Synthesis and photophysical properties of tetrafluorophenyl-modified carbazole oligomers

Article abstract of DOI:10.1016/j.tet.2010.07.040

A series of tetrafluorophenyl-modified oligo(3,6-carbazole ethynylene)s (CfCzCf, CfCz2Cf, CfCz3Cf, (CfCz)2Cf, and Cf2CzCf2) were synthesized by a Pd/Cu-catalyzed Sonogashira coupling reaction and fully characterized. Their photophysical and electronic properties as well as their thermal stabilities were investigated. It is noteworthy that these tetrafluorophenyl modified compounds showed relative thermal stabilities and low-lying HOMO levels ranging from -5.54 to -5.60 eV, which might be the promising candidates for hole-transporting materials in OLEDs.

Full text of DOI:10.1016/j.tet.2010.07.040

Tetrahedron 66 (2010) 7583e7589
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis and photophysical properties of tetrafluorophenyl-modified carbazole
oligomers
*
*
Binbin Hu, Yifei Wang, Xiaopeng Chen, Zujin Zhao, Zhitao Jiang, Ping Lu , Yanguang Wang
Department of Chemistry, Zhejiang University, Hangzhou 310027, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 27 May 2010
Received in revised form 13 July 2010
Accepted 16 July 2010
Available online 30 July 2010
A series of tetrafluorophenyl-modified oligo(3,6-carbazole ethynylene)s (CfCzCf, CfCz2Cf, CfCz3Cf, (CfCz)
2Cf, and Cf2CzCf2) were synthesized by a Pd/Cu-catalyzed Sonogashira coupling reaction and fully
characterized. Their photophysical and electronic properties as well as their thermal stabilities were
investigated. It is noteworthy that these tetrafluorophenyl modified compounds showed relative thermal
stabilities and low-lying HOMO levels ranging from ꢀ5.54 to ꢀ5.60 eV, which might be the promising
candidates for hole-transporting materials in OLEDs.
Keywords:
Carbazoles
Ó 2010 Elsevier Ltd. All rights reserved.
Fluorescence
Structureeproperty relationship
Optoelectronics material
Sonogashira coupling
1. Introduction
reported a series of oligocarbazoles with ethynylene linkage, which
presented good hole-transporting properties.10 In order to obtain
Over the past 10 years, conjugated oligomers have been subjected
to important investigations in both academic and industrial labora-
tories1 due to their promising applications, such as organic light-
emitting diodes (OLEDs),2 solar cells,3 field-effect transistors (FETs),4
and models5 for understanding the structureeproperty relation-
ships of their analogous polydisperse polymers. Development of
synthetic methodology has made it possible to synthesize a variety of
soluble monodisperse oligomers, which are designed to be tunable in
color and/or charge injection properties through introduction of
functional groups, as well as conjugated length.6 Compared with
polydispersity, the monodisperse oligomers exhibit advantages of
structural uniformity, convenient purification, and easy modification.
Because of the specific optical and electrochemical properties,
carbazole and its derivatives are well-known and have been widely
used as functional building blocks in the fabrication of the organic
photoconductors, nonlinear optical materials, and photorefractive
materials.7 Carbazole can be easily modified at its 3-, 6-, or 9-po-
sition and covalently linked to other molecular moieties.8 It is also
recognized that the introduction of carbozoles into the core
structures of organic compounds can greatly improve compounds’
thermal stability or glass-state durability.9 Recently, a series of
carbazole derivatives with ethynylene linkages have been fully
reported,10 as well as dibenzosilole.11 In our previous studies, we
better understanding of oligocarbazoles and to extend application
in its utility, here we wish to report a new set of oligocarbazoles,
which were modified with 9-tetrafluorophenyl groups. These
oligomers could be used as models to understand fluorescent
structureeproperty relationship of their corresponding polymers
and be potentially applied as hole transporting.
2. Results and discussion
2.1. Synthesis
APd/Cu-catalyzed Sonogashira couplingreactionwas used to build
ethynylene-linked molecules. Detailed experimental conditions for
oligomers’ formationwere similar to the published method. Synthetic
approach to necessary intermediates 1e11 was outlined in Scheme 1.
