Methylenepyran based dipolar and quadrupolar dyes: Synthesis, electrochemical and photochemical properties

Article abstract of DOI:10.1016/j.tet.2013.07.066

This paper presents the synthesis of a series of push-pull and quadrupolar π-conjugated structures incorporating pro-aromatic methylenepyran electron-donor groups and various electron-attracting groups. Some of the methylenepyran derivatives were oxidized by I₂ to give, after reduction by Na₂S₂O₃, bismethylenepyran compounds via successive steps. The electrochemical redox properties of methylenepyrans 5-9 and extended bismethylenepyrans 10, 14, and 15 determined by cyclic voltammetry indicate the formation of redox bistable systems with high bi-stability. Oxidation of the dimers obtained from 5 to 9 was also described. All compounds are colored and slightly fluorescent (except some bismethylenepyran derivatives). Some compound second-order nonlinear optical properties were investigated, and large positive values of μβ were obtained. A positive dimer effect was also observed for bispyran derivatives.

Full text of DOI:10.1016/j.tet.2013.07.066

Tetrahedron 69 (2013) 8392e8399
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Methylenepyran based dipolar and quadrupolar dyes: synthesis,
electrochemical and photochemical properties
a
,
a
a
,
b
*
*
ꢀ
Sebastien Gauthier , Nikolay Vologdin , Sylvain Achelle , Alberto Barsella ,
Bertrand Caro a, Franc¸ oise Robin-le Guen a
a Institut des Sciences Chimiques de Rennes UMR CNRS 6226, IUT de Lannion, rue Edouard Branly, BP 30219, F22302 Lannion Cedex, France
b
ꢀ
Departement d’Optique ultra-rapide et Nanophotonique, IPCMS-CNRS, 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 29 May 2013
Received in revised form 16 July 2013
Accepted 18 July 2013
Available online 26 July 2013
This paper presents the synthesis of a series of pushepull and quadrupolar
p-conjugated structures
incorporating pro-aromatic methylenepyran electron-donor groups and various electron-attracting
groups. Some of the methylenepyran derivatives were oxidized by I2 to give, after reduction by
Na2S2O3, bismethylenepyran compounds via successive steps.
The electrochemical redox properties of methylenepyrans 5e9 and extended bismethylenepyrans 10, 14,
and 15 determined by cyclic voltammetry indicate the formation of redox bistable systems with high bi-
stability. Oxidation of the dimers obtained from 5 to 9 was also described. All compounds are colored and
slightly fluorescent (except some bismethylenepyran derivatives). Some compound second-order non-
linear optical properties were investigated, and large positive values of mb were obtained. A positive
dimer effect was also observed for bispyran derivatives.
Keywords:
Methylenepyran
Diazines
Pushepull
Nonlinear optics
Dyes
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
and large optical nonlinearities and responses. g-Methylenepyrans
are versatile six-membered heterocycles with a pro-aromatic
electron-donor character. It is well-known that chromophores in-
Donoreacceptor
p-conjugated (DepeA) materials with both
electron-donating and electron-accepting groups linked by a
p-
corporating aromatic subunits display lower b values than the
conjugated bridge have been extensively studied during the past
decades due to their useful applications as sensitizers for dye-
sensitized solar-cells (DSSCs),1 emitters of organic light emitting
diodes (OLEDs),2 and various fluorescence sensors.3
corresponding polyenes of the same conjugation length, since their
ground states are usually dominated by neutral, aromatic forms
that lose resonance energy on charge separation.7 One way to cir-
cumvent this drawback consists of incorporating a molecular
fragment whose aromaticity will increase upon charge transfer. In
Pushepull molecules with large delocalized
are also typical second and third order nonlinear optic (NLO)
chromophores.4 Quadrupolar De
eAe eD structures also exhibit
p-electron systems
this context,
g-methylenepyrans, which acquire the aromatic
p
p
character of pyrylium upon internal charge transfer, are particularly
attracting as donor part in pushepull structures. The use of such
molecular fragments in the structure of NLO chromophores has
third order NLO properties. Second-order NLO materials have found
applications in green lasers obtained from red sources through
frequency doubling, in second-harmonic generation microscopy or
in terahertz wave generation.5 Third order NLO, in particular two-
photon absorption (TPA) materials have also attracted consider-
able attention due to their applications in photodynamic therapy,
confocal microscopy, optical power limiting and 3D data storage,
and microfabrication.6 Unlike inorganic materials, organic com-
pounds used for NLO applications offer several advantages, such as
easy syntheses, well-defined structure, easily tunable properties,
already been described in the literature.8 Moreover,
p-conjugated
structures incorporating
g-methylenepyran building blocks have
also been described as interesting redox systems.9 In particular, it
has been described that oxidative dimerization of methylenepyrans
bearing exocyclic ferrocenyl groups leads to the formation of bis-
pyrilium salts via
a radical cation intermediate. Subsequent
deprotonation led to extended diferrocenylbispyran, which were
then oxidized into unsaturated bispyrilium salts.10
On the other hand, diazines are six-membered aromatics with
two nitrogen atoms. Three different structures can be distinguished
based on the relative position of the nitrogen atoms: pyridazine
(1,2-diazine), pyrimidine (1,3-diazine), and pyrazine (1,4-diazine).
Diazines are very attractive electron accepting building blocks for
* Corresponding authors. Tel.: þ33 (0)2 96 46 93 44; fax: þ 33 (0)2 96 46 93 54
(S.G.); tel.: þ 33 (0)2 96 46 94 48 (S.A.); e-mail addresses: sebastien.gauthier@
univ-rennes1.fr (S. Gauthier), sylvain.achelle@univ-rennes1.fr (S. Achelle).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.07.066

S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
8393
the synthesis of pushepull, quadrupolar, and octupolar structures.
Such structures exhibit high fluorescence due to internal charge
transfer, important TPA properties and can be used as dyes for
DSSCs.11e13 The possibility to protonate, form hydrogen bonds, and
chelate the diazine rings also present additional advantages.
Recently, some of us have described the NLO properties of two
It has been reported that alkynyldiazines can be obtained from
iododiazines by Sonogashira cross-coupling under mild synthetic
conditions with good yield.18 Similar conditions were used to
synthesize building block 4 and a variety of monoiodo and diio-
dodiazines leading to pushepull structures 11e13 and quadrupolar
compounds 14, 15, with moderate to good yield (Scheme 3).
Dithiafulvenes and methylenepyrans have been reported to di-
merize in the presence of oxidant by oxidative coupling via a radical
cation intermediate.10b,19 This method was used with some of the
methylenepyrans described (compounds 5e9) using diiode as oxi-
dant (Scheme 4). Addition of a reducing agent (Na2S2O3) to the re-
action mixture gave bismethylenepyran coupling products 16e20,
with moderate yield. This suggests that under such oxidative con-
ditions, the formation of the dimers proceeds from the following
successive steps: (1) dimerization of compounds 5e9 via a radical
cation intermediate leading to bispyrylium salts. (2) Deprotonation
of the salts to give bismethylenepyrans 16e20. (3) Oxidation of the
neutral dimers to dicationic pyrylium species, which were then re-
duced by Na2S2O3 to give bismethylenepyrans 16e20.
pyrimidine g
-methylenepyran derivatives.14 In the present article,
we describe the synthesis, the electrochemical and the optical
properties of a series of pushepull, bispushepull, and quadrupolar
structures with an extended
p-conjugated core incorporating g-
methylenepyrans as electron-donating parts and various electron-
accepting groups, in particular diazine rings.
2. Results and discussion
2.1. Synthesis
The key intermediate for synthesis of pushepull structures is
alkyne 4. This compound can be obtained in two steps from 4-
trimethylsilylethynyl-benzaldehyde 1 and phosphonium salt 215
(Scheme 1). The first step is a Wittig reaction16 leading to in-
termediate 3 with good yield and the second step consists of the
deprotection of the trimethylsilyl group with quasi-quantitative
yield.
