Electrogenerated chemiluminescence of benzo 15-crown-5 derivatives

Article abstract of DOI:10.1002/poc.1414

Novel electrogenerated chemiluminescence (ECL) reagents C1, C2, and C3 with high fluorescence quantum yields bearing 15-crown-5 moiety have been synthesized and characterized. The photophysical, electrochemical, and ECL characters of these compounds have been studied in a 1:1 (v/v) PhH/MeCN mixed solvent. The ECL intensity is enhanced distinctly with the increase in the fluorescence quantum yield. Their ECL behaviors have been studied using annihilation and co-reactant methods (tri-n-propylamine (TPrA) was used as a co-reactant), respectively. The stable ECL emissions of compounds C1-C3 can be ascribed to the typical and simple monomer ECL emission via S-route. Copyright

Full text of DOI:10.1002/poc.1414

Research Article
Received: 22 February 2008,
Revised: 28 May 2008,
Accepted: 29 May 2008,
Published online in Wiley InterScience: 5 August 2008
(www.interscience.wiley.com) DOI 10.1002/poc.1414
Electrogenerated chemiluminescence
of benzo 15-crown-5 derivatives
a
a
b
a,c
*
Xiao Jiang , Xichuan Yang , Changzhi Zhao and Licheng Sun
Novel electrogenerated chemiluminescence (ECL) reagents C1, C2, and C3 with high fluorescence quantum yields
bearing 15-crown-5 moiety have been synthesized and characterized. The photophysical, electrochemical, and ECL
characters of these compounds have been studied in a 1:1 (v/v) PhH/MeCN mixed solvent. The ECL intensity is
enhanced distinctly with the increase in the fluorescence quantum yield. Their ECL behaviors have been studied using
annihilation and co-reactant methods (tri-n-propylamine (TPrA) was used as a co-reactant), respectively. The stable
ECL emissions of compounds C1–C3 can be ascribed to the typical and simple monomer ECL emission via S-route.
Copyright ß 2008 John Wiley & Sons, Ltd.
Supporting information may be found in the online version of this article.
Keywords: Electrogenerated Chemiluminescence (ECL), 15-Crown-5 derivatives, Annihilation ECL, Co-reactant ECL
INTRODUCTION
RESULTS AND DISCUSSION
Synthesis and characterization
Since the first detailed studies in the mid-1960s electrogenerated
chemiluminescence (ECL) has attracted much attention and been
studied extensively. It provides a powerful tool for understanding
fundamental questions in analytical chemistry, biology, and
physics. During the past two decades, numerous studies on the
ECL of inorganic complexes and/or clusters have been reported,
Compounds C1–C3 were prepared according to a general
synthetic procedure shown in Scheme 1. Diethylene glycol as the
starting material reacted with p-toluenesulfonyl chloride to give
compound 1.[27] Compound 1 was treated by catechol in the
presence of Bu4NI to afford compound 2.[28] Reaction of 2 with a
solution of HBr in acetic acid and paraformaldehyde led to the
intermediate 3, which directly reacted without purification with
triethyl phosphite to get the precursor 4.[29] Similarly, compound
4 was also directly used without further purification in the next
synthesis step. The target compound C1 was prepared by
2þ
in particular RuðbpyÞ3 and its derivatives which play a pivotal
role in transforming ECL from a laboratory curiosity to a useful,
and commercially viable, analytical technique.[1–10] In addition,
organic systems capable of generating ECL, such as polymers,
fluorescent laser dyes, polyaromatic hydrocarbons (PAHs), and
donor–acceptor functionalized compounds, are also of inter-
est.[11–21] There are several general criteria for organic materials
to be suitable for ECL: high fluorescence quantum yield,
the electrochemical stability, and the high efficiency of
electron- and energy-transfer. Additionally, its ability to produce
ECL under moderate conditions in aqueous buffered solutions
will be extremely important in practical applications. Accordingly
our work focuses on those molecules which not only are
efficient in generating ECL, but also have moderate water
solubility.
