Novel donor-acceptor type thiophene pyridine conjugates: Synthesis and ion recognition features

Article abstract of DOI:10.1016/j.tet.2013.03.008

In order to reveal the effect of the donor units on the structure-property relationship, three novel directly linked donor-acceptor type systems, 1-3, which are based on thiophene and pyridine conjugates, are designed, synthesized and characterized by spe

Full text of DOI:10.1016/j.tet.2013.03.008

Tetrahedron 69 (2013) 3523e3529
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Novel donoreacceptor type thiophene pyridine conjugates:
synthesis and ion recognition features
Fatih Algi *
Laboratory of Organic Materials (LOM), Canakkale Onsekiz Mart University, TR-17100 Canakkale, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
In order to reveal the effect of the donor units on the structureeproperty relationship, three novel di-
rectly linked donoreacceptor type systems, 1e3, which are based on thiophene and pyridine conjugates,
are designed, synthesized and characterized by spectroscopic methods. It is noteworthy that these DeA
systems exhibit distinct electrochemical and optical features depending on the strength of the D-unit or
the conjugation length. Furthermore, it is found that two of these novel systems, 2 and 3, can be used in
Received 11 October 2012
Received in revised form 13 February 2013
Accepted 4 March 2013
Available online 13 March 2013
both chromogenic and fluorogenic detection of Cu2 among other ions.
þ
In memory of Professor Ayhan S. Demir
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Donoreacceptor
0
2
,2 -Bipyridine
Thiophene
,10-Phenanthroline
1
Ion recognition
Copper (II)
Fluorescence
Colorimetric
1. Introduction
electrochromic devices.12e14 However, only a few directly linked
DeA systems with pyridine as the A-unit have been reported to
15e18
The design and syntheses of organic
p-conjugated materials has
date,
in spite of the fact that much literature concerning the
been intensively pursuedover the lastfew decades, due totheir great
potential in a variety of advanced technological applications. Gen-
erally, the intrinsic properties (electronic, optical, conductivity, sta-
bility) of these materials should be tailored with respect to the
desired application. One of the best ways of tailoring the electronic
structure and properties of organic materials is combining an ap-
design of other electron deficient units as the A-part of the DeA type
19,20
21
22
materials
2,1,3-benzoselenodiazole
exists (e.g., quinoxaline, 2,1,3-benzoxadiazole and
2
3,24
). Furthermore, it is important to note
that most of the reports concerning the directly linked DeA type
thiophene pyridine conjugates have just focused on the design and
synthesis, but not on the systematic comparison of the structur-
15
propriate electron-rich (donor, D) moiety with an electron-poor
eeproperty relationship. In this context, it is a challenging task to
attain novel directly linked DeA type thiophene pyridine conjugates
and elucidate the structureeproperty relationships in a systematical
manner.
1
(
acceptor, A) unit. This DeA strategy in the design of organic
p-
conjugated materials does not only allow fine tuning of the highest
occupied molecular orbital (HOMO), lowest unoccupied molecular
2e5
g
orbital (LUMO) energy levels and the band gap (E ) of the system,
On the other hand, the development of functional organic
compounds that allow selective and sensitive detection of target
metal ions have recently attracted considerable attention due to the
fact that these ions play essential and/or deleterious roles in bi-
but also provides perfectly controlled architectures with compati-
bility and tunable intrinsic properties offered by the structural de-
sign. Thus, the DeA approach has so far allowed the creation of
excellent molecular systems, which hold promise for
2
5e29
ological and environmental processes.
Among these metal
6
e8
2þ
the applications in the field of organic light emitting diodes,
ions, Cu is an important trace element, which plays crucial roles
in various biological processes. In addition to these crucial roles,
however, Cu is a significant environmental pollutant, and has
toxic effects to organisms especially at high concentration levels,
since it can displace other metal ions that act as cofactors in
photovoltaics,9
e11
transistors,
molecular
electronics
and
2
þ
*
Tel.: þ90 2862180018; fax: þ90 2862180536; e-mail addresses: falgi@comu.
edu.tr. falgi76@hotmail.com.
0
040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.03.008

3524
F. Algi / Tetrahedron 69 (2013) 3523e3529
enzyme-catalyzed reactions,30 thus causing Alzheimer’s, Parkin-
Convinced by the above strategy, the synthesis of the target
compounds 1e3 was started with the construction of the A-unit.