All new compounds were soluble in THF, chloroform, and
dichloromethane and were characterized using 1H and 13C NMR
and high-resolution mass analysis. These materials were also per-
fectly stable in the solid state and did not require special storage
conditions.
Scheme 1. Reagents and conditions: (i) n-BuLi, THF, ꢀ78 ꢁC/rt, 2 h (ii) K2CO3, MeOH/CH2Cl2, rt, overnight.
The intermediate 4 can be involved in a copper/palladium-
catalyzed Sonogashira cross-coupling reaction with a variety of
substituted bromobenzenes (Scheme 2).17 Compounds 5e8 have
been obtained in moderate to good yield. It should be noted that
a small proportion of dimer 10 is systematically formed during the
reaction, even when using Pd(PPh3)4 instead of Pd(PPh3)2Cl2 as
palladium catalyst. Aldehyde 8 can be used in a Knoevenagel
condensation reaction with malononitrile leading to dicyano de-
rivative 9.
2.2. Electrochemical studies
The redox properties of the series of pyrans 5e9 and 11e13,
extended bispyrans 10, 14, and 15, and diarylacetylene bispyran
16e20 (Table 1 and Fig. 1) were investigated by cyclic voltammetry
in CH2Cl2 in the presence of NBu4BF4 as supporting electrolyte. All
potentials are given versus FeCpþ2 /FeCp2 couple.
The cyclic voltammogram of 9 (Fig. 1a) shows an irreversible
anodic peak at 0.31 V and, on the reverse scan, an irreversible
R
Ph
O
Ph
(i)
4
+
Ph
O
Ph
Ph
O
5 R = CN 70%
6 R = NO2 62%
7 R = CF3 68%
8 R = CHO 75%
5-15%
10
Ph
(ii)
CN
45%
9 R =
CN
Scheme 2. Reagents and conditions: (i) bromobenzene derivative, Pd(PPh3)2Cl2, CuI, THF, NHiPr2, 60 ꢁC, overnight (ii) 2 equiv malononitrile, AcOH/AcONa, benzene, reflux, 5 h.

8394
S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
HetAr
N
11 HetAr =
12 HetAr =
48%
N
N
13 HetAr =
65%
N
Ph
O
N
N
47%
OMe
(i)
Ph
4
Ph
O
Ph
N
N
14 HetAr =
HetAr
72%
Ph
O
N
15 HetAr =
Ph
N
40%
Scheme 3. Reagents and conditions (i) iododiazine, Pd(PPh3)2Cl2, CuI, THF, NEt3, rt, overnight.
(
sCeC bond making). This dication is irreversibly reduced at ꢀ0.85 V
R
to a dipyranyl radical, which evolves into the initial methylenepyran
9 through the breakingof a sCeC bond. Unlike the chemical oxidation
by I2, the deprotonation to bismethylenepyran was not observed. As
indicated in Table 1, the whole series of pyran compounds 5e9
exhibited a similar behavior. As expected, our molecular redox
systems displayed high bi-stability properties, as shown by the peak
Ph
O
Ph
(i)
5-9
(ii)
separation value
DE¼Epa (1)ꢀEpc (2) of 1.16 V found between the
Ph
O
Ph
irreversible reduction and oxidation peak observed for compound 9.
Extended bismethylenepyrans 10, 14, and 15 displayed essen-
tially an identical behavior (Table 1), as shown by their voltam-
mograms exhibiting an irreversible oxidation peak and an
irreversible reduction peak at potential values very similar to those
of compounds 5e9. Such electrochemical behavior that was already
observed,14 differs from that of other methylenepyrans bearing
alkenyl spacers, for which dimerization did not occur.9,20 Previous
voltammetry studies have shown that vinylogues of bispyrans can
be sequentially oxidized to pyranylepyrylium radical cations and
then to pyrylium dications.9,20 Based on the substitution of the
exocyclic carbon, the oxidation of the bispyrans proceeded either
via two separated one electron reversible waves or via coalescence
of the two reversible waves indicating that the removal of the two
electrons occurred at a close potential.10b,20b
R
16 R = CN 45%
17 R = NO2 30%
18 R = CF3 32%
19 R = CHO 40%
CN
20 R =
25%
CN
Scheme 4. Reagents and conditions (i) I2, CH2Cl2, rt, overnight (ii) Na2S2O3.
cathodic peak is observed at ꢀ0.85 V. As previously described for the
pyridyl, phenyl, and ferrocenyl methylenepyrans,10,16 these obser-
vations are consistent with the formation of a pyrylium radical
cation 9þꢂ, which is transformed into a bispyrylium compound 92þ
The cyclic voltammogram of bispyran 20 (Fig. 1b) shows a re-
Table 1
versible system at E1/2 (3)¼ꢀ0.15 V ( E1/2¼70 mV). The redox be-
D
Electrochemical data for pyran and bispyran compounds, (E vs, FeCpþ2 /FeCp2) in
CH2Cl2 with NBu4BF4 as supporting electrolyte at 0.1 V sꢀ1
havior of 20 resulting in the formation of the bispyrylium cation
202þ suggests that the system E1/2 (3) corresponds to two single-
electron waves coalescing to one two-electron oxidation wave
(compression of potential). As shown in Table 1, a comparable re-
versible system was observed with the whole series of bispyrans
16e20 (ꢀ0.17 V<E1/2 (3)<ꢀ0.15 V). Finally, comparison of the po-
tential values shows that the dimers 16e20 have been oxidized at
a potential lower than that of their corresponding monomer 5e9.
This explains the oxidation of the bismethylenepyrans formed by
deprotonation during the I2 oxidative coupling. Therefore, the
isolation of dimers 16e20 required the use of a reducing agent.
Epa (1)/Va
Epc (2)/Vb
E1/2 (3)/V, (DE1/2/mV)
5
6
7
8
0.31
0.32
0.32
0.32
0.31
0.31
0.31
0.34
0.35
0.33
0.33
ꢀ0.87
ꢀ0.86
ꢀ0.89
ꢀ0.88
ꢀ0.85
ꢀ0.84
ꢀ0.84
ꢀ0.85
ꢀ0.87
ꢀ0.84
ꢀ0.83
9
10
11
12
13
14
15
16
17
18
19
20
ꢀ0.16, (63)
ꢀ0.16, (63)
ꢀ0.16, (98)
2.3. Linear and nonlinear optical properties
The UV/vis and photoluminescence (PL) spectroscopic data of
various oligomers carried out in dichloromethane at 25 ꢁC are pre-
sented in Table 2. The measurements were performed using low
ꢀ0.17, (102)
ꢀ0.15, (70)
a
Irreversible peak.
Irreversible peak on the reverse cathodic scan.
concentration solutions (1.0ꢃ10ꢀ5e3.0ꢃ10ꢀ5
M
for UV/vis
b

S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
8395
Fig. 1. Cyclic voltammograms of (a) pyran 9 in CH2Cl2þNBu4BF4 (T¼293 K, C¼8.00.10ꢀ4 M, v¼0.1 V sꢀ1, WE:Pt) and (b) bispyran 20 in CH2Cl2þNBu4BF4 (T¼293 K, C¼2.00.10ꢀ4 M,
v¼0.1 V sꢀ1, WE:Pt).