Witting–Horner reaction of
4 with 4-N,N-dimethylamino-
benzaldehyde in the presence of NaH.[30,31] Compounds C2
and C3 were obtained by a similar procedure to C1. All
*
Correspondence to: X. Yang, State Key Laboratory of Fine Chemicals, DUT-KTH
Joint Education and Research Center on Molecular Devices, Dalian University
of Technology (DUT), 158 Zhongshan Road, 116012 Dalian, PR China.
E-mail: yangxc@dlut.edu.cn
It is well known that many organic molecules with crown ether
moiety or analogous heteroatom crown ether unit have been
employed to detect the metal ions as highly sensitive fluorescent
chemosensors.[22–24] Considering the potential applications of
the compounds containing crown ether moiety for detection of
metal ions under ECL conditions,[25,26] we designed a series
of new functional organic molecules C1–C3 with 15-crown-5
moiety (a double armed unit is bound to the crown ether in the
2,3-positions) shown in Chart 1. Here we mainly report the
synthesis and their ECL behaviors in organic solvent and
the possible mechanisms.
a
X. Jiang, X. Yang, L. Sun
State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and
Research Center on Molecular Devices, Dalian University of Technology
(DUT), 158 Zhongshan Road, 116012 Dalian, PR China
b
c
C. Zhao
College of Chemistry and Molecular Engineering, Qingdao University of
Science and Technology, 53 Zhengzhou Road, 266042 Qingdao, PR China
L. Sun
KTH School of Chemical Science and Engineering, Organic Chemistry, Royal
Institute of Technology (KTH), Teknikringen 30, 10044 Stockholm, Sweden
J. Phys. Org. Chem. 2009, 22 1–8
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X. JIANG ET AL.
Chart 1. Structures of compounds C1–C3
Table 1. Photophysical, electrochemical,a and ECL characters of compounds C1–C3 in 1:1 PhH/MeCN
Epa(2)
(V)
EHOMO
(eV)e
ELUMO
(eV)f
lECL
ꢁDH8
c
Compound labs (nm)b lem (nm) Fem
Eg (eV)d Epa(1) (V)
Epc (V)
(nm) Es (eV)g (eV)
C1
C2
C3
343 (377)
364 (392)
359 (390)
483
504
479
0.166
0.253
0.487
2.86
2.74
2.81
0.29
0.24
0.68
0.42
0.58
0.99
ꢁ2.45
ꢁ2.49
ꢁ2.33
ꢁ4.90
ꢁ4.88
ꢁ5.33
ꢁ2.04
ꢁ2.14
ꢁ2.52
493
505
483
2.57
2.46
2.59
2.64
2.63
2.91
a Versus SCE.
b The shoulder peak is given in parentheses.
c Fluorescence quantum yield (Fem) were measured in MeCN with reference to quinine sulfate (Fem ¼ 0.508 in 0.05 M H2SO4).[32]
d Calculated from lonset in absorption spectrum.
e EHOMO/eV ¼ ꢁ4.74/eV ꢁ eEoonxset
.
[33]
f ELUMO/eV ¼ Eg þ EHOMO
.
g Calculated from the highest energy emission peak in fluorescence spectrum.
compounds were characterized by 1H NMR, 13C NMR, and
HRMS.
Due to the limitation of the potential window of the solvent, the
cathodic reduction wave of compound C3 is not well resolved, a
differential pulse voltammogram (DPV) displays that it has clear
cathodic reduction, which is shown in inset of Fig. 2. On the
Photophysical properties
The photophysical data of compounds C1–C3 in 1:1 PhH/MeCN
solution at a concentration of 1 ꢀ 10ꢁ5 M are listed in Table 1.
Figure 1 displays the absorption spectra of compounds C1–C3. It
can be observed that each compound shows an absorption peak
in the higher energy region and a shoulder in the lower energy
region, which can be attributed to the absorption of the
single-armed unit and the whole molecule, respectively.