Initial efforts, which were directed towards the synthesis of the A-
part, involved the bromination of 1,10-phenanthroline (4) accord-
ing to a published method (Scheme 1). The bromination reaction
was carried out in the presence of sulfur monochloride and pyri-
dine in chlorobutane to give 3,8-dibromo-1,10-phenanthroline (5)
albeit in low (ca. 35%) yield. Then, the oxidation of dibromide 5 with
son’s and Wilson diseases, hypoglycemia, dyslexia and infant liver
damage.3
1e34
Consequently, significant efforts have been devoted
2
þ
35e45
to the design and syntheses of novel Cu ion sensors.
None-
5
3
theless, the number of selective and sensitive chemosensors that
2
þ
give dual channel (fluorogenic and chromogenic) response to Cu
ions are limited,4
6e52
thus the newer ones are welcome.
. Results and discussion
.1. Design and synthesis
In order to reveal the effect of the D-units on the structur-
2
2
4
KMnO under basic conditions provided 6 after treatment with HCl.
1
13
Compound 6 was characterized on the basis of H, C NMR and
FTIR spectroscopy and elemental analysis, which firmly established
1
13
the structure (see Supplementary data for H and C NMR spectra,
Fig. S1 and 2).
eeproperty relationship, three different DeA systems, 1e3, were
taken into account (Fig. 1). At this stage, it was envisaged that each
combination would result in the formation of a different DeA
system with distinct electrochemical and photophysical properties
In the next step, diacid 6 was converted to diester 7 by treat-
1
ment with SOCl
2
in ethanol. In the H NMR spectrum of 7, two
aromatic protons resonated as two sets of doublets at 8.81 (d,
J¼2.5 Hz, 1H) and 8.50 (d, J¼2.5 Hz, 1H) ppm, whereas the methyl
and methylene protons resonated at 4.17 (q, J¼8 Hz, 2H) and 1.15 (t,
(
redox potential, absorption, emission etc.), which is not un-
13
expected, since each D-unit had a different electronic nature. It is
also noteworthy that these systems 1e3 would give the opportu-
nity to understand the effect of the D-units on both the electro-
chemical and the photophysical properties of the corresponding
DeA systems in a systematic manner.
J¼8 Hz, 3H) ppm, respectively (Fig. S3). An eight-line C NMR
spectrum was also consistent with the structure (Fig. S4).
At this stage, tributylstannyl derivatives of the D-units, 8, 954
1
6
16
and 10 were prepared. Finally, Stille coupling reaction of 7 with
8 afforded the DeA system 1 in 55% yield (Scheme 2). In a similar
O
EtO C
2
EtO C
2
O
N
S
N
S
S
N
S
N
O
CO Et
O
CO Et
2
2
2
1
EtO C
2
N
S
N
S
S
S
CO Et
2
3
Fig. 1. The structures of DeA type compounds 1e3.
HO C
2
Br2, pyridine
1. KMnO4
N
Br
Br
Br
Br
NaOH-H O
N
N
C
4
H
9
Cl, S
2
Cl
2
N
N
2
N
o
o
100 C
. HCl, 70%
CO H
2
8
0 C, 35%
4
5
2
6
SOCl2
C H OH
2
5
o
8
0 C, 95%
EtO C
2
N
Br
Br
N
CO Et
2
7
Scheme 1.

F. Algi / Tetrahedron 69 (2013) 3523e3529
3525
O
EtO C
2
O
S
N
S
SnBu3
S
N
O
O
O
CO Et
O
2
8
1
(55%)
EtO C
EtO
C
2
2
Pd[P(C H ) ]
N
S
6
5 3 4
N
S
Br
Br
SnBu3
o
S
N
C H CH , 110 C
N
6
5
3
CO Et
CO
Et
2
2
7
9
2 (60%)
EtO C
2
SnBu3
N
S
S
S
S
N
S
S
CO Et
2
10
3
(60%)
Scheme 2.
vein, compounds 2 and 3 were synthesized from the coupling
reactions of 7 with 9 and 10 in 60% yields, respectively (Scheme 2).
Note that compounds 1e3 were comprised of a 2,2 -bipyridine
310 nm) with molar extinction coefficients (
3
m
) of 9633 and
ꢀ1
ꢀ1
96,011 M cm , respectively. The low energy absorption band in
compound 1 exhibited a slight hypsochromic shift in the electronic
spectra of compound 2. This is not surprising since the electron
density of 1 is higher than 2. However, the UVevis spectrum of 3
exhibited a bathochromic shift with respect to 2 probably due to
0
scaffold as the A-part that was linked with 3,4-ethylene-
0
dioxythiophene (EDOT), thiophene and 2,2 -bithiophene, re-
spectively, as different D-units. This allows the investigation of the
effect of the D-units in a systematic manner.
Initial characterization of 1e3 was based on NMR and FTIR
spectroscopic data along with the elemental and HRMS analysis
the increased conjugation, as expected, with a
lmax¼370 nm
ꢀ
1
ꢀ1
(
3
m
¼196,724 M cm ).