Table 2
All compounds showed absorption wavelengths (lmax) in the
UV/vis and photoluminescence (PL) data in CH2Cl2 solution
visible region (403e463 nm). In all cases, a second or even a third
Compd
UV/vis lmax, nm (
3
, mMꢀ1 cmꢀ1
)
PL lmax, nm
Stokes
absorption band of higher energy could be observed. All com-
pounds, except bispyrans 17e20, were slightly fluorescent in the
green to orange region (495e614 nm) with emission quantum yield
below 0.01. In general, large Stokes shifts were obtained for the
compounds under investigation. This observation indicates signif-
icant differences (vibrational, electronic, geometric) between the
FranckeCondon state and the excited state. When comparing the
UV/vis spectra of compounds 5e9, a red shift of the visible ab-
sorption band was observed upon increase of the electron-
attracting strength of the aromatic groups. As expected, the
dicyano derivative 9 exhibited the highest value of labs. As a result
of the extension of the conjugation, compound 10 exhibited a red
shifted absorption compared to structures substituted by moder-
ately attracting groups (5 and 7). The position of the visible ab-
sorption band of the diazine derivatives 11e13 (409e414 nm)
indicates that the diazinyl groups exhibit an electron-attracting
strength similar to that of a p-cyanophenyl group (compound 5:
labs¼414 nm). In case of dimers 14 and 15 the two methylenepyran
parts are not conjugated due to 2,4 (or 6,4) substitution of the
pyrimidine ring, however a bathochromic effect is observed in
comparison with compounds 12 and 13. Oxidative coupling
shift cmꢀ1
5
6
7
8
414 (40.5)
432 (34.1)
403 (33.9)
422 (23.9)
361 (40.5), 463 (34.9)
437 (71.4)
414 (28.3)
409 (15.4)
414 (32.1)
441 (54.6)
555
551
457
610
528
534
537
514
495
614
557
576
da
6137
4999
2932
7303
2657
4157
5533
4995
3953
6389
5357
4714
da
9
10
11
12
13
14
15
16
17
18
19
20
429 (52.4)
361 (26.2), 453sh (23.5)
371 (19.5), 454sh (25.5)
360 (18.9), 425sh (16.4)
355 (32.3), 446sh (25.8)
366 (54.9), 470sh (25.7)
da
da
da
da
da
da
a
No emission signal has been detected.
measurementsand 1.0ꢃ10ꢀ6e3.0ꢃ10ꢀ6 M for PLmeasurements). For
example, the spectra of the derivatives 5, 9, and 14 are shown in Fig.1.
Under these conditions, self-absorptioneffects were notobserved. All
compounds were photo-stable under the analysis conditions (Fig. 2).
Fig. 2. Normalized UV/vis (solid line) and emission spectra (broken line) of compounds 5, 14, and 16.

8396
S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
products (16e20) spectra also show a red-shifted visible absorption
band compared to those of the compounds 5e7, 9, and 11 with
noteworthy broadened peaks.
Second-order nonlinear properties were studied in CHCl3 solu-
tion using the electric-field-induced second-harmonic generation
technique (EFISH), which provides information about the scalar
3. Conclusion
In conclusion, we have successfully synthesized and character-
ized a series of pushepull and quadripolar structures incorporating
methylenepyran as pro-aromatic electron-donating moieties. The
redox properties were studied: cyclic voltammograms of pyrans
and some bispyrans derivatives exhibited irreversible oxidation
peak around 0.31 V and, on the reverse scan, an irreversible re-
duction peak around ꢀ0.85 V. As shown previously, the oxidation
peak corresponds to the formation of a radical cation, which di-
merizes to a bispyrilium salt (sCeC bond making) and the reduction
peak to the formation of the initial compound (sCeC bond break-
ing). These redox systems have a high bi-stability as illustrated by
product mb (2
polarisability tensor
uct is derived according to Eq. 1 and considering g0(-2u,u,u
u
) of the vector component of the first hyper-
and the dipole moment vector.21 This prod-
,0), the
b
third-order term, as negligible for the pushepull compounds under
consideration. This approximation is usually used for pushepull
organic and organometallic molecules.
gEFISH
¼
mb=5kT þ g0ðꢀ2
u
;
u
;
u
; 0Þ
(1)
the difference between the two potential values (DE>1.1 V). I2 ox-
idation of methylenepyrans followed by Na2S2O3 reduction resul-
ted in the isolation of bismethylenepyran derivatives. These
compounds were reversibly oxidized (two-electron wave) to bis-
pyrylium cation. The optical properties have been also studied: all
the compounds were colored and slightly fluorescent (except some
bispyran derivatives). The second-order nonlinear optical proper-
ties have been investigated for some of the compounds and large of
positive mb values were obtained. A positive dimer effect on the mb
values was obtained for V-shaped bispyran derivatives Further in-
vestigations of this effect are currently underway.
Measurements are performed at 1907 nm, obtained from
a Raman-shifted Nd:YAGþ laser source, which allowed us to work
in conditions far from the resonance peaks of the compounds we
were investigating (5e7, 9, 11, and 16). It should be noted that the
sign and values of mb depend on the ‘direction’ of the transition
implied in the NLO phenomena and on the direction of the ground-
state dipole moment. When
b and m are a parallel (antiparallel),
positive (negative) maxima mb values are obtained.
The mb values of compounds 5e7, 9, 11, and 16 (Table 3) are
positive indicating excited states more polarized than the ground
state (me>mg). In addition, this implies that the ground and excited
4. Experimental section
4.1. General methods
states are polarized in the same direction. The mb values observed
are relatively high, and similar to or higher than Disperse Red 1, as
reported in literature.22 As expected, the trifluoromethyl derivative
6, which does not contain a mesomeric attracting group, exhibited
the lowest mb value (mb¼200ꢃ10ꢀ48 esu). On the contrary the
All solvents were reagent grade. The starting materials were
purchased from SigmaeAldrich or Acros and used without further
purification. Compound 1 was obtained according to literature
procedures.25 For air and moisture-sensitive reactions, all glassware
pieces were flame-dried and cooled under nitrogen. NMR spectra
were recorded in CDCl3, on a Bruker Advance 300 spectrometer (1H
highest value was obtained for the dicyano derivative
(
9
mb¼1150ꢃ10ꢀ48 esu), confirming the attracting strength of the
malononitrile group.23 Cyano derivatives 5 and pyrazinyl com-
pound 11 exhibited similar mb values (350 and 380ꢃ10ꢀ48 esu, re-
spectively) confirming that the attracting strength of the pyrazine
ring is similar to a p-cyanophenyl substituent. It should be noted
that compound 11 displayed a higher mb value than that of 2-[2-(4-
N,N-dimethylamino-phenyl)-vinyl]-pyrazine (230ꢃ10ꢀ48 esu)3c
confirming the good donor strength of the methylenepyran part.
When comparing the mb values of compounds 5 and 16, the value
obtained for compound 16 is more than the double that obtained
for compound 5, indicating a positive dimer effect (350ꢃ10ꢀ48 esu
at 300 MHz and 13C at 75 MHz). The chemical shifts
d are reported in
parts per million relative to the residual solvent (CHCl3). The cou-
pling constants J are given in hertz. In the 1H NMR spectra, the fol-
lowing abbreviations are used to describe the peak patterns: s
(singlet), d (doublet), dd (doublet of doublet), t (triplet), m (multi-
plet). In the 13C NMR spectra, the nature of the carbons (C, CH, CH2 or
CH3) was determined by performing a JMOD experiment. Melting
points (ꢁC) were measured on a Kofler hot-stage with a precision of
2ꢁ (ꢄ2 ꢁC). High-resolution mass analyses were performed at the
vs 830ꢃ10ꢀ48 esu). As the total dipole moment
m
depends on the
¼0 corresponds
dihedral angle
a
formed by the two pyran units (
a
ꢀ
‘Centre Regional de Mesures Physiques de l’Ouest’ (CRMPO, Uni-
to an s-cis conformation and
m
is maximum,
a
¼180ꢁ corresponds to
versity of Rennes1) using a Bruker MicroTOF-Q II apparatus. Ana-
lytical thin layer chromatographies (TLC) were performed on silica
gel plates (Merck 60F254) and compounds were visualized by irra-
diation with UV light at 254 and 365 nm. Flash chromatography was
performed using silica Acros SI 60 (60e200 mesh ASTM). UV/
vis spectra were recorded on a Varian Cary 50 scan spectropho-
tometer. Fluorescence spectroscopy studies were conducted on
a Varian Cary Eclipse spectrophotometer. Compounds were excited
at their absorption maxima for recording the emission spectra. All
solutions were measured with optical densities below 0.1. Cyclic
an s-trans conformation and
m¼0), these results suggest that the
dimer compounds exist in a pseudo cisoid staggered conformation,
as found from X-ray analysis, for similar extended ferrocenyl di-
substituted bispyran.10 In such conformation, the conjugation be-
tween the two methylenepyran moieties via the central CeC bond
is low and the two pushepull branches are globally pointing out in
the same direction amplifying the NLO response. Similar en-
hancement of NLO response by dimerization has already been de-
scribed for V-shaped binaphthol derivatives.24 Finally it should be
noted that the mb value observed for nitro derivative 7 is probably
underestimated due to the possible aggregation at the concentra-
tion used for the measurement.
voltammetry experiments were performed on a
m-AUTOLAB III
potentiostat monitored by a computer. All the potentials were
standardized against the ferroceneeferricenium couple. Ferrocene
was added as an internal standard at the end of the experiments.
