A bifunctional chromogenic calix[4]arene chemosensor for both cations and anions: A potential Ca2+ and F- switched INHIBIT logic gate with a YES logic function

Article abstract of DOI:10.1002/ejoc.201000581

A bifunctional chromogenic calix[4]arene 3, which contains both triazoles and hydroxy azophenols as both cationic and anionic recognition sites and the azophenol moiety as a coloration unit, was designed and synthesized. The recognition of Ca²⁺ by 3 gave rise to a marked colour change from green- ish to bright yellow, whereas the recognition of F^- by 3 showed a colour change from light green to bluish. The colour changes of 3 by the inputs of Ca²⁺ and F- have been implemented to construct a combinational logic circuit at the molecular level.

Full text of DOI:10.1002/ejoc.201000581

FULL PAPER
DOI: 10.1002/ejoc.201000581
A Bifunctional Chromogenic Calix[4]arene Chemosensor for Both Cations and
Anions: A Potential Ca2+ and F– Switched INHIBIT Logic Gate with a YES
Logic Function
Kai-Chi Chang,[a] In-Hao Su,[a] Yu-Yun Wang,[a] and Wen-Sheng Chung*[a]
Keywords: Calixarenes / Chromogenic sensors / Logic gates / Host–guest systems / Click chemistry
A bifunctional chromogenic calix[4]arene 3, which contains
both triazoles and hydroxy azophenols as both cationic and
anionic recognition sites and the azophenol moiety as a col-
oration unit, was designed and synthesized. The recognition
of Ca2+ by 3 gave rise to a marked colour change from green-
ish to bright yellow, whereas the recognition of F– by 3
showed a colour change from light green to bluish. The col-
our changes of 3 by the inputs of Ca2+ and F– have been
implemented to construct a combinational logic circuit at the
molecular level.
able progress has been made in the development and appli-
cation of molecular logic gates.[5] A large number of molec-
ular systems showing logic algebra, such as AND, OR,
NOR, INHIBIT, XOR, YES, NOT and XNOR have been
reported.[5,6] These systems change their properties, such as
absorptions, fluorescence and redox potential in a specific
fashion in response to a particular input. We have been in-
terested in the design, synthesis and evaluation of chromo-
genic[7] and fluorogenic[8] chemosensors. For example, re-
cently we reported a new chromogenic sensor for Ca2+ and
Pb2+ ions based on triazole- and azo-coupled calix[4]arene
5;[7c] however, it did not exhibit any chromogenic change
toward any anions added. Surprisingly, with a subtle change
in its para-substituent, compound 3 is not only sensitive to
metal ions but also anions; thus, it allows us to test its func-
tion as a logic gate. We report herein the synthesis of a
bifunctional chromogenic calix[4]arene 3 that exhibits an
INHIBIT logic gate with a YES logic function by using
Ca2+ and F– ions as chemical inputs (Figure 1).
Introduction
The development of naked-eye chemosensors capable of
recognizing and sensing anions and cations is one of the
most challenging fields in supramolecular chemistry.[1] In
the past two decades, the colour-inducing azophenol dyes
have been widely used in chromoionophores because they
change their absorption spectra upon the binding of
anions[2] or metal ions.[3] Hong and co-workers reported the
use of a series of azophenol derivatives as chromogenic
units to selectively trigger colour change upon complex-
ation with various anions.[2a–2d] Moreover, an azobenzene-
based chemosensor, which can be used under physiological
pH conditions, was reported for the colorimetric detection
of the Cu2+ ion.[3a] Calix[4]arenes have been utilized as an
excellent scaffold for creating attractive host molecules with
ion-sensing properties.[4] Shinkai and co-workers reported
that calix[4]arene containing a 4-(4-nitrophenyl)azophenol
unit with three ethyl ester groups showed a perfect lithium
ion selectively with respect to the UV/Vis band shift.[4a,4b]
Chang et al. showed that a bathochromic shift of a p-tert-
butylcalix[4]arene bearing a 1,3-diazophenol unit was ob-
served upon calcium ion complexation.[4d] Chen et al. also
reported that azocalix[4]arene derivatives allowed not only
for highly sensitive and selective detection but also for easy
colorimetric differentiation of F–, AcO– and H2PO4– of sim-
ilar basicity, depending on the azocalix[4]arene structure.[4q]
There is considerable interest in the development of
calix[4]arene derivatives that behave as molecular logic
gates.[5] Since the pioneering work by de Silva,[5a] remark-
[a] Department of Applied Chemistry, National Chiao Tung
University,
Hsinchu 30050, Taiwan, Republic of China
E-mail: wschung@cc.nctu.edu.tw
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201000581.
