Synthesis and photophysical properties of push-pull structures incorporating diazines as attracting part with a fluorene core

Article abstract of DOI:10.1002/ejoc.201300458

We report, herein, the synthesis of new push-pull chromophores that incorporate a diazine ring as the electron-withdrawing part and an N,N-dimethylaniline moiety as the electron-donating part. Both of which are connected to a fluorene core. The length of the conjugated backbone was increased by incorporating ethynyl linkers and triazole rings on the both sides of the fluorene. The optical and two-photon absorption (TPA) properties were investigated, which exhibitied high quantum yields (up to 70 %), significant Stokes shifts, and good TPA cross-sections. New push-pull fluorophores have been synthesized that contain a diazine ring as the electron-withdrawing part and an N,N-dimethylaniline moiety as the electron-donating part. Both of which are connected to a fluorene core. The syntheses of these structures consist of a copper-catalyzed Huisgen 1,3-dipolar cycloaddition as well as Sonogashira and Suzuki cross-coupling reactions. Copyright

Full text of DOI:10.1002/ejoc.201300458

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FULL PAPER
Push–Pull Chromophores
C. Denneval, O. Moldovan, C. Baudequin,*
S. Achelle,* P. Baldeck, N. Plé,
M. Darabantu, Y. Ramondenc ........ 1–13
Synthesis and Photophysical Properties of
Push–Pull Structures Incorporating Di-
azines as Attracting Part with a Fluorene
Core
Keywords: Two-photon absorption / Conju-
gation / Cross-coupling / Cycloaddition /
Fluorescence / UV/Vis spectroscopy
New push–pull fluorophores have been
synthesized that contain a diazine ring as
the electron-withdrawing part and an N,N-
dimethylaniline moiety as the electron-do-
nating part. Both of which are connected
to a fluorene core. The syntheses of these
structures consist of a copper-catalyzed
Huisgen 1,3-dipolar cycloaddition as well
as Sonogashira and Suzuki cross-coupling
reactions.
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C. Baudequin, S. Achelle et al.
FULL PAPER
DOI: 10.1002/ejoc.201300458
Synthesis and Photophysical Properties of Push–Pull Structures Incorporating
Diazines as Attracting Part with a Fluorene Core
Charline Denneval,[a] Oana Moldovan,[a,b] Christine Baudequin,*[a] Sylvain Achelle,*[c]
Patrice Baldeck,[d] Nelly Plé,[a] Mircea Darabantu,[b] and Yvan Ramondenc[a]
Keywords: Two-photon absorption / Conjugation / Cross-coupling / Cycloaddition / Fluorescence / UV/Vis spectroscopy
We report, herein, the synthesis of new push–pull chromo-
phores that incorporate a diazine ring as the electron-with-
drawing part and an N,N-dimethylaniline moiety as the elec-
tron-donating part. Both of which are connected to a fluorene
core. The length of the conjugated backbone was increased
by incorporating ethynyl linkers and triazole rings on the
both sides of the fluorene. The optical and two-photon ab-
sorption (TPA) properties were investigated, which exhibit-
ied high quantum yields (up to 70%), significant Stokes
shifts, and good TPA cross-sections.
stituent are one of the typical structures of second- and
third-order nonlinear optical chromophores.[7]
Introduction
Among the diazines, pyrimidine[8] and pyridazine[9] with
their highly π-deficient aromatic character are good candi-
dates for incorporation as an electron-withdrawing moiety
into push–pull scaffolds that favor intramolecular charge
transfer (ICT). Numerous pyrimidine derivatives have been
described as highly fluorescent molecules,[10] second-order
NLO chromophores,[11] and two-photon absorption (TPA)
dyes.[12] Although less numerous, some structures that con-
tain the pyridazine ring exhibit intense fluorescence[13] and
NLO properties.[14]
Fluorene is a π-conjugated molecule of choice for incor-
poration into oligomers and polymers for NLO applica-
tions.[15] These fluorene-based compounds are of great
interest, as their extended π-electron conjugation leads to
high fluorescence efficiency. Another advantage of fluorene
is related to the easy substitution at the 9-position by long
alkyl chains, which increase its solubility.
Over the past two decades, there has been considerable
interest in the synthesis and characterization of π-conju-
gated compounds because of their applications to a wide
range of electronic and optoelectronic devices. Indeed, such
compounds are used as liquid crystals,[1] components of
light-emitting devices (OLEDs) for displays and lighting,[2]
field-effect transistors (OFETs),[3] dye-sensitized solar
cells,[4] and single molecular electronics.[5] Moreover, or-
ganic molecules with large delocalized π-electron systems
are relevant to the display of important nonlinear optical
(NLO) responses and have applications to photodynamic
therapy, confocal microscopy, optical power limiting, and
3D data storage.[6] A crucial factor for exhibiting such prop-
erties is the presence and nature of electron-donating and
-accepting groups. Push–pull molecules that are constituted
of a dissymmetrical conjugated π-electron system that con-
sists of an electron-donor and an electron-withdrawing sub-
Since the discovery of the CuI-catalyzed Huisgen 1,3-di-
polar cycloaddition (CuAAC) by Sharpless[16] and Mel-
dal,[17] many examples that incorporate the 1,2,3-triazole
ring have been reported. This methodology known as “click
chemistry” has been widely used for linking two moieties to
lead to more elaborate structures. Otherwise, there are only
few examples of the use of this triazole unit as a linker in
[a] Normandie Univ, COBRA, UMR 6014 et FR 3038, Univ
Rouen; INSA Rouen, CNRS, IRCOF,
1 Rue Tesnière, 76821 Mont Saint Aignan Cedex, France
E-mail: christine.baudequin@univ-rouen.fr
Homepage: http://ircof.crihan.fr/V2/
rubrique.php3?id_rubrique=77
[b] Department of Chemistry, Babes-Bolyai University,
11 Arany Jànos St., 400028 Cluj-Napoca, Romania
[c] Institut des Sciences Chimiques de Rennes UMR 6226, IUT de the conjugation backbone of fluorescent and TPA com-
pounds.[18] Recently, the intramolecular charge transfer in
Lannion,
Rue Edouard Branly, BP 30219, 22302 Lannion Cedex, France
triazole bridge-linked fluorene derivatives has been investi-
gated.[19] At about the same time, we reported the synthesis
of push–triazole–pull fluorophores in which the triazole
ring allows for better photoluminescence properties, in
terms of both quantum yields and Stokes shifts, than a tri-
ple bond.[20] These spectral properties are essential for the
detection of fluorescent probes.
E-mail: sylvain.achelle@univ-rennes1.fr
Homepage: www.scienceschimiques.univ-rennes1.fr/
equipes/omc
[d] Laboratoire de Spectrométrie Physique, UMR 5588, Université
Joseph Fourier/CNRS,
140 Rue de la Physique, BP 87, 38402 Saint Martin d’Hères
Cedex, France
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201300458.
2
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Synthesis and Photophysical Properties of Push–Pull Structures
The goal of this work is to describe the synthesis of a key steps of this synthetic route involved two successive pal-
series of new push–pull chromophores that contain a pyr- ladium-catalyzed Suzuki cross-coupling reactions.[22]
imidine or pyridazine ring as the electron-attracting part
The first step was a Suzuki mono-cross-coupling reaction
and the N,N-dimethylaniline moiety as the electron-donat- of 4-(dimethylamino)phenylboronic acid with 1. The re-
ing part. Both are connected to the fluorene core by various gioselectivity at the iodine atom was sufficient to obtain
π-conjugated linkers (see Figure 1). The connection be- compound 2 as the main product with a moderate yield
tween the fluorene core and the external parts is achieved (64%). However, in addition to compound 2, a small
by the incorporation of ethynyl linkers or 1,2,3-triazole amount of 4,4Ј-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis(N,N-
rings on both sides of the fluorene. The syntheses of these dimethylbenzenamine), which resulted from two simulta-
structures consist of Suzuki and Sonogashira cross-cou- neous coupling reactions, was obtained in less than 20%
pling reactions as well as a CuAAC reaction. Herein, we yield. The second step involved the synthesis of boronic
report the synthesis of a wide range of fluorophores by acid 3, which resulted from a halogen–metal exchange fol-
varying both the length and nature of the conjugated core lowed by treatment with triisopropylborate as an electro-
as well as the electron-withdrawing moiety. The influence of phile and a further acidic hydrolysis. Compound 3 was used
these structural units on the photophysical properties was directly without purification. The last step involved a sec-
investigated.
ond Suzuki cross-coupling reaction with compound 3 and
a halogenated diazine. Compound 4 was obtained in low
yield (16%) in two steps as a result of the reaction with 2-
iodo-4,6-dimethylpyrimidine, whereas compound 5 was pre-
pared in 44% yield under the same conditions by using 3-
chloro-6-phenyl-4(trifluoromethyl)pyridazine. As reported
of Suzuki couplings, a low reactivity is generally observed
with chloro derivatives, which can be a result of the strength
of the C–Cl bond compared to the C–I bond. Amazingly,
the better yield observed for 5 can be explained by the elec-
tron-withdrawing trifluoromethyl substituent on the pyrid-
azine ring, which makes the oxidative addition of palladium
to a chlorine–carbon bond easier.[23–25]
Figure 1. Design of push–pull diazinic fluorophores.
Results and Discussion
To increase the length of the conjugated bridge between
the 4-(dimethylamino)phenyl donor group and the π-de-
ficient diazine ring, ethynyl spacers were introduced, which
led to a second family of compounds of type II (see
Scheme 2).
