Calix[4]arenes with electroactive tetrathiafulvalene and quinone units: Metal-ion-promoted electron transfer

Article abstract of DOI:10.1021/jo200985y

Metal-ion-promoted electron transfer was observed for compounds 1 and 2 based on the absorption and ESR spectral studies. These results imply that spatially adjacent arrangement of TTF and quinone units in 1 and 2 due to the calix[4]arene platform is favo

Full text of DOI:10.1021/jo200985y

NOTE
pubs.acs.org/joc
Calix[4]arenes with Electroactive Tetrathiafulvalene and Quinone
Units: Metal-Ion-Promoted Electron Transfer
Fei Sun,†,‡ Fang Hu,†,‡ Guanxin Zhang,*,† Qiyu Zheng,† and Deqing Zhang*,†
†Beijing National Laboratory for Molecular Sciences, Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences,
Beijing 100190, China
‡Graduate School of Chinese Academy of Sciences, Beijing 100049, China
S Supporting Information
b
ABSTRACT: Metal-ion-promoted electron transfer was observed
for compounds 1 and 2 based on the absorption and ESR spectral
studies. These results imply that spatially adjacent arrangement of
TTF and quinone units in 1 and 2 due to the calix[4]arene platform
is favorable for the intramolecular electron transfer.
etrathiafulvalene (TTF) and its derivatives as components
of charge-transfer complexes have been intensively investi-
transfer from TTF to quinone units occurs in both compounds
1 and 2 in the presence of certain metal ions.
T
gated for conducting materials.1 Meanwhile, TTF derivatives
have been widely employed as building blocks for switchable
systems.2ꢀ6 All of these versatile applications greatly benefit from
the well-defined electrochemical properties of TTF derivatives,
which can be easily and reversibly transformed into the corre-
sponding radical cations (TTF•+) and dications (TTF2+). TTF
derivatives as electron donors are also incorporated into electron
donor (D)ꢀacceptor (A) dyads for studies of charge-transfer
interactions and photoinduced electron-transfer processes.7 We
have recently reported the metal-ion-promoted electron transfer
within TTFꢀquinone dyads, in which the TTF and quinone
groups were covalently linked by an oligoethylene glycol chain.8
The results manifest that the coordination of a metal ion with the
oxygen atoms of the glycol chain and quinone anion as well as
sulfur atoms of the TTF cation plays an important role in
facilitating the electron transfer. It is assumed that such metal
ion coordination induces the conformation transformation
from the extended one to the folded one in which the TTF
and quinone units are adjacent in space.
The synthetic approaches of compounds 1 and 2 are shown in
Scheme 1 and Scheme 2, respectively. The synthesis of com-
pound 1 started from p-tert-butylcalix[4]arene 3, which was
transformed into compound 5 after reaction with compound 4
in 70% yield. Reaction of 1,3-dibromopropane with compound 5
led to compound 6 in 51% yield. After removal of tetrahydropyr-
an (THP) groups with concentrated HCl solution, compound 7
was obtained in 90% yield. Compound 7 was allowed to react
with compound 8, leading to compound 9 in 83% yield, which
was further reacted with tetrachloro-1,4-benzoquinone in the
presence of NaH to reach compound 1 in 35% yield. Two
doublets at 4.33 and 3.18 ppm were detected for the protons of
1
bridging ꢀCH2 groups in the H NMR spectrum of 1 (see
Supporting Information, page S2). In the 13C NMR spectrum of
1, the signals for bridging ꢀCH2 groups appeared around
31 ppm (see Supporting Information, page S2). These NMR
data indicate that compound 1 adopts the cone conformation
according to previous studies,14 and accordingly, the TTF and
quninone units in 1 are spatially adjacent.
Calixarenes are widely used in supramolecular chemistry as
receptors for neutral molecules, cations, anions, and even ion
pairs.9ꢀ11 They can be readily modified at the phenolic hydroxy
groups (lower rim) as well as at the para positions (upper rim).12
In fact, calixarenes have been employed as versatile molecular
scaffolds to control the spatial arrangements of functional
groups.13 In this Note, we describe two p-tert-butylcalix[4]arenes
1 and 2 (Schemes 1 and 2) containing TTF and quinone units in
the lower rim. It is expected that the calix[4]arene framework
enables TTF and quinone groups to be close in space. Both
absorption and ESR spectral studies indicate that electron
For the synthesis of compound 2, after reaction with
p-toluenesulfonyl chloride in the presence of triethylamine,
compound 10 (see Experimental Section) was transformed into
compound 11 in 34% yield. Reaction of compound 11 and
compound 8 led to compound 12 in 70% yield, which was further
reacted with tetrachloro-1,4-benzoquinone in the presence of
NaH to afford compound 2 in 51% yield. Multiple broad H
NMR signals were observed for protons of bridging ꢀCH2
1
Received: May 20, 2011
Published: July 20, 2011
r
2011 American Chemical Society
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|

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Scheme 1. Chemical Structure and Synthetic Approach for
Compound 1
Figure 1. Absorptionspectra ofcompound 1 (3.0 ꢁ 10ꢀ5 M in CH2Cl2)
in the presence of different amounts of Sc3+ [Sc(SO3CF3)3]; inset shows
the variation of absorbance at 850 nm upon addition of 0ꢀ2.5 equiv
of Sc3+.
compound 1, new absorption bands around 450 and 850 nm
emerged; their absorption intensities increased with the amounts
of Sc3+ added to the solution, reaching the maxima after addition
of approximately 2.0 equiv of Sc3+, as shown in the inset of
Figure 1. According to previous studies,8 these new absorption
bands are due to the generation of the radical cation TTF•+.
