Synthesis and evaluation of a novel pyrenyl-appended triazole-based thiacalix[4]arene as a fluorescent sensor for Ag+ ion

Article abstract of DOI:10.1016/j.tet.2011.03.008

New fluorescent chemosensors 1,3-alternate-1 and 2 with pyrenyl-appended triazole-based on thiacalix[4]arene were synthesized. The fluorescence spectra changes suggested that chemosensors 1 and 2 are highly selective for Ag ⁺ over other metal i

Full text of DOI:10.1016/j.tet.2011.03.008

Tetrahedron 67 (2011) 3248e3253
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis and evaluation of a novel pyrenyl-appended triazole-based
thiacalix[4]arene as a fluorescent sensor for Agþ ion
,
Xin-Long Ni a, Xi Zeng b, Carl Redshawc, Takehiko Yamato a
*
a Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi 1, Saga 840-8502, Japan
b Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, People’s Republic of China
c School of Chemistry, University of East Anglia, Norwich NR4 7TJ, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
New fluorescent chemosensors 1,3-alternate-1 and 2 with pyrenyl-appended triazole-based on thiacalix
[4]arene were synthesized. The fluorescence spectra changes suggested that chemosensors 1 and 2 are
highly selective for Agþ over other metal ions by enhancing the monomer emission of pyrene in neutral
solution. However, other heavy metal ions, such as Cu2þ, and Hg2þ quench both the monomer and ex-
cimer emission of pyrene acutely. The 1H NMR results indicated that Agþ can be selectively recognized by
the triazole moieties on the receptors 1 and 2 together with the ionophoricity cavity formed by the two
inverted benzene rings and sulfur atoms of the thiacalix[4]arene.
Received 15 February 2011
Received in revised form 1 March 2011
Accepted 2 March 2011
Available online 9 March 2011
Keywords:
Thiacalix[4]arene
Metal ion recognition
Pyrenyl-appended triazole
Fluorescent sensor
Silver cation
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
and hard transition-metal ions.7 Acetates are amongst the most
versatile compounds in calixarene chemistry, because the acetate
Owing to their simplicity, high sensitivity, and high detection
limits for trace chemicals in chemistry, biology, and the environ-
ment,1 fluorescent chemosensors have received much attention in
the field of supramolecular chemistry. Generally, an effective fluo-
rescent chemosensor includes an ion recognition unit (ionophore)
and a fluorogenic unit (fluorophore), that effectively converts the
information of binding recognition from the ionophore unit into an
easily monitored and a highly sensitive light signal from the fluo-
rophore. Amongst the different fluorogenic units, pyrene is one of
the most useful tools due to its relatively efficient monomer and
excimer emissions. The sensing mechanism of pyrene is attribut-
able to the intensity ratio of the excimer-to-monomer emission,
which is very sensitive to conformational change.2 On the other
hand, the simple, effective, and versatile chemical modifications
possible for calixarenes, together with their unique topology, offer
a wide range of scaffolds enabling them to be selective for many
different metal ions.3ꢀ5
group is easily converted to carboxylic acids, amides, and other
esters.7c Given this, one of the most interesting features of thiacalix
[4]arenes is that the conformation can be controlled by the reaction
with ethyl bromoacetate in the presence of alkali carbonate as base.
Additionally, with the development of the electronics industry and
photographic and imaging industry, more attention has been paid to
the negative effect of silver ions on the environment. For example, it
is believed that silver ions can bind to various metabolites and en-
zymes, such as in the deactivation of sulphydryl enzyme,8 and as
a consequence, many methods have been utilized to measure trace
amounts of silver ion; including atomic absorption, ICP atomic
emission, UVevis absorption, and fluorescence spectroscopy.
Among these approaches, fluorescence spectroscopy is widely used
because of its high sensitivity and facile operation. However, due to
silver belonging to heavy transition-metal ions, which usually
quench fluorescence emission via enhanced spin-orbital coupling,9
energy or electron transfer,10 only a few fluorescent ‘turn on’ che-
mosensor for detecting silver ion have been reported at present.11
Fluorescence quenching is not only disadvantageous for a high sig-
nal output during detection but is also undesirable for analytical
purposes.12 As a result, the development of highly selective che-
mosensors for the Agþ ion still remains a challenge.