Starting from compound 1, a regioselective Sonogashira
cross-coupling reaction was carried out with 4-ethynyl-N,N-
dimethylaniline to give compound 6 in moderate yield
Synthesis
Four types of compounds (i.e., I–IV) were synthesized by
starting from 2-bromo-9,9-dihexyl-7-iodo-9H-fluorene
(1).[21] First, compounds of type I were prepared with 9,9-
dihexyl-9H-fluorene as the central core that was linked by
aryl–aryl bonds to a N,N-dimethylaniline group on one side
and a diazine ring on the other side (see Scheme 1). The
Scheme 1. Synthesis of the two push–pull fluorophores 4 and 5 of type I. Reagents and conditions: (i) 4-(dimethylamino)phenylboronic
acid (1 equiv.), Pd(PPh3)4 (10 mol-%), toluene/aqueous Cs2CO3 (2:1 v/v), 90 °C, 24 h; (ii) nBuLi (2.5 m solution, 1.3 equiv.), tetra-
hydrofuran (THF), followed by B(OiPr)3 (3.0 equiv.), –78 °C to room temp., 15 h, then HCl (0.1 n); (iii) 2-iodo-4,6-dimethylpyrimidine
(1.0 equiv.) or 3-chloro-6-phenyl-4-(trifluoromethyl)pyridazine (1.0 equiv.), Pd(PPh3)4 (10 mol-%), carbonate base (2.0 equiv.), toluene,
room temp., 20 h.
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Scheme 2. Synthesis of push–pull fluorophores (i.e., 9–12) of type II. Reagents and conditions: (i) 4-ethynyl-N,N-dimethylaniline
(1.0 equiv.), CuI (0.02 equiv.), Pd(PPh3)4 (0.02 equiv.), iPr2NH/THF (1:1 v/v), room temp., 12 h; (ii) trimethylsilylacetylene (1.5 equiv.),
CuI (0.02 equiv.), Pd(PPh3)4 (0.02 equiv.), iPr2NH/N,N-dimethylformamide (DMF, 1:1 v/v), 65 °C, 12 h; (iii) KOH (1 m in MeOH), 80 °C,
12 h; (iv) aryl halide (1.0 equiv.), CuI (0.02 equiv.), Pd(PPh3)4 (0.02 equiv.), iPr2NH/DMF (1:1 v/v), 65 °C, 18 h.
(67%). A second Sonogashira cross-coupling reaction at the of type IV. The triazole moiety was introduced through a
remaining bromine atom by treatment with trimethyl- copper-catalyzed Huisgen 1,3-dipolar cycloaddition
silylacetylene followed by trimethylsilyl (TMS) deprotection (CuAAC) between azidopyrimidine 13a and compound 8.
afforded alkyne 8 in good yield. A final Sonogashira cou- Previously, the corresponding open-chain azidopyrimidine
pling reaction was achieved by using three different halogen- 13a, which is in equilibrium with its ring-tautomeric form
ated diazine derivatives. Contrary to other palladium-cata- 13b, was prepared from pentane-2,4-dione through a cyclo-
lyzed cross-coupling reactions, the Sonogashira reaction dehydration in the presence of 5-aminotetrazole.[27] By this
generally requires an iodine atom even when diazine rings synthetic route, the fluorophore 14 (type III) with only one
are employed.[25] As previously described, because of the triazole ring on the diazine side was obtained in moderate
strong electron-withdrawing effect of the trifluoromethyl yield (53%, see Scheme 3).
group, 3-chloro-6-phenyl-4-(trifluoromethyl)pyridazine[26]
Fluorophore 20 with two triazole rings was obtained in
was used to obtain compound 11 under smooth conditions six steps by starting from 1 (see Scheme 4). Two successive
in good yield. To compare the effect of the diazine rings Sonogashira cross-coupling reactions were performed with
with that of a para-nitrophenyl group, compound 12 was trimethylsilylacetylene and then triisopropylsilylacetylene to
also synthesized.
lead to compounds 15 and 16, respectively, in good yields.
To evaluate the influence of the linker in compound 9 of The next step involved a selective deprotection of the tri-
type II, either one or two of the ethynyl units were replaced methylsilyl group by treatment with potassium carbonate to
by a triazole ring to give compounds 14 of type III and 20 give 17 with an excellent yield (90%). The following step
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Synthesis and Photophysical Properties of Push–Pull Structures
Scheme 3. Synthesis of push–pull fluorophores 14 of type III. Reagents and conditions: (i) CuCl2 (0.1 equiv.), sodium ascorbate (0.1 equiv.)
in EtOH and then pentane-2,4-dione (1.0 equiv.), 5-aminotetrazole (1.0 equiv.), room temp. 12 h; (ii) 13 (1.1 equiv.), 8 (1.0 equiv.), sodium
ascorbate (0.3 equiv.), CuSO4·5H2O (0.15 equiv.), H2O/tBuOH (1:1 v/v), 65 °C, 12 h.
Scheme 4. Synthesis of push–pull fluorophores 20 of type IV. Reagents and conditions: (i) trimethylsilylacetylene (1.0 equiv.), CuI
(0.02 equiv.), Pd(PPh3)4 (0.02 equiv.), iPr2NH/DMF (1:1 v/v), room temp., 12 h; (ii) triisopropylsilylacetylene (1.5 equiv.), CuI
(0.02 equiv.), Pd(PPh3)4 (0.02 equiv.), iPr2NH/DMF (1:1 v/v), room temp., 12 h; (iii) K2CO3 (5.0 equiv.), THF/MeOH, room temp., 16 h;
(iv) 4-azido-N,N-dimethylaniline (1.1 equiv.), sodium ascorbate (0.30 equiv.), CuSO4·5H2O (0.15 equiv.), H2O/tBuOH (1:1 v/v), 65 °C,
12 h; (v) TBAF (1 m solution, 1.06 equiv.), THF, room temp. 12 h; (vi) 13 (1.1 equiv.), sodium ascorbate (0.3 equiv.), CuSO4·5H2O
(0.15 equiv.), H2O/tBuOH (1:1 v/v), 65 °C.
involved a click reaction of terminal alkyne 17 with the 4- Table 1. Photoluminescence data of chromophores 4, 5, 9–12, 14,
and 20 in CH2Cl2.
azido-N,N-dimethylaniline to afford compound 18. Further
[a]
deprotection of the triisopropylsilyl (TIPS) group was
achieved by using tetra-n-butylammonium fluoride (TBAF)
to give compound 19. A second click reaction between com-
pounds 19 and 13 afforded fluorophore 20 of type IV in
85% yield.
Type Compd. λabs
ε
λem
ΦF
Stokes shift
[cm–1]
[nm] [m–1 cm–1] [nm]
I
4
5
360
358
372
377
392
391
362
334
58800
39300
52094
58100
74700
51900
71500
82000
483
423
515
539
500
474
450
422
0.69
0.01
7074
4292
7464
7972
5510
4478
5402
6243
II
9
0.64[b]
0.21
10
11
12
14
20
0.05
0.01
UV/Vis and Photoluminescence Spectroscopy
III
IV
0.71
0.47[b]
The UV/Vis and photoluminescence spectroscopic data
of all the chromophores were recorded in dichloromethane
at 25 °C (see Table 1).
[a] Ϯ10%, harmane (0.1 m in H2SO4) was used as reference (ΦF
0.58), excitation at 360 nm. [b] Excitation at 300 nm.
=
All the studied compounds (see Table 1) contain the
same 4-(dimethylamino)phenyl moiety as the electron-do- 5 (type I) reveals similar λabs, but a lower value for the mo-
nating group and differ by the electron-withdrawing aro- lar extinction coefficient (ε), an important blueshift for λem
,
matic group and the nature of the linkers (optimized geo- and a dramatic decrease of the quantum yield (ΦF) are ob-
metries of compounds 4 and 5 are shown in Figures 2 and served for 5. These spectroscopic data for 5 could be a con-
3). These compounds exhibit absorption maxima (λabs) in sequence of the steric hindrance from the trifluoromethyl
the UV region (358–392 nm) and emission maxima (λem) in group at the position adjacent to the fluorene-pyridazine
the purple to green region (411–539 nm, see Figures 4 and bond, and, therefore, we speculate that twisting could occur
5). The comparison between the data for compounds 4 and with a loss of conjugation between the two moieties. This
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hypothesis is supported by the fully optimized geometry of
5, for which a dihedral angle of 37° was established (see
Figure 3), whereas the geometry of 4 reveals a nearly copla-
nar structure with a dihedral angle of 0.075° between the
fluorene core and the pyrimidine ring (see Figure 2). For
both compounds, a value of about 35° was determined for
the dihedral angle between the central fluorene unit and the
benzene ring, which is a result of the steric hindrance from
the ortho hydrogen atoms.
Figure 5. Color of compounds 14, 4, 9, 20, and 10 in CH2Cl2 under
UV irradiation (365 nm).
Figure 2. Optimized B3LYP/6-31G* geometry for compound 4.
The printed values correspond to dihedral angles.
moiety that is present in compounds 9–11. Replacing the 4-
nitrophenyl group by the 4,6-(dimethyl)pyrimidine or pyrid-
azine ring caused a redshift of the emission wavelength (Δλ
= 26–65 nm) with an appreciable increase of the quantum
yield for compounds 9 and 10. Incorporating the most elec-
tron-attractive trifluoromethylpyridazine moiety rather
than the pyridazine ring did not improve the spectroscopic
data with the exception of the molecular extinction coeffi-
cient (ε) and the decrease of the quantum yield (ΦF). This
result can be explained by the change in the symmetry of
the molecule compared to 10.
Figure 3. Optimized B3LYP/6-31G* geometry for compound 5.
The printed values correspond to dihedral angles.
The comparison of compounds 4, 9, 14, and 20 that have
the 4,6-dimethyl-2-pyrimidinyl and 4-(dimethylamino)-
phenyl groups as external substituents allows to evaluate
the influence of the linkers. The incorporation of an ethynyl
linker instead of a simple bond led to a redshift of the max-
ima absorption (λabs) and emission (λem) with similar values
of ε and ΦF. When a triple bond was replaced by one or two
1,2,3-triazole rings, an increase of the molecular extinction
coefficient (ε) was observed in addition to a slight blueshift
of the maxima absorption (λabs) and emission (λem) as well
as high values for the quantum yields.