According to literature, the N,N-diaryl-substituted stilbene
derivatives have inherently greater fluorescence quantum yields
(Fem) and longer lifetimes due to the prominent ‘‘amino
conjugation effect,’’ as compared with the N,N-dialkyl-substituted
stilbene derivatives.[34] Therefore, we can see from Table 1 that
the Fem of C3 is close to 0.5, which is obviously larger than that of
C1 and C2. Furthermore, the high fluorescence quantum
efficiency is advantageous for ECL which will be discussed below.
Electrochemical analysis
The redox potentials of compounds C1–C3 in 1:1 PhH/MeCN
solution at a concentration of 1 ꢀ 10ꢁ3 M are listed in Table 1.
Cyclic voltammogram (CV) of compound C3 is shown in Fig. 2.
Figure 1. Normalized absorption spectra of C1 (dot), C2 (solid), and C3
(dash) in 1:1 PhH/MeCN
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ECL OF BENZO 15-CROWN-5 DERIVATIVES
Figure 4. ECL (1 ꢀ 10ꢁ3 M, solid) and fluorescence (1 ꢀ 10ꢁ5 M, dash)
spectra of C3 in 1:1 PhH/MeCN
Figure 2. CV of C3 with 0.05 M TBAPF6 as a supporting electrolyte in 1:1
PhH/MeCN using a platinum working electrode and an Ag/Agþ reference
electrode, scan rate 100 mV sꢁ1. Inset: DPV of C3
oxidation side, the first wave at þ0.68 V (vs. SCE) is ascribed to the
oxidation of one of substituted amino groups, and the second
wave at þ0.99 V (vs. SCE) is assigned to the oxidation of the other
substituted amino group. On the reduction side, the irreversible
wave at ꢁ2.33 V (vs. SCE) is ascribed to the reduction of the crown
ether moiety. It is also observed that the presence of
triphenylamine unit in the backbone decreases the highest
occupied molecular orbital (HOMO) and the lowest unoccupied
molecular orbital (LUMO) energy levels of compound C3
compared with the other two compounds C1 and C2.
reactions between an oxidized and a reduced species, both of
which were generated at an electrode by alternate pulsing of the
electrode potential. This approach is a typical double-potential
step.[1] It is also possible to generate ECL in a single-potential step
using a co-reactant. A co-reactant is a species that, upon
oxidation or reduction, produces an intermediate that can react
with an ECL luminophore to produce excited states. In an ECL
system, addition of a co-reactant assisting to generate ECL is fairly
common, such as tri-n-propylamine (TPrA), which is an especially
important ‘‘oxidative–reductive’’ co-reactant for practical appli-
cations because it allows efficient ECL not only in aqueous media
but also at physiological pH (ꢂ7.4).[1–5] In this section, the ECL
behaviors of compounds C1–C3 will be discussed using
annihilation and co-reactant methods in nonaqueous system
(1:1 PhH/MeCN), respectively.
Electrogenerated chemiluminescence (ECL) in nonaqueous
system
Annihilation ECL and co-reactant ECL are two of general ECL
reaction mechanisms. Annihilation ECL involved electron-transfer
Figure 3. ECL spectra of C1 (dot), C2 (solid), and C3 (dash) with a sample
concentration of 1 ꢀ 10ꢁ3 M in 1:1 PhH/MeCN containing 0.05 M TBAPF6
as a supporting electrolyte. The potential was stepped from ꢁ2.7 V to
þ1.0 V, pulsed for 0.5 s
Figure 5. X-ray crystal structure of compound C3
J. Phys. Org. Chem. 2009, 22 1–8
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X. JIANG ET AL.
Figure 6. Time-intensity ECL spectra of (a) 1 ꢀ 10ꢁ5 M and (b) 1 ꢀ 10ꢁ3 M solutions of C3 in 1:1 PhH/MeCN containing 0.05 M TBAPF6 as a supporting