Table 3
4.2. [4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-trimethyl-silane (3)
mb values for compounds 5e7, 9, 11, 14, and 16
5
6
7
9
11
16
mb [10ꢀ48 esu]a
350
200
700
1150
380
830
A n-BuLi solution (4 mL, 2.5 M in pentane, 9.9 mmol) was added
to a solution of phosphonium salt 2 (5.26 g, 9 mmol) in THF (50 mL)
at ꢀ78 ꢁC under nitrogen. The reaction mixture was stirred at this
a
mb (2u) at 1907 nm in CHCl3. Molecular concentrations used for the measure-
ments were in the range 10ꢀ3e10ꢀ2 M. mbꢄ10%.

S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
8397
temperature for 15 min, and 4-[(timethylsilyl)ethynyl]benzalde-
hyde 1 (1.82 g, 9 mmol) was added. The resulted mixture was
allowed to warm to room temperature and stirred for 2 h. The sol-
vent was removed and the residue was purified by column chro-
matography (SiO2, Petroleum Ether/CH2Cl2,1:2) to give compound 3
as orange brown solid, yield 70% (2.6 g); mp: 124e125 ꢁC; 1H NMR
d
6.17 (s, 1H), 6.84 (d, J¼1.9 Hz, 1H), 7.30 (d, J¼1.8 Hz, 1H), 7.57e7.71
(m, 10H), 7.91 (d, J¼8.9 Hz, 2H), 8.03 (d, J¼7.2 Hz, 4H), 8.43 (d,
J¼8.9 Hz, 2H); 13C NMR: no measurement due to the low solubility
of the compound. HRMS (ESI/ASAP) m/z calculated for C32H22NO3
[MþH]þ: 468.1600, found 468.1606.
(300 MHz, CDCl3)
6.95 (d, J¼1.3 Hz, 1H), 7.30 (d, 2H, J¼8.1 Hz), 7.41e7.47 (m, 8H),
7.70e7.75 (m, 4H); 13C NMR and JMOD (75 MHz, CDCl3)
153.0 (C),
d
0.25 (s, 9H), 5.88 (s, 1H), 6.39 (d, J¼1.8 Hz, 1H),
4.7. 2,6-Diphenyl-4-[4-(4-trifluoromethyl-phenylethynyl)-
benzylidene]-4H-pyran (7)
d
151.2 (C), 138.9 (C), 133.9 (CH), 133.7 (CH), 133.4 (C), 133.2 (C), 132.1
(CH), 130.2 (C), 129.4 (CH), 129.2 (CH), 128.7 (CH), 128.6 (CH), 127.5
(CH), 124.9 (CH), 124.6 (CH), 119.7 (C), 113.6 (CH), 108.5 (CH), 105.7
(C), 102.0 (CH), 94.3 (C), 0.1 (CH3). HRMS (ESI/ASAP) m/z calculated
for C29H27OSi [MþH]þ: 419.1831, found 419.1832.
Yellow solid; obtained according to general procedure A and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1); yield 68% (167 mg); mp: 244e245 ꢁC; 1H NMR (300 MHz,
CD2Cl2)
d 5.97 (s, 1H), 6.50 (s, 1H), 7.06 (s, 1H), 7.56e7.42 (m, 10H),
7.64 (d, J¼8.7 Hz, 2H), 7.68 (d, J¼8.7 Hz, 2H), 7.83e7.80 (m, 4H); 13
C
NMR (75 MHz, CD2Cl2) d 153.3, 151.3, 139.4, 133.3, 133.0, 131.8, 131.7,
4.3. 4-(4-Ethynyl-benzylidene)-2,6-diphenyl-4H-pyran (4)
130.5, 129.5, 129.1, 128.6, 127.6, 125.3, 125.34, 125.29, 125.2, 124.9,
124.5, 118.9, 113.4, 108.5, 101.8, 92.3, 88.1. HRMS (ESI/ASAP) m/z
calculated for C33H22OF3 [MþH]þ: 491.1623, found 491.1621.
Potassium carbonate (K2CO3 (0.91 g, 6.6 mmol)) was added to
a solution of compound 3 (2.53 g, 6 mmol) in CH2Cl2/MeOH (2:1,
100 mL). The mixture was stirred at room temperature overnight
under air, diluted with CH2Cl2, and washed with water. The organic
layer was separated, dried over MgSO4, and evaporated under vac-
uum leading to compound 4, an orange brown solid, yield 94%
4.8. 4-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-benzaldehyde (8)
Orange solid; obtained according to general procedure A and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:2); yield 75% (169 mg); mp: 250e251 ꢁC; 1H NMR (300 MHz, THF-
(1.94 g); mp: 135e136 ꢁC; 1H NMR (300 MHz, CDCl3)
d 3.12 (s, 1H),
5.90 (s, 1H), 6.40 (d, J¼1.8 Hz, 1H), 6.97 (d, J¼1.3 Hz, 1H), 7.34 (d, 2H,
J¼8.2 Hz), 7.40e7.49 (m, 8H), 7.73e7.78 (m, 4H); 13C NMR and JMOD
d8)
d 6.16 (s, 1H), 6.83 (s, 1H), 7.30 (s, 1H), 7.70e7.56 (m, 10H), 7.86
(75 MHz, CDCl3)
d
153.2 (C), 151.2 (C), 139.3 (C), 133.9 (CH), 133.7
(d, J¼7.8 Hz, 2H), 8.09e8.01 (m, 6H), 10.16 (s, 1H); 13C NMR and
(CH),133.4 (C),133.2 (C),132.3 (CH),130.4 (C),129.4 (CH),129.2 (CH),
128.7 (CH), 128.6 (CH), 127.5 (CH), 125.0 (CH), 124.6 (CH), 118.6 (C),
113.4 (CH),108.5 (CH),101.9 (CH), 84.2 (C), 77.2 (C). HRMS (ESI/ASAP)
m/z calculated for C26H18O [M]þ: 346.1358, found 346.1360.
JMOD (75 MHz, THF-d8) d 191.8 (C), 154.8 (C), 152.6 (C), 141.2 (C),
137.5 (C), 134.9 (C), 134.7 (C), 133.2 (CH), 132.0 (C), 130.8 (CH), 130.7
(CH), 130.5 (CH), 130.1 (CH), 130.0 (CH), 129.1 (CH), 126.3 (CH), 125.9
(CH), 120.5 (C), 115.2 (CH), 110.1 (CH), 106.0 (C), 103.3 (CH), 95.1 (C),
90.2 (C). HRMS (ESI/ASAP) m/z calculated for C33H23O2 [MþH]þ:
451.1698, found 451.1703.
4.4. General procedure A for Sonogashira cross-coupling
reaction
4.9. 2-{4-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-benzylidene}-malononitrile (9)
Bromobenzene derivatives (0.5 mmol), compound 4 (173 mg,
0.5 mmol), CuI (5 mg, 5 mol %), Pd(PPh3)2Cl2 (18 mg, 5 mol %) were
added to a mixture of THF (5 mL) and i-Pr2NH (5 mL). The sus-
pension was stirred at 60 ꢁC overnight under nitrogen atmosphere.
The resulting solution was diluted with a mixture of water and
dichloromethane (1:1, 20 mL) and the organic layer separated. The
aqueous layer was extracted with dichloromethane (2ꢃ20 mL). The
combined organic extracts were dried over MgSO4, filtered, and
evaporated.