Next, the metal cation complexing properties of 1e3 were in-
(
see Supplementary data), which confirmed the structures.
vestigated by spectrophotometric titrations with different metal
ions. First of all, it was found that the absorption of 1 was quite
3
þ
2þ
2þ
2þ
2
.2. Electrochemical properties
sensitive to the presence of metal ions (e.g., Fe , Cu , Ni , Zn
2þ
and Co ), although did not exhibit any selectivity (Fig. 2A). This
behaviour of 1 was attributed to the presence of extra oxygen atoms
on the EDOT units, which donate a greater amount of electron
density into the bipyridine, increasing the basicity of nitrogens and
consequently increasing their ion binding strength but reducing
selectivity, when compared to the thiophenes on 2 and 3. In con-
trast, the absorption spectra of 2 and 3 were not influenced upon
In order to determine the role of the D-units on the redox be-
haviour of pyridine based DeA systems 1e3, cyclic voltammetry
studies were carried out in 0.1 M Bu NPF , which was dissolved in
acetonitrile. During anodic scans, irreversible oxidation waves were
observed at ðE Þ 0.82 V, 1.72 V and 1.24 V (vs Ag/AgCl) for 1e3, re-
4
6
ox
a
spectively (Fig. S11). It was found that the voltammograms nicely
reflected the electronic nature of the D units; 3 had an oxidation
potential of 1.24 V, which was between those of 1 and 2, as depicted
in Fig. 2. It is well established that EDOT is electron rich compared to
thiophene, due to the presence of electron donating alkoxy sub-
stituents. For that reason, compound 1, which has the EDOT ring as
a D-unit, gave rise to the lowest oxidation potential when compared
to 2 and 3. However, compound 3 had a lower oxidation potential
when compared to 2. This could be attributed to the increased
2
þ
þ
2þ
2þ
þ
2þ
3þ
þ
2þ
2þ
addition of Hg , Ag , Cd , Co , Cu , Fe , Fe , Li , Mn , Pb ,
2
þ
2þ
Pt and Zn (1 equiv) ions, all of which gave no significant change
as shown in Fig. 2B and C. On the other hand, it was noted that Cu
ions revealed dramatic changes in both the shape and the maxima
of the original absorption bands of 2 and 3 (Fig. 2B and C). As an
aside, it was also noted that Ni ions caused slight changes in the
absorption spectra of 2 and 3.
2
þ
2
þ
Fig. 3 shows the absorption spectral changes of 2 and 3 as
2þ
conjugation in 3, which provided strong coupling between the
p-
a function of Cu concentration in CH
perature. Notably, during the addition of Cu ions, a progressive
decrease in absorbance at the max was observed with simultaneous
3
CN solution at room tem-
2
þ
systems of the thiophene and pyridine rings. The electron density of
systems 1e3 probably followed an increasing order as 2, 3 and 1, as
well as with the ease of oxidation in the same order (Fig. S11).
l
formation of a new red shifted absorption band, which increased in
intensity, at 392 nm and 460 nm for 2 and 3, respectively. Similarly,
2
þ
2
.3. Photophysical properties
Ni ions also caused bathochromic shifts in the absorption spectra
of 2 and 3, but in these cases the changes were not so distinct when
2
þ
The absorption profiles of the compounds 1e3 were examined
compared to Cu ions (see Fig. S12).
in CH
3
CN solution. The UVevis spectra of 1 and 2 were character-
max¼315 and
Furthermore, the red shift of the absorption bands of 2 and 3
were around 80 and 90 nm for Cu ions, respectively. Fortunately,
2
þ
ized by broad bands between 280 and 350 nm (
l

3526
F. Algi / Tetrahedron 69 (2013) 3523e3529
Fig. 2. UVevis spectra of (A) 1 (6ꢁ10ꢀ M), (B) 2 (5.7ꢁ10ꢀ6 M) and (C) 3 (2.85ꢁ10ꢀ6 M) in the presence of various metal ions (1 equiv) in CH
5
CN.
3
solution of 3 turned red with Cu2 and orange with Ni ions
(Fig. S14a). It is important to note that colour change is one of the
most convenient visual detection methods used in classical
chemical analysis, which is straightforward without the need for
þ
2þ
such red-shifts were enough to make the colour of the solution of 2
change from a colourless state to a yellow colour, thus allowing the
2
þ
2þ
naked-eye (colorimetric) detection of Cu and/or Ni ions among
the others (Fig. S13a). On the other hand, the yellow colour of the
ꢀ
6
2þ
Fig. 3. UVevis spectra of (A) 2 (8.57ꢁ10 M) in the presence of various amounts of Cu ions (0, 0.08, 0.16, 0.25, 0.33, 0.42, 0.50, 0.58, 0.66, 0.75, 0.83, 0.92, 1.0, 1.5, 2.0, 3.0 equiv) in
6
2þ
CH
3
CN and (B) 3 (3.35ꢁ10ꢀ M) in the presence of various amounts of Cu ions (0, 0.08, 0.16, 0.25, 0.33, 0.42, 0.50, 0.58, 0.66, 0.75, 0.83, 0.92, 1.0, 2.0 equiv) in CH
3
CN.