electrolyte. The potential was stepped from 2.7 to þ1.0 V
Annihilation ECL
ECL spectra are recorded at room temperature using a setup
consisting of a fluorescence spectrophotometer and a cyclic
voltammograph with a computer interface.[35] Measurements are
obtained in the same concentration (1 ꢀ 10ꢁ3 M) as used for the
CV. The ECL data of all compounds are summarized in Table 1.
Figure 3 shows the ECL spectra of compounds C1–C3 under the
same experimental conditions. It is found that there is a good
correlation between the observed ECL intensity and Fem. The ECL
intensities of C1–C3 are enhanced greatly with the increases in
Figure 7. Fluorescence spectra of compound C3 (a) 1 ꢀ 10ꢁ5 M,
(b) 1 ꢀ 10ꢁ3 M in 1:1 PhH/MeCN
Scheme 2. Proposed mechanism for annihilation ECL of compounds
C1–C3
Scheme 3. Proposed mechanisms for co-reactant ECL of compounds
C1–C3
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ECL OF BENZO 15-CROWN-5 DERIVATIVES
Scheme 1. Synthesis of compounds C1–C3
their Fem. Thus those compounds with high Fem are more
suitable for ECL. Figure 4 exhibits the ECL and fluorescence
spectra of compound C3. As illustrated in Fig. 4, the ECL emission
curve and bandwidth of C3 are similar to those of fluorescence,
and the ECL maximum (lECL) are in good match with its
fluorescence maximum (lem) with slight red shift (only 4 nm),
indicating the formation of the same excited state in both
experiments.
The X-ray crystal structure of compound C3 (Fig. 5) shows that
the molecule has a completely nonplanar structure.[36] The crown
ether ring shows a zigzag conformation and the structure of
triphenylamine group looks like a windstick. The two bridge units
linked by double bond between crown ether ring and substituted
amino group are also torsional (the dihedral angle between
planes 1 and 2 is 14.48, and that between planes 1 and 3 is 22.78).
In addition, there is no observable increase in ECL intensity of
compound C3 when the sample concentration is enhanced from
1 ꢀ 10ꢁ5 to 1 ꢀ 10ꢁ3 M (Fig. 6).
Figure 7 shows the fluorescence spectra of C3 with different
concentrations in 1:1 PhH/MeCN mixed solvent excited at
360 nm. The monomer fluorescence emission intensity at ca.
480 nm is decreased dramatically with increasing the sample
concentration from 1 ꢀ 10ꢁ5 to 1 ꢀ 10ꢁ3 M. However, no any new
emission band is observed in the longer or shorter wavelength
region.
As a result, on the basis of our previous studies,[13,14] the
possibility of excimer or aggregate formation can be excluded
during the ion annihilation process due to the following reasons:
(i) The absence of planar molecular structure. (ii) No remarkable
shift between the ECL spectrum and fluorescence spectrum.
J. Phys. Org. Chem. 2009, 22 1–8
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X. JIANG ET AL.
(iii) Almost no changes in ECL intensities at different concen-
trations. (iv) No characteristic peak occurred in fluorescence
spectra when the sample concentration is enhanced greatly.
Therefore, the ECL of compounds C1–C3 can be ascribed to the
typical and simple monomer ECL emission produced by the
annihilation of radical anions and cations during repeated
pulsing (Scheme 2). The enthalpy change of the radical ion
þ0.89 V in the same manner, both of which are lower than the
oxidation potential of the solvent. Under the same experimental
conditions, the ECL maxima produced by co-reactant method are
the same as that produced by annihilation method. However, the
ECL intensities formed in co-reactant reactions are distinctly
higher than those formed in annihilation reactions (Fig. 8).
À
Á
annihilation reaction ꢁDHaonn is calculated from the following
Electrogenerated chemiluminescence (ECL) in
water-containing system
equation:[37]
ꢁDH0ann=eV ¼ Epað1Þ ꢁ Epcð1Þ ꢁ 0:1 eV
It can be seen from Table 1, the energy ꢁDHoann provided by
the ion-annihilation reaction is larger than that (Es) required for
direct production of the singlet excited state (S-route), and the
equation is presented as follows:[37]
(1)
The ECL behaviors of compounds C1–C3 have been studied in 4:1
(v/v) MeCN/H2O mixed solvent. Unfortunately, no matter what
method is used, annihilation method or co-reactant method, no
any ECL signal is found, which can be ascribed to the following
three reasons: (i) The reduction potentials of C1–C3 are beyond
that of water, so negative radicals are difficult to be formed
and the ECL emissions could not be observed. (ii) The water
which is a strong polar solvent could quench the ECL of
compounds. (iii) The hydrogen bond between the oxygen atoms
in the 15-crown-5 unit and water in the solvent could also make
the ECL quench.