Compound 1 was synthesized by Ullmann reaction between 3-iodo-
9H-carbazole12 and 1,2,3,4,5-pentafluoro-6-iodobenzene.13 After
treatment 1 and trimethylsilylacetylene via Sonogashira coupling and
subsequent deprotection, 3 was obtained in 85% yield. Compound 5
was synthesized in a similar procedure with 65% yield and 4 was
prepared according to the reported method.14 Coupling 3 with 3 equiv
of 4 in the presence of CuI/Pd(PPh3)2Cl2/PPh3/NEt3 afforded in-
termediate (6)13 in 76% yield. Sequentially, 6 was converted to 8 in 78%
yield. Similarly, 9 was obtained bycoupling 3 and 5 in81% yield, which
was further converted to 11 in 68% yield.
* Corresponding authors. E-mail addresses: Pinglu@zju.edu.cn (P. Lu), orgwyg@
zju.edu.cn (Y. Wang).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.07.040

7584
B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
I
I
I
R
N
I
C7H15
N
d 73%
b
N
R
a
I
I
F
F
F
F
F
F
F
F
4
85%
N
H
I
I
N
H
1
TMS
H
2
=
a
65%
c
N
100%
F
F
F
3 R
=
F
C7H15
N
5
C7H15
N
R
I
4, e
b
76%
TMS
H
7
8
R
=
76%
c
N
100%
N
F
F
F
F
R
=
F
F
F
F
F
F
F
F
F
F
F
F
6
3
N
N
I
R
5, e
b
N
N
10
TMS
H
R
R
=
81%
68%
F
F
F
F
F
c
100%
F
F
F
11
=
9
Scheme 1. (a) Iodopentafluorobenzene, Cu(powder), K2CO3, 18-crown-6, DMF, N2, reflux; (b) trimethylsilylacetylene CuI, Pd(PPh3)2Cl2, PPh3, NEt3, N2, reflux; (c) K2CO3, n-Bu4NF,
methanol, THF, N2, reflux; (d) n-C7H15Br, KOH, tetrabutylammonium hydrogen sulfate, acetone, rt; (e) CuI, Pd(PPh3)2Cl2, PPh3, NEt3, N2, reflux.
Final construction to target molecules was illustrated in Scheme 2.
CfCzCfandCfCz2Cfwere obtainedin53%and55%yields, respectively.
Coupling of 4 with 2 equiv of 8 led to CfCz3Cf in 62% yield. Similarly,
(CfCz)2Cf and Cf2CzCf2 were obtained in 53% and 46% yields, re-
spectively. Due to the presence of the flexible n-heptyl substitutes, all
of these synthesized oligomers were soluble in common organic
solvents, such as dichloromethane (DCM) and tetrahydrofuran (THF).
Attempt to obtain pure Cf5 via coupling of 5 and 11 failed due to the
soluble problem.
Structures of the target compounds were characterized by NMR,
MALDI-TOF mass spectroscopy, and high resolution mass spec-
troscopy. Further, these compounds showed good thermal stabili-
ties. The glass transition, melting, and decomposition temperatures
of these compounds, determined by differential scanning calo-
rimetry (DSC) and thermogravimetric analysis (TGA) under N2 at
a heating rate of 10 ꢁC/min, were shown in Table 1. The de-
composition temperatures (Td, 5% loss of initial weight) of these
oligomers CfCzCf, CfCz2Cf, CfCz3Cf, (CfCz)2Cf, and Cf2CzCf2 were
551.3 ꢁC, 534.2 ꢁC, 458.5 ꢁC, 317.3 ꢁC, and 497.2 ꢁC, respectively.
orbitals. Figure 1 illustrated the energy-minimized structure of
Cf2CzCf2 as a representative. Others were listed in Supplementary
data. It was noteworthy that each tetrafluorophenyl group was
perpendicular to its carbazole matrix, which inferred that the steric
hindrance could hamper the intermolecular packing of oligo-
carbazoles and thereafter hinder its aggregation and/or excimer
formation. Similar situations were observed in the cases of other
four compounds.
Figure 2 illustrated the HOMO and LUMO orbitals of Cf2CzCf2.
Electron cloud at its ground state was mostly located at the central
carbazole, while the electron cloud at its excited state was ex-
tremely centered at one of tetrafluorophenyl groups. Similar dis-
tribution of electron cloud of HOMOs and LUMOs could be observed
in other four compounds (see Supplementary data). We could infer
that the electron be promoted from carbazole to tetrafluorophenyl
group when the molecule was excited.
