5.33/−2.56
178/364
199/381
228/387
328/487
207/340
222/347
227/407
144/399
390/440
320/452
1.18
0.69
1.17
0.66
0.74
AFirst absorption peak in dilute CH2Cl2 solution (10−6 mol L−1).
BQuantum yields (ꢀ) in CH2Cl2 solutions were determined using Rhodamine 6G as the standard (ꢀ = 0.595 in ethanol).
CDetermined from UV-visible absorption spectra.
DEpc and Epa potential were determined by cyclic voltammetry in CH2Cl2 (1.0 × 10−4 mol L−1) containing 0.1 M Bu4NPF6 as a supporting electrolyte, scan
rate 100 mV s−1. Platinum was used as working electrode and as a counter electrode, and scanning calomel electrode as a reference electrode.
EEHOMO = −(Epa + 4.4) (eV), LUMO = HOMO + Eg.
FMeasured by thermal gravity analysis and differential thermal analysis under N2 at a heating rate of 10◦C min−1
.
ꢃ1.0 ꢂ 10ꢃ5
ꢃ8.0 ꢂ 10ꢃ6
ꢃ6.0 ꢂ 10ꢃ6
ꢃ4.0 ꢂ 10ꢃ6
10a
10b
10c
10d
10e
10f
10a
350
300
250
200
150
100
50
10g
10h
ꢃ2.0 ꢂ 10ꢃ6
0.0
2.0 ꢂ 10ꢃ6
4.0 ꢂ 10ꢃ6
6.0 ꢂ 10ꢃ6
0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
450
500
550
600
650
700
E [V] versus SCE
Wavelength [nm]
Fig. 3. Cyclic voltammogram of compound 10a in 0.1 mol L−1
Bu4NPF6/CH2Cl2, scan rate 100 mV s−1
Fig. 2. Photoluminescence emission spectra of compounds 10a–h in
CH2Cl2 solution.
.
CDCl3) 14.45, 22.97, 27.36, 29.33, 31.95, 43.63, 55.88, 85.56,
102.30, 109.38, 109.46, 112.34, 115.11, 120.06, 120.95, 121.72,
122.66, 123.34, 123.39, 125.01, 126.80, 127.55, 128.29, 128.74,
129.14, 129.90, 130.00, 130.51, 131.15, 131.91, 132.16, 133.20,
141.05, 141.18, 159.91, 164.51, 164.81. m/z (HRMS) 576.2408
(M+), calc. for C39H32N2O3: 576.2413.
(t, J 7.4, 2H), 4.34 (t, J 7.0, 2H), 7.30 (t, J 7.4, 1H), 7.45 (d, J 8.4,
2H), 7.53 (t, J 8.0, 1H), 7.78 (d, J 8.0, 1H), 7.87 (t, J 7.8, 1H), 7.98
(d, J 7.6, 1H), 8.16 (d, J 7.6, 1H), 8.44 (s, 1H), 8.58 (d, J 7.6, 1H),
8.66 (d, J 7.2, 1H), 8.86 (d, J 8.0, 1H). δC (100 MHz, CDCl3)
14.35, 14.49, 20.89, 23.02, 27.42, 29.40, 30.70, 32.01, 40.75,
43.72, 85.55, 101.94, 123.33, 123.44, 125.01, 126.85, 127.57,
128.51, 128.86, 129.92, 130.56, 130.86, 131.85, 131.91, 132.96,
141.09, 141.25, 164.24, 164.52. m/z (HRMS) 526.2613 (M+),
calc. for C36H34N2O2: 526.2620.
2-Butyl-6-((9-phenyl-9H-carbazol-3-yl)ethynyl)-
1H-benzo[de]isoquinoline-1,3(2H)-dione 10g
65% yield; yellow solid. Mp 208–209◦C. νmax(KBr)/cm−1 3056,
2954, 2929, 2869, 2197, 1699, 1662, 1587, 1506. δH (400 MHz,
CDCl3) 0.98 (t, J 7.2, 3H), 1.41–1.48 (m, 2H), 1.67–1.73 (m,
2H), 4.14 (t, J 7.4, 2H), 7.22–7.46 (m, 4H), 7.51–7.57 (m, 3H),
7.62–7.67 (m, 3H), 7.80 (t, J 7.4, 1H), 7.89 (t, J 7.2, 1H), 8.11
(d, J 7.6, 1H), 8.30–8.38 (m, 1H), 8.49 (d, J 7.2, 1H), 8.58 (d,
J 6.8, 1H), 8.71–8.77 (m, 1H). δC (100 MHz, CDCl3) 14.31,
20.86, 30.65, 40.72, 85.76, 101.55, 110.52, 110.58, 112.03,
113.69, 120.91, 121.14, 121.88, 123.10, 123.33, 123.95, 124.91,
127.15, 127.39, 127.51, 127.59, 128.41, 128.48, 128.69, 130.19,
130.50, 130.65, 130.81, 131.86, 131.89, 132.91, 137.45, 141.46,
6-((9-Hexyl-9H-carbazol-3-yl)ethynyl)-2-(4-
methoxyphenyl)-1H-benzo[de]isoquinoline-
1,3(2H)-dione 10f
74%yield;orangesolid. Mp177–178◦C. νmax(KBr)/cm−1 3056,
2956, 2924, 2856, 2189, 1701, 1663, 1583, 1510. δH (400 MHz,
CDCl3) 0.86 (t, J 6.4, 3H), 1.29–1.37 (m, 6H), 1.83–1.86 (m,
2H), 3.85 (s, 3H), 4.24 (t, J 7.0, 2H), 7.05 (d, J 8.8, 2H), 7.23–
7.26 (m, 3H), 7.37 (t, J 9.2, 2H), 7.49 (t, J 7.4, 1H), 7.72–7.79
(m, 2H), 7.87 (d, J 7.6, 1H), 8.05 (d, J 7.6, 1H). δC (100 MHz,

Novel ‘Ethyne-Linked’ Compounds
939
141.82, 164.18, 164.46. m/z (HRMS) 518.1986 (M+), calc. for
C36H26N2O2: 518.1994.
Higher Education (grant no. 20060285001), and Key Laboratory of Organic
Synthesis of Jiangsu Province (grant no. JSK008).
References
2-(4-Methoxyphenyl)-6-((9-phenyl-9H-carbazol-3-
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Acknowledgements
The present work was partially supported by the National Natural Science
Foundation of China (grant no. 20672079), Natural Science Foundation
of Jiangsu Province (grant no. BK2006048), Nature Science of Jiangsu
Province for Higher Education (grant no. 05KJB150116), Nature Science
Key Basic Research of Jiangsu Province for Higher Education (grant no.
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