Indeed, direct oxidation of compound 1 with Fe3+ [Fe(ClO4)3]
also led to new absorption bands around 450 and 850 nm, as
shown in Figure S1. Therefore, it can be concluded that intra-
molecular electron transfer occurs between TTF and quinone
units of compound 1 in the presence of Sc3+, being in line with
previous results reported by us recently.8 The fact that the
absorption intensity at 850 nm for the solution of 1 (3.0 ꢁ
10ꢀ5 M) after addition of more than 2.0 equiv of Sc3+ is almost
equal to that by direct oxidation with 2.0 equiv of Fe3+ (see
Figure S1) implies that both TTF units in 1 can be oxidized into
the TTF•+ species in the presence of enough Sc3+. Notably,
further addition of 2,20-bipyridine to the solution of 1 and Sc3+
led to gradual decrease for the absorptions at 450 and 850 nm
(see Figure S4). This is probably due to the release of Sc3+ from 1
because of the strong binding of Sc3+ with 2,20-bipyridine, and as
a result, back electron transfer takes place, regenerating the
neutral TTF and quinone units in 1. Interestingly, the absorp-
tions at 450 and 850 nm due to TTF•+ re-emerged after more
Sc3+ was introduced (see Figure S4).
Scheme 2. Chemical Structure and Synthetic Approach for
Compound 2
It should be noted that the absorptions around 450 and
850 nm due to respective TTF•+ could be neglected for the
mixture of compound 8 and tetrachloro-p-benzoquinone after
addition of Sc3+ under similar conditions (see Figure S5). In fact,
the absorptions around 450 and 850 nm did not emerge for the
TTFꢀquinone dyad in which the TTF and quinone units were
linked by a ꢀCH2CH2ꢀ group after addition of metal ions.8a
It was anticipated that such successive oxidation of TTF units
groups at room temperature (see Supporting Information, page S3).
The H NMR signals due to protons of bridging ꢀCH2 groups
1
became sharp at low temperatures, but they were still multiple
(see Supporting Information, page S4). These 1H NMR data indicate
that compound 2 possesses different conformers in solution.
Figure 1 shows the absorption spectrum of compound 1
and those in the presence of increasing amounts of Sc3+
[Sc(SO3CF3)3].15 Compound 1 shows the absorption bands
around 230, 296, and 336 nm, which are due to calixarene,
neutral quinone, and TTF moieties based on previous studies.8a,9
Moreover, the redox potentials of compound 1 were determined
to be E1/2(ox1) = 0.48 V, E1/2(ox2) = 0.89 V, and E1/2(red1) =
0.07 V, being close to those of compound 8 and similarly sub-
stituted quinone.8a These results clearly indicate that the inter-
action between TTF and quinone units in 1 can be considered
negligible. However, after introducing Sc3+ to the solution of
•+
may induce the formation of mixed-valence complex [(TTF)]2
and radical cation dimer (TTF•+)2.16 However, typical absorp-
•+
tions of both [(TTF)]2 and (TTF•+)2 in the near-infrared
region were not detected for compound 1 upon gradual addition
of Sc3+ (see Figure S6). In addition, cyclic voltammograms
of compound 1 in the presence of increasing amounts of Sc3+
at different scan rates were measured. Only two oxidation waves
corresponding to the oxidation of TTF into TTF•+ and TTF2+
were detected, and no intermediate oxidation peaks were ob-
served (see Figure S7). Such electrochemical studies also indicate
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Figure 2. ESR spectrum of compound 1 in CH2Cl2 (1.0 ꢁ 10ꢀ4 M) in
the presence of 2.0 equiv of Sc3+ [Sc(SO3CF3)3] recorded at room
temperature; the solution was degassed before measurement.
Figure 3. Absorptionspectra ofcompound 2 (5.0 ꢁ 10ꢀ5 M in CH2Cl2)
in the presence of different amounts of Sc3+ [Sc(SO3CF3)3]; inset shows
the variation of absorbance at 850 nm upon addition of 0ꢀ1.6 equiv
of Sc3+.
that neither [(TTF)]2•+ nor (TTF•+)2 is formed for compound 1
in the presence of Sc3+. This observation is likely due to the fact
that the two TTF units in the lower rim of 1 are well separated,
and accordingly, the formation of both [(TTF)]2•+ and (TTF•+)2
is not favorable.