Figure 1. Azocalix[4]arenes 3 and 5 and control compound 4.
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Eur. J. Org. Chem. 2010, 4700–4704
4700

A Bifunctional Chromogenic Calix[4]arene Chemosensor
chromic shifts to Ca2+, Pb2+ and Ba2+, respectively. More-
over, the UV/Vis spectra of control compound 4 did not
show any change in the presence of 10 equivalents of thir-
teen different metal perchlorates (see Figures S5 and S6 in
the Supporting Information).
Results and Discussion
The synthesis of host 3 is illustrated in Scheme 1. The
diazo coupling reaction of 25,27-bis(O-propargyl)calix[4]-
arene (1),[9] by using p-nitroaniline in HCl and NaNO2,
gave the desired product 2 in 81% yield. The CuI-catalyzed
1,3-dipolar cycloaddition reaction of 2 with 1-(azidometh-
yl)benzene under Click conditions afforded the 5,17-bis(p-
nitrophenyl)azo-25,27-bis(1,2,3-triazole)calix[4]arene (3) in
64% yield. Control compound 4[10] was synthesized in 80%
yield by using a method similar to that used in the prepara-
tion of 2. All compounds synthesized in this work were fully
characterized by spectroscopic data including H and 13C
1
NMR, MS and HRMS. The absorption maxima (λmax) and
molar extinction coefficients of the chromogenic calix[4]-
arenes and control compounds synthesized in this work are
summarized in Table 1. Next, we investigated the affinities
of these azo compounds 2–4 for a series of groups 1A, 2A,
transition-metal ions and anions in MeCN/CHCl3 (v/v =
1000:4) solution.
Figure 2. UV/Vis spectra of 3 (10 µ) before and after adding an
100 µ concentration of various metal perchlorates in MeCN/
CHCl3 (v/v = 1000:4).
The two triazole moieties of 3 are proven to form an
efficient metal-ion binding site, whereas compounds 2 and
4, which lack such an efficient metal-ion binding site,
showed either little or no binding affinities toward all the
metal ions studied here. The geometry of the binding site
of the host, comprising the two nitrogen atoms of triazole
units and two hydroxys of the azophenol units, seems to be
ideal in terms of size and arrangement for the recognition
of doubly charged metal cations. Among all attractive
forces, the electrostatic interaction of metal cations with two
azophenol moieties and the ion-dipole interaction of metal
ions with the triazole units are of primary importance.
Upon interaction with Ca(ClO4)2, the chromogenic sen-
sor 3 in MeCN/CHCl3 (v/v = 1000:4) solution experienced
a marked bathochromic shift in its λmax from 390 to 496 nm
(∆λmax = 106 nm; Figure 3). The greenish solution of free 3
turned a bright-yellow colour upon complexation with Ca2+
and exhibited an isosbestic point at 426 nm. The spectral
features in Figure 3 are consistent with a 1:1 binding ratio
between calix[4]arene 3 and Ca2+. Further support of the
1:1 binding ratio comes from a Job plot[11] experiment, in
Scheme 1. Synthetic route for 3: Reagents and conditions: (i) p-
nitroaniline/acetone, NaNO2/4  HCl, pyridine, 0 °C, 24 h. (ii) 1-
(azidomethyl)benzene, CuI, THF/H2O, 50 °C, 18 h.
Table 1. The absorption λmax and corresponding extinction coeffi-
cients of azo compounds 2–4 in MeCN/CHCl3 (v/v = 1000:4).
Compound
λmax [nm]
ε [–1 cm–1]
2
3
4
390
390
384
26,000
32,000
23,000
Excess (10 equiv.) perchlorate salts of Li+, Na+, K+,
Mg2+, Ca2+, Ba2+, Ag+, Zn2+, Pb2+, Ni2+, Hg2+, Mn2+ and
Cr3+ were tested to evaluate the metal-ion binding proper-
ties of 2–4. Ligand concentration in all titration experi-
ments was fixed at 10 µ in MeCN/CHCl3 (v/v = 1000:4).