Thiacalix[4]arenes, which have received growing interest since
their discovery in 1997,6 possess additional coordination sites and
have shown a more flexible structure and strong affinity for both soft
With these observations in mind, we continue our studies into
* Corresponding author. Fax: þ81 952 28 8548; e-mail address: yamatot@cc.sa-
the design and synthesis of chemosensors for heavy metal ions.13
ga-u.ac.jp (T. Yamato).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.03.008

X.-L. Ni et al. / Tetrahedron 67 (2011) 3248e3253
3249
t
Herein, we have designed a new fluorescent sensor through pyr-
ene-appended triazole-based thiacalix[4]arene with 1,3-alternate
conformation. Such chemosensors display high affinity for silver
ion by changing the monomer and excimer emission of the pyrene
moieties.
was prepared by O-propargyl Bu phenyl reactions with azide 8
through Click chemistry in a yield of 60%.
The fluorescence spectra of 1,3-alternate-1 and 2 appeared with
a typical intramolecular excimer emission around 485 nm and
monomer emissions around 378 and 396 nm in organic solution,
and a typical monomer emission appeared for reference compound
3 (excitation at 343 nm) in CH3CN/CH2Cl2 (1000:1, v/v) (Fig. 1). The
excimer emission band was attributed to the interaction of two
2. Results and discussion
pyrene units forming an intramolecular p/p stacking, which was
fixed by the thiacalix[4]arene scaffold.15 The cation-binding prop-
erties of receptors 1e3 were then investigated by fluorescence
spectroscopy. The fluorescence intensity changes upon addition of
various perchlorate salts, such as Liþ, Naþ, Kþ, Csþ, Zn2þ, Pb2þ, Agþ,
Cu2þ, Hg2þ, Cd2þ, Ni2þ, Co2þ, and Cr3þ in aqueous solution, are
depicted in Fig. 1. It was observed that both the excimer and
monomer emissions of receptor 1,3-alternate-1 were strongly
quenched by Hg2þ, and Cu2þ. By contrast, upon addition of Agþ ion
into the solution of receptor 1, an obvious enhancement of the
As shown in Scheme 1, compound cone-4 can be obtained fol-
lowing the reported precedures.14 Thus, compound 1,3-alternate-5
was prepared in 64% yield by the reaction of compound cone-4
with propargyl bromide in the presence of Cs2CO3 in dry acetone.
Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction of compound
1,3-alternate-5 with 1-azidomethylpyrene 8 under Click conditions
afforded the 1,2,3-triazole thiacalix[4]arene 1,3-alternate-1 in 73%
yield. A similar procedure was employed in the synthesis of
receptor 1,3-alternate-2 with 51% yield. The reference compound 3
O
O
t-Bu
t-Bu
S
O
t-Bu
S
O
t-Bu
O
O
O
O
S
S
S
S
S
S
O
O
O
O
N
N
N
N
t-Bu
t-Bu
N
N
N
N
t-Bu
t-Bu
N
N
N
N
2
1
N3
O
O
O
O
O
O
t-Bu
O
t-Bu
O
Br
OH
O
OH
S
O
O
O
8
S
S
S
S
S
S
S
THF/H2O (v/v=4:1)
CuI
Cs2CO3
dry
O
O
ac
eto
ne
1
65
C
64%
t-Bu
for
20
h
65oC for 24h
73%
t-Bu
t-Bu
t-Bu
4
t-Bu
t-Bu
5
t-Bu
S
8
t-Bu
THF/H2O (v/v=4:1)
CuI
2
Br
Cs2CO3
O
O
S
OH
O
OH
O
S
S
S
S
S
65oC for 24h
51%
S
O
O
dr
y a
ceto
ne
t-Bu
t-Bu
65
C fo
r 2
0 h
t-Bu
t-Bu
t-Bu
t-Bu
6
81%
7
8
N
N
N
THF/H2O (v/v=4:1)
CuI
t-Bu
O
t-Bu
O
65oC for 24h
60%
3
Scheme 1.

3250
X.-L. Ni et al. / Tetrahedron 67 (2011) 3248e3253
The fluorescence spectra of 1,3-alternate-1 at various concen-
trations of Agþ ion are shown in Fig. 2. As can be seen, the fluores-
cence intensity of the monomer emission of receptor 1 gradually
increased on increasing concentrations of Agþ ion from 0 to 100
mM
and was accompanied by a concomitant decrease in the excimer
emission. A discernible isoemissive point appeared at 430 nm. On
the basis of the fluorescence titration experiments, the association
constant (Ka)18 for 1$Agþ was determined to be 1.33ꢁ105 Mꢀ1, and
ajob plot19 for the complexation showed a 1:1 stoichiometry (Fig. 2).