Both compound 1 and Sc3+ are ESR silent. However, the
mixture solution of compound 1 and Sc3+ exhibited strong
doublet ESR signals, as depicted in Figure 2. The signals are
likely attributed to the radical cation (TTF•+) of the TTF moiety
of compound 1, and the doublet signal stems from the splitting
of one H atom of the TTF unit (g = 2.00945, RH = 1.17 G). Thus,
the formation of TTF•+ in the presence of Sc3+ is also confirmed
by ESR spectroscopy. Nevertheless, the corresponding radical
anion of the quinone unit, which should be generated through
the intramolecular electron transfer from the TTF moiety to the
quinone unit after introduction of Sc3+, was not detected with
ESR spectroscopy. It is probably due to the facile disproportio-
nation of the radical anion of quinone (Q•ꢀ) into the corre-
sponding neutral (Q) and dianion (Q2ꢀ) species in the presence
of metal ions according to previous studies.8a,17
Figure 4. ESR spectrum of compound 2 (1.0 ꢁ 10ꢀ4 M in CH2Cl2) in
the presence of 1.0 equiv of Sc3+ [Sc(SO3CF3)3] recorded at room
temperature; the solution was degassed before measurement.
concentration of Sc3+ in the solution, as depicted in the inset
of Figure 3. Furthermore, the absorption intensity at 850 nm of 2
(5.0 ꢁ 10ꢀ5 M) in the presence of 1.6 equiv of Sc3+ is comparable
to that of 1 (3.0 ꢁ 10ꢀ5 M) in the presence of 2.5 equiv of Sc3+.19
As detailed above, those two absorption bands are ascribed to the
formation of TTF•+ in the solution. Strong doublet ESR signal
due to TTF•+ was also detected for the mixture solution of
compound 2 and Sc3+, as depicted in Figure 4 (g = 2.00784,
RH = 1.12 G). These spectral results indicate that intramole-
cular electron transfer occurs between TTF and quinone units
within compound 2 in the presence of Sc3+ as discussed for
compound 1.
Apart from Sc3+, both absorption and ESR spectral studies
indicate that other metal ions including Pb2+ [Pb(ClO4)2] and
Zn2+ [Zn(ClO4)2] can also trigger the intramolecular electron
transfer between TTF and quinone units within compound 1
(see Figures S2 and S3 in Supporting Information). Only absorp-
tions around 450 and 850 nm were observed, and characteristic
absorptions for [(TTF)]2•+ and (TTF•+)2 were not detected in
all cases for compound 1 after addition of metal ions.
The mechanism for the metal-ion-promoted intramolecular
electron transfer within 1 can be understood as follows: it is
known that the electron-accepting capacities of quinones are
enhanced in the presence of certain metal ions.8,17 The TTF and
quinone units in compound 1 are spatially adjacent because of
the cone conformation of calix[4]arene, and such conformation
is beneficial for intramolecular electron transfer from TTF to the
quinone unit. Moreover, the coordination of metal ions, which
may involve oxygen atoms from quinone units and those of
alkoxyl groups in the lower rim of calix[4]arene as well as sulfur
atoms from TTF units, may further contribute to the intramo-
lecular electron transfer in compound 1.18
The absorption and ESR spectra of compound 2 were also
measured upon addition of other metal ions. Metal ions includ-
ing Pb2+ and Zn2+ can also facilitate the intramolecular electron
transfer within compound 2. New absorption bands around 450
and 850 nm were also observed for compound 2 in the presence
of these metal ions (see Figures S11ꢀS13). Moreover, absorp-
tion intensities at 850 nm were found to be higher with Sc3+ or
Pb2+ than with Zn2+ and Cd2+ under the same conditions. Thus,
Sc3+ and Pb2+ can promote the intramolecular electron transfer
within 2 more efficiently. ESR signals due to the radical cation of
the TTF moiety in compound 2 were detected after addition
of metal ions including Pb2+, Zn2+, and Cd2+, as depicted in
Figures S11ꢀS13, respectively.
Metal-ion-promoted electron transfer was also observed for
compound 2 after addition of certain metal ions. Figure 3 shows
the absorption spectra of compound 2 after addition of increas-
ing amounts of Sc3+. New absorption bands around 450 and
850 nm appeared for compound 2 upon addition of Sc3+. The
absorption intensity at 850 nm increased by increasing the
As mentioned above, different conformers of 2 exist in solution
1
based on the H NMR data, but this is probably due to the
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inversion of two methoxyl groups.20 The TTF and quinone units
of 2 may still be spatially adjacent, and accordingly, intramolecular
electron transfer can take place within 2 in the presence of certain
metal ions.
Synthesis of Compound 7. In a 50 mL round-bottom flask, 6
(0.4 g, 0.34 mmol) was dissolved in 20 mL of the mixture of CH2Cl2 and
CH3OH (v/v, 1/1). Then, 0.1 mL of the concentrated HCl was added to
the above solution. The mixture was stirred at room temperature for
2.0 h. After that, 15 mL of 2.0 M NaOH was added and extracted with
CH2Cl2. The organic layer was washed with brine and water, and it was
further dried over anhydrous MgSO4, filtered, and evaporated. The
residue was subjected to column chromatography with CH2Cl2/ethyl
acetate (v/v, 10/1) as eluent. Compound 7 was obtained as a white
powder (0.31 g) in 90% yield: mp 107 °C; 1H NMR (400 MHz, CDCl3)
δ 6.89 (4H, s), 6.70 (4H, s), 4.36 (4H, d, J = 12.5 Hz), 4.05 (4H, t, J = 7.2
Hz), 3.97 (4H, t, J = 6.7 Hz), 3.92 (4H, t, J = 6.3 Hz), 3.69 (4H, t, J = 6.6
Hz), 3.18 (4H, d, J = 12.6 Hz), 2.50 (4H, m), 2.25 (4H, m), 1.16 (18H,
s), 1.01 (18H, s); 13C NMR (100 MHz, CDCl3) δ 153.7, 152.7, 144.9,
134.2, 133.2, 125.4, 125.2, 73.5, 72.4, 60.4, 34.1, 33.9, 33.2, 31.7, 31.5,
31.1, 31.0; MS (MALDI-TOF) m/z 1029.4 [M + Na+]. Anal. Calcd for
C56H78Br2O6: C, 66.79; H, 7.81; Br, 15.87. Found: C, 67.06; H, 7.98;
Br, 15.60.