2.3. Photophysical properties
The UVevis absorption and photoluminescence of these com-
pounds in dilute solutions (10ꢀ5 M) as well as their emissions in
solid states were presented in Table 1.
2.2. Visualization and simulation
Structures of the synthesized compounds were optimized by
Gaussian 03 through PM3 method, as well as the HOMO and LUMO
Absorption spectra of these oligomers were complex with
multiple overlapping broad bands. Figure 3a and b illustrated their

B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
7585
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
C7H15
N
N
N
N
N
1
e, 53%
CfCzCf
F
F
N
N
N
F
F
F
F
F
F
F
F
C7H15
C7H15
N
F
F
Cf2CzCf2
N
e,46%
6
CfCz2Cf
e, 55%
4 + 11
N
N
C7H15
F
F
F
F
F
F
F
F
F
F
F
F
8
C7H15
N
N
N
CfCz3Cf
4
e, 62%
N
C7H15
N
C7H15
F
F
F
F
F
F
F
F
F
F
F
F
N
N
N
5
(CfCz)2Cf
e, 53%
N
N
C7H15
C7H15
Scheme 2. (e) CuI, Pd(PPh3)2Cl2, PPh3, NEt3, N2, reflux.
Table 1
Optical and electrochemical properties of the oligomers
Abs (nm)a
Em. (nm)
THF
Fb
Egc (eV)
E
d (V)
HOMO/LUMOe (eV)
Tg/Tm/Td (ꢁC)
f
ox
Compound
onset
THF(
3
ꢂ105)
Powder
CfCzCf
355(0.50)
360(0.31)
363(0.77)
356(1.51)
339(1.71)
382, 400
382, 402
382, 403
382, 400
380, 400
431
454
441e465
464
409
0.25
0.32
0.38
0.28
0.31
3.25
3.21
3.16
3.14
3.23
1.17
1.16
1.14
1.17
1.20
ꢀ5.57/ꢀ2.32
ꢀ5.56/ꢀ2.35
ꢀ5.54/ꢀ2.38
ꢀ5.57/ꢀ2.43
ꢀ5.60/ꢀ2.37
110.4/d/551.3
133.1/d/534.2
131.1/d/458.5
223.0/266.5/317.3
d/220.0/497.2
CfCz2Cf
CfCz3Cf
(CfCz)2Cf
Cf2CzCf2
a
First absorption peak;
Measured in THF solutions using DPA as a standard.
b
c
d
e
f
Determined from UVevis absorption spectra.
ox
E
¼onset oxidation potential; Potentials vs Ag/AgCl, working electrode Pt, 0.1 M Bu4NPF6eTHF, scan rate 100 mV/s.
onset
ox
HOMO ¼ E
þ 4:4eV; LUMO¼HOMOꢀEg eV.
onset
Measured by DSC and TGA analysis in N2 at heating rate of 10 ꢁC/min.
UVevis absorption spectra with the same concentration (10ꢀ5 M)
in THF. CfCzCf, CfCz2Cf, and CfCz3Cf (Fig. 3a) exhibited similar
absorption patterns but different maximum absorption wave-
lengths, varied from 355 nm to 363 nm, increasing with the elon-
gation of the conjugated length of these molecules.14 With the
same conjugation lengths, CfCz3Cf, (CfCz)2Cf, and Cf2CzCf2
(Fig. 3b) presented the decreasing maximum absorption wave-
lengths as the number of tetrafluorophenyl group increased. In
addition, the more tetrafluorophenyl groups attached the higher
molar absorptivity (Table 1). The pep energy gaps (Eg, Table 1) of
*
these oligomers were calculated from the UVevis absorption
threshold, which ranged from 3.14 eV to 3.25 eV. It is noteworthy
that all of these UVevis spectra exhibited the broad absorption
peaks ranging from 230 nm to 380 nm, which indicated that these
compounds could absorb light and be excited within a wide range.
Figure 1. Energy-minimized Cf2CzCf2 calculated by Gaussian 03 through PM3 method.

7586
B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
Figure 2. HOMO (left) and LUMO (right) orbitals of Cf2CzCf2, calculated by Gaussian 03 through PM3 method.