Similar fluorescence titration behavior was also evaluated in the
case of receptors 1 and 2 with related metal ions (Figs. S3eS7). From
these observations, the association constants for complexationwere
calculated to be: 1$Hg2þ¼ 4.24ꢁ104
M
ꢀ1, 1$Cu2þ¼ 3.97ꢁ104 Mꢀ1
,
2$Agþ¼ 5.40ꢁ104
M
ꢀ1, 2$Hg2þ¼ 2.46ꢁ104
M
ꢀ1, 2$Cu2þ¼ 5.39
ꢁ104 Mꢀ1, respectively.
Fig. 1. Fluorescence spectra of the receptor 1 (5.0
intensity changes of the receptors 1e3 (each of 5.0
v/v) at 298 K upon addition of various metal ions (100
is fluorescent emission intensity at 378 nm for free receptors, and I is the fluorescent
intensity after adding metal cations with an excitation at 343 nm.
m
m
M) (a) and relative fluorescence
M) (b) in CH3CN/CH2Cl2 (1000:1,
M) as their aqueous solution. Io
Fig. 2. Changes in the fluorescence emission spectra of 1 (5.0
m
M) upon addition of
increasing concentrations of Agþ ion in aqueous solution (0e100
mM) at 298 K in
m
CH3CN/CH2Cl2 (1000:1, v/v) with an excitation at 343 nm. Inset: Job’s plot showing
a 1:1 stoichiometry.
To better investigate the practical applicability of the receptors 1
and 2 as Agþ ion selective fluorescent sensor, competitive experi-
monomer emission occurred, whilst the accompanying excimer
emission declined (Fig. 1a). Much weaker responses for fluores-
cence emissions of the monomer and excimer quenching were
given by addition of Pb2þ, Ni2þ, Co2þ, and Cr3þ ions, and no sig-
nificant fluorescence intensity changes were observed upon addi-
tion of alkali metal ions. Similar selective fluorescent behavior
caused by metal ions was also observed for receptor 2 (Fig. 1b and
Fig. S1). However, under the same analytical conditions, the fluo-
rescent intensity of compound 3 (Fig. 1b and Fig. S2) was not ob-
viously changed upon addition of Agþ ion and other metal ions,
except in the cases of Hg2þ and Cu2þ ions, where acute quenching
was observed. These results indicated that the fluorescent sensitive
and selective binding of Agþ ion requires the coordination of two
triazole rings of receptors 1 and 2. Generally, the fluorescence of
monomer emission quenching by heavy atoms, such as Hg2þ and
Cu2þ in the chemosensors 1e3 can be attributed to the reverse PET
(photon electron transfer)16 from the pyrene unit to the nitrogen
atoms of triazole ring or a heavy atom effect.17 The excimer
quenching is a result of a conformational change, which occurs
during the binding of the targeted metal ions with the nitrogen
atoms on the triazole ring. In this procedure, the coordination
forces make the pyrene groups move far away from each other and
ments were carried out in the presence of Agþ ion (100
m
M) mixed
with Liþ, Naþ, Kþ, Csþ, Zn2þ, Pb2þ, Cu2þ, Hg2þ, Cd2þ, Ni2þ, Co2þ, and
Cr3þ at 100
M; as shown in Fig. 3 and Fig. S8, no significant in-
m
terference in detection of Agþ with receptors 1 and 2 was observed
in the presence of most other competitive metal ions except for the
Hg2þ ion, for which interference with the detection signal abol-
ished the ratiometric effect on binding of Agþ ion. Accordingly,
these observations suggested that receptors 1 and 2 can be used as
selective fluorescent sensors for Agþ ion in the presence of most
completive metal ions.
In order to obtain detailed information on the complexation
structure of receptors 1 and 2 with Agþ ion, 1H NMR titration ex-
periments in CDCl3/CD3CN (10:1, v/v) were carried out. The partial
spectral changes are shown in Fig. 4. Upon addition of 1.0 equiv of
Agþ ion to the solution of 1,3-alternate-1, as expected, the chemical
shift of proton Hb on the triazole ring exhibited a significant
downfield shift by Dd 0.45 ppm from
the OCH2-triazole unit and Hf also demonstrated a similar but
smaller downfield shift from 4.87 to 5.06 ppm and 4.42 to
d 7.29 ppm. The peak of Hc on
d
d
4.58 ppm, respectively, whereas the peaks of the protons on the
ester moieties were little affected. Additionally, similar coordination
behavior was observed for the complexation 2$Agþ (Fig. S12). These
inhibits the p/p stacking for generating excimer emission.