In summary, two calix[4]arenes 1 and 2 with TTF and quinone
units were synthesized and characterized. Both absorption
and ESR spectral studies indicate that TTF units in 1 and 2 can
be successively oxidized upon addition of metal ions (e.g.,
Sc3+, Pb2+). Thus, intramolecular electron transfer occurs among
the TTF and quinone units in 1 and 2 in the presence of metal ions
as reported for TTFꢀquinone dyads linked with glycol chains.8
These results have the following implications: (1) the adjacent
arrangement of TTF and quinoneunits inspace isfavorablefor the
metal-ion-promoted intramolecular electron transfer. This is con-
sistent with the mechanism proposed for the metal-ion-promoted
electron transfer within TTFꢀquinone dyads.8 (2) The metal-
ion-promoted electron transfer may be universal for compounds
with TTF and quinone units which can be spatially close.
Synthesis of Compound 9. To a degassed solution (10 mL) of 8
(0.23 g, 0.6 mmol) in THF was added a degassed solution (5.0 mL) of
CsOH H2O (0.15 g, 0.9 mmol) in CH3OH over a period of 5.0 min
3
’ EXPERIMENTAL SECTION
under nitrogen atmosphere. The mixture was stirred for an additional
30 min, followed by the addition of a degassed solution (8.0 mL) of 7
(0.22 g, 0.22 mmol) in THF. The reaction mixture was stirred overnight
at room temperature. Then, the solvents were evaporated under reduced
pressure, and the residue was subjected to column chromatography with
CH2Cl2 as eluent. Compound 9 was obtained as an orange powder
(0.28 g) in 83% yield: Mmp 131 °C; 1H NMR (400 MHz, CDCl3) δ
6.96 (4H, s), 6.63 (4H, s), 4.33 (4H, d, J = 12.4 Hz), 4.05 (4H, t, J = 7.1
Hz), 3.90 (8H, m), 3.28 (8H, s), 3.16 (4H, d, J = 12.5 Hz), 2.95 (4H, t,
J = 7.0 Hz), 2.23 (8H, m), 1.21 (18H, s), 0.95 (18H, s); 13C NMR
(100 MHz, CDCl3) δ 154.0, 152.4, 144.9, 144.7, 134.6, 132.9, 125.5,
125.1, 73.6, 72.5, 60.5, 34.1, 33.9, 33.2, 31.7, 31.4, 31.1, 30.4, 29.7; MS
(MALDI-TOF) m/z 1496.0 [M]. Anal. Calcd for C72H88O6S14: C,
57.71; H, 5.92; S, 29.96. Found: C, 57.86; H, 6.05; S, 29.68.
Synthesis of Compound 1. An anhydrous solution (25 mL) of 9
(0.18 g, 0.12 mmol) in THF was cooled to 0 °C with an ice bath. After
5.0 min, NaH (58 mg, 2.4 mmol) was added to the solution in one
portion under nitrogen atmosphere. The mixture was stirred for 30 min,
followed by the addition of p-chloranil (0.30 g, 1.2 mmol). The reaction
mixture was stirred overnight. Then, the solvents were evaporated under
reduced pressure, and the residue was subjected to column chromatog-
raphy with CH2Cl2/petroleum ether (60ꢀ90 °C) (v/v, 2/1) as eluent.
Compound 1 was obtained as a brown powder (80 mg) in 35% yield: mp
110 °C; 1H NMR (400 MHz, CDCl3) δ 6.91 (4H, s), 6.68 (4H, s), 4.63
(4H, t, J = 6.0 Hz), 4.33 (4H, d, J = 12.5 Hz), 4.14 (4H, t, J = 7.3 Hz), 3.93
(4H, t, J = 7.1 Hz), 3.26 (8H, s), 3.18 (4H, d, J = 12.6 Hz), 2.98 (4H, t,
J = 7.0 Hz), 2.54 (4H, m), 2.30 (4H, m), 1.17 (18H, s), 0.99 (18H, s);
13C NMR (100 MHz, CDCl3) δ 172.7, 171.8, 154.6, 153.5, 152.7, 145.2,
144.9, 140.6, 138.9, 134.3, 133.0, 126.2, 125.5, 125.2, 122.9, 73.6, 73.4,
71.5, 34.1, 33.9, 31.7, 31.4, 31.2, 30.2, 30.0, 29.8; HR-MS (ESI) calcd for
C84H86Cl6O10S14 (m/z) 1912.04366, found 1912.04066.