Figure 4. Normalized emission spectra of chromophores 20, 5, 14,
12, 4, 11, 9, and 10 in CH2Cl2.
Two-Photon Absorption Properties
The comparison between compounds 9–12 (type II) dem-
Two-photon absorption cross-sections (δTPA) were mea-
onstrates the influence of the electron-withdrawing aro- sured by a two-photon-inducted fluorescence technique
matic group, as this moiety is linked by a triple bond to that used a femtosecond (fs) laser pulse. Because of the laser
the fluorene central unit, which separates the core from the availability (Ti:sapphire laser), the solutions were excited in
aromatic ring and allows for an absolute planar geometry the range of 690 to 940 nm. In all cases, the output intensity
to force the system into conjugation. The spectral data of of two-photon excited fluorescence was linearly dependent
compound 12 with a 4-nitrophenyl group could be used as on the square of the input laser intensity, thereby confirm-
a reference (λabs = 391 nm, ε = 51900 m–1 cm–1, λem
474 nm, ΦF = 0.01) to evaluate the influence of the diazine and Figure 6.
=
ing the TPA process. The results are summarized in Table 2
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Synthesis and Photophysical Properties of Push–Pull Structures
Figure 6. TPA absorption spectra of compounds 4, 5, 9–12, 14, and 20 in CH2Cl2.
Table 2. Results of TPA absorption spectra (λTPA) and two-photon contain fluorene, π-conjugated linkers, and the (dimeth-
absorption cross-sections (δTPA).
ylamino)phenyl electron-donating group. The optical prop-
erties were studied, and all the molecules displayed absorp-
tion wavelengths in the UV region and emitted visible light
with significant Stokes shifts. An emission quantum yield
up to 0.71 was observed for compound 14, which contained
both an ethynyl group and a triazole ring as linkers. Pyrim-
idine derivatives exhibited higher quantum yields than
pyridazine derivatives. The TPA properties were investi-
gated, and TPA cross-sections were observed up to 367 GM
in the red region of the spectrum and were higher for pyrid-
azine derivatives than for pyrimidine compounds. Some
molecules such as pyrimidine derivatives 4 and 14 and
pyridazine derivative 10 have a combination of a high quan-
tum yield and high TPA cross-section. Current investi-
gations are being carried out in our laboratories to func-
tionalize these structures to obtain water soluble TPA bio-
imaging dyes.
4
5
9
10
740 700 760 780 740 750 760 700
δTPA [GM][b] 123 263
82 269 367 114 148 39
11
12
14
20
λTPA [nm][a]
[a] Wavelength of maximum TPA cross-section. [b] TPA cross-sec-
tion (1M = 10–50 cm4 sphoton–1).
All the compounds exhibited TPA in the red to the near
infrared region. Push–pull structures 4, 5, 9–12, 14, and 20
exhibited TPA cross-sections in CH2Cl2 between 39 and
367 GM, which is comparable or higher than that of com-
mercially available TPA dyes. The highest cross-sections
were obtained for pyridazine derivatives 5, 10, and 11.
When comparing compounds 10 and 11, the trifluorome-
thyl group on the pyridazine ring significantly increased the
TPA cross-section up to 367 GM. Pyridazine derivatives 10
and 11 exhibited a much higher TPA cross-section than
nitro derivative 12. When comparing compounds 9, 14, and
20, as observed for the fluorescence quantum yield, the re-
placement of only one triple bond by a triazole unit on the
pyrimidine side (i.e., compound 14) increased the TPA
cross-section. When two triazole rings were present on each
side of the fluorene (i.e., compound 20), the TPA cross-
section dramatically decreased. Because of the low value of
the fluorescence quantum yield for compounds 5 and 12,
the uncertainty of the TPA cross-sections for these com-
pounds is important.
Experimental Section
General Remarks: All chemicals were purchased from commercial
sources and were used without further purification unless otherwise
specified. Analytical thin layer chromatography was performed
with silica gel plates (Merck® TLC Silica gel 60 F254), and com-
pounds were detected by irradiation with UV light (254 and
365 nm). The chromatographic purification of compounds was
achieved with silica gel (mesh size 60–80 μm). IR spectra were re-
corded with a universal attenuated total reflectance (ATR) sam-
pling accessory on a Perkin–Elmer FTIR Spectrum 100 spectrome-
ter. Absorption bands are given in cm–1. HRMS spectra (APCI+ or
ESI+) were recorded with a LC Waters Acquity that was coupled to
a Waters LCT Premier XE instrument. Elemental analyses were
Conclusions
In summary, we have successfully synthesized and char-
acterized a new series of push–pull diazine derivatives that performed with a Carlo Erba 1106 apparatus, and the measurement
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accuracy is approximately Ϯ0.4% for carbon. Melting points (°C)
0.26 mmol, 1.0 equiv.) in THF (3.5 mL) at –78 °C. The resulting
solution was stirred at –78 °C for 1 h. Then, triisopropylborate
(0.18 mL, 0.78 mmol, 3.0 equiv.) was added, and the solution was
warmed to room temp. overnight. HCl (0.1 n solution, 5 mL) was
added, and the layers were separated. The aqueous layer was then
extracted with EtOAc (3ϫ 15 mL). The combined organic layers
were dried with MgSO4, filtered, and then evaporated under re-
duced pressure to give the crude product 3 (65 mg). A mixture of
crude compound 3 (65 mg, 0.13 mmol, 1.0 equiv.), 2-iodo-4,6-di-
methylpyrimidine (30 mg, 0.13 mmol, 1.0 equiv.), and [Pd(PPh3)4]
(10 mg, 0.009 mmol, 7 mol-%) was dissolved into a 2:1 (v/v) solu-
tion of toluene (3.0 mL) and aqueous Na2CO3 (2 m solution
1.5 mL). After degassing, the mixture was heated to 90 °C over-
were measured with a Kofler hot-stage with a precision of 2 °C
1
(Ϯ2 °C). The H and 13C NMR spectroscopic data were recorded
with a Bruker Advance spectrometer that operated at 300 and
75 MHz, respectively. The chemical shifts (δ) are reported in parts
per million (ppm) relative to the residual solvent peak (7.26 and
77.16 ppm, respectively for CDCl3 and 0.00 ppm for CFCl3). The
data appear in the order of chemical shift in ppm, number of pro-
tons, multiplicity [singlet (s), doublet (d), doublet of doublet (dd),
triplet (t), multiplet (m)], and coupling constant J in Hz. For the
13C NMR spectroscopic data, the nature of the carbons (C, CH,
CH2, or CH3) was determined by recording DEPT and hetero-
nuclear multiple quantum coherence (HMQC) experiments. UV/Vis
spectra were recorded with a Varian Can 50 scan spectrophotome- night and then cooled to room temp. Distilled water (10 mL) was
ter. Fluorescence spectroscopic studies were performed with a Var-
ian Cary Eclipse spectrophotometer. Compounds were excited at
their absorption maxima to record the emission spectra, however,
different wavelengths were used to determine fluorescence quantum
yields in cases where the compounds and standards absorbed sig-
nificantly. All solutions were measured with optical densities below
0.1. The TPA cross-sections in the range of 790–950 nm were ob-
tained by up-conversion fluorescence using a mode locked with a
Ti:sapphire femtosecond laser (Tsunami Spectra-Physics) with a
pulse duration of 100 fs and at a repetition rate of 82 MHz. The
measurements were carried out at room temperature in dichloro-
methane (DCM) at a concentration of approximately 5ϫ10–6 to
5ϫ10–5 m. The excitation beam (5 mm diameter) was focused with
a lens (focal length 10 cm) at the middle of the fluorescence cell
(10 mm). The fluorescence, which was collected at 90° to the exci-
tation beam, was focused into an optical fiber (diameter 600 μm)
that was connected to an Ocean Optics S2000 spectrometer. The
incident beam intensity was adjusted to 50 mW to ensure an inten-
sity-squared dependence of the fluorescence over the whole range.
The detector integration time was fixed at 1 s. The spectra were
compared with the published fluorescein and rhodamine B two-
photon absorption spectra.
added, and the organic products were extracted with CH2Cl2 (3ϫ
5 mL). The combined organic layers were dried with MgSO4, fil-
tered, and then concentrated under reduced pressure to give the
crude product. Purification by flash column chromatography on
silica gel (petroleum ether/CH2Cl2, from 90:10 to 50:50) gave com-
pound 4 (12 mg, 16 %); m.p. 100–102 °C. Rf = 0.54 (petroleum
1
ether/CH2Cl2, 9:1). H NMR (300 MHz, CDCl3): δ = 8.47 (dd, J
= 1.5, 8.0 Hz, 1 H), 8.42 (s, 1 H), 7.77 (dd, J = 2.5, 8.0 Hz, 2 H),
7.61–7.54 (m, 4 H), 6.92 (s, 1 H), 6.85 (d, J = 8.5 Hz, 1 H), 3.02
(s, 6 H), 2.57 (s, 6 H), 2.12–2.04 (m, 4 H), 1.13–1.04 (m, 12 H),
0.76–0.72 (m, 10 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 166.8
(Cq), 164.8 (Cq), 152.3 (Cq), 151.3 (Cq), 150.1 (Cq), 143.5 (Cq),
140.6 (Cq), 139.0 (Cq), 136.8 (Cq), 129.9 (Cq), 127.9 (CHAr), 127.5
(CHAr), 125.2 (CHAr), 122.6 (CHAr), 120.8 (CHAr), 120.4 (CHAr),
119.6 (CHAr), 117.7 (CHAr), 113.0 (CHAr), 55.4 (Cq), 40.8 (CH3),
40.6 (CH2), 31.7 (CH2), 29.9 (CH2), 24.4 (CH3), 23.9 (CH2), 22.7
(CH ), 14.2 (CH ) ppm. IR (neat): ν = 2925, 2854, 1603, 1589,
˜
2
3
1526, 1357, 1200, 813, 794 cm–1. HRMS (TOF MS ESI+): calcd.
for C39H49N3 [M + H]+ 560.4005; found 560.3984.