1.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
(c)
(a)
(e)
CfCzCf
CfCzCf
CfCzCf
1.0
0.8
0.6
0.4
0.2
0.0
CfCz2Cf
CfCz3Cf
CfCz2Cf
CfCz3Cf
CfCz2Cf
CfCz3Cf
0.8
0.6
0.4
0.2
0.0
240
280
320
360
400
360
400
440
480
400
450
Wavelength(nm)
500
550
600
Waveleng
th(nm)
Wavelenght(nm)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
(d)
(b)
CfCz3Cf
Cf3Cz2
CfCz3Cf
Cf3Cz2
)
(
CfCz3Cf
Cf3Cz2
f
1.0
0.8
0.6
0.4
0.2
0.0
Cf2CzCf2
Cf2CzCf2
Cf2CzCf2
240
280
320
360
400
360
400
440
480
400
450
500
g
550
600
g
Wavelen ht(nm)
ng
Wavele th
(nm)
(nm)
Wavelen th
Figure 3. UVevis absorption spectra (a and b), PL emission spectra in THF (c and d), and solid state (e and f).
Figure 3c and d presented the photoluminescence (PL) emission
spectra of these oligomers excited at about 360 nm. These com-
pounds showed blue PL emissions with the maximum emission
peaks at about 400 nm and shoulder peaks at 382 nm in THF solu-
tions. Stokes shifts were 27 nm, 22 nm, and 19 nm for CfCzCf,
CfCz2Cf, and CfCz3Cf, respectively. The more tetrafluorophenyl
groups attached the larger Stokes shift. As for Cf2CzCf2, Stokes shift
was determined up to 41 nm in THF, which indicated that the con-
formational variation between the twisty ground state and planar
excited state was the largest.15 PL quantum yield was measured in
the range of 0.25e0.38 in degassed THF solutions using 9,10-
solid
1.0
0.8
0.6
0.4
0.2
0.0
cyclohexane
THF
DCM
350 400 450 500 550 600
Wavelength(nm)
diphenylanthracene (DPA,
F
¼0.95)16 as a standard. The relatively
Figure 4. PL emission spectra of Cf2CzCf2 in cyclohexane, THF, DCM, and solid state.
low quantum yield might be due to the decentralization of excitons
caused by the strong electron withdrawing moiety.17 Figure 3e and f
illustrated thePL emission spectra of their solid states. It was obvious
that the emission in solid state was red-shifted greatly except
Cf2CzCf2. Moreover, the full width at half emission maximum at
solid state was much wider than that in solutions.
Solvent effect was investigated in solutions of cyclohexane, THF,
and DCM. The representative spectrum of Cf2CzCf2 is shown in
Figure 4. The emission wavelength was red-shifted slightly with the
increment of solvent polarity. The emission of Cf2CzCf2 at solid state
was red-shifted 9 nm with respect to that in solutions (Table 1). It
inferred that the conformation of Cf2CzCf2 at solid state was similar
to that in THF. Four 2,3,5,6-tetrafluorophenyls not only restrained
delocalization of the lone electron pair of the nitrogen atoms18 but
also decreased the intermolecular interaction in solid state due to
their strong steric hindrance.
investigated (Fig. 5). In diluted solution (10ꢀ7 M) the emission
spectra have two peaks: shoulder peak at 382 nm and major peak
at 400 nm. As the concentration of Cf2CzCf2 increased, the
-7
1*10
M
1.0
0.8
0.6
0.4
0.2
0.0
-6
1*10
1*10
M
-4
M
-4
5*10
M
-3
1*10
M
solid
360
400
440
480
520
Wavelenght(nm)
In order to understand the broaden emission spectrum in film,
emission of Cf2CzCf2 in THF with different concentrations was
Figure 5. PL emission spectra of Cf2CzCf2 in THF with different concentrations.

B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
7587
emission peak was slightly red-shifted while the relative intensity
of the shoulder peak decreased. Finally, this shoulder peak dis-
appeared when the concentration was up to 1ꢂ10ꢀ3 M. It indicated
that Cf2CzCf2 displayed a highly structured emission in diluted
solution. While at higher concentrations, restricted rotation of
equipped with a xenon lamp. UVevis absorption spectra were
recorded on Shimadzu UV-2450 spectrophotometer. Cyclic vol-
tammetric measurements were performed with CHI660A electro-
chemical work station, using Pt working electrode, an auxiliary Pt
electrode, and an Ag/AgCl reference electrode. The solvents were
distilled before used. Commercially available reagents were used
without further purification unless otherwise.
tetrafluorophenyl made the formation of intermolecular
pep
stacking of backbone possible, and the profile of the emission be-
came structureless and broadish.