General Information. 1H NMR, 13C NMR, MS (including HRMS),
elemental analysis, UVꢀvis absorption, and ESR spectra were measured
with conventional spectrometers. All solvents were purified and dried by
following standard procedures unless otherwise stated. Compounds 3, 4, 8,
and 10 were prepared according to reported procedures.21
Synthesis of Compound 5. A suspension of 3 (5.85 g, 9.0 mmol),
4 (4.0 g, 18 mmol), and anhydrous K2CO3 (15.8 g, 115 mmol) in
CH3CN (50 mL) was heated to reflux for 24 h under nitrogen atmo-
sphere. After being cooled to room temperature, the mixture was poured
into water (100 mL) and extracted with CH2Cl2. The organic layer was
dried over anhydrous MgSO4, filtered, and evaporated under reduced
pressure. The residue was subjected to column chromatography with
CH2Cl2/ethyl acetate (v/v, 20/1) as eluent. Compound 5 was obtained
as a white powder (5.88 g) in 70% yield: mp 59 °C; 1H NMR (400 MHz,
CDCl3) δ 7.79 (1H, s), 7.75 (1H, d, J = 4.0 Hz), 7.05 (4H, m), 6.86 (4H,
m), 4.73 (2H, m), 4.38ꢀ3.85 (14H, m), 3.53 (2H, m), 3.32 (4H, dd, J =
22.0 Hz, 12.7 Hz), 2.30 (4H, m), 1.83 (2H, m), 1.72 (2H, m), 1.61ꢀ1.45
(8H, m), 1.29 (18H, s), 1.02 (18H, s); 13C NMR (100 MHz, CDCl3) δ
150.9, 150.0, 149.9, 146.9, 141.4, 133.2, 132.9, 132.8, 128.1, 127.9, 127.8,
127.6, 125.8, 125.6, 125.5, 125.3, 125.2, 99.2, 73.4, 73.3, 64.1, 64.0, 62.5,
34.1, 33.9, 32.2, 32.0, 31.8, 31.6, 31.2, 30.9, 30.5 25.7, 19.8; MS (MALDI-
TOF) m/z 955.5 [M + Na+]. Anal. Calcd for C60H84O8: C, 77.21; H,
9.07. Found: C, 77.23; H, 9.15.
Synthesis of Compound 6. A suspension of 5 (0.93 g, 1.0 mmol)
and NaH (0.12 g, 5.0 mmol) in DMF (70 mL) was stirred for 1.0 h under
nitrogen atmosphere. Then 1,3-dibromopropane (2.0 mL, 20 mmol)
was added. The mixture was heated to 75 °C and stirred for 12 h. After
being cooled to room temperature, the solvents were removed under
reduced pressure. The residue was taken up in CH2Cl2, and the organic
phase was washed with 3 M HCl, brine, and water. The organic layer was
dried over anhydrous MgSO4, filtered, and evaporated. The residue was
subjected to column chromatography with CH2Cl2/petroleum ether
(60ꢀ90 °C) (v/v, 2/3) as eluent. Compound 6 was obtained as a white
powder (0.6 g) in 51% yield: mp 47 °C; 1H NMR (400 MHz, CDCl3) δ
6.93 (4H, s), 6.64 (4H, s), 4.60 (2H, s), 4.35 (4H, d, J = 12.5 Hz), 4.06
(4H, t, J = 6.9 Hz), 3.93 (6H, m), 3.85 (2H, m), 3.67 (4H, t, J = 6.4 Hz),
3.59 (2H, m), 3.50 (2H, m), 3.16 (4H, d, J = 12.6 Hz), 2.59 (4H, m),
2.26 (4H, m), 1.83 (2H, m), 1.71 (2H, m), 1.56 (8H, m), 1.19 (18H, s),
0.97 (18H, s); 13C NMR (100 MHz, CDCl3) δ 153.6, 153.0, 145.1,
144.5, 134.6, 133.0, 125.5, 125.0, 99.1, 73.2, 73.1, 65.0, 62.4, 34.1, 33.9,
33.3, 31.7, 31.4, 31.2, 31.0, 30.9, 30.8, 29.8, 25.6, 19.8; MS (MALDI-
TOF) m/z 1195.5 [M + Na+].
Synthesis of Compound 11. A solution (50 mL) of 10 (3.06 g,
4.0 mmol), triethylamine (2.1 mL, 15 mmol), and catalytic amount of
DMAP in CH2Cl2 was cooled to 0 °C with an ice bath. Then, a solution
(30 mL) of p-toluenesulfonyl chloride (1.14 g, 6 mmol) in CH2Cl2 was
added dropwise to the mixture over a period of 2.0 h under nitrogen
atmosphere. The reaction mixture was stirred overnight at room
temperature. After the reaction was complete, 3 M HCl (50 mL) was
added and the mixture was stirred for additional 30 min. The organic
layer was washed with brine and water and dried over anhydrous
MgSO4. After filtration, the solvents were evaporated under reduced
pressure. The residue was subjected to column chromatography
with CH2Cl2 as eluent. Compound 11 was obtained as a white powder
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NOTE
(1.22 g) in 34% yield: mp 97 °C; 1H NMR (400 MHz, CDCl3) δ 7.82
(2H, d, J = 8.0 Hz), 7.33 (2H, d, J = 7.9 Hz), 7.11ꢀ6.58 (8H, m), 4.57
(1H, s), 4.35ꢀ2.94 (22H, m), 2.45 (3H, s), 1.29ꢀ0.83 (36H, m); 13C
NMR (100 MHz, CDCl3) δ 156.0, 154.0, 153.6, 153.2, 152.8, 146.3,
145.6, 145.1, 144.8, 135.2, 134.8, 133.5, 133.3, 132.5, 129.9, 128.2, 125.6,
125.0, 76.2, 70.1, 68.5, 62.4, 58.9, 38.9, 37.6, 34.2, 34.1, 33.8, 31.7, 31.3,
31.0, 30.8, 21.8; MS (MALDI-TOF) m/z 941.7 [M + Na+]. Anal. Calcd
for C57H74O8S: C, 74.47; H, 8.11; S, 3.49. Found: C, 74.32; H,
8.39; S, 3.32.