4-{9,9-Dihexyl-7-[6-phenyl-4-(trifluoromethyl)pyridazin-3-yl]-9H-
fluoren-2-yl}-N,N-dimethylaniline (5): nBuLi (2.5 m in cyclohexane,
0.14 mL, 1.3 equiv.) was added to a solution of compound 2
(140 mg, 0.26 mmol, 1.0 equiv.) in THF at –78 °C. The resulting
solution was stirred at –78 °C for 1 h. Then, triisopropylborate
(0.18 mL, 0.78 mmol, 3.0 equiv.) was added, and the solution was
warmed to room temp. overnight. HCl (0.1 n solution, 5 mL) was
added, and the layers were separated. The aqueous layer was then
extracted with EtOAc (3ϫ 15 mL). The combined organic layers
were dried with MgSO4, filtered, and then evaporated under re-
duced pressure to give the crude product. A mixture of the crude
{7-[4-(dimethylamino)phenyl]-9,9-dihexyl-9H-fluoren-2-yl}boronic
acid (65 mg, 0.13 mmol, 1.0 equiv.), 3-chloro-6-phenyl-4-(trifluoro-
methyl)pyridazine (34 mg, 0.13 mmol, 1.0 equiv.), Cs2CO3 (42 mg,
0.13 mmol, 1.0 equiv.), K2CO3 (2 m solution, 0.1 mL, 1.0 equiv.),
and [Pd(PPh3)4] (15 mg, 0.013 mmol, 0.1 equiv.) was dissolved in a
solution of toluene (10 mL) and ethanol (0.1 mL). After degassing,
the mixture was agitated at room temp. for 24 h. Distilled water
(20 mL) was added at room temp., and the aqueous layer was ex-
tracted with EtOAc (3ϫ 20 mL). The combined organic layers were
dried with MgSO4, filtered, and then concentrated under reduced
pressure to give the crude product. Purification by flash column
chromatography on silica gel (petroleum ether/EtOAc, 95:5) gave
compound 5 (39 mg, 44%); m.p. 106–108 °C. Rf = 0.38 (petroleum
ether/EtOAc, 5:5). 1H NMR (300 MHz, CDCl3): δ = 8.24–8.21 (m,
2 H), 8.17 (s, 1 H), 7.85 (d, J = 7.8 Hz, 1 H), 7.80 (d, J = 7.8 Hz,
1 H), 7.68–7.56 (m, 10 H), 6.86 (d, J = 8.7 Hz, 2 H), 3.02 (s, 6 H),
2.07–2.02 (m, 4 H), 1.15–1.06 (m, 12 H), 0.78–0.72 (m, 10 H) ppm.
13C NMR (75 MHz, CDCl3): δ = 158.2 (Cq), 157.7 (Cq), 152.0 (Cq),
150.9 (Cq), 150.2 (Cq), 143.0 (Cq), 141.0 (Cq), 138.5 (Cq), 135.1
4-(7-Bromo-9,9-dihexyl-9H-fluoren-2-yl)-N,N-dimethylaniline (2): A
mixture of 2-bromo-9,9-dihexyl-7-iodo-9H-fluorene (1, 250 mg,
0.464 mmol, 1.0 equiv.), 4-(dimethylamino)phenylboronic acid
(77 mg, 0.464 mmol, 1.0 equiv.), and [Pd(PPh3)4] (53 mg,
0.046 mmol, 10 mol-%) were dissolved in a 2:1 (v/v) solution of
toluene (8 mL) and aqueous Cs2CO3 (2 m solution, 4 mL). After
degassing, the reaction mixture was heated to 90 °C for 24 h and
then cooled to room temp. Distilled water (10 mL) was added, and
the organic products were extracted with EtOAc (3ϫ 15 mL). The
combined organic layers were dried with MgSO4, filtered, and then
evaporated under reduced pressure to give a black solid residue.
Purification by flash column chromatography on silica (petroleum
ether/toluene, 5:5) gave compound 2 (152 mg, 64%) as a white so-
lid; Rf = 0.30 (petroleum ether/toluene). 1H NMR (300 MHz,
CDCl3): δ = 7.68 (d, J = 8.0 Hz, 1 H), 7.60–7.52 (m, 4 H), 7.49–
7.43 (m, 3 H), 6.86 (d, J = 9.0 Hz, 2 H), 3.02 (s, 6 H), 2.02–1.91
(m, 4 H), 1.16–1.04 (m, 12 H), 0.77 (t, J = 7.0 Hz, 6 H), 0.69–0.63
(m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 153.3 (Cq), 151.1
(Cq), 140.7 (Cq), 140.2 (Cq), 130.0 (CHAr), 127.9 (CHAr), 126.1
(CHAr), 125.3 (CHAr), 121.0 (CHAr), 120.7 (CHAr), 120.0 (CHAr),
113.0 (CHAr), 55.5 (Cq), 40.8 (CH3), 40.5 (CH2), 31.6 (CH2), 29.8
(CH2), 23.8 (CH2), 22.7 (CH2), 14.1 (CH3) ppm. HRMS [TOF MS
APCI+ (atmospheric pressure)]: calcd. for C33H43NBr [M + H]+
532.2579; found 532.2586.
4-[7-(4,6-Dimethylpyrimidin-2-yl)-9,9-dihexyl-9H-fluoren-2-yl]-
N,N-dimethylaniline (4): nBuLi (2.5 m in cyclohexane, 0.14 mL,
1.3 equiv.) was added to a solution of compound 2 (140 mg,
8
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Synthesis and Photophysical Properties of Push–Pull Structures
(Cq), 133.8 (Cq), 131.0 (CHAr), 129.7 (Cq), 129.5 (CHAr), 128.7 The mixture was stirred and heated to 80 °C for 12 h. After it was
(Cq), 128.4 (CHAr), 128.3 (Cq), 128.0 (CHAr), 127.5 (Cq), 127.3 cooled to room temperature, the solution was neutralized with HCl
(CHAr), 125.3 (CHAr), 123.9 (CHAr), 120.8 (CHAr), 120.7 (CHAr), (1 m aqueous solution, 10 mL), and organic products were ex-
120.6 (CHAr), 119.5 (CHAr), 113.0 (CHAr), 55.5 (Cq), 40.8 (CH3), tracted with CH2Cl2 (3ϫ 50 mL). The combined organic layers
40.7 (CH2), 31.6 (CH2), 29.8 (CH2), 23.8 (CH2), 22.7 (CH2), 14.1
were dried with MgSO4, filtered, and concentrated under reduced
pressure to give the crude product (0.653 g). Purification by flash
column chromatography on silica (petroleum ether/EtOAc, 9:1)
gave compound 8 (0.461 g, 79%) as a light orange solid; m.p. 119–
121 °C. Rf = 0.70 (petroleum ether/EtOAc, 9:1). 1H NMR
(300 MHz, CDCl3): δ = 7.62 (dd, J = 8.0, 7.5 Hz, 2 H), 7.42–7.50
(m, 6 H), 6.68 (d, J = 9.0 Hz, 2 H), 3.15 (s, 1 H, 1 H), 3.00 (s, 6
H), 1.92–1.98 (m, 4 H), 1.03–1.25 (m, 12 H), 0.76 (t, J = 7.0 Hz, 6
H), 0.57–0.61 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ =
151.2 (Cq), 151.1 (Cq), 150.1 (Cq), 141.6 (Cq), 139.8 (Cq), 132.9
(CHAr), 131.3 (CHAr), 130.5 (CHAr), 126.6 (CHAr), 125.8 (CHAr),
123.2 (Cq), 120.5 (Cq), 120.1 (CHAr), 119.9 (CHAr), 112.1 (CHAr),
110.3 (Cq), 91.2 (Cq), 88.5 (Cq), 84.9 (Cq), 77.3 (Cq), 55.3 (Cq), 40.5
(CH2), 23.8 (CH2), 40.4 (CH3), 31.7 (CH2), 29.8 (CH2), 22.8 (CH2),
14.1 (CH3) ppm. HRMS (TOF MS APCI+): calcd. for C37H44N
[M + H]+ 502.3474; found 502.3485.
(CH ) ppm. IR (neat): ν = 2927, 1455, 1411, 1343, 1261, 1189,
˜
3
1135, 1101, 906, 771, 693, 671 cm–1. HRMS (TOF MS ESI+):
calcd. for C44H49N3F3 [M + H]+ 676.3879; found 676.3859.
4-[(7-Bromo-9,9-dihexyl-9H-fluoren-2-yl)ethynyl]-N,N-dimethyl-
aniline (6): A mixture of compound 1 (2.0 g, 3.708 mmol,
1.0 equiv.) and 4-ethynyl-N,N-dimethylaniline (0.538 g,
3.708 mmol, 1.0 equiv.) was added to a solution of iPr2NH/THF
(1:1 v/v, 20 mL). After degassing, CuI (14 mg, 0.074 mmol,
0.02 equiv.) and [Pd(PPh3)4] (85.5 mg, 0.074 mmol, 0.02 equiv.)
were introduced to the mixture. The resulting solution was stirred
at room temp. for 12 h. Distilled water (20 mL) was added, and
the organic products were extracted with EtOAc (3ϫ 15 mL). The
combined organic layers were dried with MgSO4, filtered, and con-
centrated under reduced pressure to give the crude product. Purifi-
cation by flash column chromatography on silica (petroleum ether/
CH2Cl2, 6:4) gave compound 6 (1.37 g, 67%) as a light yellow solid;
m.p. 118–120 °C. Rf = 0.67 (petroleum ether/CH2Cl2, 6:4). 1H
NMR (300 MHz, CDCl3): δ = 7.61 (d, J = 8.0 Hz, 1 H), 7.50 (d,
J = 8.5 Hz, 1 H), 7.48 (d, J = 7.0 Hz, 1 H), 7.42–7.46 (m, 5 H),
6.68 (d, J = 9.0 Hz, 2 H), 3.01 (s, 6 H), 1.90–1.97 (m, 4 H), 1.04–
1.15 (m, 12 H), 0.77 (t, J = 7.0 Hz, 6 H), 0.58–0.62 (m, 4 H) ppm.