The compound 8 (165 mg, 0.37 mmol), malononitrile (49 mg,
0.74 mmol, 2 equiv), AcONa (1 mg), and AcOH (5e6 drops) were
dissolved in benzene (10 mL) to form a suspension that was
refluxed for 5 h. The reaction mixture was then allowed to cool; the
solvent was evaporated and the residue was purified by column
chromatography (SiO2, Petroleum Ether/CH2Cl2, 3:2 then Petro-
leum Ether/CH2Cl2, 1:1). Yield 45% (83 mg) as a dark-red solid. Mp:
208e209 ꢁ 1H NMR (300 MHz, CD2Cl2)
C d 5.95 (s, 1H), 6.49 (d, 1H,
4.5. 4-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-benzonitrile (5)
J¼2 Hz), 7.06 (d,1H, J¼2 Hz), 7.42e7.52 (m, 8H), 7.54 (d, 2H, J¼8 Hz),
7.67 (d, 2H, J¼8 Hz), 7.78 (s, 1H), 7.78e7.84 (m, 4H), 7.91 (d, 2H,
J¼8 Hz); 13C NMR and JMOD (75 MHz, CD2Cl2)
d 159.1 (CH), 153.8
Orange solid; obtained according to the general procedure A and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1); yield 70% (157 mg); mp: 241e242 ꢁC; 1H NMR (300 MHz, THF-
(C), 151.8 (C), 140.3 (C), 133.7 (C), 133.4 (C), 132.6 (CH), 132.5 (CH),
131.2 (CH), 130.6 (C), 130.4 (C), 130.0 (CH), 129.7 (CH), 129.1 (CH),
128.1 (CH), 125.4 (CH), 125.0 (CH), 119.0 (C), 114.4 (C), 113.8 (CH),
113.2 (C), 109.0 (CH), 102.3 (CH), 96.05 (C), 89.4 (C), 82.9 (C). HRMS
(ESI/ASAP) m/z calculated for C36H23N2O [MꢀH]þ: 499.1810, found
499.1807.
d8)
d 6.16 (s, 1H), 6.83 (s, 1H), 7.29 (s, 1H), 7.69e7.58 (m, 10H), 7.83
(d, J¼8.1 Hz, 2H), 7.92 (d, J¼8.1 Hz, 2H), 8.02 (d, J¼6.9 Hz, 4H); 13C
NMR and JMOD (75 MHz, THF-d8)
d 154.8 (C), 152.7 (C), 141.4 (C),
134.9 (C), 134.6 (C), 133.6 (CH), 133.4 (CH), 133.2 (CH), 132.1 (C),
130.8 (CH), 130.5 (CH), 130.1 (CH), 130.0 (CH), 129.7 (C), 129.1 (C),
126.4 (CH),125.9 (CH), 120.2 (C),119.4 (C), 115.1 (CH), 113.2 (C),110.1
(CH), 103.3 (CH), 95.5 (C), 89.5 (C). HRMS (ESI/ASAP) m/z calculated
for C33H22NO [MþH]þ: 448.1701, found 448.1701.
4.10. Butadiyne derivative (10)
Red solid; obtained as by-product during the procedure B. Yield
5e15% (17e52 mg); mp: 257e258 ꢁC; 1H NMR (300 MHz, CDCl3)
d
5.91 (s, 2H), 6.43 (s, 2H), 7.00 (s, 2H), 7.52e7.37 (m, 20H),
4.6. 4-[4-(4-Nitro-phenylethynyl)-benzylidene]-2,6-diphenyl-
7.78e7.76 (m, 8H); 13C NMR and JMOD (75 MHz, CDCl3)
d
153.3 (C),
4H-pyran (6)
151.3 (C), 139.7 (C), 134.2 (CH), 133.3 (C), 133.1 (C), 132.7 (CH), 130.7
(C), 129.5 (CH), 129.2 (CH), 128.7 (CH), 127.6 (CH), 125.0 (CH), 124.6
(CH), 118.3 (C), 113.4 (CH), 108.6 (CH), 102.0 (CH), 82.6 (C), 74.7 (CH).
HRMS (ESI/ASAP) m/z calculated for C52H35O2 [MþH]þ: 691.2631,
found 691.2630.
Dark-red solid; obtained according to general procedure A and
purified by column chromatography (SiO2, hexane/CH2Cl2, 1:1);
yield 62% (145 mg); mp: 260e261 ꢁC; 1H NMR (300 MHz, THF-d8)

8398
S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
4.11. General procedure B for Sonogashira cross-coupling
reaction
7.02 (s, 2H), 7.47e7.42(m, 17H), 7.61(d, 2H, J¼8 Hz), 7.77e7.75 (m,
8H), 9.16 (s, 1H); 13C NMR and JMOD (75 MHz, CDCl3)
153.6 (C),
d
151.5 (C), 151.0 (C), 140.8 (C), 133.2 (C), 133.0 (C), 132.7 (CH), 133.2
(C), 129.6 (CH), 129.3 (CH), 128.71 (CH), 128.68 (CH), 127.6 (CH),
125.4 (CH), 125.0 (CH), 124.6 (CH), 117.2 (C), 113.2 (CH), 108.6 (CH),
101.9 (CH), 95.9 (C), 87.2 (C). HRMS (ESI/ASAP) m/z calculated for
Compound 4 (1 equiv per iodine atom), NEt3 (0.5 mL), CuI
(6 mol %), and Pd(PPh3)2Cl2 (6 mol %) were added to iododiazine
(1 mmol) in THF (5 mL). The suspension was stirred at room tem-
perature overnight under nitrogen atmosphere. The suspension
was then diluted with a mixture of water and dichloromethane
(1:1, 20 mL) and the organic layer separated. The aqueous layer was
extracted with dichloromethane (2ꢃ20 mL). The combined organic
extracts were dried over MgSO4, filtered, and evaporated.
C
56H37N2O2 [MꢀH]þ: 769.2855, found 769.2849.
4.16. 2,4-Bis-[4-(2,6-diphenyl-pyran-4-ylidenemethyl)-phe-
nylethynyl]-pyrimidine (15)
Red solid; obtained according to the general procedure B and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1 then CH2Cl2, then CH2Cl2/MeOH 9:1); yield 40% (307 mg); mp:
4.12. 2-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-pyrazine (11)
125e126 ꢁC; 1H NMR (300 MHz, CDCl3)
d 5.92 (s, 2H), 6.44 (s, 2H),
Orange solid; obtained according to the general procedure B and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1 then CH2Cl2, then CH2Cl2/MeOH, 95:5); yield 48% (203 mg);
7.02 (s, 2H), 7.34 (d, 1H, J¼5.1 Hz), 7.47e7.37 (m, 16H), 7.60 (d, 2H,
J¼8 Hz), 7.66 (d, 2H, J¼8 Hz), 7.79e7.76 (m, 8H), 8.72 (d, 1H,
J¼5.1 Hz); 13C NMR and JMOD (75 MHz, CDCl3)
d 157.4 (CH), 153.7
mp: 156e157 ꢁC; 1H NMR (400 MHz, CDCl3)
d 5.91 (s, 1H), 6.43 (s,
(C), 153.6 (C), 151.68 (C), 151.65 (C), 151.5 (C), 140.9 (C), 140.5 (C),
133.44 (C), 133.40 (C), 133.3 (CH), 133.2 (CH), 133.1 (CH), 133.0 (CH),
131.3 (C), 131.0 (C), 129.7 (CH), 129.6 (CH), 129.4 (CH), 129.3 (CH),
128.80 (CH), 128.77 (CH), 127.8 (CH), 127.7 (CH), 125.1 (CH), 124.7
(CH), 121.4 (CH), 117.8 (C), 117.4 (C), 113.5 (CH), 113.3 (CH), 108.81
(CH), 108.78 (CH) 102.11 (CH), 102.07 (CH), 95.9 (C), 89.4 (C), 88.6
(C), 87.2 (C). HRMS (ESI/ASAP) m/z calculated for C56H37N2O2
[MþH]þ: 769.2855, found 769.2852.