’ REFERENCES
(1) (a) Yamada, J., Sugimoto, T., Eds. TTF Chemistry. Fundamentals
and Applications of Tetrathiafulvalene; Springer Verlag: Heidelberg,
2004. (b) Bryce, M. R. Adv. Mater. 1999, 11, 11–23. (c) Shibaeva,
R. P.; Yagubskii, E. B. Chem. Rev. 2004, 104, 5347–5378.
(2) (a) Collier, C. P.; Mattersteig, G.; Wong, E. W.; Luo, Y.; Beverly,
K.; Sampaio, J.; Raymo, F. M.; Stoddart, J. F.; Heath, J. R. Science 2000,
289, 1172–1175. (b) Klajn, R.; Stoddart, J. F.; Grzybowski, B. A. Chem.
Soc. Rev. 2010, 39, 2203–2237. (c) Wang, C.; Olson, M. A.; Fang, L.;
Benítez, D.; Tkatchouk, E.; Basu, S.; Basuray, A. N.; Zhang, D.; Zhu, D.;
Goddard, W. A.; Stoddart, J. F. Proc. Natl. Acad. Sci. U.S.A. 2010,
107, 13991–13996.
(3) (a) Canevet, D.; Sallꢀe, M.; Zhang, G.; Zhang, D.; Zhu, D. Chem.
Commun. 2009, 2245–2269. (b) Wang, C.; Chen, Q.; Sun, F.; Zhang, D.;
Zhang, G.; Huang, Y.; Zhao, R.; Zhu, D. J. Am. Chem. Soc. 2010,
132, 3092–3096. (c) Feng, Y.; Zhang, Q.; Tan, W.; Zhang, D.; Tu, Y.;
Agren, H.; Tian, H. Chem. Phys. Lett. 2008, 455, 256–260.
(4) (a) Lyskawa, J.; Le Derf, F.; Levillain, E.; Mazari, M.; Sallꢀe, M.;
Dubois, L.; Viel, P.; Bureau, C.; Palacin, S. J. Am. Chem. Soc. 2004,
126, 12194–12195. (b) Zhao, B.-T.; Blesa, M.-J.; Mercier, N.; Le Derf,
F.; Sallꢀe, M. J. Org. Chem. 2005, 70, 6254–6257. (c) Liao, J.; Agustsson,
J. S.; Wu, S.; Sch€onenberger, C.; Calame, M.; Leroux, Y.; Mayor, M.;
Jeannin, O.; Ran, Y.-F.; Liu, S.-X.; Decurtins, S. Nano Lett. 2010,
10, 759–764.
Synthesis of Compound 12. To a degassed solution (20 mL) of
8 (0.4 g, 1.06 mmol) in THF was added a degassed solution (8.0 mL) of
CsOH H2O (0.2 g, 1.2 mmol) in CH3OH over a period of 5.0 min
3
under nitrogen atmosphere. The mixture was stirred for an additional
30 min, and then a degassed solution (10 mL) of 11 (0.75 g, 0.8 mmol)
in THF was added in one time. The reaction mixture was stirred
overnight at room temperature. Then, the solvents were evaporated
under reduced pressure, and the residue was subjected to column
chromatography with CH2Cl2 as eluent. Compound 12 was obtained
1
as an orange powder (0.60 g) in 70% yield: mp 139 °C; H NMR
(400 MHz, CDCl3) δ 7.19ꢀ6.57 (8H, m), 6.30ꢀ6.25 (1H, m),
4.44ꢀ2.95 (26H, m), 1.34ꢀ0.87 (36H, m); 13C NMR (100 MHz,
CDCl3) δ 156.0, 154.0, 153.7, 153.3, 152.8, 146.2, 145.7, 145.1, 135.3,
135.0, 133.2, 132.4, 126.9, 126.5, 126.1, 125.6, 125.0, 114.1, 71.9, 62.9,
62.6, 61.8, 59.0, 39.2, 37.8, 34.2, 33.8, 31.7, 31.3, 30.8, 30.3; MS
(MALDI-TOF) m/z 1072.4. Anal. Calcd for C58H72O5S7: C, 64.88;
H, 6.76; S, 20.91. Found: C, 64.94; H, 6.90; S, 20.65.
(5) Bigot, J.; Charleux, B.; Cooke, G.; Delattre, F.; Fournier, D.;
Lyskawa, J.; Sambe, L.; Stoffelbach, F.; Woisel, P. J. Am. Chem. Soc. 2010,
132, 10796–10801.