À
Á
ꢁDH0ann ꢃ Es
(2)
As a result, in this energy sufficient system, all stable ECL
emissions can be observed via S-route without the addition of
any co-reactant or additional compound.
Co-reactant ECL
CONCLUSION
The annihilation ECL mentioned above is generated in a
double-potential step by pulsing between the potentials of first
oxidation and first reduction of compound. But, the high
reduction potentials of C1–C3 are difficult to obtain in many
solvents due to the limited solvent windows in our case.
Alternatively, ECL can also be generated in a single-potential step
(only at the oxidation side) by utilizing TPrA as a co-reactant.
Oxidation of TPrA is known to generate a strong reducing agent
that reacts with the ECL luminophore to form an excited state and
then produce ECL emission (Scheme 3).[1–5]
In conclusion, a series of compounds C1–C3 have been
synthesized and the photophysical, electrochemical, and ECL
characters in 1:1 PhH/MeCN have been measured. The stable ECL
emissions of all compounds can be ascribed to the typical and
simple monomer ECL emission via S-route. The ECL intensity is
enhanced distinctly with the increase in the fluorescence
quantum yield. Under the same experimental conditions, the
ECL maxima produced by co-reactant method are the same as
that produced by annihilation method. However, the ECL
intensities formed in co-reactant reactions are distinctly higher
than those formed in annihilation reactions. Although the ECL
behaviors of all compounds in water-containing system (4:1 (v/v)
MeCN/H2O) are never found, this study is of vital importance to
an understanding of the basic chemistry of the crown ether
system and provides evidence for the structure’s modification in
order to get efficient ECL sensors in the aqueous solution.
In this study, the first oxidation potentials of C1–C3 occur at <
þ0.7 V (vs. SCE) in 1:1 PhH/MeCN, and that of TPrA peaks at ꢂ
EXPERIMENTAL SECTION
Materials and measurements
Anhydrous acetonitrile (chromatographic grade), tetra-n-
butylammonium hexafluorophosphate (TBAPF6) were obtained
from Aldrich and used as received. 4-diphenylamino-
benzaldehyde
and
2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]
quinoline-9-carbaldehyde were prepared in-house. Solvents were
distilled according to the standard methods and purged with
nitrogen before use. N,N-Dimethylformamide (DMF) was dried
˚
over 4A molecular sieves and further purified by vacuum
distillation over calcined baryta. Tetrahydrofuran (THF) and
benzene were purified by distillation over sodium chips and
benzophenone under N2 atmosphere. All other solvents
and reagents were of analytical grade quality purchased
commercially and used as received unless otherwise stated.
1H NMR spectra were recorded on a VARIAN INOVA 400 MHz
NMR instrument (Varian, America) and 13C NMR spectra were
Figure 8. ECL spectra of the (a) co-reactant reaction and (b) annihilation
reaction of 1 ꢀ 10ꢁ4 M solution of C3 in 1:1 PhH/MeCN with 0.05 M
TBAPF6 as a supporting electrolyte. TPrA (0.01 M) in sample (a), and
the potential was stepped from 0 to þ1.0 V, pulsed for 0.5 s
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ECL OF BENZO 15-CROWN-5 DERIVATIVES
recorded on the same instrument at 100 MHz. HRMS were
Benzo 15-crown-5 (2). To a stirred solution of catechol (3.3 g,
30 mmol) and Bu4NI (2.8 g (25 mmol%), 7.5 mmol) in toluene
(180 ml) 50% NaOH aq (60 ml) at 50–60 8C was added. The
mixture was stirred at this temperature for further 30 min,
whereupon a solution of ditosylate 1 (15.1 g, 30 mmol) in toluene
(180 ml) was added. The resulting mixture was vigorous stirred at
reflux for 16 h. The organic layer was separated and washed
with H2O (3 ꢀ 150 ml), brine (100 ml), and dried over anhydrous
MgSO4. The solvent was removed under vacuum to afford a
semisolid. Further purification was performed by recrystallization
from hexane to afford compound 2 (4.2 g, 52%) as snow flate
solid; 1H NMR (400 MHz, CDCl3), d (ppm): 6.89 (s, 4H), 4.14 (t,
J ¼ 4.4 Hz, 4H), 3.91 (t, J ¼ 4.4 Hz, 4H), 3.77 (s, 8H); HRMS
(EIþ): C14H20O5, 268.1313 (calculated: 268.1311).