X.-L. Ni et al. / Tetrahedron 67 (2011) 3248e3253
3251
that Agþ ion was included in the
p-basic benzene cavity at the lower
rim, where the two distal benzene rings were being flattened and
the residual two benzene rings were standing upright for binding
Agþ ion. Thus, we conclude that the two triazole groups and the
ionophoricity cavity, formed by the two inverted benzene rings with
the sulfur atoms framework based on thiacalix[4]arene, are all
involved in the complexation with the Agþ ion.21
3. Conclusion
In conclusion, we have synthesized a new type of fluorescent
sensor having triazole rings as cation-binding sites on the lower
rim of a thiacalix[4]arene scaffold with 1,3-alternate conformation.
The selective binding behavior of receptors 1 and 2 has been
evaluated by fluorescence spectra and 1H NMR analysis. All the
results suggested that the triazole moieties on the receptors 1 and 2
are highly sensitive and selective for Agþ. This is due to cooperative
coordination by the ionophoricity cavity, formed by the two
inverted benzene rings and the sulfur atoms of the thiacalix[4]
arene, by enhancement of the monomer emission of pyrene.
Fig. 3. Fluorescence response of 1 (5.0
various tested metal ions (black bar) and to the mixture of 100
with 100
M Agþ ion (blue bar) at 298 K. I0 is the fluorescence intensity at 378 nm for
free 1, and I is the fluorescence intensity after adding metal ions with an excitation at
343 nm.
m
M) in CH3CN/CH2Cl2 (1000:1, v/v) to 100
mM
m
M tested metal ions
m
4. Experimental section
4.1. General
All melting points (Yanagimoto MP-S1) are uncorrected. NMR
spectra were determined at 300 MHz with a Nippon Denshi JEOL
FT-300 spectrometer with Me4Si as an internal reference: J values
are given in hertz. IR spectra were measured for samples as KBr
pellets in a JASCO FT/IR 4200. All the fluorescence spectra were
recorded on a JASCO FP-6200 spectrometer. Mass spectra were
obtained on a Nippon Denshi JMS-01SG-2 mass spectrometer at
ionization energy of 70 eV using a direct inlet system through GLC.
Elemental analyses were performed by Yanaco MT-5.
4.2. Materials
Compounds 4,14 6,22 and 815b were prepared following the
reported procedure.
4.2.1. 5,11,17,23-Tetra-tert-butyl-25,27-bis(ethoxycarbonylmeth
oxy)-26,28-[bis(propargyloxy)]-tetrathiacalix[4]arene (1,3-alternate-
5). Cone-4 (300 mg, 0.34 mmol) and Cs2CO3 (1.085 g, 3.33 mmol)
were refluxed for 1 h in dry acetone (15 mL). 3-Bromo-1-propyne
[propargyl bromide (396 mg, 3.33 mmol)] and dry acetone (10 mL)
was added and the mixture refluxed for 20 h. The solvents were
evaporated and the residue partitioned between 10% HCl and
CH2Cl2. The organic layer was separated and dried (MgSO4) and the
solvents were evaporated. The residue was recrystallized from
CHCl3/hexane (3:1) to afford 1,3-alternate-5 (210 mg, 64%) as
prisms. Mp 223e225 ꢂC. 1H NMR (300 MHz, CDCl3)
d 1.06 (18H, s,
Fig. 4. Plausible complexation structure of receptor 1 for Agþ ion, and partial 1H NMR
spectra of 1 (5.0 mM) in CDCl3/CD3CN (10:1, v/v) upon addition of 1.0 equiv Agþ ion at
298 K; (partial tert-butyl moieties are omitted for clarity).
tBu), 1.28 (6H, m, CH2CH3), 1.40 (18H, s, Bu), 2.10 (1H, t, J¼3.0 Hz,
acetylene-H), 2.44 (1H, m, acetylene-H), 4.25 (4H, q, J¼7.1 Hz,
CH2CH3), 4.61 (4H, s, CH2), 4.83 (4H, s, CH2), 7.46 (4H, s, ArH), 7.59
(4H, s, ArH). IR: nmax (KBr)/cmꢀ1 3309, 2958, 1768, 1575, 1440, 1367,
1268, 1193, 1085, 1010. FABMS: m/z 969.39 (Mþ). Anal. Calcd for
C54H64O8S4 (969.35): C, 66.91; H, 6.66. Found: C, 67.09; H, 6.70.