13C NMR (75 MHz, CDCl3): δ = 207.0 (Cq), 153.3 (Cq), 150.4 (Cq),
150.2 (Cq), 139.7 (Cq), 139.5 (Cq), 132.8 (CHAr), 130.5 (CHAr),
130.1 (CHAr), 126.2 (CHAr), 125.6 (CHAr), 123.0 (Cq), 121.3
(CHAr), 119.7 (CHAr), 111.9 (CHAr), 110.0 (Cq), 91.1 (Cq), 88.3
(Cq), 55.5 (Cq), 40.4 (CH2), 40.3 (CH3), 31.6 (CH3), 29.7 (CH2),
23.8 (CH2), 22.7 (CH2), 14.1 (CH3) ppm. HRMS (TOF MS
APCI+): calcd. for C35H43NBr [M + H]+ 556.2579; found
556.2587.
4-({7-[(4,6-Dimethylpyrimidin-2-yl)ethynyl]-9,9-dihexyl-9H-
fluoren-2-yl}ethynyl)-N,N-dimethylaniline (9): A mixture of 8
(50 mg, 0.100 mmol, 1.0 equiv.) and 2-iodo-4,6-dimethylpyrimidine
(23 mg, 0.1 mmol, 1.0 equiv.) was added to a solution of iPr2NH/
THF (1:1 v/v, 2 mL). After degassing, CuI (0.4 mg, 0.002 mmol,
0.02 equiv.) and [Pd(PPh3)4] (2.3 mg, 0.002 mmol, 0.02 equiv.) were
introduced to the mixture. The resulting solution was stirred at
65 °C for 18 h. Distilled water (5 mL) was added, and the organic
products were extracted with Et2O (3ϫ 10 mL). The combined or-
ganic layers were dried with MgSO4, filtered, and concentrated un-
der reduced pressure to give the crude product. Purification by
flash column chromatography on silica (petroleum ether/EtOAc,
8:2) gave compound 9 (52 mg, 86%) as a yellow solid; m.p. 84–
86 °C. Rf = 0.31 (petroleum ether/EtOAc, 8:2). 1H NMR
(300 MHz, CDCl3): δ = 7.65 (m, 4 H), 7.43–7.50 (m, 4 H), 6.99 (s,
1 H), 6.67 (d, J = 9.0 Hz, 2 H), 3.00 (s, 6 H), 2.53 (s, 6 H), 1.93–
1.98 (m, 4 H), 0.97–1.15 (m, 12 H), 0.76 (t, J = 7.0 Hz, 6 H), 0.54–
0.63 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 167.3 (Cq),
152.8 (Cq), 151.4 (Cq), 160.0 (Cq), 150.2 (Cq), 142.2 (Cq), 139.8
(Cq), 132.9 (CHAr), 130.7 (CHAr), 130.5 (CHAr), 127.5 (CHAr),
125.7 (CHAr), 123.4 (Cq), 120.2 (CHAr), 119.9 (CHAr), 119.8
(CHAr), 112.0 (CHAr), 110.1 (Cq), 91.4 (Cq), 88.48 (Cq), 88.46 (Cq),
88.4 (Cq), 55.3 (Cq), 40.6 (CH2) 40.3 (CH3), 31.7 (CH2), 29.8 (CH2),
4-({9,9-Dihexyl-7-[(trimethylsilyl)ethynyl]-9H-fluoren-2-yl}ethyn-
yl)-N,N-dimethylaniline (7): A mixture of compound 6 (1.10 g,
1.976 mmol, 1.0 equiv.) and trimethylsilylacetylene (0.291 g,
2.964 mmol, 1.5 equiv.) was added to a solution of iPr2NH/THF
(1:1 v/v, 10 mL). After degassing, CuI (7.6 mg, 0.040 mmol,
0.02 equiv.) and [Pd(PPh3)4] (46.2 mg, 0.040 mmol, 0.02 equiv.)
were introduced to the mixture. The resulting solution was stirred
at 65 °C for 18 h. Distilled water (5 mL) was added, and the organic
products were extracted with Et2O (3ϫ 10 mL). The combined or-
ganic layers were dried with MgSO4, filtered, and concentrated un-
der reduced pressure to give the crude product. Purification by
flash column chromatography on silica (petroleum ether/toluene,
9:1) gave compound 7 (0.987 g, 87%) as a light yellow solid; m.p.
154–156 °C. Rf = 0.60 (petroleum ether/toluene, 9:1). 1H NMR
(300 MHz, CDCl3): δ = 7.61 (m, 2 H), 7.43–7.50 (m, 6 H), 6.72 (d,
J = 7.0 Hz, 2 H), 3.0 (s, 6 H), 1.93–1.98 (m, 4 H), 0.98–1.15 (m,
12 H), 0.77 (t, J = 7.1 Hz, 6 H), 0.49–0.64 (m, 4 H), 0.29 (s, 9
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 150.1 (Cq), 150.0 (Cq),
149.2 (Cq), 140.3 (Cq), 139.0 (Cq), 131.9 (CHAr), 130.3 (CHAr),
129.5 (CHAr), 125.3 (CHAr), 124.7 (CHAr), 122.0 (Cq), 120.5 (Cq),
119.0 (CHAr), 118.8 (CHAr), 111.0 (CHAr), 109.1 (Cq), 105.4 (Cq),
93.2 (Cq), 90.2 (Cq), 87.5 (Cq), 54.3 (Cq), 39.6 (CH2), 39.3 (CH3),
30.7 (CH2), 28.9 (CH2), 22.8 (CH2), 21.8 (CH2), 13.2 (CH3), 0.8
(CH3 TMS) ppm. HRMS (TOF MS APCI+): calcd. for C40H52NSi
[M + H]+ 574.3869; found 574.3869.
24.1 (CH ), 23.8 (CH ), 22.7 (CH ), 14.1 (CH ) ppm. IR (neat): ν
˜
3
2
2
3
= 2925, 2853, 2212, 1600, 1520, 1466, 1363, 1195, 1124, 946, 817,
747, 692, 532 cm–1. HRMS (TOF MS ESI+): calcd. for C43H50N3
[M + H]+ 608.4005; found 608.4006.
4-({9,9-Dihexyl-2-[(6-phenylpyridazin-3-yl)ethynyl]-9H-fluoren-7-
yl}ethynyl)-N,N-dimethylaniline (10): A mixture of 8 (50 mg,
0.100 mmol, 1.0 equiv.) and 3-iodo-6-phenylpyridazine (28 mg,
0.1 mmol, 1.0 equiv.) was added to a solution of iPr2NH/THF (1:1
v/v, 2 mL). After degassing, CuI (0.4 mg, 0.002 mmol, 0.02 equiv.)
and [Pd(PPh3)4] (2.3 mg, 0.002 mmol, 0.02 equiv.) were introduced
to the mixture. The resulting solution was stirred at 65 °C for 18 h.
Distilled water (5 mL) was added, and the organic products were
extracted with Et2O (3ϫ 10 mL). The combined organic layers
were dried with MgSO4, filtered, and concentrated under reduced
pressure to give the crude product. Purification by flash column
chromatography on silica (petroleum ether/EtOAc, 8:2) gave com-
pound 10 (54 mg, 82%) as a yellow solid; m.p. 109–111 °C. Rf =
1
4-[(7-Ethynyl-9,9-dihexyl-9H-fluoren-2-yl)ethynyl]-N,N-dimethyl- 0.31 (petroleum ether/EtOAc, 8:2). H NMR (300 MHz, CDCl3):
aniline (8): A solution of potassium hydroxide (1 m in methanol,
30 mL) and 7 (0.650 g, 1.168 mmol) were combined under nitrogen.
δ = 8.13 (d, J = 9.0 Hz, 2 H), 7.85 (d, J = 9.0 Hz, 1 H), 7.70 (d, J
= 9.0 Hz, 1 H), 7.61–7.68 (m, 4 H), 7.48–7.57 (m, 5 H), 7.46 (d, J
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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C. Baudequin, S. Achelle et al.
FULL PAPER
= 9.0 Hz, 2 H), 6.68 (d, J = 9.0 Hz, 2 H), 3.00 (s, 6 H), 1.97–2.03
(m, 4 H), 1.01–1.17 (m, 12 H), 0.77 (t, J = 7.0 Hz, 6 H), 0.57–0.67
(Cq), 134.5 (Cq), 132.9 (CHAr), 132.3 (CHAr), 131.2 (CHAr), 130.6
(CHAr), 126.2 (CHAr), 125.7 (CHAr), 123.8 (CHAr), 123.5 (Cq),
(m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 157.0 (Cq), 151.3 120.4 (Cq), 120.2 (CHAr), 120.1 (CHAr), 111.9 (CHAr), 110.0 (Cq),
(Cq), 151.2 (Cq), 150.2 (Cq), 146.8 (Cq), 142.3 (Cq), 139.6 (Cq), 96.2 (Cq), 91.5 (Cq), 88.4 (Cq), 88.0 (Cq), 55.4 (Cq), 40.5 (CH2),
136.0 (Cq), 132.9 (CHAr), 131.4 (CHAr), 130.6 (CHAr), 130.4
40.3 (CH3), 31.7 (CH2), 29.8 (CH2), 23.9 (CH2), 22.7 (CH2), 14.1
(CHAr), 130.4 (CHAr), 129.2 (CHAr), 127.3 (CHAr), 126.7 (CHAr), (CH ) ppm. IR (neat): ν = 2926, 2847, 2194, 1601, 1520, 1465,
˜
3
125.7 (CHAr), 123.5 (Cq), 123.1 (CHAr), 120.2 (Cq), 120.0 (CHAr),
1367, 1337, 1192, 1120, 948, 816, 747, 692 cm–1. HRMS (TOF MS
119.98 (CHAr), 112.0 (CHAr), 110.0 (Cq), 95.6 (Cq), 55.4 (Cq), 91.5 ESI+): calcd. for C43H46N2O2 [M + H]+ 622.3559; found 622,3574.