recorded with
England). All the melting points were not corrected.
All UV–Visible spectra were measured on
a GC-TOF mass spectrometry (Micromass,
a
HP-8453
spectrophotometer (HP, America) with 1 ꢀ 10ꢁ5 M solution of
the compounds in 1:1 PhH/MeCN solution and all fluorescence
spectra on a PTI-C-700 Felix fluorescence spectrophotometer
(Hitachi, Japan) using proper solution concentrations in the same
solution.
CVs were performed with a BAS-100W Electrochemical Work
Station (BAS, America) using a three-electrode conventional
electrochemical cell. Measurements were obtained with
1 ꢀ 10ꢁ3 M solution of the compounds in 1:1 PhH/MeCN solution
with 0.05 M TBAPF6. Platinum disk was used as working electrode,
platinum wire served as a counter electrode, a Ag/Agþ electrode
was utilized as a reference electrode, and the scan rate was
100 mV sꢁ1. All potentials were calibrated versus an aqueous SCE
by the addition of ferrocene as an internal standard taking E8(Fc/
Fcþ) ¼ 0.424 V versus SCE.[38]
2,3-(4(,5(-Bis(diethoxyphosphinylmethyl)benzo)-1,4,7,10,
13-pentaoxacyclopentadeca-2-ene (4). A 50 ml flask fitted with
a reflux condenser was charged with benzo-15-crown-5 (1.01 g,
3.7 mmol), paraformaldehyde (0.44 g, 14.8 mmol) and HOAc
(8 ml), HBr in HOAc (5 ml, 40%) was added and the solution
was heated on an oil-bath in a well-ventilated fume cupboard at
50 8C overnight. After cooling the solution, the reaction mixture
was extracted with CH2Cl2 (3 ꢀ 50 ml) and washed with
cold water (3 ꢀ 50 ml), dried over anhydrous Na2SO4, and the
solvent was finally evaporated to afford colorless crystals of 3.
Then, compound 3 was mixed with triethyl phosphite (2.46 g,
14.8 mmol). The viscous solution was stirred at 150 8C overnight.
Evaporation of the excess of triethylphosphite, crude product 4
(dark oil) was obtained. This crude product was used without
further purification in the next synthesis step.
ECL spectra were recorded at room temperature using a setup
consisting of a fluorescence spectrophotometer and a cyclic
voltammograph with a computer interface. Measurements were
obtained with 1 ꢀ 10ꢁ3 M solution of the compounds in 1:1 PhH/
MeCN solution with 0.05 M TBAPF6. In the annihilation reaction,
the platinum electrode was pulsed between the first reduction
and first oxidation potentials with a pulse width of 0.5 s. In the
co-reactant reaction, the platinum electrode was pulsed only on
the oxidation side with a pulse width of 0.5 s.