t
spectral changes suggested that Agþ ion can be selectively bound by
the nitrogen atoms on the triazole rings. On the other hand, it
should be noted that the protons of Hd and He on the phenol 1,3-
alternate thiacalix[4]arene also experienced a downfield shift from
4.2.2. 5,11,17,23-Tetra-tert-butyl-25,27-bis(ethoxycarbonylmeth
oxy)-26,28-bis[1H-(1-pyrenylmethyl-(1,2,3-triazolyl)-4-methoxy)]-
tetrathiacalix[4]arene (1,3-alternate-1). Copper iodide (20 mg) was
added to a solution of 1,3-alternate-5 (174 mg, 0.18 mmol) and 1-
(azidemethyl)pyrene 8 (139 mg, 0.54 mmol) in 20 mL THF/H2O
(4:1) and the mixture was heated at 65 ꢂC for 24 h. The resulting
solution was cooled and diluted with water and extracted thrice
with CH2Cl2. The organic layer was separated and dried (MgSO4)
d
7.32 to 7.50 ppm and an upfield shift from d 7.26 to 6.98 ppm,
respectively. These data further indicated that there must be a con-
formational change for receptor 1 in the presence of Agþ ion. As
a matter of fact, it is believed that the conformation of thiacalix[4]
arene can be preorganized for the binding of Agþ ion in solution in
a manner, that is, similar to an example described by Shinkai and co-
workers.20 In that case, the X-ray structure clearly demonstrated

3252
X.-L. Ni et al. / Tetrahedron 67 (2011) 3248e3253
and evaporated to give the solid crude product. The residue eluted
from a column chromatography of silica gel with hexane/ethyl ac-
etate (v/v¼4:1) to give the desired product 1,3-alternate-1 (194 mg,
73%) as colorless prisms. Mp 154e156 ꢂC. 1H NMR (300 Hz, CDCl3)
solid crude product. The residue eluted from a column chroma-
tography of silica gel with hexane/ethyl acetate (6:1, v/v) to give the
desired product 3 (134 mg, 60%) as pale yellow prisms. Mp
147e149 ꢂC. 1H NMR (300 MHz, CDCl3) 1.24 (9H, s, tBu), 5.07 (2H,
d
d
0.88 (18H, s, tBu), 1.08 (18H, s, tBu), 1.22 (6H, t, J¼7.1 Hz, CH2CH3),
s, CH2), 6.25 (2H, s, CH2), 6.82 (2H, d, J¼5.4 Hz, ArH), 7.22 (2H, d,
4.15 (4H, q, J¼7.1 Hz, CH2CH3), 4.45 (4H, s, CH2), 4.84 (4H, s, CH2),
6.28 (4H, s, CH2), 7.24 (4H, s, ArH), 7.28 (2H, s, Triazole-H), 7.33 (4H,
s, ArH), 7.88 (2H, d, J¼9.0 Hz, Pyrene-H), 7.99e8.23 (14H, m, Pyrene-
H), 8.34 (2H, d, J¼9.0 Hz, Pyrene-H). 13C NMR (75 MHz, CDCl3):
14.07, 22.59, 31.01, 33.82, 52.08, 60.43, 64.85, 67.60, 122.18, 123.22,
124.45, 124.85, 124.94, 125.62, 125.71, 126.21, 127.18, 127.25, 128.04,
128.23, 128.79, 129.07, 130.54, 131.13, 131.84, 131.96, 133.15, 144.59,
145.97, 146.00, 156.51, 157.20, 167.91. IR: nmax (KBr)/cmꢀ1 2960,
2360, 1768, 1442, 1380, 1265, 1190, 1045. FABMS: m/z 1483.42 (Mþ).
Anal. Calcd for C88H86N6O8S4 (1483.92): C, 71.23; H, 5.84; N, 5.66.
Found: C, 71.09; H, 5.70; N, 5.64.
J¼5.4 Hz, ArH), 7.37 (1H, s, Triazole-H), 7.94e8.25 (9H, m, Pyrene-
H). 13C NMR (75 MHz, CDCl3)
d 31.41, 33.98, 52.42, 62.10, 114.19,
121.85, 124.42, 124.88, 125.02, 125.79, 125.90, 126.15, 126.35, 126.61,
127.15, 127.62, 128.27, 129.03, 129.26, 130.51, 131.12, 132.10, 143.84,
155.88. IR: nmax (KBr)/cmꢀ1 2954, 2360, 1768, 1442, 1380, 1265,
1190, 1045. FABMS: m/z 445.26 (Mþ). Anal. calcd for C30H27N3O
(445.57): C, 80.87; H, 6.11; N, 9.43. Found: C, 80.62; H, 6.03; N, 9.36.