(Cq), 88.4 (Cq), 86.5 (Cq), 40.5 (CH2), 40.3 (CH3), 31.7 (CH2), 29.8
2-Azido-4,6-dimethylpyrimidine (13a) and 5,7-Dimethyltetrazolo-
(CH ), 25.7 (CH ), 22.7 (CH ), 14.1 (CH ) ppm. IR (neat): ν =
˜
2
2
2
3
[1,5-a]pyrimidine (13b): CuCl2 (79 mg, 0.588 mmol, 0.1 equiv.) was
dissolved in EtOH (18 mL) to give a green solution, and then so-
dium ascorbate (104 mg, 0.588 mmol, 0.1 equiv.) was added. The
resulting solution was stirred until the solution turned colorless.
Then, pentane-2,4-dione (0.6 mL, 5.88 mmol, 1.0 equiv.) and 5-
aminotetrazole (500 mg, 5.88 mmol, 1.0 equiv.) were added. The re-
sulting mixture was stirred at room temp. for 12 h under argon.
The solution was quenched with a saturated solution of NH4Cl
(20 mL), and the organic product was extracted with EtOAc (5ϫ
40 mL). The organic layer was dried with MgSO4 and concentrated
under reduced pressure to give a mixture of compounds 13a and
13b (719 mg, 81%) as a white solid that was kept at –20 °C. Data
for 13a: 1H NMR (300 MHz, CDCl3): δ = 2.42 (s, 6 H, CH3), 6.76
(s, 1 H, 5-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 23.9 (CH3),
2925, 2854, 2194, 1600, 1521, 1466, 1451, 1400, 1360, 1192, 1110,
818, 747, 691, 572, 529, 412 cm–1. HRMS (TOF MS ESI+): calcd.
for C43H51N9 [M + H]+ 656.4005; found 656.3997.
4-[(9,9-Dihexyl-7-{[6-phenyl-4-(trifluoromethyl)pyridazin-3-
yl]ethynyl}-9H-fluoren-2-yl)ethynyl]-N,N-dimethylaniline (11): A
mixture of 8 (50 mg, 0.1 mmol, 1.0 equiv.) and 3-chloro-6-phenyl-
4-(trifluoromethyl)pyridazine (39 mg, 0.1 mmol, 1.0 equiv.) was
added to a solution of iPr2NH/THF (1:1 v/v, 2 mL). After degas-
sing, CuI (0.4 mg, 0.002 mmol, 0.02 equiv.) and [Pd(PPh3)4]
(2.3 mg, 0.002 mmol, 0.02 equiv.) were introduced to the mixture.
The resulting solution was stirred at 65 °C for 18 h. Distilled water
was added (5 mL), and the organic products were extracted with
Et2O (3ϫ 10 mL). The combined organic layers were dried with
MgSO4, filtered, and concentrated under reduced pressure to give
the crude product. Purification by flash column chromatography
on silica (petroleum ether/EtOAc, 9:1) gave compound 11 (54 mg,
76%) as an orange solid; m.p. 170–172 °C. Rf = 0.51 (petroleum
ether/EtOAc, 9:1). 1H NMR (300 MHz, CDCl3): δ = 8.16–8.19 (m,
2 H), 8.07 (s, 1 H), 7.65–7.73 (m, 4 H), 7.57–7.63 (m, 3 H), 7.50–
7.53 (m, 2 H), 7.46 (d, J = 9.0 Hz, 2 H), 6.69 (d, J = 9.0 Hz, 2 H),
3.01 (s, 2 H), 1.93–2.03 (m, 4 H), 1.06–1.22 (m, 12 H), 0.77 (t, J =
7.0 Hz, 6 H), 0.56–0.67 (m, 4 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 157.1 (Cq), 151.5 (Cq), 151.3 (CHAr), 150.2 (Cq), 143.0
(Cq), 142.7 (Cq), 139.5 (Cq), 134.8 (Cq), 132.9 (CHAr), 131.8
(CHAr), 131.2 (CHAr), 131.0 (CF3), 130.6 (CHAr), 129.5 (CHAr),
127.4 (CHAr), 126.8 (CHAr), 125.8 (CHAr), 124.0 (Cq), 123.7 (Cq),
120.3 (CHAr), 120.1 (CHAr), 119.5 (Cq), 119.3 (CHAr), 112.0
(CHAr), 110.1 (Cq), 101.3 (-CϵC-), 91.6 (-CϵC-), 88.5 (-CϵC-),
83.4 (Cq), 55.4 (Cq), 40.5 (CH2), 40.4 (2 C, CH3), 31.7 (CH3), 29.8
1
116.2 (CHAr), 161.7 (Cq), 169.3 (Cq) ppm. Data for 13b: H NMR
(300 MHz, CDCl3): δ = 2.77 (s, 3 H, CH3), 2.96 (s, 3 H, CH3), 6.92
(s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 17.0 (CH3), 25.5
(CH3), 112.8 (CHAr), 144.7 (Cq), 155.1 (Cq), 169.3 (Cq) ppm.
4-({7-[1-(4,6-Dimethylpyrimidin-2-yl)-1H-1,2,3-triazol-4-yl]-9,9-
dihexyl-9H-fluoren-2-yl}ethynyl)-N,N-dimethylaniline (14): A mix-
ture of product 9 (50 mg, 0.100 mmol, 1.0 equiv.) and 2-azido-4,6-
dimethylpyrimidine 13 (16 mg, 0.110 mmol, 1.1 equiv.) was added
to a solution of tBuOH/H2O (1:1 v/v, 1 mL). Sodium ascorbate
(5.94 mg, 0.03 mmol, 0.3 equiv.) and CuSO4·5H2O (3.75 mg,
0.015 mmol, 0.15 equiv.) were added to the solution. The resulting
mixture was stirred at 65 °C for 12 h. Then, NH4OH (6 mL) was
added at room temp., and the organic products were extracted with
EtOAc (3ϫ 15 mL). The combined organic layers were dried with
MgSO4, filtered, and concentrated under reduced pressure to give
the crude product. Purification by flash column chromatography
on silica (EtOAc) gave compound 14 (35 mg, 53%) as a pale yellow
solid; m.p. 166–168 °C. Rf = 0.80 (EtOAc). 1H NMR (300 MHz,
CDCl3): δ = 8.89 (s, 1 H), 7.97 (s, 1 H), 7.92 (d, J = 8.0 Hz, 1 H),
7.74 (d, J = 8.0 Hz, 1 H), 7.67 (d, J = 9.0 Hz, 1 H), 7.51–7.52 (m,
2 H), 7.46 (d, J = 9.0 Hz, 2 H), 7.12 (s, 1 H), 6.69 (d, J = 9.0 Hz,
2 H), 3.01 (s, 6 H), 2.65 (s, 6 H), 2.00–2.07 (m, 4 H), 1.03–1.33 (m,
12 H), 0.74 (t, J = 7.0 Hz, 6 H), 0.59–0.64 (m, 4 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 169.8 (Cq), 154.1 (Cq), 151.8 (Cq), 151.1
(Cq), 150.1 (Cq), 148.5 (Cq), 141.2 (Cq), 140.3 (Cq), 132.8 (CHAr),
130.4 (CHAr), 129.0 (Cq), 125.7 (CHAr), 125.1 (CHAr), 122.7 (Cq),
120.4 (CHAr), 120.3 (CHAr), 119.9 (CHAr), 119.8 (CHAr), 118.6
(CH), 111.9 (CHAr), 110.1 (Cq), 91.0 (Cq), 88.6 (Cq), 55.5 (Cq), 40.6
(CH2), 40.3 (CH3), 31.7 (CH2), 29.8 (CH2), 24.2 (CH3), 23.9 (CH2),
(CH ), 24.0 (CH ), 22.7 (CH ), 14.1 (CH ) ppm. IR (neat): ν =
˜
3
3
2
3
2925, 2853, 2200, 1599, 1522, 1466, 1450, 1396, 1362, 1265, 1193,
1179, 1140, 947, 912, 890, 815, 784, 689, 528 cm–1. HRMS (TOF
MS ESI+): calcd. for C48H49N3F3 [M + H]+ 724.3879; found
724.3880.
4-({9,9-Dihexyl-7-[(4-nitrophenyl)ethynyl]-9H-fluoren-2-yl}ethyn-
yl)-N,N-dimethylaniline (12): A mixture of 8 (50 mg, 0.100 mmol,
1.0 equiv.) and p-nitroiodobenzene (25 mg, 0.1 mmol, 1.0 equiv.)
was added to a solution of iPr2NH/THF (1:1 v/v, 2 mL). After
degassing, CuI (0.4 mg, 0.002 mmol, 0.02 equiv.) and [Pd(PPh3)4]
(2.3 mg, 0.002 mmol, 0.02 equiv.) were introduced to the mixture.
The resulting solution was stirred at 65 °C for 18 h. Distilled water
(5 mL) was added, and the organic products were extracted with
Et2O (3ϫ 10 mL). The combined organic layers were dried with
MgSO4, filtered, and concentrated under reduced pressure to give
the crude product. Purification by flash column chromatography
on silica (petroleum ether/EtOAc, 9:1) gave compound 12 (49 mg,
79%) as an orange solid; m.p. 91–93 °C. Rf = 0.56 (petroleum ether/
EtOAc, 9:1). 1H NMR (300 MHz, CDCl3): δ = 8.24 (d, J = 9.0 Hz,
22.7 (CH ), 14.1 (CH ) ppm. IR (neat): ν = 2925, 2851, 1600, 1524,
˜
2
3
1467, 1440, 1412, 1345, 1229, 1199, 1019, 945, 823, 806, 780, 756,
656, 623 cm–1. HRMS (TOF MS ESI+): calcd. for C43H51N6 [M +
H]+ 651.4175; found 651.4190.