F. Algi / Tetrahedron 69 (2013) 3523e3529
3527
(365 nm) (Figs. S13B and S14B). Upon binding of Cu2 ions to
compounds 2 and 3, the fluorescence emissions were totally
quenched. The quenching mechanism was presumably based on the
electron transfer between 2/3 and the metal cation, which might
provide an efficient non-radiative decay of the excited state. Simi-
þ
any instrument. It was reasonable to assume that the colorimetric
responses of 2 and 3 to metal ions were probably based on the
mechanism of internal charge transfer (ICT). The metal cation
interacting with the acceptor group enhances the electron-
withdrawing character of this group; thus, the absorption spec-
trum is, red-shifted.
2
þ
larly, Ni ions also quenched the emissions of 2 and 3 to an extent,
On the other hand, the fluorescence spectra of 2 and 3 in CH
exhibited broad emission peaks with max(emis) at 423 nm and
05 nm, respectively. Increased conjugation length in 3 provided
3
CN
but the changes in these cases were not so distinct when compared
2
þ
l
to Cu ions (Fig. S17), thus the emission was not turned off.
On the basis of the above spectrophotometric titrations, the
5
5
5
a dramatic enhancement of fluorescence properties. This was
probably a consequence of the increased rigidity of the system in
the excited state, which could reduce the non-radiative processes.
It was found that the emissions of 2 and 3 were not influenced at all
detection limit of compounds 2 and 3 was calculated to be
ꢀ
6
ꢀ6
3.09ꢁ10 M and 1.44ꢁ10 M, respectively. Considering the fact
that the limit of copper in drinking water determined by the U.S.
ꢀ
5
Environmental Protection Agency (EPA) is around 2ꢁ10
M
þ
2þ
2þ
þ
2þ
3þ
2þ
þ
2þ
56
upon addition of Ag , Cd , Co , Cu , Fe , Fe , Hg , Li , Mn
,
(20
mM), these compounds serve as promising dual channel
2
þ
2þ
2þ
Pb , Pt and Zn ions, all of which gave no significant change in
the emission profiles of 2 and 3 as shown in Fig. 4.
(colorimetric and fluorometric) responsive probes for the detection
2
þ
a
of Cu ions. Furthermore, the binding constants (K ) of 2 and 3
Fig. 4. Fluorescence spectra of (A) 2 (1.42ꢁ10ꢀ M) (
6
l
exc¼310 nm) and (B) 3 (0.4ꢁ10ꢀ6 M) (
l
exc¼370 nm) in the presence of various metal ions in CH
3
CN.
þ
However, the blue emission of 2 and green emission of 3 were
with Cu2 were determined from the emission intensity data fol-
2
þ
57
totally quenched upon addition of Cu ions (turn off). Clearly, the
lowing the steady-state fluorometric method, in which I
to the fluorescence intensities of solutions of 2 or 3. When I
0
referred
/(IꢀI
2
þ
changes in the emission profiles of 2 and 3 upon addition of Cu
0
0
)
ꢀ1
5
indicated the formations of well-defined complexes between these
compounds and the metal ions. Evaluation of Job plots for the de-
termination of the stoichiometry of the complexes of 2 and 3 with
is plotted against [M] , K
a
was calculated to be 1.08ꢁ10 and
6
2.75ꢁ10 for 2 and 3, respectively, from the ratio of intercept/slope
with good correlation coefficients (R¼0.9777 and 0.9896 for 2 and
3, respectively).
2
þ
Cu ions revealed `1 ratios (Fig. S15). NMR titrations of compound
3
with Cu(II) indicated that there is no significant change (ca.