Acknowledgements
We would like to thank the OTEC at Saga University and the
International Collaborative Project Fund of Guizhou province at
Guizhou University for financial support. We also would like to
thank the EPSRC (for a travel grant to C.R.).
4.2.3. 5,11,17,23-Tetra-tert-butyl-25,27-dibenzyloxy-26,28-[bis-
(propargyloxy)]-tetrathiacalix[4]arene (7). A suspension of com-
pound 6 (300 mg, 0.333 mmol) and Cs2CO3 (1.085 g, 3.33 mmol)
was refluxed for 1 h in dry acetone (15 ml). A solution of 3-bromo-
1-propyne [propargyl bromide (396 mg, 3.33 mmol)] in dry acetone
(10 ml) was added and the mixture refluxed for 20 h. The solvents
were evaporated and the residue partitioned between 10% HCl and
CH2Cl2. The organic layer was dried (MgSO4) and evaporated. The
residue was recrystallized from CHCl3/hexane (1:3, v/v) to afford
the desired product 7 as colorless prisms with a yield of 81%
Supplementary data
Experimental procedures, 1H and 13C NMR spectral data, fluo-
rescence and 1H NMR titration spectra data are available. Supple-
mentary data related to this article can be found online at
doi:10.1016/j.tet.2011.03.008.
(263.5 mg). Mp 180e182 ꢂC. 1H NMR (300 MHz, CDCl3)
d
0.60, 0.85,
t
0.98, 1.11, 1.31 (each s, 36H, Bu), 2.20e2.51, 4.41e5.08 (m, 10H,
acetylene-H, ArOeCH2eacetylene and ArOeCH2ePh) and 7.0e8.8
(18H, m, ArH). IR: nmax (KBr)/cmꢀ1 3307, 2960, 1575, 1432, 1367,
1265, 1085, 1008. FABMS: m/z 977.4 (Mþ). Anal. Calcd for
C60H64O4S4 (977.42): C, 73.74; H, 6.61. Found: C, 74.10; H, 6.67. The
splitting pattern in 1H NMR shows that the isolated compound is
a mixture of cone- and partial-cone-7.
References and notes
1. (a) de Silva, A. P.; Gunaratne, H. Q. N.; Gunnlaugsson, T.; Huxley, A. J. M.; McCoy,
C. P.; Rademacher, J. T.; Rice, T. E. Chem. Rev. 1997, 97, 1515e1566; (b) Desvergne,
J.-P.; Czarnik, A. W. Chemosensors of Ion and Molecular Recognition; Kluwer:
Dordrecht, The Netherlands, 1997.
2. (a) Winnik, F. M. Chem. Rev. 1993, 93, 587e614; (b) Fabbrizzi, L.; Poggi, A. Chem.
Soc. Rev. 1995, 24, 197e202; (c) Suzuki, Y.; Morozumi, T.; Nakamura, H. J. Phys.
Chem. B 1998, 102, 7910e7917; (d) Yang, J.-S.; Lin, C.-S.; Hwang, C.-Y. Org. Lett.
2001, 3, 889e892; (e) Kim, J. S.; Choi, M. G.; Song, K. C.; No, K. T.; Ahn, S.; Chang,
S.-K. Org. Lett. 2007, 9, 1129e1132.
4.2.4. 5,11,17,23-Tetra-tert-butyl-25,27-bisbenzyl-26,28-bis[1H-(1-
pyrenylmethyl-(1,2,3-triazolyl)-4-methoxy)]-tetrathiacalix[4]arene
(1,3-alternate-2). Copper iodide (20 mg) was added to compound 7
(112 mg, 0.12 mmol) and azide 8 (92 mg, 0.36 mmol) in 20 mL THF/
H2O (4:1) and the mixture was heated at 65 ꢂC for 24 h. The
resulting solution was cooled and diluted with water and extracted
thrice with CH2Cl2. The organic layer was separated and dried
(MgSO4) and evaporated to give the solid crude product. The resi-
due eluted from a column chromatography of silica gel with hex-
€
3. (a) Bohmer, V. Angew. Chem., Int. Ed. Engl.1995, 24, 713e745; (b) Ikeda, A.; Shinkai,
S. Chem. Rev. 1997, 97, 1713e1734; (c) Kim, J. S.; Quang, D. T. Chem. Rev. 2007, 107,
3780e3799; (d) Leray, I.; Valeur, B. Eur. J. Inorg. Chem. 2009, 3525e3535.