Synthesis of Compound 2. An anhydrous solution (30 mL) of 12
(0.28 g, 0.26 mmol) in THF was cooled to 0 °C with an ice bath. Then,
NaH (0.1 g, 4.2 mmol) was added to the solution in one portion under
nitrogen atmosphere. The mixture was stirred for 30 min, followed by the
addition of p-chloranil (0.13 g, 0.52 mmol). The reaction mixture was
stirred overnight. Then, the solvents were evaporated under reduced
pressure, and the residue was subjected to column chromatography with
CH2Cl2/petroleum ether (60ꢀ90 °C) (v/v, 1/3) as eluent. Compound
2 was obtained as a brown powder (0.17 g) in 51% yield: mp 123 °C; 1H
NMR (400 MHz, CDCl3) δ 7.34ꢀ7.17 (1H, m), 7.15ꢀ6.83 (4H, m),
6.82ꢀ6.40 (3H, m), 5.00ꢀ4.52 (2H, m), 4.50ꢀ4.10 (4H, m), 4.08ꢀ3.90
(4H, m), 3.88ꢀ3.50 (4H, m), 3.45ꢀ3.25 (6H, m), 3.25ꢀ3.08 (4H, m),
3.05ꢀ2.90 (2H, m), 1.50ꢀ1.36 (5H, m), 1.35ꢀ1.20 (14H, s), 1.20ꢀ1.03
(10H, s), 0.98ꢀ0.82 (7H, s); 13C NMR (100 MHz, CDCl3) δ 172.7,
171.7, 167.8, 155.9, 155.4, 154.3, 153.4, 152.8, 145.3, 144.9, 144.8, 143.7,
140.5, 138.7, 135.2, 133.4, 133.1, 132.6, 131.9, 131.9, 131.0, 128.9, 127.4,
126.2, 125.3, 124.7, 122.8, 74.2, 65.7, 61.0, 60.4, 58.1, 38.0, 34.2, 33.8,
31.7, 31.4, 30.7, 30.2, 29.8; MS (MALDI-TOF) m/z 1282.6; HR-MS
(ESI) calcd for C64H71Cl3O7S7 (m/z) 1280.23048, found 1280.22929.
(6) (a) Pꢀerez, E. M.; Sierra, M.; Sꢀanchez, L.; Torres, M. R.; Viruela,
R.; Viruela, P. M.; Ortí, E.; Martín, N. Angew. Chem., Int. Ed. 2007,
46, 1847–1851. (b) Segura, J. L.; Martín, N. Angew. Chem., Int. Ed. 2001,
40, 1372–1409.
(7) (a) Park, J. S.; Karnas, E.; Ohkubo, K.; Chen, P.; Kadish, K. M.;
Fukuzumi, S.; Bielawski, C. W.; Hudnall, T. W.; Lynch, V. M.; Sessler,
J. L. Science 2010, 329, 1324–1327. (b) Jia, H.-P.; Liu, S.-X.; Sanguinet,
L.; Levillain, E.; Decurtins, S. J. Org. Chem. 2009, 74, 5727–5729.
(c) Leroy-Lhez, S.; Baffreau, J.; Perrin, L.; Levillain, E.; Allain, M.
Blesa, M.-J.; Hudhomme, P. J. Org. Chem. 2005, 70, 6313–6320.
(d) Tsiperman, E.; Becker, J. Y.; Khodorkovsky, V.; Shames, A.; Shapiro,
L. Angew. Chem., Int. Ed. 2005, 44, 4015–4018. (e) Farren, C.;
Christensen, C. A.; FitzGerald, S.; Bryce, M. R.; Beeby, A. J. Org. Chem.
2002, 67, 9130–9139.
(8) (a) Wu, H.; Zhang, D.; Su, L.; Ohkubo, K.; Zhang, C.; Yin, S.;
Mao, L.; Shuai, Z.; Fukuzumi, S.; Zhu, D. J. Am. Chem. Soc. 2007,
129, 6839–6846. (b) Wu, H.; Zhang, D.; Zhang, G.; Zhu, D. J. Org.
Chem. 2008, 73, 4271–4274. (c) Zeng, Y.; Zhang, G.; Zhang, D.; Zhu, D.
J. Org. Chem. 2009, 74, 4375–4378. (d) Jia, L.; Zhang, G.; Zhang, D.;
Xiang, J.; Xu, W.; Zhu, D. Chem. Commun. 2011, 47, 322–324.
(9) (a) Ghidini, E.; Ugozzoli, F.; Ungaro, R.; Harkema, S.; Abu
El-Fadl, A.; Reinhoudt, D. N. J. Am. Chem. Soc. 1990, 112, 6979–6985.
(b) Blesa, M.-J.; Zhao, B.-T.; Allain, M.; Le Derf, F.; Sallꢀe, M. Chem.—
Eur. J. 2006, 12, 1906–1914. (c) Ogata, M.; Fujimoto, K.; Shinkai, S.
J. Am. Chem. Soc. 1994, 116, 4505–4506. (d) Webber, P. R. A.; Cowley,
A.; Drew, M. G. B.; Beer, P. D. Chem.—Eur. J. 2003, 9, 2439–2446.
(10) Schmidtchen, F. P.; Berger, M. Chem. Rev. 1997, 97, 1609–1646.
(11) (a) Ikeda, A.; Shinkai, S. Chem. Rev. 1997, 97, 1713–1734.
(b) Scheerder, J.; van Duynhoven, J. P. M.; Engbersen, J. F. J.;
Reinhoudt, D. N. Angew. Chem., Int. Ed. Engl. 1996, 35, 1090–1093.
(12) (a) Cao, Y.-D.; Luo, J.; Zheng, Q.-Y.; Chen, C.-F.; Wang, M.-X.;
Huang, Z.-T. J. Org. Chem. 2004, 69, 206–208. (b) Miao, R.; Zheng,
Q.-Y.; Chen, C.-F.; Huang, Z.-T. J. Org. Chem. 2005, 70, 7662–7671.
(13) Kim, J. S.; Quang, D. T. Chem. Rev. 2007, 107, 3780–3799.