0
.1 ppm) in the protons of the ester groups, whereas significant up
3. Conclusion
field shifts (ca. 0.5 ppm) in the protons of the pyridine ring were
1
observed in the H NMR spectrum (Fig. S16). This mainly suggested
In summary, the design, synthesis, electrochemical and photo-
that metal ion is coordinated to the pyridine nitrogens rather than
the ester units.
physical properties of three novel directly linked DeA type com-
0
pounds 1e3 has been described. EDOT, thiophene and 2,2 -
0
Fig. 5 shows the fluorescence spectral changes of 2 and 3 as
bithiophene were chosen as D-units while 2,2 -bipyridine with
a function of the Cu2 concentration in CH
þ
ester subunits was taken as the A-unit in these systems. It was
noteworthy that these DeA systems 1e3 exhibited distinct elec-
trochemical and optical features depending on the strength of the
D-unit and the conjugation length. Moreover, it was found that two
of these novel systems, 2 and 3, could be used as molecular probes
3
CN at room tempera-
ture. Note that a progressive decrease in emissions at
observed.
lmax(emis) was
The changes in the fluorescence spectra of 2 and 3 upon addition
of Cu2 could also be observed by the naked eye when the solutions
þ
5
8,59
2þ
detection of Cu among
of compounds with metal ions were illuminated under UV light
for both chromogenic and fluorogenic

3528
F. Algi / Tetrahedron 69 (2013) 3523e3529
ꢀ
6
Fig. 5. Fluorescence spectra of (A) 2 (1.42ꢁ10 M) (
l
exc¼310 nm) in the presence of various amounts (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.5, 2.0, 3.0, 4.0, 5.0 equiv) of
2
þ
ꢀ6
2þ
Cu ions in CH
CH CN.
3
CN and (B) 3 (0.44ꢁ10 M) (
l
exc¼370 nm) in the presence of various amounts (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0 equiv) of Cu ions in
3
other ions. Further work to elucidate the versatility of these novel
compounds is currently underway in our laboratory, and the results
will be reported in due time.
(0.8 g, 0.02 mol) and potassium permanganate (4.74 g, 0.03 mol) in
distilled water (200 mL) was heated under reflux for 6 h with
vigorous stirring. The brown precipitate of MnO was filtered while
2
hot and the volume of the filtrate was reduced to 70 mL on a rotary
evaporator. Concentrated HCl was added dropwise to the filtrate to
give needle shaped crystals when the pH reached 2e3. The solid
4
4
. Experimental
.1. General methods
was filtered off, washed with water, ethanol and dried in air to give
ꢂ
6
; 2.82 g, 70% yield, white solid, mp 252e254 C (with de-
1
All chemicals were purchased from SigmaeAldrich or Merck
composition); H NMR (400 MHz, DMSO-d
6
)
d
/ppm: 8.82 (br s, 2H),
8.34 (br s, 2H); C NMR (100 MHz, DMSO-d ) d/ppm: 160.7, 155.3,
150.3,139.0,131.0,119.1; FTIR (cm ): 3079, 2806, 2601, 2444, 2324,
1848, 1738, 1684, 1570, 1560, 1428, 1284, 1196, 1105, 1085, 1036, 916,
13
and used as received unless otherwise noted. FTIR spectra were
recorded on a PerkineElmer Spectrum 100 model FTIR with an
attenuated total reflectance (ATR). H (400 or 300 MHz) and
6
ꢀ1
1
13
C
(
100 or 75 MHz) NMR spectra were recorded on a Bruker DPX-400
6 2 2 4
843, 738, 711. Anal. Calcd for C12H Br N O : C, 35.85; H, 1.50; N,
or Ultrashield 300 NMR Spectrometers. Combustion analysis was
carried out by using an LECO CHNS-932 analyzer. High resolution
mass spectra (HRMS ESI ) were recorded on a Waters SYNAPT MS
system. UVevis and fluorescence measurements were recorded on
Varian Cary 50 and Varian Cary Eclipse spectrophotometers, re-
6.97; Found: C, 35.83; H, 1.48; N, 6.95. HRMS Calcd for
þ
C
12
H
7
Br
2
N
2
O
4
: 400.8773; Found: 400.8788 [MþH] .
þ
0
0
0
4.2.2. Diethyl 5,5 -dibromo-2,2 -bipyridine-3,3 -dicarboxylate (7). SO-
Cl (0.28 mL, 4 mmol) was dropwise added to a solution of diacid 6
2
spectively. 0.1 M Bu
4
NPF
6
, dissolved in acetonitrile was used as
(402 mg, 1 mmol) in ethanol (30 mL) at room temperature. Then the
solution was heated under reflux until the starting material was
totally consumed. The solvent was removed and the residue was
2
electrolyte solution. A platinum button (0.02 cm ) and a platinum
wire were used as working and counter electrodes, respectively, as
well as an Ag/AgCl reference electrode (calibrated externally using
chromatographed on silica gel by eluting with CH
product; 435 mg, 95% yield, white solid, mp 90e92 C; H NMR
(400 MHz, CDCl
/ppm: 8.81 (d, J¼2.5 Hz, 2H), 8.50 (d, J¼2.5 Hz,
2H), 4.17 (q, J¼8 Hz, 4H), 1.15 (t, J¼8 Hz, 6H); C NMR (400 MHz,
CDCl /ppm: 164.1, 156.8, 152.6, 140.5, 126.9, 119.8, 61.8, 13.8; FTIR
(cm ): 3057, 2983, 2935, 1723, 1699, 1420, 1274, 1207, 799; Anal.