4. Diamond, D.; McKervey, M. A. Chem. Soc. Rev. 1996, 25, 15e24.
5. Gutsche, C. D. In Calixarenes Revisited: Monographs in Supramolecular Chemistry;
Stoddart, J. F., Ed.; The Royal Society of Chemistry: Cambridge, 1998.
6. (a) Kumagai, J.; Hasegawa, M.; Miyanari, S.; Sugawa, Y.; Sato, Y.; Hori, T.; Ueda,
S.; Kamiyama, H.; Miyano, S. Tetrahedron Lett. 1997, 38, 3971e3972; (b) Iki, N.;
Kabuto, C.; Fukushima, T.; Kumagai, H.; Takeya, H.; Miyanari, S.; Miyashi, T.;
Miyano, S. Tetrahedron 2000, 56, 1437e1443.
ꢀ
7. (a) Lhotak, P. Eur. J. Org. Chem. 2004, 1675e1692; (b) Shokova, E. A.; Kovalev, V.
ane/CH2Cl2 (1:1, v/v) to give the desired product (92 mg, 51%). Mp
V. Russ. J. Org. Chem. 2003, 39, 1e28; (c) Morohashi, N.; Narumi, F.; Iki, N.;
t
134e136 ꢂC. 1H NMR (300 MHz, CDCl3)
d
0.46 (18H, s, Bu), 1.14
€
Hattori, T.; Miyano, S. Chem. Rev. 2006, 106, 5291e5316; (d) Csokai, V.; Grun, A.;
t
ꢀ
ꢀ
Balazs, B.; Simon, A.; Toth, G.; Bitter, I. Tetrahedron 2006, 62, 10215e10222; (e)
Stoikov, I. I.; Yushkova, E. A.; Zhukov, A. Y.; Zharov, I.; Antipin, I. S.; Konovalov,
A. I. Tetrahedron 2008, 64, 7489e7497; (f) Kumar, M.; Dhir, A.; Bhalla, V.
Tetrahedron 2009, 65, 7510e7515.
(18H, s, Bu), 4.64 (4H, s, CH2eTriazole), 5.08 (4H, s, CH2Ph), 6.24
(4H, CH2ePyrene), 6.74 (4H, s, ArH), 7.11e6.9 (14H, m, PheH), 7.45
(2H, s, TriazoleeH) 7.86e8.28 (18H, m, PyreneeH). 13C NMR
8. (a) Ratte, H. T. Environ. Toxicol. Chem. 1999, 18, 89e108; (b) Zhang, X. B.; Han, Z.
X.; Fang, Z. H.; Shen, G. L.; Yu, R. Q. Anal. Chim. Acta 2006, 562, 210e215.
9. McClure, D. S. J. Chem. Phys. 1952, 20, 682e686.
(75 MHz, CDCl3)
d 30.38, 31.25, 33.41, 34.15, 52.26, 63.93, 72.69,
122.29, 123.29, 124.52, 124.84, 125.01, 125.75, 125.79, 126.29,
126.83, 126.97, 127.23, 127.29, 127.34, 127.41, 127.85, 127.99, 128.16,
128.98, 129.24, 129.69, 129.76, 130.62, 131.22, 131.98, 132.98, 137.86,
143.99, 145.58, 146.01, 155.56, 158.09. IR: nmax (KBr)/cmꢀ1 2960,
2364, 1646, 1434, 1375, 1265, 1083. FABMS: m/z 1491.23 (Mþ). Anal.
Calcd for C94H86N6O4S4 (1491.99): C, 75.67; H, 5.81; N, 5.63. Found:
C, 75.35; H, 5.67; N, 5.54.
10. Varnes, A. W.; Dodson, R. B.; Whery, E. L. J. Am. Chem. Soc. 1972, 94, 946e950.
11. (a) Rurack, K.; Kollmannsberger, M.; Resch-Genger, U.; Daub, J. J. Am. Chem. Soc.
2000, 122, 968e969; (b) Kim, J. S.; Shon, O. J.; Rim, J. A.; Kim, S. K.; Yoon, J. J. Org.