Free hosts 2, 3 and 4 exhibited absorption bands at 390,
390 and 384 nm in MeCN/CHCl3 (v/v = 1000:4), respec-
tively. The triazole–azophenol host 3, containing triazoles
as the metal-ligating groups, is found to exhibit remarkable
selectivity toward Ca2+, Pb2+ and Ba2+ over all other metal
ions. The addition of 10 equivalents of Ca2+, Pb2+ and Ba2+
induced a bathochromic shift of the triazole–azophenol 3
from λmax = 390 to 496, 501 and 485 nm, respectively (Fig-
ure 2). However, the UV/Vis spectra of 2, which does not
Figure 3. UV/Vis spectra of 3 (10 µ) upon titration with various
contain the triazole groups, showed only weak batho- equivalents of Ca(ClO4)2 in MeCN/CHCl3 (v/v = 1000:4).
Eur. J. Org. Chem. 2010, 4700–4704
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4701

K.-C. Chang, I.-H. Su, Y.-Y. Wang, W.-S. Chung
FULL PAPER
which the absorbances of the complexes at 496 nm were
Upon interacting with TBA+F–, the chromogenic sensor
plotted against molar fractions of 3 under the conditions of 3 in MeCN/CHCl3 (v/v = 1000:4) solution experienced a
an invariant total concentration. As a result, the concentra- marked bathochromic shift in its λmax as shown in Fig-
tion of complex 3·Ca2+ approached a maximum when the ure S15 (Supporting Information). The absorption maxi-
molar fraction of [3]/([3] + [Ca2+]) was about 0.5 (see Fig- mum at 390 nm gradually decreased in intensity with the
ure S7 in the Supporting Information).
formation of a new absorption band at approximately
From the titration experiment, the association constant 626 nm (∆λmax = 236 nm). An isosbestic point at 452 nm
for 3·Ca2+ in MeCN/CHCl3 (v/v = 1000:4) was determined was observed in the titration spectra of 3 by TBA+F–. Job
to be 1.01ϫ105 –1 by a Benesi–Hildebrand plot[12] (see plot experiments were carried out for 3 and revealed a 1:1
Figure S8 in the Supporting Information). Similar UV/Vis complex for 3 with F– (see Figure S16 in the Supporting
titration behaviour and 1:1 binding stoichiometry was ob- Information). From the titration, the association constant
served in the cases of 3·Pb2+ and 3·Ba2+, respectively (see of 3 with F– is calculated to be 4.38ϫ104 –1 (see Fig-
Figures S9–S14 in the Supporting Information), and the as- ure S17 in the Supporting Information). Similar UV/Vis ti-
sociation constants for complexation of Pb2+ and Ba2+ by tration behaviour and 1:1 binding stoichiometry was ob-
3 were estimated, yielding 3·Pb2+ = 6.35ϫ104 –1 and served in the cases of 3·AcO– and 3·H2PO4 , respectively
–
3·Ba2+ = 2.53ϫ104 –1.
(see Figures S18–S23), and the association constants for
–
In addition to the metal ions binding properties, we have complexation of AcO– and H2PO4 by 3 were estimated,
–
also investigated the sensing properties of azo compounds yielding 3·AcO–
=
2.50ϫ104 –1 and 3·H2PO4
=
–
2–4 towards anions (F–, Cl–, Br–, I–, HSO4 , CH3COO–, 5.50ϫ103 –1.