X-ray crystal diffraction data of compounds C3 were collected
at 273 K with a Bruker Smart APEX CCD diffractometer using
2,3-{4,5-Bis[(4-dimethylamino-phenyl)-vinyl]-benzo}-1,4,7,
10,13-pentaoxacyclopentadeca-2-ene (C1). A suspension of
NaH (185 mg (>52% in mineral oil), 4.0 mmol) was thoroughly
washed with anhydrous hexane and then suspended in
anhydrous THF (8 ml). A solution of 4 (569 mg, 1.0 mmol) in
THF (8 ml) was added under nitrogen to this suspension, followed
˚
graphite monochromated Mo-Ka radiation (l ¼ 0.71073 A). The
structures were solved by direct methods and subsequent
difference Fourier syntheses, and refined by the full-matrix least
squares on (F2) by using the SHELXL-97 program package. The
hydrogen atoms were placed in calculated positions and were
held riding on their parent non-hydrogen atoms during
the subsequent refinement calculations. All non-hydrogen atoms
were refined with anisotropic thermal displacement parameters.
after 10 min by the addition of
a solution of 4-N,N-
dimethylamino-benzaldehyde (300 mg, 2.0 mmol) in the same
solvent (8 ml). The mixture was cautiously heated on an oil-bath
at 50 8C until the evolution of hydrogen had ceased, and then at
reflux for 3 h. The mixture was poured into ice water (100 ml) and
the aqueous phase was extracted with diethyl ether (4 ꢀ 50 ml).
The organic phases were combined, washed with water and dried
over anhydrous Na2SO4, and the solvent was finally evaporated to
afford a dark solid. Further purification was performed by silica
gel chromatography (ethyl acetate/hexane 7:2, v/v) to afford
compound C1 (246 mg, 44%) as pale yellow solid; mp:
166–168 8C; 1H NMR (400 MHz, CDCl3), d (ppm): 7.40 (d, J ¼ 8.8 Hz,
Hz, 4H), 7.23 (d, J ¼ 16.4 Hz, 2H), 7.06 (s, 2H), 6.81 (d, J ¼ 16.0 Hz,
2H), 6.32 (d, J ¼ 8.4 Hz, 4H), 4.22 (t, J ¼ 4.0 Hz, 4H), 3.94 (t, J ¼
4.0 Hz, 4H), 3.78 (s, 8H), 2.98 (s, 12H); 13C NMR (100 MHz, CDCl3),
d (ppm): 150.12, 148.72, 130.05, 129.55, 127.61, 126.56, 122.43,
112.73, 111.81, 71.31, 70.73, 69.84, 69.40, 40.70; HRMS
(EIþ): C34H42N2O5, 558.3086 (calculated: 558.3094).
Synthetic procedures
1,11-Bis(tosyloxy)-triethylene glycol [Ts(OCH2CH2)4OTs] (1). A
solution of tetraethylene glycol (43.3 g, 0.22 mol) and
p-toluenesulfonyl chloride (127.3 g, 0.67 mol) in THF (500 ml)
was placed in a 1 L three-necked round-bottom flask and stirred
with a mechanical stirrer. The flask was cooled with an ice–water
bath, and a solution of KOH (81.9 g, 1.46 mol) in water (170 ml)
was added slowly over a period of 1 h. The ice–water bath was
removed, and the system was stirred for an additional 7 h. The
resulting suspension was poured into a mixture of CH2Cl2
(200 ml) and ice–water (200 ml), and the aqueous layer was
extracted with CH2Cl2. The combined organic solutions were
washed three times with distilled water and dried over anhydrous
MgSO4 overnight. After removal of MgSO4 and solvent, the oil
was purified by silica gel column chromatography (petroleum
ether/ethyl acetate 1:2, v/v) to provide the corresponding
2,3-{4,5-Bis[9-(2,3,6,7-tetrahydro-1H,5H-Pyrido[3,2,1-ij ]q-
uinoline)-vinyl]-benzo}-1,4,7,10,13-pentaoxacyclo-pentadeca-
2-ene (C2). Compound C2 (4.2 g, 52%) were obtained as brown
yellow solid using a similar procedure to C1. mp: 177–179 8C;
1H NMR (400 MHz, CDCl3), d (ppm): 7.12 (d, J ¼ 16.0 Hz, 2H), 7.01 (s,
2H), 6.96 (s, 4H), 6.70 (d, J ¼ 16.0 Hz, 2H), 4.20 (t, J ¼ 4.0 Hz, 4H),
3.92 (t, J ¼ 4.0 Hz, 4H), 3.77 (s, 8H), 3.16 (bs, 8H), 2.77 (bs, 8H), 1.99
(m, 8H); 13C NMR (100 MHz, CDCl3), d (ppm): 148.52, 142.74,
130.29, 129.93, 125.65, 125.48, 121.90, 121.64, 111.97, 71.30,
1
ditosylate compound 1 (103.1 g, 92%) as colorless oil; H NMR
(400 MHz, CDCl3), d (ppm): 7.79 (d, J ¼ 8.4 Hz, 4H), 7.34 (d,
J ¼ 8.0 Hz, 4H), 4.15 (t, J ¼ 4.8 Hz, 4H), 3.68 (t, J ¼ 4.8 Hz, 4H), 3.55
(s, 8H), 2.44 (s, 6H); HRMS (EIþ): C22H30O9S2, 502.1333 (calculated:
502.1331).