Chem. 2002, 67, 2348e2351; (c) Yang, R.-H.; Chan, W.-H.; Lee, A. W. M.; Xia, P.-F.;
Zhang, H.-K.; Li, K. J. Am. Chem. Soc. 2003,125, 2884e2885; (d) Coskun, A.; Akkaya,
E. U. J. Am. Chem. Soc. 2005, 127, 10464e10465; (e) Iyoshi, S.; Taki, M.; Yamamoto,
Y. Inorg. Chem. 2008, 47, 3946e3948; (f) Nolan, E. M.; Lippard, S. J. Chem. Rev. 2008,
108, 3443e3480; (g) Joseph, R.; Ramanujam, B.; Acharya, A.; Rao, C. P. J. Org. Chem.
2009, 74, 8181e8190; (h) Chatterjee, A.; Santra, M.; Won, N.; Kim, S.; Kim, K. J.;
Kim, B. S.; Ahn, H. K. J. Am. Chem. Soc. 2009, 131, 2040e2041; (i) Wang, H.-H.; Xue,
L.; Qian, Y.-Y.; Jiang, H. Org. Lett. 2010, 12, 292e295.
12. Rurack, K.; Resch-Genger, U.; Rettig, W. J. Photochem. Photobiol., A 1998, 118,
143e149.
13. Ni, X.-L.; Wang, S.; Zeng, X.; Tao, Z.; Yamato, T. Org. Lett. 2011, 13, 552e555.
14. Iki, N.; Narumi, F.; Fujimoto, T.; Morohashi, N.; Miyano, S. J. Chem. Soc., Perkin
Trans. 2 1998, 2745e2750.
4.2.5. 4-tert-Butyl-[1H-(1-pyrenylmethyl-(1,2,3-triazolyl)-4-me-
thoxy)] benzene (3). A mixture of 4-tert-butyl-1-(propargyloxy)
benzene (95 mg, 0.5 mmol) and 8 (140 mg, 1.1 mmol) in 20 mL THF/
H2O (4:1) and the mixture was heated at 65 ꢂC for 24 h at the
presence of CuI as catalyst. The resulting solution was cooled and
diluted with water and extracted thrice with CH2Cl2. The organic
layer was separated and dried (MgSO4) and evaporated to give the
15. (a)Broan,C.J.Chem.Commun.1996, 699e700;(b)Park,S.-Y.;Yoon,J.-H.;Hong, C.-S.;
Souane, R.; Kim, J.-S.; Matthews, S. E.; Vicens, J. J. Org. Chem. 2008, 73, 8212e8218.

X.-L. Ni et al. / Tetrahedron 67 (2011) 3248e3253
3253
16. (a) Chang, K.-C.; Su, I.-H.; Senthilvelan, A.; Chung, W.-S. Org. Lett. 2007, 9,
3363e3366; (b) Ojida, A.; Mito-oka, Y.; Inoue, M.-A.; Hamachi, I. J. Am. Chem.
Soc. 2002, 124, 6256e6258; (c) Choi, M.; Kim, M.; Lee, K. D.; Han, K.-N.; Yoon,
I.-A.; Chung, H.-J.; Yoon, J. Org. Lett. 2001, 3, 3455e3457.
17. Chae, M.-Y.; Cherian, X. M.; Czarnik, A. W. J. Org. Chem. 1993, 58, 5797e5801.
18. (a) Benesi, H. A.; Hildebrand, J. H. J. Am. Chem. Soc. 1949, 71, 2703e2707; (b)
Stern, O.; Volmer, M. Phys. Z. 1919, 20, 183e188.
19. Job, P. Ann. Chim. 1928, 9, 113e203.
20. Ikeda, A.; Tsuzuki, H.; Shinkai, S. J. Chem. Soc., Perkin Trans. 2 1994, 2073e2080.
ꢀ
ꢁ
ꢀ
ꢀ
21. (a) Sykona, J.; Himl, M.; Stibor, I.; Císarova, I.; Lhotak, P. Tetrahedron 2007, 63,
2244e2248; (b) Iki, N. J. Inclusion Phenom. Macrocyclic Chem. 2009, 64, 1e13; (c)
Kumar, M.; Kumar, R.; Bhalla, V. Org. Lett. 2011, 13, 366e369.
ꢀ
22. Ni, X.-L.; Tomiyasu, H.; Shimizu, T.; Perez-Casas, C.; Zeng, X.; Yamato, T.
J. Inclusion Phenom. Macrocyclic Chem. 2010, 68, 99e108.