(14) (a) Jaime, C.; De Mendoza, J.; Prados, P.; Nieto, P. M.;
Sanchez, C. J. Org. Chem. 1991, 56, 3372–3376. (b) Iwamoto, K.; Araki,
K.; Shinkai, S. J. Org. Chem. 1991, 56, 4955–4962.
’ ASSOCIATED CONTENT
Supporting Information. 1H NMR and 13C NMR spec-
S
b
tra of compounds 1, 2, 5, 6, 7, 9, 11, and 12; absorption, ESR
spectra, cyclic voltammograms, and 1H NMR spectra of 1, 2, 9,
and 12 in the presence of metal ions. This material is available
free of charge via the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Authors
*E-mail: dqzhang@iccas.ac.cn and gxzhang@iccas.ac.cn.
’ ACKNOWLEDGMENT
The present research was financially supported by NSFC,
TRR61, Chinese Academy of Sciences, and State Key Basic
Research Program. The authors also thank the anonymous
reviewers for their critical comments and suggestions.
(15) Previous studies (see ref 8) indicate that Sc3+ can induce the
positive shift of the reduction potentials of quinones and trigger the
intramolecular electron transfer within TTFꢀquinone dyads. For this
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The Journal of Organic Chemistry
NOTE
reason, Sc3+ was selected for the current investigations of compounds
1 and 2.
(16) (a) Lyskawa, J.; Salle, M.; Balandier, J.-Y.; Le Derf, F.; Levillain,
E.; Allain, M.; Viel, P.; Palacin, S. Chem. Commun. 2006, 2233–2235.
(b) Spanggaard, H.; Prehn, J.; Nielsen, M. B.; Levillain, E.; Allain, M.;
Becher, J. J. Am. Chem. Soc. 2000, 122, 9486–9494. (c) Rosokha, S. V.;
Kochi, J. K. J. Am. Chem. Soc. 2007, 129, 828–838. (d) Spruell, J. M.;
Coskun, A.; Friedman, D. C.; Forgan, R. S.; Sarjeant, A. A.; Trabolsi, A.;
Fahrenbach, A. C.; Barin, G.; Paxton, W. F.; Dey, S. K.; Olson, M. A.;
Benítez, D.; Tkatchouk, E.; Colvin, M. T.; Carmielli, R.; Caldwell, S. T.;
Rosair, G. M.; Hewage, S. G.; Duclairoir, F.; Seymour, J. L.; Slawin,
A. M. Z.; Goddard, W. A.; Wasielewski, M. R.; Cooke, G.; Stoddart, J. F.
Nat. Chem. 2010, 2, 870–879.
(17) Fukuzumi, S.; Ohkubo, K. Coordin. Chem. Rev. 2010, 254,
372–385 and further references therein.
(18) In order to understand the coordination mode of Sc3+ with 1,
1H NMR spectra of 9 and 1 were recorded in the presence of different
amounts of Sc3+ as shown in Figures S8 and S9 (Supporting In-
formation), respectively. The 1H NMR signals, especially those due to
ꢀCH2CH2CH2ꢀ and TTF moieties in the region of 4.10ꢀ2.10 ppm for
compound 9, kept almost unaltered after addition of Sc3+. This result
suggests that the binding of Sc3+ with oxygen atoms of alkoxyl groups in
the lower rim of calix[4]arene and sulfur atoms of TTF moieties in 9
should be rather weak. The coordination of Sc3+ with the radical anion of
quinone was reported previously (see refs 8 and 17). However, the 1H
NMR signals due to the ꢀCH2CH2CH2ꢀ and TTF moieties in the
region of 4.80ꢀ2.20 ppm became broad because the solution of 1 was
paramagnetic after the addition of Sc3+ (see Figure S9). Accordingly, it is
rather difficult to determine the exact coordination mode of Sc3+ with 1
based on 1H NMR spectra of 1 in the presence of Sc3+. It is assumed that
oxygen atoms of quinone units in 1 are coordinated to Sc3+ (or Pb2+),
and oxygen atoms of alkoxyl groups and sulfur atoms from TTF units in
the lower rim of calix[4]arene may also involve in the coordination to
stabilize the coordination complex.
(19) The binding stoichiometry between compound 2 and Sc3+ or
Pb2+ was estimated to be 1:1 based on the corresponding Job plots
(see Figures S15 and S16).
(20) Shinkai and other groups have already indicated that methoxyl
group is not bulky enough to suppress the oxygen through the annulus
rotation, and accordingly, the methoxy group can penetrate through the
cavity of calix[4]arenas (see ref 14). 1H and 13C NMR spectra of
compound 2 were recorded after addition of different amounts of Sc3+.
Because the solution of 2 became paramagnetic after addition of Sc3+,
1H NMR signals of 2 were broad (see Figure S18). Thus, it is rather
difficult to obtain structural information from these data.
(21) (a) Gutsche, C. D.; Iqbal, M. Org. Synth. 1990, 68, 234–237.
(b) Capson, T. L.; Thompson, M. D.; Dixit, V. M.; Gaughan, R. G.;
Poulter, C. D. J. Org. Chem. 1988, 53, 5903–5906. (c) Jia, C.; Zhang, D.;
Guo, X.; Wan, S.; Xu, W.; Zhu, D. Synthesis 2002, 15, 2177–2182.
(d) Kerdpaiboon, N.; Tomapatanaget, B.; Chailapakul, O.; Tuntulani, T.
J. Org. Chem. 2005, 70, 4797–4804.
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