4.2. General procedure for the synthesis of compounds 9,
CfCzCf, CfCz2Cf, CfCz3Cf, (CfCz)2Cf, and Cf2CzCf2
2.4. Cyclic voltammetric studies
The electronic properties of these compounds were investigated
by cyclic voltammetry at room temperature and the results were
listed in the Table 1. Figure 6 shows cyclic voltammograms (CVs) of
these compounds. All these oligomers displayed an irreversible
reduction peak, which might be due to the nature of the electron
withdrawing of tetrafluorophenyl groups, as well as an irreversible
oxidation peak, which might be attributed to the nature of the
electron donating of carbazole segment. According to CVs and
UVevis absorptions, the highest occupied molecular orbital
(HOMO) and lowest unoccupied molecular orbital (LUMO) energy
levels were estimated (Table 1). The HOMO energy levels ranged
from ꢀ5.54 eV to ꢀ5.60 eV with a steady increment as the number
of tetrafluorophenyl units rose up. Furthermore, the HOMO and
LUMO energy levels of these oligomers were comparable to those of
widely used hole-transporting materials (NPB: HOMO, ꢀ5.2 eV;
LUMO, ꢀ2.2 eV),19 and therefore, these compounds might be used
for hole-transporting materials in OLEDs.
These compounds were obtained following an essentially sim-
ilar procedure. An illustrative example is provided for 9.
Compound 9: 3 (339 mg, 1 mmol), 5 (1707 mg, 3 mmol), cu-
prous iodide (10 mg, 0.05 mmol), dichlorobis(triphenylphosphine)
palladium(II) (3.5 mg, 0.005 mmol), triphenylphosphine (5 mg,
0.02 mmol), dry triethylamine 100 mL were placed in a 150 mL
round bottle flask equipped with a Teflon covered magnetic stir bar.
After the solution was purged with nitrogen for half an hour, it was
refluxed under nitrogen for 4 h. The reaction mixture was filtered
and the filtration was evaporated under reduced pressure. The
residue was purified through column chromatography (silica gel,
hexane/methylene chloride as eluent).
4.2.1. Compound 9. Yield 82%; 1H NMR (400 MHz, CDCl3)
d 8.48 (d,
J¼1.3 Hz, 1H), 8.39 (s, 1H), 8.32 (s, 1H), 8.18 (d, J¼7.6 Hz, 1H),
7.81e7.62 (m, 3H), 7.51 (t, J¼7.6 Hz, 1H), 7.43e7.28 (m, 3H), 7.18 (dd,
J¼16.9, 8.2 Hz, 3H), 6.96 (d, J¼8.6 Hz, 1H) ppm; 13C NMR (CDCl3)
Figure 6. Cyclic voltammograms of oligomers (0.25 mM) in 0.1 M Bu4NPF6eCH2Cl2, scan rate 100 mV/s.
3. Conclusions
d
147.93e147.65 (m), 145.32e144.93 (m), 142.47 (d, JCF¼16.2 Hz),
140.20, 139.45, 139.34, 139.22, 135.20, 130.66, 130.00, 129.62,
126.96, 125.99, 124.18, 124.02, 123.95, 123.57, 122.84, 121.60, 120.71,
116.99e116.13 (m), 111.93, 110.06, 109.95, 106.34 (q, JCF¼23.1 Hz),
89.24, 88.52, 77.35, 77.04, 76.72.
In summary, we had successfully synthesized and fully charac-
terized a series of novel compounds with well-controlled, alter-
native alkyl carbazole and tetrafluorophenyl carbazole structures. It
was obvious that the introduction of tetrafluorophenyl moiety
influenced the emissions no matter in solutions or in solids. These
synthesized compounds might be used as models to study struc-
tureeproperty relationship for their corresponding polymers or
applied in optoelectronic devices directly. Further study will be
focused on their applications in devices.