–
–
H2PO4 and NO3 ) by using tetrabutylammonium as a
Cation and anion-induced chemical-shift changes in the
counter cation. In the absence of cations or anions, the UV/ 1H NMR spectra supports the fact that Ca2+ is bound to
Vis spectrum of 3 is characterized by the presence of one one of the two nitrogen atoms of the triazole units and the
absorption band with a λmax at 390 nm. The addition of F–, two hydroxy azophenol groups of 3 (see Figure 5, b); how-
–
AcO– and H2PO4 to 3 induced a red absorption band in ever, F– is bound to the two hydroxy azophenol groups of
its UV/Vis spectra to a different extent, whereas no obvious 3 by hydrogen bonding (see Figure 5, c). In the presence of
spectral change was observed in the addition of the other one equivalent of Ca2+, chemical shifts of protons Ha–Hd
anions. The new absorption bands were found to have λmax on the azophenol unit of 3 changed significantly; the peaks
–
at 626 nm for F–, 618 nm for AcO– and 622 nm for H2PO4 , of Ha and Hb were shifted upfield by 0.07 and 0.33 ppm,
respectively, corresponding to a maximum absorption in- respectively, but the peak of Hd was shifted downfield by
–
tensity trend of F– Ͼ AcO– Ͼ H2PO4 (see Figure 4). It 2.35 ppm. In particular, the peak of Hc was split into two
is known[1a] that the electronic excitation of an azophenol peaks, one shifted upfield by 0.16 ppm and the other shifted
chromophore generally occurs through a charge transfer downfield by 0.06 ppm. Furthermore, the signals of methyl-
from the donor oxygen atom of the phenol to the acceptor ene bridges, Hg, were also split into two sets of signals and
substituent (NO2) of the chromophore. The extent of the the peak of Hi on the triazole group was shifted downfield
bathochromic shifts by the basic anions (F–, AcO– and by 0.12 ppm. These results suggest that Ca2+ is not only
–
H2PO4 ) may be due to the subtle balance between the de- bound by triazole–azophenol host 3; the metal complex
protonation of the azophenol and complexation induced re- also breaks the symmetry of the host molecule.[7c] By con-
lease of protons from the azophenol units. Similar observa- trast, upon adding one equivalent of TBA+F– to the solu-
tion in chromogenic sensing of anions by azocalix[4]arene tion of 3, the peak of Hd on the hydroxy of the azophenol
derivatives, reported by Chen et al.,[4q] was also ascribed to
the hydrogen-bonding ability and basicity of the anions to
the azophenols of the calix[4]arenes.
Figure 5. 1H NMR spectra of 3 (2.5 m) in a CDCl3/CD3CN (3:1)
solution (a) and in the presence of 1.0 equiv. of (b) Ca(ClO4)2 and
(c) TBA+ F–, in which * denotes external standards CHCl3 and
CH2Cl2.
Figure 4. UV/Vis spectra of 3 (10 µ) before and after adding an
100 µ concentration of various anions in MeCN/CHCl3 (v/v =
1000:4).
4702
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 4700–4704

A Bifunctional Chromogenic Calix[4]arene Chemosensor
unit disappeared, which can be explained by the participa- Vis spectra of 3 (10 µ) did not show any change after add-
tion of the OH of the azophenol group in F– complexation. ing 100 equivalents of CaF2. The results indicated that com-
The high-field shifts of all protons of 3 in the presence of pound 3 is not a ditopic receptor to recognizing the ion pair
one equivalent of F– supported the statement that depro- of Ca2+ and F– (see Figure S25 in the Supporting Infor-
tonation of one of the azophenols occurred due to the ba- mation).
sicity of the anion. 1H NMR titration spectra of 3 with
various aliquots of TBA+ F– are shown in Figure S24 (Sup-
porting Information).
Since different colours were observed when compound 3
was treated with either Ca2+ or F–, we further utilized our
system as molecular logic gates. In the absence of any chem-
ical input, the receptor 3 shows the absorption band at
390 nm. Addition of 10 equivalents of Ca2+ to the solution
of 3 shows the absorption band at 496 nm. The addition of
10 equivalents of F– to 3 induced a red absorption band at
626 nm. Note that no such red absorption band at 626 nm
was observed when 10 equivalents of F– were added to the
Figure 7. Logic diagram of the combinational logic circuit and
truth table.
solution of 3·Ca2+ (1:10; see Figure 6). As a consequence
of the UV/Vis spectral behaviour of 3 toward Ca2+ and F–
ions, the molecular system 3 provides us with a promising
structure to mimic an INHIBIT logic gate with a YES logic
Conclusions
function.