1H), 7.01 (s, 1H), 7.46e7.40 (m, 8H), 7.59 (d, 2H, J¼8 Hz), 7.77e7.76
(m, 4H), 8.48 (s, 1H), 8.58 (s, 1H), 8.77 (s, 1H); 13C NMR and JMOD
(75 MHz, CDCl3)
d 153.4 (C), 151.4 (C), 147.7 (CH), 144.5 (CH), 142.5
(CH), 140.7 (C), 140.2 (C), 133.3 (C), 133.1 (C), 132.4 (CH), 130.9 (C),
129.5 (CH), 129.2 (CH), 128.69 (CH), 128.66 (CH), 127.6 (CH), 125.0
(CH), 124.6 (CH), 117.8 (C), 113.3 (CH), 108.6 (CH), 101.9 (CH), 94.3
(C), 86.2 (C). HRMS (ESI/ASAP) m/z calculated for C30H21N2O
[MþH]þ: 425.1654, found 425.1757.
4.17. General procedure C for oxidative coupling
4.13. 2-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-4,6-dimethyl-pyrimidine (12)
I2 (255 mg, 1 mmol) was added to a solution of methylenepyran
(compounds 5e9) (0.2 mmol) in CH2Cl2 (20 mL). After being stirred
at room temperature overnight, the resulting black greenish mix-
ture was quenched with saturated Na2S2O3 aqueous solution
(20 mL). The mixture was kept under stirring for another 1 h, and
then the orange organic layer was separated, washed with H2O,
dried over MgSO4, and concentrated in vacuo.
Orange solid; obtained according to the general procedure B and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1 then CH2Cl2/MeOH, 95:5); yield 47% (213 mg); mp: 185e186 ꢁC;
1H NMR (400 MHz, CDCl3)
d
2.51 (s, 6H), 5.89 (s, 1H), 6.42 (s, 1H),
6.96 (s, 1H), 6.99 (s, 1H), 7.44e7.35 (m, 8H), 7.63 (d, 2H, J¼8 Hz),
7.77e7.74 (m, 4H); 13C NMR and JMOD (75 MHz, CDCl3)
167.0 (C),
d
153.3 (C), 152.8 (C), 151.3 (C), 140.0 (C), 133.3 (C), 133.1 (C), 132.8
(CH), 130.7 (C), 129.4 (CH), 129.1 (CH), 128.7 (CH), 128.6 (CH), 127.4
(CH), 125.0 (CH), 124.6 (CH), 118.7 (CH), 117.9 (C), 113.5 (CH), 108.6
(CH), 102.0 (CH), 88.6 (C), 87.8 (C). HRMS (ESI/ASAP) m/z calculated
for C32H24N2O [M]þ: 452.1889, found 452.1883.
4.18. Bispyrane derivative (16)
Red solid; obtained according to the general procedure C and pu-
rified by column chromatography (SiO2, CH2Cl2); yield 45% (40 mg);
mp: 188 ꢁC (dec); 1H NMR (300 MHz, THF-d8)
d 6.86 (s, 2H), 7.22 (s,
2H), 7.69e7.48 (m, 20H), 7.80 (d, J¼8.4 Hz, 4H), 7.89 (d, J¼8.4 Hz, 4H),
7.90 (d, J¼6.9 Hz, 4H), 7.96 (d, J¼6.9 Hz, 4H); 13C NMR and JMOD
4.14. 4-[4-(2,6-Diphenyl-pyran-4-ylidenemethyl)-phenyl-
ethynyl]-6-methoxy-pyrimidine (13)
(75 MHz, THF-d8) d 154.2 (C),153.4 (C),143.9 (C),134.9 (C),133.6 (CH),
133.4 (CH), 133.1 (CH), 131.1 (CH), 130.7 (CH), 130.6 (CH), 130.1 (CH),
130.0 (CH),129.5 (C),126.0 (CH),125.5 (C),121.3 (C),119.3 (C),113.2 (C),
107.4 (CH), 105.5 (CH), 95.2 (C), 89.5 (C). HRMS (ESI/ASAP) m/z cal-
culated for C66H40N2O2 [M.]þ: 892.3084, found 892.3090.
Orange solid; obtained according to the general procedure B and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
1:1); yield 65% (244 mg); mp: 155e156 ꢁC; 1H NMR (400 MHz,
CDCl3)
d
4.00 (s, 3H), 5.89 (s, 1H), 6.41 (d, 1H, J¼2 Hz), 6.88 (d, 1H,
J¼2 Hz), 6.99 (d,1H, J¼2 Hz), 7.38 (d, 2H, J¼8 Hz), 7.44e7.40 (m, 6H),
4.19. Bispyrane derivative (17)
7.56 (d, 2H, J¼8 Hz), 7.77e7.74 (m, 4H), 8.76 (d, 1H, J¼2 Hz); 13C
NMR and JMOD (75 MHz, CDCl3)
d 169.7 (C), 158.5 (CH), 153.4 (C),
Red solid; obtained according to the general procedure C and
purified by column chromatography (SiO2, hexane/CH2Cl2, 1:1);
yield 30% (28 mg); mp: 192 ꢁC (dec); 1H NMR (500 MHz, THF-d8)
151.4 (C), 150.7 (C), 140.3 (C), 133.3 (C), 133.1 (C), 132.5 (CH), 130.9
(C), 129.5 (CH), 129.2 (CH), 128.7 (CH), 128.6 (CH), 127.6 (CH), 125.0
(CH), 124.6 (CH), 117.6 (CH), 113.3 (CH), 110.3 (CH), 108.6 (CH), 101.9
(CH), 93.6 (C), 87.1 (C), 54.0 (CH3). HRMS (ESI/ASAP) m/z calculated
for C31H23N2O2 [MꢀH]þ: 455.1759, found 455.1751.
d
6.85 (d, J¼2.0 Hz, 1H), 7.23 (d, J¼2.0 Hz, 1H), 7.50e7.68 (m, 10H),
7.40e7.49 (m, 4H), 7.95 (d, J¼7.2 Hz, 2H), 8.40 (d, J¼8.9 Hz, 2H); 13
C
NMR (125 MHz, THF-d8)
d 154.2, 153.4, 148.7, 144.1, 134.9, 134.8,
133.6,133.2,131.5, 131.2, 130.7, 130.6,130.1,130.0,126.1,126.0,125.4,
125.0, 121.2, 107.4, 105.6, 96.2, 89.3. HRMS (ESI/ASAP) m/z calcu-
lated for C64H40N2O6 [M.]þ: 932.2881, found 932.2880.
4.15. 4,6-Bis-[4-(2,6-diphenyl-pyran-4-ylidenemethyl)-phe-
nylethynyl]-pyrimidine (14)
Red solid; obtained according to the general procedure B and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
4:1 then CH2Cl2, then CH2Cl2/MeOH 93:7); yield 72% (554 mg); mp:
4.20. Bispyrane derivative (18)
Orange solid; obtained according to the general procedure C and
purified by column chromatography (SiO2, Petroleum Ether/CH2Cl2,
204 ꢁC (dec); 1H NMR (400 MHz, CDCl3)
d
5.92 (s, 2H), 6.44 (s, 2H),

S. Gauthier et al. / Tetrahedron 69 (2013) 8392e8399
8399
2:1); yield 32% (31 mg); mp: 260 ꢁC (dec); 1H NMR (300 MHz, THF-
Houbrechts, S.; Kauranen, M.; Clays, K.; Persoons, A. J. Mater. Chem. 1997, 7,
2175; (d) Wang, C.; Zhang, T.; Lin, W. Chem. Rev. 2012, 112, 1084; (e) Kim, H. M.;
Cho, B. R. Chem. Commun. 2009, 153.
d8)
d 6.86 (s, 2H), 7.23 (s, 2H), 7.66e7.51 (m, 20H), 7.84 (s, 8H), 7.89
(d, J¼7.8 Hz, 4H), 7.95 (d, J¼6.9 Hz, 4H); 13C NMR and JMOD
5. (a) Taniuchi, T.; Okada, S.; Nakanishi, H. Appl. Phys. Lett. 2004, 95, 5984; (b)
Taniuchi, T.; Ikeda, S.; Okada, S.; Nakanishi, H. Jpn. J. Appl. Phys. 2005, 44, L652;
(75 MHz, THF-d8) d 154.2 (C),153.4 (C),143.7 (C),134.9 (C),134.8 (C),
€
(c) Schneider, A.; Neis, M.; Stillhart, M.; Ruiz, B.; Khan, R. U. A.; Gunter, P. J. Opt.