4.2.2. Compound CfCzCf. Yield 53% ; 1H NMR (400 MHz, CDCl3)
d
8.36 (d, J¼11.5 Hz, 4H), 8.15 (d, J¼7.7 Hz, 2H), 7.69 (t, J¼7.6 Hz, 4H),
7.47 (t, J¼7.6 Hz, 2H), 7.40e7.24 (m, 6H), 7.15 (t, J¼7.8 Hz, 4H), 4.25
(t, J¼6.8 Hz, 2H), 1.92e1.76 (m, 2H), 1.33 (s, 4H), 1.26 (s, 4H), 0.86 (t,
J¼6.8 Hz, 3H) ppm; 13C NMR (CDCl3)
d 147.90e147.78 (m),
145.29e144.95 (m), 142.52 (d, JCF¼16.6 Hz), 140.34, 140.23, 139.23,
130.02,129.65,126.89,124.19,124.04,123.84,123.66,122.56,121.56,
120.71, 117.08 (t, JCF¼13.9 Hz), 116.63, 114.13, 109.90, 109.02, 106.13
(t, JCF¼22.6 Hz), 89.49, 88.37, 77.36, 77.04, 76.72, 43.32, 31.72, 29.05,
28.99, 27.24, 22.58, 14.06 ppm; MS (MALDI) (m/z): 393.3 (Mþ).
HRMS: calcd for C59H37F8N3 [Mþ] (m/z) 939.2860, found 939.2854.
4. Experimental
4.1. General
1H and 13C NMR spectra were obtained on a Bruker AVANCE
DMX400 spectrometer operating in the FT mode. Five percent w/v
solutions in chloroform-d were used to obtain NMR spectra. TMS
was used as an internal standard. IonSpec HiResMALDI was used to
obtain mass spectra. Fluorescence measurements were made with
4.2.3. Compound CfCz2Cf. Yield 55%; 1H NMR (400 MHz, CDCl3)
d
8.36 (d, J¼10.3 Hz, 6H), 8.14 (d, J¼7.7 Hz, 2H), 7.70 (dd, J¼13.3,
7.3 Hz, 6H), 7.46 (t, J¼7.7 Hz, 2H), 7.39e7.24 (m, 8H), 7.14 (t,
J¼7.9 Hz, 4H), 4.25 (t, J¼7.0 Hz, 4H), 1.92e1.78 (m, 4H), 1.34 (s, 8H),
a
RF-5301pc spectrofluorometer (Shimadzu, Kyoto, Japan)

7588
B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
1.25 (s, 8H), 0.86 (t, J¼6.6 Hz, 6H) ppm; 13C NMR (CDCl3)
THF (50 mL) were placed in a 150 mL round bottle flask equipped
with a Teflon covered magnetic stir bar. After the solution was
purged with nitrogen for half an hour, it was refluxed under nitrogen
for 4 h. The solvent was then removed and the crude product was
purified by column chromatography (silica gel, hexane/methylene
chloride as eluent) to afford 8 (488 mg, in 81% total yield).
d
147.94e147.66 (m), 145.70e144.67 (m), 142.50 (d, JCF¼15.7 Hz),
140.32, 140.23, 140.21, 139.21, 130.03, 129.66, 129.60, 126.88, 124.18,
124.04, 123.95, 123.83, 123.66, 122.57, 122.54, 121.56, 120.72, 117.07
(t, JCF¼14.4 Hz), 116.64, 114.40, 114.05, 109.91, 109.00, 106.13 (t,
JCF¼22.6 Hz), 89.55, 88.95, 88.35, 77.37, 77.05, 76.74, 43.30, 31.74,
29.06, 29.00, 27.25, 22.60, 14.08. ppm; MS (MALDI) (m/z): 1226.5
(Mþ). HRMS: calcd for C80H58F8N4 [Mþ] (m/z) 1226.4534, found
1226.4528.