We have developed a novel bifunctional chromogenic ca-
lix[4]arene sensor 3 with bistriazoles and azophenols as the
binding site for both cations and anions and azophenols as
the signal transduction unit, which showed selective color-
ation toward not only Ca2+, Pb2+ and Ba2+, but also F–,
–
AcO– and H2PO4 . The recognition of Ca2+ by 3 gave rise
to a marked colour change from greenish to bright yellow.
In sharp contrast, the recognition of F– by 3 showed a col-
our change from light green to bluish. In addition, a dual
output molecular switch is designed when the system is op-
erated by inputs of Ca2+ and F–. The concept presented
here contributes to the construction of a miniaturized and
integrated molecular level device with logic gate functions.
Figure 6. UV/Vis spectra of 3 (10 µ) before and after adding an
100 µ concentration of Ca(ClO4)2, TBA+F– and Ca(ClO4)2 with
TBA+F– in MeCN/CHCl3 (v/v = 1000:4).
Experimental Section
General: All melting points are uncorrected. 1H and 13C NMR
spectra were recorded on 300 MHz instruments. Data are reported
as follows: chemical shifts in ppm (δ), multiplicity (s = singlet, d =
doublet, br. s = broad singlet, m = multiplet), coupling constant
(Hz), integration, and interpretation. Mass spectra were obtained
on a Micromass-Trio 2000 GC-MS instrument. High resolution
mass spectra were recorded on a JMS-700 high performance mass
spectrometer. Column chromatography was performed with SiO2
[Merck Silica Gel 60 (230–400 mesh)]. UV/Vis spectra were re-
corded by using a HP-8453 spectrophotometer with a diode array
detector, and the resolution was set at 1 nm.
As seen in Figure 7, we constructed two logic circuits
along with the truth Table for the absorption bands at 496
and 626 nm upon the addition of two input signals (Ca2+
and F–). The two input signals are Ca2+ (input 1) and F–
(input 2). The output signals are output 1 (absorption band
at 496 nm) and output 2 (absorption band at 626 nm). As
can be seen from the truth table in Figure 7, monitoring
the absorption band at 496 nm (output 1), upon addition
of Ca2+, F– and an equimolar mix of Ca2+ and F– leads to
a YES logic gate. The YES logic gate is a single input device 5,17-Bis(p-nitrophenyl)azo-25,27-dipropargyloxy-26,28-dihydroxy-
calix[4]arene (2): A solution of para-nitroaniline (0.14 g,
1.01 mmol) in acetone (8 mL) was added to an ice-cold solution of
NaNO2 (0.14 g, 2.02 mmol) in HCl (4 , 6 mL) and the mixture
was stirred for 30 s. The combined solution was then added to an-
other ice-cold solution of 25,27-dipropargyloxy-26,28-dihydroxy-
calix[4]arene (1) (0.10 g, 0.20 mol) in pyridine (12 mL) to produce
a coloured solution. The reaction mixture was stirred at 0 °C for
24 h and then treated with HCl (4 , 50 mL) to give a coloured
precipitate. The solid residue was recrystallized from a CH2Cl2/
that delivers the same output signal given by the input.
However, output 2 results in an INHIBIT logic gate. An
INHIBIT (INH) logic gate is a result of concatenation of
AND and NOT gates, but in contrast to other logic gates
with concatenated NOT, the logic inversion concerns not
the output but one of the input.[6] So the strength of the
INHIBIT gate is acknowledged in combination with a YES
logic gate to lead to the construction of a combinational
logic circuit. Last but not least, we have also investigated
methanol mixture to give 2 (0.13 g, 81%) as a red solid; m.p. 214–
1
the ditopic binding ability of ligand 3 with CaF2. The UV/ 216 °C. Rf = 0.23 (hexane/ethyl acetate = 3:1). H NMR (CDCl3,
Eur. J. Org. Chem. 2010, 4700–4704
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4703

K.-C. Chang, I.-H. Su, Y.-Y. Wang, W.-S. Chung
FULL PAPER
2006, 47, 6413–6416; d) S. J. Lee, S. S. Lee, I. Y. Jeong, J. Y.
Lee, J. H. Jung, Tetrahedron Lett. 2007, 48, 393–396.
[4] a) H. Shimizu, K. Iwamoto, K. Fujimoto, S. Shinkai, Chem.