[(7-Bromo-9,9-dihexyl-9H-fluoren-2-yl)ethyny]trimethylsilane (15):
2 H), 7.70 (d, J = 9.0 Hz, 2 H), 7.64–7.67 (m, 2 H), 7.50–7.56 (m, A mixture of 2-bromo-9,9-dihexyl-7-iodo-9H-fluorene (1, 500 mg,
4 H), 7.46 (d, J = 9.0 Hz, 2 H), 6.69 (d, J = 9.0 Hz, 2 H), 3.00 (s,
6 H), 1.97–2.02 (m, 4 H), 0.99–1.17 (m, 12 H), 0.77 (t, J = 7.0 Hz,
0.926 mmol, 1.0 equiv.) and trimethylsilylacetylene (0.926 mmol,
1.0 equiv.) was added to a solution of iPr2NH/THF (1:1 v/v, 4 mL).
6 H), 0.56–0.64 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ = After degassing, CuI (3.6 mg, 0.019 mmol, 0.02 equiv.) and
151.3 (Cq), 151.2 (Cq), 150.2 (Cq), 146.9 (Cq), 142.1 (Cq), 139.6 [Pd(PPh3)4] (22.0 mg, 0.019 mmol, 0.02 equiv.) were introduced to
10
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Pages: 13
Synthesis and Photophysical Properties of Push–Pull Structures
the mixture. The resulting solution was stirred at room temp. for
12 h. Distilled water (10 mL) was added, and the organic products
were extracted with EtOAc (3ϫ 15 mL). The combined organic
layers were dried with MgSO4, filtered, and concentrated under
reduced pressure to give the crude product. Purification by flash
column chromatography on silica (petroleum ether) gave com-
pound 15 (305 mg, 65%) as a yellow viscous oil; Rf = 0.58 (petro-
leum ether). 1H NMR (300 MHz, CDCl3): δ = 7.59 (d, J = 7.5 Hz,
0.39 mmol, 1.0 equiv.) and 4-azido-N,N-dimethylaniline (70 mg,
0.43 mmol, 1.1 equiv.) were introduced to a mixture of tBuOH/H2O
(1:1 v/v, 3 mL). Sodium ascorbate (23 mg, 0.12 mmol, 0.3 equiv.)
and CuSO4·5H2O (15 mg, 0.06 mmol, 0.15 equiv.) were added, and
the resulting mixture was stirred at 65 °C for 12 h. Then, NH4OH
was added (6 mL), and the organic products were extracted with
EtOAc (3ϫ 10 mL). The combined organic layers were dried with
MgSO4 and concentrated under reduced pressure to give the crude
1 H), 7.53 (d, J = 9.0 Hz, 1 H), 7.42–7.47 (m, 4 H), 1.90–1.95 (m, product. Purification by flash column chromatography on silica
4 H), 1.02–1.26 (m, 12 H), 0.78 (t, J = 7.5 Hz, 6 H), 0.49–0.60 (m,
(petroleum ether/EtOAc, 9:1) gave compound 18 (186 mg, 68%);
4 H), 0.29 (s, 9 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 153.4 Rf = 0.23 (petroleum ether/EtOAc, 9:1). 1H NMR (300 MHz,
(Cq), 152.7 (Cq), 150.4 (Cq), 140.6 (Cq), 139.5 (CHAr), 131.4 CDCl3): δ = 8.14 (s, 1 H), 7.98 (s, 1 H), 7.81 (dd, J = 1.0, 8.0 Hz,
(CHAr), 130.2 (CHAr), 126.3 (CHAr), 121.9 (Cq), 121.7 (Cq), 121.5
1 H), 7.72 (d, J = 8.0 Hz, 1 H), 7.63–7.59 (m, 3 H), 7.48 (dd, J =
(CHAr), 119.7 (CHAr), 106.1 (Cq), 94.4 (Cq), 55.6 (Cq), 40.4 (CH2), 1.0, 8.0 Hz, 1 H), 7.43 (br. s, 1 H), 6.77 (d, J = 9 Hz); 3.01 (s, 6
31.7 (CH2), 29.8 (CH2), 23.8 (CH2), 22.8 (CH2), 0.2 (CH2) ppm. H), 2.06–1.99 (m, 4 H), 1.18 (s, 18 H), 1.14–0.90 (m, 15 H), 0.75
HRMS (TOF MS APCI+): calcd. for C30H41SiBr [M + H]+
508.2161; found 508.2179.
(t, J = 7.0 Hz, 6 H), 0.63–0.66 (m, 4 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 152.0 (Cq), 151.0 (Cq), 150.7 (Cq), 148.5 (Cq), 141.2
(Cq), 140.7 (Cq), 131.5 (CHAr), 129.9 (Cq), 126.9 (Cq), 126.2
(CHAr), 124.8 (CHAr), 122.1 (CHAr), 122.0 (Cq), 121.5 (CHAr),
120.2 (CHAr), 119.6 (CHAr), 118.0 (CH), 112.4 (CHAr), 108.3 (Cq),
90.5 (Cq), 55.5 (Cq), 40.6 (CH3), 40.5 (CH2), 31.6 (CH2), 29.8
(CH2), 23.8 (CH2), 22.7 (CH2), 18.9 (CH), 14.1 (CH3), 11.6
(CH3) ppm. HRMS (TOF MS ESI+): calcd. for C46H65N4Si [M +
H]+ 701.4979; found 701.4968.
({9,9-Dihexyl-7-[(triisopropylsilyl)ethynyl]-9H-fluoren-2-yl}ethyn-
yl)trimethylsilane (16): A mixture of 15 (0.280 g, 0.549 mmol,
1.0 equiv.) and triisopropylsilylacetylene (190 μL, 0.824 mmol,
1.5 equiv.) was added to a solution of iPr2NH/DMF (1:1 v/v,
2 mL). After degassing, CuI (2.1 mg, 0.011 mmol, 0.02 equiv.) and
[Pd(PPh3)4] (12.7 mg, 0.011 mmol, 0.02 equiv.) were introduced to
the mixture. The resulting solution was stirred at room temp. for
12 h. Distilled water (10 mL) was added, and the organic product
was extracted with EtOAc (3ϫ 15 mL). The combined organic lay-
ers were dried with MgSO4, filtered, and concentrated under re-
duced pressure to give the crude product. Purification by flash col-
umn chromatography on silica (pentane) gave compound 16
(0.266 g, 79%) as a white solid; m.p. 144–146 °C. Rf = 0.44 (pent-
4-[4-(7-Ethynyl-9,9-dihexyl-9H-fluoren-2-yl)-1H-1,2,3-triazol-1-yl]-
N,N-dimethylaniline (19): 4-(4-{9,9-dihexyl-7-[(triisopropylsilyl)eth-
ynyl]-9H-fluoren-2-yl}-1H-1,2,3-triazol-1-yl)-N,N-dimethylaniline
(18, 186 mg, 0.27 mmol, 1.0 equiv.) and tetra-n-butylammonium
fluoride (1 m in THF, 0.45 mL, 0.45 mmol, 1.06 equiv.) were intro-
duced to THF (27 mL) under argon. After 12 h of stirring at room
temp., the solvent was evaporated under reduced pressure to give
the crude product. Purification by flash column chromatography
on silica (petroleum ether/EtOAc, 6:4) gave compound 19 (129 mg,
88 %); Rf = 0.60 (petroleum ether/EtOAc, 6:4). 1H NMR
(300 MHz, CDCl3): δ = 8.14 (s, 1 H), 7.97 (s, 1 H), 7.83 (d, J =
8.0 Hz, 1 H), 7.74 (d, J = 8.0 Hz, 1 H), 7.64 (dd, J = 9.0, 8.5 Hz,
3 H), 7.48–7.51 (m, 2 H), 6.80 (d, J = 9.0 Hz, 2 H), 3.16 (s, 1 H),
3.04 (s, 6 H), 2.10–1.93 (m, 4 H), 1.13–0.97 (m, 12 H), 0.75 (t, J =
7.0 Hz, 6 H), 0.68–0.54 (m, 4 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 152.0 (Cq), 151.1 (Cq), 150.8 (Cq), 148.4 (Cq), 141.7
(Cq), 140.5 (Cq), 131.3 (CHAr), 130.1 (Cq), 126.9 (Cq), 126.6
(CHAr), 124.8 (CHAr), 122.6 (CHAr), 122.2 (CHAr), 120.4 (Cq),
120.2 (CHAr), 119.8 (CHAr), 118.0 (CH), 112.5 (CHAr), 84.9 (Cq),
77.4 (Cq), 55.5 (Cq), 40.64 (CH3), 40.56 (CH2), 31.7 (CH2), 29.8
(CH2), 22.7 (CH2), 14.1 (CH3) ppm. HRMS (TOF MS ESI+):
calcd. for C37H45N4 [M + H]+ 545.3644; found 545.3660.
1
ane). H NMR (300 MHz, CDCl3): δ = 7.59–7.62 (m, 2 H), 7.42–
7.49 (m, 4 H), 1.94–1.99 (m, 4 H), 1.19 (s, 18 H), 1.04–1.15 (m, 15
H), 0.79 (t, J = 6.9 Hz, 6 H), 0.56–0.63 (m, 4 H), 0.30 (m, 3
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 151.1 (Cq), 151.0 (Cq),
141.0 (Cq), 140.8 (Cq), 131.6 (CHAr), 131.4 (CHAr), 126.4 (CHAr),
126.2 (CHAr), 122.5 (Cq), 121.9 (Cq), 119.9 (CHAr), 108.2 (Cq),
106.3 (Cq), 94.3 (Cq), 90.7 (Cq), 55.4 (Cq), 40.4 (CH2), 31.7 (CH2),
29.8 (CH2), 23.7 (CH2), 22.8 (CH2), 18.9 (CH), 14.2 (CH3), 11.6
(CH3), 0.2 (CH3) ppm. HRMS (TOF MS APCI+): calcd. for
C41H63Si2 [M + H]+ 611.4468; found 611.4468.