Calcd for C16 : C, 41.95; H, 3.08; N, 6.12; Found: C, 41.80; H,
3.16; N, 6.22. HRMS Calcd for NaC16 : 478.9218; Found:
2 2
Cl to give the
ꢂ
1
10 mM solution of ferrocene/ferrocenium couple, which is an in-
ternal standard calibrated to be 0.44 V in acetonitrile solution
vs Ag/AgCl). Melting points were determined on a Schorrp MPM-
H2 model apparatus and are uncorrected. Column chromatogra-
phy was performed on silica gel (60e200 mesh) from Merck
Company. TLC was carried out on Merck 0.2 mm silica gel 60 F254
analytical aluminium plates. For spectrophotometric titrations,
metal ions were freshly prepared from perchlorate salts. The syn-
3
) d
13
3
) d
ꢀ1
2 2 4
H14Br N O
H
2 2 4
14Br N O
þ
478.9209/480.9192/482.9198 [MþNa] .
5
3
16
54
16
theses of compounds 5, 8,
9
and 10 were carried out
according to previously published procedures.
4.2.3. Representative procedure for the synthesis of DeA conjugates
1
e3. To an argon degassed solution of 7 (92 mg, 0.20 mmol) and
8/9 or 10 (0.44 mmol) in dry toluene (25 mL) was added Pd(PPh
5 mg) and the mixture was heated under reflux until all the
4
.2. Synthesis
3 4
)
(
0
0
0
4
.2.1. 5,5 -Dibromo-2,2 -bipyridine-3,3 -dicarboxylic acid (6). A
starting materials were consumed. After cooling to room temper-
ature, the solvent was removed under reduced pressure. The crude
5
3
mixture of dibromide 5 (3.38 g, 0.01 mol), sodium hydroxide

F. Algi / Tetrahedron 69 (2013) 3523e3529
3. Zhu, Y.; Kulkarni, A. P.; Jenekhe, S. A. Chem. Mater. 2005, 17, 5225.
3529
mixture was chromatographed on silica gel by eluting with chlo-
roform to give 1/2 or 3.
4. Chen, C.-T.; Lin, J.-S.; Moturu, M. V. R. K.; Lin, Y.-W.; Yi, W.; Tao, Y.-T.; Chen, C.-H.
Chem. Commun. 2005, 3980.
5
. Heeney, M.; Zhang, W.; Crouch, D. J.; Chabinyc, M. L.; Gordeyev, S.; Hamilton, R.;
Higgins, S. J.; McCulloch, I.; Skabara, P. J.; Sparrowe, D.; Tierney, S. Chem.
Commun. 2007, 5061.
0
0
4
.2.4. Diethyl 5,5 -bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,2 -
0
bipyridine-3,3 -dicarboxylate (1). Viscous liquid, 63 mg, 55% yield;
H NMR (400 MHz, CDCl
6
. Greenham, N. C.; Moratti, S.; Bradley, D. D. C.; Friend, R. H.; Holmes, A. B. Nature
1
3
)
d
/ppm: 9.07 (d, J¼2.5 Hz, 2H), 8.57 (d,
1993, 365, 628.
J¼2.5 Hz, 2H), 6.43 (s, 2H), 4.36e4.34 (m, 4H), 4.28e4.26 (m, 4H),
7. Goel, A.; Dixit, M.; Chaurasia, S.; Kumar, A.; Raghunandan, R.; Maulik, P. R.;
13
Anand, R. S. Org. Lett. 2008, 10, 2553.
. King, S. M.; Perepichka, I. I.; Perepichka, I. F.; Dias, F. B.; Bryce, M. R.; Monkman,
A. P. Adv. Funct. Mater. 2009, 19, 586.
4
d
.17 (q, J¼8 Hz, 4H), 1.08 (t, J¼8 Hz, 6H); C NMR (400 MHz, CDCl
3
)
8
/ppm: 166.2, 155.7, 147.8, 142.3, 140.1, 134.3, 132.0, 128.7, 126.2,
ꢀ1
9
1
1
9.7, 64.9, 64.4, 61.3, 13.8; FTIR (cm ): 3058, 2955, 2922, 2870,
9. Fr eꢀ chet, J. M. J.; Thompson, B. C. Angew. Chem., Int. Ed. 2008, 47, 58.
10. Dance, Z. E. X.; Ahrens, M. J.; Vega, A. M.; Ricks, A. B.; McCamant, D. W.; Ratner,
722, 1590, 1501, 1454, 1437, 1363, 1306, 1272,1251, 1242,1169, 1118,
070, 1039, 1029, 998, 959, 910, 876, 866, 789, 721, 693. Anal.