Lett. 1991, 2147–2150; b) H. Yamamoto, K. Ueda, K. R. A. S.
Sandanayake, S. Shinkai, Chem. Lett. 1995, 497–498; c) Y.
Kubo, S. Takita, Y. Kojima, Y. T. Osano, T. Matsuzaki, J. Org.
Chem. 1996, 61, 3758–3765; d) N. Y. Kim, S.-K. Chang, J. Org.
Chem. 1998, 63, 2362–2364; e) N. J. van der Veen, R. J. M. Eg-
berink, J. F. J. Engbersen, F. J. C. M. van Veggel, D. N. Rein-
houdt, Chem. Commun. 1999, 681–682; f) J. S. Kim, O. J. Shon,
J. W. Ko, M. H. Cho, I. Y. Yu, J. Vicens, J. Org. Chem. 2000,
65, 2386–2392; g) F. Oueslati, I. Dumazet-Bonnamour, R. La-
martine, Tetrahedron Lett. 2001, 42, 8177–8180; h) J. S. Kim,
O. J. Shon, J. K. Lee, S. H. Lee, J. Y. Kim, K.-M. Park, S. S.
Lee, J. Org. Chem. 2002, 67, 1372–1375; i) H. Halouani, I. Du-
mazet-Bonnamour, R. Lamartine, Tetrahedron Lett. 2002, 43,
3785–3788; j) J. S. Kim, O. J. Shon, S. H. Yang, J. Y. Kim, M. J.
Kim, J. Org. Chem. 2002, 67, 6514–6518; k) H. Halouani, I.
Dumazet-Bonnamour, C. Duchamp, C. Bavoux, N. Ehlinger,
M. Perrin, R. Lamartine, Eur. J. Org. Chem. 2002, 4202–4210;
l) J. Y. Kim, G. Kim, C. R. Kim, S. H. Lee, J. H. Lee, J. S. Kim,
J. Org. Chem. 2003, 68, 1933–1937; m) S. H. Lee, J. Y. Kim, J.
Ko, J. Y. Lee, J. S. Kim, J. Org. Chem. 2004, 69, 2902–2905; n)
S. K. Kim, S. H. Kim, H. J. Kim, S. H. Lee, S. W. Lee, J. Ko,
R. A. Bartsch, J. S. Kim, Inorg. Chem. 2005, 44, 7866–7875; o)
H. M. Chawla, S. P. Singh, S. Upreti, Tetrahedron 2006, 62,
9758–9768; p) H. J. Kim, S. K. Kim, J. Y. Lee, J. S. Kim, J. Org.
Chem. 2006, 71, 6611–6614; q) C.-F. Chen, Q.-Y. Chen, New J.
Chem. 2006, 30, 143–147; r) M. H. Lee, D. T. Quang, H. S.
Jung, J. Yoon, C.-H. Lee, J. S. Kim, J. Org. Chem. 2007, 72,
4242–4245.
[5] a) A. P. De Silva, H. Q. N. Gunaratne, C. P. McCoy, Nature
1993, 364, 42–44; b) H.-F. Ji, R. Dabestain, G. M. Brown, J.
Am. Chem. Soc. 2000, 122, 9306–9307; c) Z. Guo, W. Zhu, L.
Shen, H. Tian, Angew. Chem. Int. Ed. 2007, 46, 5549–5553; d)
J. W. Lee, S. Y. Park, B.-K. Cho, J. S. Kim, Tetrahedron Lett.
2007, 48, 2541–2546; e) Z. Liang, Z. Liu, L. Jiang, Y. Gao,
Tetrahedron Lett. 2007, 48, 1629–1632; f) A. Dhir, V. Bhalla,
M. Kumar, Tetrahedron Lett. 2008, 49, 4227–4230; g) A. Dhir,
V. Bhalla, M. Kumar, Org. Lett. 2008, 10, 4891–4894; h) M.
Yuan, W. Zhou, X. Liu, M. Zhu, J. Li, X. Yin, H. Zheng, Z.
Zuo, C. Ouyang, H. Liu, Y. Li, D. Zhu, J. Org. Chem. 2008,
73, 5008–5014; i) N. Kaur, N. Singh, D. Cairns, J. F. Callan,
Org. Lett. 2009, 11, 2229–2232; j) R. Joseph, B. Ramanujam,
A. Acharya, C. P. Rao, J. Org. Chem. 2009, 74, 8181–8190.
[6] K. Szaciłowski, Chem. Rev. 2008, 108, 3481–3548.