4.3.1. Compound 8. 1H NMR (400 MHz, CDCl3)
d
8.37 (d, J¼1.1 Hz,
1H), 8.31 (d, J¼1.2 Hz, 1H), 8.26 (d, J¼1.2 Hz, 1H), 8.16 (d, J¼7.6 Hz,
1H), 7.69 (ddd, J¼9.9, 8.6, 1.5 Hz, 2H), 7.61 (dd, J¼8.5, 1.5 Hz, 1H),
7.52e7.46 (m, 1H), 7.41e7.29 (m, 4H), 7.15 (t, J¼8.3 Hz, 2H), 4.28 (t,
J¼7.2 Hz, 2H), 3.09 (s, 1H), 1.92e1.80 (m, 2H),1.41e1.30 (m, 4H), 1.25
(m, 4H), 0.86 (t, J¼6.9 Hz, 3H) ppm; 13C NMR (CDCl3)
4.2.4. Compound CfCz3Cf. Yield 62%; 1H NMR (400 MHz, CDCl3)
d
8.35 (s, 8H), 8.13 (d, J¼7.7 Hz, 2H), 7.69 (dd, J¼17.4, 8.7 Hz, 8H),
7.46 (t, J¼7.6 Hz, 2H), 7.40e7.25 (m, 10H), 7.14 (t, J¼8.3 Hz, 4H), 4.26
(t, J¼6.6 Hz, 6H), 1.85 (d, J¼6.5 Hz, 6H), 1.34 (s, 12H), 1.25 (s, 12H),
d
148.34e147.35 (m), 145.48e145.43 (m), 142.86e142.21 (m)
0.86 (t, J¼6.1 Hz, 9H) ppm; 13C NMR
d
147.91e147.58 (m),
140.64, 140.28, 139.24, 130.00, 129.73, 126.87, 124.77, 123.91, 122.39,
121.54, 120.68, 117.45e116.79 (m), 116.54, 114.25, 112.53, 109.89,
108.95, 106.13 (t, JCF¼22.6 Hz), 89.32, 88.39, 84.85, 75.36, 43.30,
31.66, 28.95, 27.19, 22.53, 14.00 ppm; MS (MALDI) (m/z): 626.2
(Mþ). HRMS: calcd for C41H30F4N2 [Mþ] (m/z) 626.2345, found
626.2340.
145.25e144.87 (m), 142.48 (d, JCF¼13.1 Hz), 140.30, 140.22, 140.18,
139.18, 129.99, 129.67, 129.58, 126.83, 124.15, 124.03, 123.93, 123.80,
123.64, 122.56, 122.52, 121.52, 120.70, 117.39e116.77 (m), 116.61,
114.41, 114.32, 114.03, 109.87, 108.95, 106.09 (t, JCF¼22.9 Hz), 89.51,
88.94, 88.87, 88.32, 43.30, 31.72, 29.04, 28.99, 27.24, 22.57,
14.06 ppm; MS (MALDI) (m/z): 1513.6 (Mþ). HRMS: calcd for
C101H79F8N5 [Mþ] (m/z) 1513.6208, found 1513.6202.
4.3.2. Compound 11. Yield 68%; 1H NMR (400 MHz, CDCl3)
d 8.37 (s,
1H), 8.33 (s, 1H), 8.29 (s, 1H), 8.15 (d, J¼7.7 Hz, 1H), 7.68 (ddd, J¼8.4,
4.8, 1.4 Hz, 2H), 7.60 (dd, J¼8.5, 1.3 Hz, 1H), 7.48 (t, J¼7.7 Hz, 1H),
7.41e7.25 (m, 3H), 7.20e7.07 (m, 4H), 3.11 (s, 1H) ppm; 13C NMR
4.2.5. Compound (CfCz)2Cf. Yield 53%; 1H NMR (400 MHz, CDCl3)
d
8.38 (d, J¼9.3 Hz, 8H), 8.14 (d, J¼7.7 Hz, 2H), 7.70 (dd, J¼18.3,
10.5 Hz, 8H), 7.47 (t, J¼7.6 Hz, 2H), 7.42e7.26 (m, 9H), 7.15 (t,
J¼8.6 Hz, 6H), 4.30 (t, J¼6.8 Hz, 4H), 1.93e1.80 (m, 4H), 1.36 (s, 8H),
1.26 (s, 8H), 0.87 (t, J¼6.3 Hz, 6H) ppm; 13C NMR (CDCl3)
(CDCl3) d 147.94e147.66 (m), 145.45e144.98 (m), 142.45 (t,
JCF¼12.3 Hz), 140.21, 140.01, 139.63, 139.35, 130.85, 130.54, 130.02,
126.96, 124.84, 124.18, 124.02, 123.97, 123.61, 123.58, 123.56, 121.60,
120.72, 116.97e116.79 (m), 116.14, 115.19, 110.11, 110.05, 109.96,
106.35 (d t, JCF¼32.0, 22.6 Hz), 89.22, 88.58, 84.06, 77.35, 77.03,
76.72, 76.28 ppm; MS (MALDI) (m/z): 676.1 (Mþ). HRMS: calcd for
C40H16F8N2 [Mþ] (m/z) 676.1186, found 676.1180.