Calcd for C28 : C, 57.92; H, 4.17; N, 4.82; S, 11.04; Found: C,
M. A.; Wasielewski, M. R. J. Am. Chem. Soc. 2008, 130, 830.
11. Boudreault, P.-L. T.; Najari, A.; Leclerc, M. Chem. Mater. 2011, 23, 456.
24 2 8 2
H N O S
12. Gunbas, G.; Toppare, L. Chem. Commun. 2012, 1083.
1
3. Beaujuge, P. M.; Reynolds, J. R. Chem. Rev. 2010, 110, 268.
14. Cihaner, A.; Algi, F. Adv. Funct. Mater. 2008, 18, 3583.
5. Jenkins, I. H.; Salzner, U.; Pickup, P. G. Chem. Mater. 1996, 8, 2444.
6. Zhu, S. S.; Swager, T. M. J. Am. Chem. Soc. 1997, 119, 12568.
5
5
7.70; H, 4.30; N, 4.96; S, 10.90. HRMS Calcd for C28
81.1052; Found: 581.1056 [MþH] .
H
25
N
2
O
8
S
2
:
þ
1
1
0
0
0
4
.2.5. Diethyl 5,5 -di(thiophen-2-yl)-2,2 -bipyridine-3,3 -dicarbox-
17. Irvin, D. J.; DuBois, C. J. J.; Reynolds, J. R. Chem. Commun. 1999, 2121.
18. Chevallier, F.; Charlot, M.; Katan, C.; Mongin, F.; Blanchard-Desce, M. Chem.
Commun. 2009, 692.
ꢂ
1
ylate (2). Yellow solid, 55 mg, 60% yield; mp 125e127 C; H NMR
400 MHz, CDCl
(
2
4
3
)
d
/ppm: 9.00 (d, J¼2.5 Hz, 2H), 8.50 (d, J¼2.5 Hz,
19. Balan, A.; Baran, D.; Toppare, L. Polym. Chem. 2011, 2, 1029.
H), 7.49 (dd, J¼4, 2 Hz, 2H), 7.43 (dd, J¼5, 2 Hz, 2H), 7.17 (dd, J¼5,
20. Balan, A.; Baran, D.; Toppare, L. J. Mater. Chem. 2010, 20, 9861.
21. Pamuk, M.; Tirke s¸ , S.; Cihaner, A.; Algi, F. Polymer 2010, 51, 62.
13
Hz, 2H), 4.19 (q, J¼8 Hz, 4H), 1.12 (t, J¼8 Hz, 6H); C NMR
/ppm: 165.6, 157.2, 148, 139.1, 134.8, 129.8, 128.5,
€
_
€
€
22. Ozkut, M. I.; Algi, M. P.; Ozta s¸ , Z.; Algi, F.; Onal, A. M.; Cihaner, A. Macromole-
(
400 MHz, CDCl
3
) d
cules 2012, 45, 729.
ꢀ1
_
€
1
1
C
26.8, 126.2, 125, 61.5, 13.8; FTIR (cm ): 3122, 2983, 2927, 1724,
713, 1445, 1291, 1237, 1199, 1093, 1025, 793, 712. Anal. Calcd for
H N O S : C, 62.05; H, 4.34; N, 6.03; S, 13.80; Found: C, 62.15;
24 20 2 4 2
H, 4.45; N, 6.20; S, 14.10. HRMS Calcd for C24
23. I c¸ li, M.; Pamuk, M.; Algı, F.; Onal, A. M.; Cihaner, A. Organic Electron. 2010, 11,
255.
1
_
€
2
2
4. I c¸ li, M.; Pamuk, M.; Algı, F.; Onal, A. M.; Cihaner, A. Chem. Mater. 2010, 22, 4034.
5. Czarnik, A. W. In Fluorescent Chemosensors for Ion and Molecule Recognition,
American Chemical Society: Washington, DC, 1993.
H
21
N
2
O
4
S
2
: 465.0943;
þ
26. de Silva, A. P.; Gunaratne, H. Q. N.; Gunnlaugsson, T.; Huxley, A. J. M.; McCoy, C. P.;
Found: 465.0927 [MþH] .
Rademacher, J. T.; Rice, T. E. Chem. Rev. 1997, 97, 1515.