[7] a) T.-L. Kao, C.-C. Wang, Y.-T. Pan, Y.-J. Shiao, J.-Y. Yen, C.-
M. Shu, G.-M. Lee, S.-M. Peng, W.-S. Chung, J. Org. Chem.
2005, 70, 2912–2920; b) I.-T. Ho, G.-H. Lee, W.-S. Chung, J.
Org. Chem. 2007, 72, 2434–2442; c) K.-C. Chang, I.-H. Su, G.-
H. Lee, W.-S. Chung, Tetrahedron Lett. 2007, 48, 7274–7278;
d) Y.-J. Chen, W.-S. Chung, Eur. J. Org. Chem. 2009, 4770–
4776.
300 MHz): δ = 8.37 (d, J = 8.9 Hz, 4 H, Ha), 8.04 (s, 2 H, Hd),
7.97 (d, J = 8.9 Hz, 4 H, Hb), 7.83 (s, 4 H, Hc), 6.99 (d, J = 7.5 Hz,
4 H, Hf), 6.81 (t, J = 7.5 Hz, 2 H, He), 4.87 (d, J = 2.3 Hz, 4 H,
Hh), 4.48 (d, J = 13.5 Hz, 4 H, Hg), 3.60 (d, J = 13.5 Hz, 4 H, Hg),
2.66 (t, J = 2.3 Hz, 2 H, Hi) ppm. 13C NMR (CDCl3, 75.4 MHz):
δ = 157.8 (Cq), 156.2 (Cq), 151.2 (Cq), 148.0 (Cq), 145.8 (Cq),
132.5 (Cq), 129.5 (CH), 128.8 (Cq), 126.1 (CH), 124.7 (CH), 124.7
(CH), 122.9 (CH), 77.8 (Cq), 63.7 (CH2), 31.8 (CH2) ppm.
FABMS: m/z (%) 799 [M+ + 1, 6], 459 (6), 306 (100). HR-FABMS:
calcd. for C46H35N6O8 799.2516; found 799.2506 [M + H+].
5,17-Bis(p-nitrophenyl)azo-25,27-bis(1-benzyl-1H-1,2,3-triazolyl-
methyloxy)-26,28-dihydroxycalix[4]arene (3): A mixture of com-
pound
2 (0.15 g, 0.19 mmol), 9-(azidomethyl)benzene (0.06 g,
0.45 mmol) and CuI (about 1 mg, 0.005 mmol) in THF and water
(v/v = 2:1, 15 mL) was stirred vigorously at 50 °C for 18 h. The
mixture was extracted thrice with chloroform. The chloroform
layer was dried with MgSO4 and the solvent was removed under
reduced pressure. The residue obtained was purified over a silica-
gel column eluting with hexane/ethyl acetate (v/v = 1:1) to give 3
(0.13 g, 64%) as a red solid; m.p. 191–193 °C. Rf = 0.18 (hexane/
ethyl acetate = 1:1). 1H NMR (CDCl3, 300 MHz): δ = 8.56 (s, 2 H,
Hd), 8.39 (d, J = 9.0 Hz, 4 H, Ha), 8.00 (d, J = 9.0 Hz, 4 H, Hb),
7.89 (s, 2 H, Hi), 7.84 (s, 4 H, Hc), 7.42–7.36 (m, 10 H, Hl–n), 7.03
(d, J = 7.5 Hz, 4 H, Hf), 6.85 (t, J = 7.5 Hz, 2 H, He), 5.65 (s, 4
H, Hj), 5.24 (s, 4 H, Hh), 4.21 (d, J = 13.3 Hz, 4 H, Hg), 3.41 (d,
J = 13.3 Hz, 4 H, Hg) ppm. 13C NMR (CDCl3, 75.4 MHz): δ =
158.2 (Cq), 156.6 (Cq), 151.8 (Cq), 148.4 (Cq), 146.2 (Cq), 135.2
(Cq), 132.9 (Cq), 130.0 (CH), 129.5 (CH), 129.2 (CH), 129.0 (Cq),
128.5 (CH), 126.4 (CH), 125.1 (CH), 125.1 (CH), 123.3 (CH), 70.1
(CH2), 54.9 (CH2), 31.9 (CH2) ppm. FABMS: m/z (%) 1065 [M+
+
1, 11], 1064 [M+, 5], 467 (23), 391 (52), 136 (100). HR-FABMS:
calcd. for C60H49N12O8 1065.3796; found 1065.3784 [M + H+].