133.2 (CH), 133.1 (CH), 131.1 (CH), 130.63 (CH), 130.58 (CH), 130.5
(C), 130.1 (CH), 130.0 (CH), 129.1 (C), 126.8 (CH), 126.7 (CH), 126.1
(CH), 126.0 (CH) 125.6 (C), 121.6 (C), 107.4 (CH), 105.6 (CH), 93.7 (C),
89.5 (C). HRMS (ESI/ASAP) m/z calculated for C66H40F6O2 [Mꢂ]þ:
978.2933, found 978.2931.
€
Soc. Am. B 2006, 23, 1822; (d) Schneider, A.; Stillhart, M.; Gunter, P. Opt. Express
2006, 14, 5376; (e) Yang, Z.; Mutter, L.; Stillhart, M.; Ruiz, B.; Aravazhi, S.; Jaz-
ꢁ
€
binsek, M.; Schneider, A.; Gramlich, V.; Gunter, P. Adv. Funct. Mater. 2007, 17,
2018.
6. (a) Li, Z.; Li, Q.; Qin, J. Polym. Chem. 2011, 2, 2723; (b) He, G. S.; Tan, L. S.; Zheng,
Q.; Prasad, P. N. Chem. Rev. 2008, 108, 1245; (c) Kim, H. N.; Guo, Z.; Zhu, W.;
Yoon, J.; Tian, H. Chem. Soc. Rev. 2011, 40, 79; (d) Xia, R. J.; Malval, J. P.; Jin, M.;
Spangenberg, A.; Wan, D. C.; Pu, H. T.; Vergote, T.; Morlet-Savary, F.; Chaumeil,
H.; Baldeck, P.; Poizat, O.; Soppera, O. Chem. Mater. 2012, 24, 237.
7. Tiemann, B. G.; Cheng, L.-T.; Marder, S.-R. J. Chem. Soc., Chem. Commun. 1993,
735.
4.21. Bispyrane derivative (19)
Red solid; obtained according to the general procedure C and
purified by column chromatography (SiO2, CH2Cl2); yield 40%
8. (a) Faux, N.; Caro, B.; Robin-le Guen, F.; le Poul, P.; Nakatani, K.; Ishow, E. J.
Organomet. Chem. 2005, 690, 4982; (b) Faux, N.; Robin-le Guen, F.; le Poul, P.;
Caro, B.; Nakatani, K.; Ishow, E.; Golhen, S. Eur. J. Inorg. Chem. 2006, 3489; (c)
Millan, I.; Fuentealba, M.; Manzur, C.; Carrillo, D.; Faux, N.; Caro, B.; Robin-le
Guen, F.; Sinbandhit, S.; Ledoux-Rak, I.; Hamon, J. R. Eur. J. Inorg. Chem. 2006,
1131; (d) Andreu, R.; Carrasquer, L.; Franco, S.; Garín, J.; Orduna, J.; Martínez de
Baroja, N.; Alicante, R.; Villacampa, B.; Allain, M. J. Org. Chem. 2009, 74, 6647;
(36 mg); mp: 178 ꢁC (dec); 1H NMR (300 MHz, THF-d8)
d 6.87 (s,
2H), 7.23 (s, 2H), 7.67e7.51 (m, 20H), 7.83 (d, J¼8.4 Hz, 4H), 7.88 (d,
J¼7.2 Hz, 4H), 7.96 (d, J¼7.2 Hz, 4H), 8.04 (d, J¼8.4 Hz, 4H), 10.1 (s,
2H); 13C NMR and JMOD (75 MHz, THF-d8)
d 191.9 (CH), 154.2 (C),
153.4 (C), 143.7 (C), 137.5 (C), 134.9 (C), 133.2 (CH), 133.1 (CH), 131.1
(CH), 130.7 (CH), 130.6 (CH), 130.5 (C), 130.1 (CH), 130.0 (CH), 126.0
(CH), 125.6 (C), 121.6 (C), 107.4 (CH), 105.6 (CH), 94.8 (C), 90.2 (C).
HRMS (ESI/ASAP) m/z calculated for C66H42O4 [M.]þ: 898.3083,
found 898.3087.
ꢀ
(e) Andreu, R.; Galan, E.; Garín, J.; Herrero, V.; Lacarra, E.; Orduna, J.; Alicante,
ꢀ
R.; Villacampa, B. J. Org. Chem. 2010, 75, 1684; (f) Andreu, R.; Galan, E.; Orduna,
ꢀ
J.; Villacampa, B.; Alicante, R.; Lopez Navarrete, J. T.; Casado, J.; Garín, J. Chem.
ꢀ
dEur. J. 2011, 17, 826; (g) Galan, E.; Andreu, R.; Garín, J.; Orduna, J.; Villacampa,
B.; Diosdado, B. Org. Biomol. Chem. 2012, 10, 8684; (h) Marco, A. B.; Andreu, R.;
Franco, S.; Garín, J.; Orduna, J.; Villacampa, B.; Alicante, R. Tetrahedron 2013, 69,
3919; (i) Porotnik, Y. M.; Hugues, V.; Blanchard-Desce, M.; Gryko, D. T. Chem.
dEur. J. 2012, 18, 9258.
4.22. Bispyrane derivative (20)
9. Faux, N.; Robin-Le Guen, F.; Le Poul, P.; Caro, B.; Le Poul, N.; Le Mest, Y.; Green,
S. J.; Le Roux, S.; Kahlal, S.; Saillard, J. Y. Tetrahedron 2007, 63, 7142.
10. (a) Ba, F.; Cabon, N.; Robin-Le Guen, F.; Le Poul, P.; Le Poul, N.; Le Mest, Y.;
Golhen, S.; Caro, B. Organometallics 2008, 27, 6396; (b) Ba, F.; Cabon, N.; Le Poul,
P.; Kahlal, S.; Saillard, J.-Y.; Le Poul, N.; Golhen, S.; Caro, B.; Robin-Le Guen, F.
New J. Chem. 2013, , http://dx.doi.org/10.1039/C3NJ41126E
Dark-red solid; obtained according to the general procedure C
and purified by column chromatography (SiO2, CH2Cl2); yield 25%
(25 mg); mp: 174 ꢁC (dec); 1H NMR (300 MHz, CDCl3)
d 6.60 (s, 2H),
ꢀ
11. For pyrimidine: (a) Achelle, S.; Ple, N. Curr. Org. Synth. 2012, 9, 163 and articles
6.98 (s, 2H), 7.47e7.37 (m, 20H), 7.63 (d, J¼8.7 Hz, 4H), 7.76e68 (m,
10H), 7.89 (d, J¼8.7 Hz, 4H); 13C NMR and JMOD (75 MHz, THF-d8)
cited herein; (b) Chen, D.; Zhong, C.; Dong, X.; Liu, Z.; Qin, J. J. Mater. Chem. 2012,
ꢀ
22, 4343; (c) Hadad, C.; Achelle, S.; García-Martinez, J.; Rodríguez-Lopez, J. J.
d
160.2 (CH),154.3 (C),153.5 (C),144.0 (C),134.9 (C),133.5 (CH),133.2
Org. Chem. 2011, 76, 3837; (d) Aranda, A. I.; Achelle, S.; Hammerer, F.; Mahu-
teau-Betzer, F.; Teulade-Fichou, M. P. Dyes Pigm. 2012, 95, 400.