[(7-Ethynyl-9,9-dihexyl-9H-fluoren-2-yl)ethynyl]triisopropylsilane
(17): A solution of 16 (240 g, 0.392 mmol, 1.0 equiv.) and K2CO3
(272 mg, 1.960 mmol, 5.0 equiv.) were added to a solution of THF
(8 mL) and MeOH (8 mL) under argon. The mixture was stirred
at room temp. for 16 h. K2CO3 was removed by filtration, and the
filter cake was washed with CH2Cl2. The solvents were evaporated
under reduce pressure to give the crude product. Purification by
flash column chromatography on silica (petroleum ether) gave com-
pound 17 (170 mg, 80 %) as a yellow oil; Rf = 0.30 (petroleum
4-(4-{7-[1-(4,6-Dimethylpyrimidin-2-yl)-1H-1,2,3-triazol-4-yl]-9,9-di-
hexyl-9H-fluoren-2-yl}-1H-1,2,3-triazol-1-yl)-N,N-dimethylaniline
(20): A mixture of 4-[4-(7-ethynyl-9,9-dihexyl-9H-fluoren-2-yl)-1H-
1,2,3-triazol-1-yl]-N,N-dimethylaniline (19, 129 mg, 0.237 mmol,
1.0 equiv.) and 2-azido-4,6-dimethylpyrimidine (13, 44.7 mg,
0.300 mmol, 1.1 equiv.) was added to a solution of tBuOH/H2O
(1:1 v/v, 1 mL). Sodium ascorbate (14.1 mg, 0.07 mmol, 0.30 equiv.)
and CuSO4·5 H2O (9.0 mg, 0.036 mmol, 0.15 equiv.) were added to
the solution. The resulting mixture was stirred at 65 °C for 3 d.
Then, NH4OH was added (6 mL), and the organic products were
extracted with EtOAc (3ϫ 15 mL). The combined organic layers
were dried with MgSO4 and concentrated under reduced pressure
to give a yellow residue. Purification by flash column chromatog-
raphy on silica (petroleum ether/EtOAc, 5:5) gave compound 20
(138 mg, 85%) as a pale yellow solid; m.p. 235–237 °C. Rf = 0.4
(petroleum ether/EtOAc, 5:5). 1H NMR (300 MHz, CDCl3): δ =
8.87 (s, 1 H), 8.15 (s, 1 H), 7.99 (s, 1 H), 7.90 (d, J = 8.0 Hz, 1 H),
1
ether). H NMR (300 MHz, CDCl3): δ = 7.61 (m, 2 H), 7.46–7.49
(m, 2 H), 7.45 (s, 1 H), 7.39 (s, 1 H), 3.15 (s, 1 H), 1.91–1.97 (m, 4
H), 1.17 (s, 18 H), 0.97–1.12 (m, 15 H), 0.77 (t, J = 7.0 Hz, 6 H),
0.56–0.60 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 151.1
(Cq), 151.06 (Cq), 141.2 (Cq), 140.6 (Cq), 131.5 (CHAr), 131.3
(CHAr), 126.6 (CHAr), 126.2 (CHAr), 122.5 (Cq), 121.8 (Cq), 120.0
(CHAr), 119.9 (CHAr), 108.1 (Cq), 90.8 (Cq), 84.7 (Cq), 77.4 (Cq),
55.3 (Cq), 40.3 (CH2), 31.0 (CH2), 29.7 (CH2), 23.7 (CH2), 22.7
(CH2), 18.8 (CH), 14.1 (CH3), 11.5 (CH3) ppm. HRMS (TOF MS
APCI+): calcd. for C38H55Si [M + H]+ 539.4073; found 539.4065.
4-(4-{9,9-Dihexyl-7-[(triisopropylsilyl)ethynyl]-9H-fluoren-2-yl}-1H-
1,2,3-triazol-1-yl)-N,N-dimethylaniline (18): [(7-Ethynyl-9,9-di-
hexyl-9H-fluoren-2-yl)ethynyl]triisopropylsilane (17, 208 mg,
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Pages: 13
C. Baudequin, S. Achelle et al.
FULL PAPER
Lu, P. Wang, C. Ye, Chem. Commun. 2001, 171–172; c) T. Verb-
iest, S. Houbrechts, M. Kauranen, K. Clays, A. Persoons, J.
Mater. Chem. 1997, 7, 2175–2189; d) C. Wang, T. Zhang, W.
Lin, Chem. Rev. 2012, 112, 1084–1104; e) H. M. Kim, B. R.
Cho, Chem. Commun. 2009, 153–164; f) L. Beverina, J. Fu, A.
Leclercq, E. Zojer, P. Pacher, S. Barlow, E. W. W. Stryland, D. J.
Hagan, J.-L. Brédas, S. R. Marder, J. Am. Chem. Soc. 2005,
127, 7282–7283.
S. Achelle, N. Plé, Curr. Org. Synth. 2012, 9, 163–187.
S. Achelle, N. Plé, A. Turck, RSC Adv. 2011, 1, 364–388.
For example, see: a) K. Itami, D. Yamazaki, J.-i. Yoshida, J.
Am. Chem. Soc. 2004, 126, 15396–15397; b) G. Hughes, C.
Wang, A. S. Batsanov, M. Fern, S. Frank, M. R. Bryce, I. F.
Perepichka, A. P. Monkman, B. P. Lyons, Org. Biomol. Chem.
2003, 1, 3069–3077; c) S. Achelle, I. Nouira, B. Pfaffinger, Y.
Ramondenc, N. Plé, J. Rodríguez-López, J. Org. Chem. 2009,
74, 3711–3717; d) C. Hadad, S. Achelle, J. García-Martinez, J.
Rodríguez-López, J. Org. Chem. 2011, 76, 3837–3845; e) A. I.
Aranda, S. Achelle, F. Hammerer, F. Mahuteau-Betzer, M.-P.
Teulade-Fichou, Dyes Pigments 2012, 95, 400–407.
7.77 (d, J = 9.0 Hz, 1 H), 7.75–7.72 (m, 2 H), 7.69 (d, J = 9.0 Hz,
2 H), 7.08 (s, 1 H), 6.77 (d, J = 9.0 Hz, 2 H), 3.00 (s, 6 H), 2.61 (s,
6 H), 2.12–2.06 (m, 4 H), 1.11–0.99 (m, 12 H), 0.73–0.66 (m, 10
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 169.8 (Cq), 154.1 (Cq),
151.9 (Cq), 151.8 (Cq), 150.6 (Cq), 148.5 (Cq), 141.3 (Cq), 140.8
(Cq), 129.6 (Cq), 129.0 (Cq), 126.8 (Cq), 125.1 (CHAr), 124.7
(CHAr), 122.0 (CHAr), 120.4 (CHAr), 120.3 (Cq), 120.2 (CHAr),
119.8 (CHAr), 118.5 (CHAr), 117.9 (CHAr), 112.4 (CHAr), 55.6 (Cq),
40.6 (CH3), 40.5 (CH2), 31.6 (CH2), 29.8 (CH2), 24.1 (CH3), 23.9
[8]
[9]
[10]
(CH ), 22.7 (CH ), 14.1 (CH ) ppm. IR (neat): ν = 2955, 2927,
˜
2
2
3
2855, 1602, 1529, 1439, 1348, 1232, 1023, 817 cm–1. HRMS (TOF
MS ESI+): calcd. for C43H51N9 [M + H]+ 694.4346; found
694.4338.
Supporting Information (see footnote on the first page of this arti-
cle): Characterization data, 1H and 13C NMR spectra, UV/Vis
absorption, excitation spectra.
[11]
[12]
Acknowledgments
a) E. Botek, F. Castet, B. Champagne, Chem. Eur. J. 2006, 12,
8687–8695; b) M. He, Y. Zhou, R. Liu, J. Dai, Y. Cui, T.
Zhang, Dyes Pigments 2009, 80, 6–10; c) H. Akdas-Kilig, T.
Roisnel, I. Ledoux, H. Le Bozec, New J. Chem. 2009, 33, 1470–
1473; d) S. Achelle, A. Barsella, C. Baudequin, B. Caro, F. Ro-
bin-le Guen, J. Org. Chem. 2012, 77, 4087–4096.
The authors thank Dr. Anthony Romieu and Pr. Jean-Philippe
Bouillon (Université de Rouen, UMR 6014) for the helpful dis-
cussions and Pr. Georges Dupas for performing the optimized ge-
ometry. The authors are grateful to Mr. Jean Bernard for his help
with the two-photon absorption cross-section measurements. The
financial support from a grant provided by the Research Council
Romania (project PN-II-ID-PCE-3-0128) is gratefully acknowl-
edged. O. M. thanks for “Investing in people! Ph.D. scholarship”,
Project co-financed by the Sectorial Operational Program for Hu-
man Resources Development 2007–2013. Priority Axis 1. “Educa-
tion and training in support for growth and development of a
knowledge-based society” Key area of intervention 1.5: Doctoral
and post-doctoral programs in support of research. Contract no.:
POSDRU/88/1.5/S/60185 e “Innovative Doctoral Studies in a
Knowledge Based Society” Babes-Bolyai University, Cluj-Napoca,
Romania.
a) Z. Liu, P. Shao, Z. Huang, B. Liu, T. Chen, J. Qin, Chem.
Commun. 2008, 2260–2262; b) L. Li, Y. P. Tian, J. X. Yang,
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Xing, C. K. Wang, M. Li, G. H. Cheng, H. H. Tang, W. H.
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Job/Unit: O30458
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Date: 18-07-13 19:04:50
Pages: 13
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Received: March 28, 2013
Published Online: ᭿
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