Supporting Information (see also the footnote on the first page of
this article): 1H and 13C NMR spectra for compounds 2 and 3.
UV/Vis titration spectra, Job Plots and Benesi–Hildebrand plots of
compounds 2–4 with cations and anions. 1H NMR titration spectra
of 3 with various equivalents of TBA+F–.
Acknowledgments
We thank the National Science Council (NSC), Taiwan and the
Ministry of Education (MOE) Approaching Top University (ATU)
Program of the Ministry of Education, Taiwan, Republic of China
for financial support.
[1] a) H. G. Löhr, F. Vögtle, Acc. Chem. Rev. 1985, 18, 65–72; b)
P. B ühlmann, E. Pretsh, E. Bakker, Chem. Rev. 1998, 98, 1593–
1688; c) R. Martínez-Máñez, F. Sancenón, Chem. Rev. 2003,
103, 4419–4476.
[8] a) Y.-J. Shiao, P.-C. Chiang, A. Senthilvelan, M.-T. Tsai, G.-H.
Lee, W.-S. Chung, Tetrahedron Lett. 2006, 47, 8383–8386; b)
A. Senthilvelan, M.-T. Tsai, K.-C. Chang, W.-S. Chung, Tetra-
hedron Lett. 2006, 47, 9077–9081; c) K.-C. Chang, I.-H. Su, A.
Senthilvelan, W.-S. Chung, Org. Lett. 2007, 9, 3363–3366; d)
A. Senthilvelan, I.-T. Ho, K.-C. Chang, G.-H. Lee, Y.-H. Liu,
W.-S. Chung, Chem. Eur. J. 2009, 15, 6152–6160.
[2] a) K. H. Lee, H.-Y. Lee, D. H. Lee, J.-I. Hong, Tetrahedron
Lett. 2001, 42, 5447–5449; b) D. H. Lee, K. H. Lee, J.-I. Hong,
Org. Lett. 2001, 3, 5–8; c) D. H. Lee, H. Y. Lee, K. H. Lee, J.-
I. Hong, Chem. Commun. 2001, 1188–1189; d) D. H. Lee, J. H.
Im, S. U. Son, Y. K. Chung, J.-I. Hong, J. Am. Chem. Soc.
2003, 125, 7752–7753; e) F. Sancenón, R. Martínez-Máñez, J.
Soto, Angew. Chem. Int. Ed. 2002, 41, 1416–1419; f) E. J. Cho,
B. J. Ryu, Y. J. Lee, K. C. Nam, Org. Lett. 2005, 7, 2607–2609.
[3] a) T. Gunnlaugsson, J. P. Leonard, N. S. Murray, Org. Lett.
2004, 6, 1557–1560; b) S. J. Lee, J. H. Jung, J. Seo, I. Yoon, K.-
M. Park, L. F. Lindoy, S. S. Lee, Org. Lett. 2006, 8, 1641–1643;
c) Y.-F. Cheng, D.-T. Zhao, M. Zhang, Z.-Q. Liu, Y.-F. Zhou,
T.-M. Shu, F.-Y. Li, T. Yi, C.-H. Huang, Tetrahedron Lett.
[9] W. Xu, J. J. Vittal, R. J. Puddephatt, Can. J. Chem. 1996, 74,
766–774.
[10] A. Tsuge, T. Moriguchi, S. Mataka, M. Tachiro, J. Chem. Soc.
Perkin Trans. 1 1993, 2211–2215.
[11] K. A. Connors, Binding Constants, Wiley, New York, 1987.
[12] H. A. Benesi, J. H. Hildebrand, J. Am. Chem. Soc. 1949, 71,
2703–2707.
Received: April 27, 2010
Published Online: July 6, 2010
4704
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 4700–4704