(CH),132.6 (CH),132.1 (CH),131.1 (C),130.8 (CH),130.7 (CH),130.0(C),
126.0 (CH), 125.5 (CH), 125.4 (C), 121.4 (C), 115.3 (C), 114.3 (C), 107.4
(CH), 105.8 (CH), 96.1 (C), 90.3 (C), 84.0 (C). HRMS (ESI/ASAP) m/z
calculated for C72H42N4O2 [M.]þ: 994.3308, found 994.3290.
ꢀ
12. For pyridazine: (a) Achelle, S.; Ple, N.; Turck, A. RSC Adv. 2011, 1, 364 and articles
cited herein; (b) Cho, H. H.; Kang, T. E.; Kim, K.-H.; Kang, H.; Kim, H. J.; Kim, B. J.
Macromolecules 2012, 45, 6415.
13. For pyrazine: Achelle, S.; Baudequin, C.; Ple,, N. Dyes Pigm. 2013, 98, 575, and
ꢀ
articles cited herein.
14. Achelle, S.; Malval, J. P.; Aloise, S.; Barsella, A.; Spangenberg, A.; Mager, L.;
Akdas-Kilig, H.; Fillaut, J. L.; Caro, B.; Robin-Le Guen, F. ChemPhysChem 2013, ,
http://dx.doi.org/10.1002/cphc.201300419
Acknowledgements
15. Reynolds, G. A.; Chen, C. H. J. Org. Chem. 1980, 45, 2453.
16. Ba, F.; Robin-Le Guen, F.; Cabon, N.; Le Poul, P.; Golhen, S.; Le Poul, N.; Caro, B. J.
Organomet. Chem. 2010, 695, 235.
N.V. thanks the region Bretagne for a post-doctoral fellowship.
ꢀ
Dr. Christine Baudequin from UMR6014, Universite de Rouen, is
gratefully acknowledged for preliminary optical measurements. We
also thank UMR176 at Institut Curie in Orsay for the access to the
spectrophotometers.
ꢀ
17. (a) Chinchilla, R.; Najera, C. Chem. Rev. 2007, 107, 874; (b) Negishi, E. i; Anastasia,
L. Chem. Rev. 2003, 103, 1979.
ꢀ
ꢀ
18. (a) Maes, B. U. W.; Tapolcsanyi, P.; Meyers, C.; Matyus, P. Curr. Org. Chem. 2006,
ꢀ
10, 377; (b) Achelle, S.; Ple, N.; Kreher, D.; Mathevet, F.; Turck, A.; Attias, A.-J.
ꢀ
Heterocycles 2008, 75, 357; (c) Achelle, S.; Ramondenc, Y.; Dupas, G.; Ple, N.
Tetrahedron 2008, 64, 2783; (d) Achelle, S.; Saettel, N.; Baldeck, P.; Teulade-
Fichou, M.-P.; Maillard, P. J. Porphyrins Phthalocyanines 2010, 14, 877.
19. See for example: (a) Priego, E. M.; Sanchez, L.; Herranz, M. A.; Martín, N.; Vi-
Supplementary data
ꢀ
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2013.07.066.
ruela, R.; Ortí, E. Org. Biomol. Chem. 2007, 5, 1201; (b) Lorcy, D.; Cartlier, R.;
ꢂ
Robert, A.; Tallec, A.; Le Megueres, P.; Ouahab, L. J. Org. Chem. 1995, 60, 2443; (c)
ꢂ
Frere, P.; Skabara, P. J. Chem. Soc. Rev. 2005, 34, 69; (d) Cheng, G.; Mahmud, I.;
Dawe, L. N.; Daniels, L. M.; Zhao, Y. J. Org. Chem. 2011, 76, 2701.
20. (a) Chen, C. H.; Doney, J. J.; Reynolds, G. A.; Saeva, F. D. J. Org. Chem. 1983, 48,
2757; (b) Reynolds, G. A.; Saeva, F. D.; Doney, J.; Chen, C. H. J. Org. Chem. 1984,
49, 4843.
21. (a) Singer, K. D.; Garito, A. F. J. Phys. Chem. 1981, 75, 3572; (b) Levine, B. F.;
Bethea, C. G. Appl. Phys. Lett. 1974, 24, 445; (c) Ledoux, I.; Zyss, J. Chem. Phys.
1982, 73, 203; (d) Thami, T.; Bassoul, P.; Petit, M. A.; Simon, J.; Fort, A.; Bar-
zoukas, M.; Villaeys, A. J. Am. Chem. Soc. 1992, 114, 915.
References and notes
1. (a) Lin, Y.; Li, Y.; Zhan, X. Chem. Soc. Rev. 2012, 41, 4245; (b) Hagfeldt, A.; Bos-
chloo, G.; Sun, L.; Kloo, L.; Pettersson, H. Chem. Rev. 2010, 110, 6595; (c) Gunes,
S.; Neugebauer, H.; Sariciftci, N. S. Chem. Rev. 2007, 107, 1324.
€
2. (a) Kraft, A.; Grimsdale, A. C.; Holmes, A. B. Angew. Chem., Int. Ed. 1998, 37, 402;
€
(b) Mitshke, U.; Bauerle, P. J. Mater. Chem. 2000, 10, 1471; (c) Lo, S.-C.; Burn, P. L.
22. Cheng, L.-T.; Tam, W.; Stevenson, S. H.; Meredith, G. R.; Rikken, G.; Marder, S. R.
J. Phys. Chem. 1991, 95, 10631.
Chem. Rev. 2007, 107, 1097.
3. See for example: (a) Ooyama, Y.; Okamoto, T.; Yamagushi, Y.; Suzuki, T.; Hayashi,
A.; Yoshida, K. Chem.dEur. J. 2006, 12, 7827; (b) Xue, L.; Liu, C.; Jiang, H. Chem.
Commun. 2009, 1061; (c) Achelle, S.; Barsella, A.; Baudequin, C.; Caro, B.; Robin-
Le Guen, F. J. Org. Chem. 2012, 77, 4087; (d) Gulliev, R.; Coskun, A.; Akkaya, E. U. J.
Am. Chem. Soc. 2009, 131, 9007; (e) Liu, R. L.; Lu, H. Y.; Li, M.; Hu, S. Z.; Chen, C. F.
RSC Adv. 2012, 2, 4415; (f) Costero, A. M.; Parra, M.; Gil, S.; Gotor, R.; Mancini, P.
M. E.; Martinez-Manez, R.; Sancenon, F.; Royo, S. Chem.dAsian J. 2010, 5, 1573.
4. (a) Zhang, C. Z.; Lu, C. G.; Zhu, J.; Lu, G. Y.; Wang, X.; Shi, Z. W.; Liu, F.; Cui, Y. P.
Chem. Mater. 2006, 18, 6091; (b) Luo, J. D.; Hua, J. L.; Qin, J. G.; Cheng, J. Q.; Shen,
Y. C.; Lu, Z. H.; Wang, P.; Ye, C. Chem. Commun. 2001, 171; (c) Verbiest, T.;
ꢀ
ꢀ
23. (a) Hebbar, N.; Fiol-Petit, C.; Ramondenc, Y.; Ple, G.; Ple, N. Tetrahedron 2011,
67, 2287; (b) Wu, Y. L.; Jarowski, P. D.; Schweizer, W. B.; Diederich, F. Chem.
dEur. J. 2010, 16, 202; (c) Morales, A. R.; Frazer, A.; Woodward, A. W.; Ahn-
White, H. Y.; Forani, A.; Tongwa, P.; Timofeeva, T.; Belfield, K. D. J. Org. Chem.
2013, 78, 1014.
24. Deussen, H.-J.; Boutton, C.; Thorup, N.; Geisler, T.; Hendrickx, E.; Bechgaard, K.;
Persoons, A.; Bjørnholm, T. Chem.dEur. J. 1998, 4, 240.
25. Wang, X.; Ervithayasuporn, V.; Zhang, Y.; Kawajkami, Y. Chem. Commun. 2011,
1282.