d
147.86e147.79 (m), 145.40e144.92 (m), 142.48 (d, JCF¼11.2 Hz),
140.37,140.33,140.20,139.56,139.20,130.40,129.99,129.69,126.84,
124.16, 124.07, 123.96, 123.81, 123.64, 122.56, 121.52, 120.69,
117.08e117.01 (m), 116.58, 114.13, 114.04, 110.04, 109.88, 109.02,
106.09 (t, JCF¼22.6 Hz), 89.69, 89.43, 88.35, 88.19, 43.34, 31.70,
29.03, 28.98, 27.23, 22.56, 14.03 ppm; MS (MALDI) (m/z): 1563.5
(Mþ). HRMS: calcd for C100H65F12N5 [Mþ] (m/z) 1563.5048, found
1563.5043.
Acknowledgements
We thank the National Nature Science Foundation of China
(No. 20972137, J0830413) and the Fundamental Research Funds
for the Central Universities (2009QNA3011) for financial support.
4.2.6. Compound Cf2CzCf2. Yield 46%; 1H NMR (400 MHz, CDCl3)
d
8.37 (s, 8H), 8.14 (d, J¼7.7 Hz, 2H), 7.77e7.61 (m, 8H), 7.46 (t,
J¼7.7 Hz, 2H), 7.34 (m, 8H), 7.15 (d, J¼7.8 Hz, 8H), 4.28 (s, 2H), 1.87 (s,
Supplementary data
2H), 1.35 (s, 4H), 1.26 (s, 4H), 0.87 (t, J¼6.1 Hz, 3H) ppm; 13C NMR
(CDCl3)
d 147.88e47.76 (m), 145.35e145.08 (m), 142.46 (d,
Supplementary data associated with this article can be found in
online version at doi:10.1016/j.tet.2010.07.040.
JCF¼13.7 Hz), 140.37, 140.20, 139.63, 139.55, 139.32, 130.43, 130.37,
130.03, 129.68, 126.90, 124.17, 124.05, 123.94, 123.80, 123.75, 123.60,
122.56, 121.57, 120.71, 116.93 (d, JCF¼32.0 Hz), 116.23, 114.04, 110.07,
109.91, 109.03, 106.25 (q, JCF¼22.5 Hz), 89.74, 89.14, 88.72, 88.19,
43.31, 31.72, 29.04, 28.99, 27.24, 22.58,14.06 ppm; MS (MALDI) (m/z):
1614.4 (Mþ). HRMS: calcd for C99H51F16N5 [Mþ] (m/z) 1613.3889,
found 1613.3883.
References and notes
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4.3. General procedure for the synthesis of the compounds 8
and 11
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Both compounds were obtained following an essentially similar
procedure. An illustrative example is provided for 8.
Compound 8:
6 (729 mg, 1 mmol), trimethylsilylacetylene
(196 mg, 2 mmol), cuprous iodide (10 mg, 0.05 mmol), dichlorobis
(triphenylphosphine)palladium (II) (3.5 mg, 0.005 mmol), triphe-
nylphosphine (5 mg, 0.02 mmol), dry triethylamine 100 mL were
placed in a 150 mL round bottle flask equipped with a Teflon covered
magnetic stir bar. After the solution was purged with nitrogen for
half an hour, it was refluxed under nitrogen for 4 h. The reaction
mixture was filtered and the filtration was evaporated under re-
duced pressure. The residue was purified through column chroma-
tography (silica gel, hexane/methylene chloride as eluent) to get 7.
Then 7, n-Bu4NF (287 mg), K2CO3 (500 mg), methanol (50 mL), and
11. Li, L.; Xu, C.; Li, S. Tetrahedron Lett. 2010, 51, 622.

B. Hu et al. / Tetrahedron 66 (2010) 7583e7589
7589
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