2
7. de Silva, A. P.; Fox, D. B.; Huxley, A. J. M. Coord. Chem. Rev. 2000, 205, 41.
0
0
0
0
4
.2.6. Diethyl 5,5 -di(2,2 -bithiophen-5-yl)-2,2 -bipyridine-3,3 -di-
28. Callan, J. F.; de Silva, A. P.; Magri, D. C. Tetrahedron 2005, 61, 8551.
29. Kim, J. S.; Quang, D. T. Chem. Rev. 2007, 107, 3780.
ꢂ
1
carboxylate (3). Yellow solid, 75 mg, 60% yield; mp 168e170 C; H
NMR (400 MHz, CDCl
30. Koval, I. A.; Gamez, P.; Belle, C.; Selmeczi, K.; Reedijk, J. J. Chem. Soc. Rev. 2006,
3
)
d/ppm: 9.00 (d, J¼2.5 Hz, 2H), 8.50 (d,
35, 814.
J¼2.5 Hz, 2H), 7.42 (d, J¼4 Hz, 2H), 7.29e7.27 (m, 4H), 7.23 (d,
J¼4 Hz, 2H), 7.07 (dd, J¼4, 4 Hz, 2H), 4.21 (q, J¼8 Hz, 4H), 1.14 (t,
31. Millhauser, G. L. Acc. Chem. Res. 2004, 37, 79.
32. Gaggelli, E.; Kozlowski, H.; Valensin, D.; Valensin, G. Chem. Rev. 2006, 106, 1995.
33. Linder, M. C.; Hazegh-Azam, M. Am. J. Clim. Nutr. 1996, 63, 797S.
13
J¼8 Hz, 6H); C NMR (400 MHz, CDCl
3
) d/ppm: 165.5, 157.0, 147.7,
3
3
4. Uauy, R.; Olivares, M.; Gonzalez, M. Am. J. Clim. Nutr. 1998, 67, 952S.
5. Shen, Q.; Tang, S.; Li, W.; Nie, Z.; Liu, Z.; Huang, Y.; Yao, S. Chem. Commun. 2012,
281.
1
1
1
38.9, 137.4, 136.7, 134.3, 129.5, 128.0, 126.2, 125.8, 125.1, 124.8,
ꢀ1
24.3, 61.5, 13.9; FTIR (ATR, cm ): 3096, 3059, 2982, 2966, 1729,
707, 1547, 1463, 1288, 1251, 1216, 1079, 803; Anal. Calcd for
: C, 61.12; H, 3.85; N, 4.46; S, 20.40; Found: C, 61.08;
3
6. Dodani, S. C.; Leary, S. C.; Cobine, P. A.; Winge, D. R.; Chang, C. J. J. Am. Chem. Soc.
2011, 133, 8606.
32 24 2 4 4
C H N O S
37. Weerasinghe, A. J.; Abebe, F. A.; Sinn, E. Tetrahedron Lett. 2011, 52, 5648.
H, 3.83; N, 4.49; S, 20.30. HRMS Calcd for C32
Found: 629.0696 [MþH] .
25
H N
2
O
4
S
4
: 629.0697;
38. Hou, J.; Wang, L.-Y.; Li, D.-H.; Wu, X. Tetrahedron Lett. 2011, 52, 2710.
39. Chandrasekhar, V.; Pandey, M. D. Tetrahedron Lett. 2011, 52, 1938.
þ
40. Chandrasekhar, V.;Pandey, M. D.;Maurya, S. K.;Sen, P.;Goswami, D. Chem.dAsian
J. 2011, 6, 2246.
Acknowledgements
41. Paul, B. K.; Kar, S.; Guchhait, N. J. Photochem. Photobiol., A 2011, 220, 153.
4
4
2. Wang, H.; Lin, J.; Huang, W.; Wei, W. Sens. Actuators, B 2010, B150, 798.
3. Xi, P.; Dou, J.; Huang, L.; Xu, M.; Chen, F.; Wu, Y.; Bai, D.; Li, W.; Zeng, Z. Sens.
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F.A. is indebted to Scientific and Technological Research Council
of Turkey (TUBITAK, Contract No. 109R009) for financial support,
which came in the early critical stage of his career. European Co-
operation in Science and Technology (COST) and Canakkale Onsekiz
Mart University (COMU BAP 2010/32 and 2010/180) are also
gratefully acknowledged. The author thanks Dr. S. Tirkes and Dr. A.
Cihaner for CV measurements.
44. Jisha, V. S.; Thomas, A. J.; Ramaiah, D. J. Org. Chem. 2009, 74, 6667.
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Supplementary data
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5
5
5
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Copies of H, 13C NMR and HRMS spectra for all new compounds.
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2013.03.008.
1
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