J. Phys. Org. Chem. 2009, 22 1–8
Copyright ß 2008 John Wiley & Sons, Ltd.
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X. JIANG ET AL.
70.76, 69.87, 69.43, 50.18, 27.87, 22.23; HRMS (EIþ): C42H50N2O5,
662.3719 (calculated: 662.3720).
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2,3-{4,5-Bis[(4-diphenylamino-phenyl)-vinyl]-benzo}-1,4,7,10,
13-pentaoxacyclopentadeca-2-ene (C3). Compound C3 (4.2 g,
52%) were obtained as yellow solid using a similar procedure to
C1. mp: 109–111 8C; 1H NMR (400 MHz, CDCl3), d (ppm): 7.37
(d, J ¼ 8.4 Hz, 4H), 7.30 (d, J ¼ 16.0 Hz, 2H), 7.27–7.23 (m, 8H),
7.12–7.00 (m, 18H), 6.82 (d, J ¼ 16.0 Hz, 2H), 4.22 (t, J ¼ 3.6 Hz, 4H),
3.94 (t, J ¼ 3.6 Hz, 4H), 3.78 (s, 8H); 13C NMR (100 MHz, CDCl3),
d (ppm): 149.08, 147.70, 147.39, 132.04, 129.80, 129.43, 129.21,
127.43, 124.74, 124.61, 123.80, 123.16, 111.72, 71.26, 70.67, 69.76,
69.30; HRMS (EIþ): C54H50N2O5, 806.3719 (calculated: 806.3720).
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SUPPORTING INFORMATION
This paper contains supplememtary information.
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2007, 72(6), 2187–2191. DOI: 10.1021/jo062506r
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Acknowledgements
Marder, J. W. Perry, J. Am. Chem. Soc. 2004, 126(30), 9291–9306. DOI:
10.1021/ja049013t
Financial supports of this work from the following sources are
gratefully acknowledged: the Programme of Introducing Talents
of Discipline to Universities (Grant 20633020), China Natural
Science Foundation (Grant 20128005), the Ministry of Science
and Technology (MOST) (Grant 2001CCA02500), the Ministry of
Education (MOE), the Swedish Energy Agency, the Swedish
Research Council and K&A Wallenberg Foundation.
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[36] Crystal structure data for C3: C54H50N2O5 ꢄ 0.5(C7H8), Mr ¼ 851.01,
Triclinic, space group: Pꢁ1, a ¼ 13.0034(4), b ¼ 14.4871(5),
˚
c ¼ 15.1303(5) A, a ¼ 113.429 (2)8, b ¼ 103.637 (2)8, g ¼ 91.994(2)8,
3
˚
V ¼ 2515.00(14) A , T ¼ 273(2) K, Z ¼ 2, F(000) ¼ 902, Dc ¼
1.124 g cmꢁ3, R ¼ 0.1014, Rw ¼ 0.2899 GOF ¼ 1.110. CCDC-642414
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from the Director, CCDC,
12 Union Road, Cambridge, CB21EZ, UK (Fax: þ44-1233-336-033;
e-mail: deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
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Copyright ß 2008 John Wiley & Sons, Ltd.
J. Phys. Org. Chem. 2009, 22 1–8