Cu(I) and Zn(II) chelations on polymer beads modified by attachment of a bipyridyl-calixarene-based chelate

Article abstract of DOI:10.1016/j.tetlet.2009.07.131

A new chelating calix[4]arene derivative incorporating two bipyridyl groups and one primary amino attachment function at the lower rim has been synthesised and coupled to Wang benzaldehyde resin. The new material effectively displayed complexation abiliti

Full text of DOI:10.1016/j.tetlet.2009.07.131

Tetrahedron Letters 50 (2009) 5793–5797
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Cu(I) and Zn(II) chelations on polymer beads modified by attachment
of a bipyridyl-calixarene-based chelate
*
Yannick de Gaetano, Igor Clarot, Jean-Bernard Regnouf-de-Vains
SRSMC, UMR 7565 Nancy Université, CNRS, équipe GEVSM, Faculté de Pharmacie, 5, rue Albert Lebrun, 54001 Nancy Cedex, France
a r t i c l e i n f o
a b s t r a c t
Article history:
A new chelating calix[4]arene derivative incorporating two bipyridyl groups and one primary amino
attachment function at the lower rim has been synthesised and coupled to Wang benzaldehyde resin.
The new material effectively displayed complexation abilities towards Cu(I) and Zn(II) transition metal
cations. The grafting efficiency was evaluated and quantified by complexation experiments, using UV/vis-
ible spectrophotometry, and ionic chromatography.
Received 9 May 2009
Revised 17 July 2009
Accepted 27 July 2009
Available online 6 August 2009
Ó 2009 Published by Elsevier Ltd.
Keywords:
Calixarene
Bipyridine
Copper(I)
Zinc(II)
Polymer supported
Extraction
UV/visible spectroscopy
Ionic chromatography
Copper and zinc are common metals widely employed in house
roofs and rain collectors, prone to atmospheric aggression, dissolu-
tion by rain and introduction as salts in local watersheds.1 Collect-
ing these ions before dilution in waterways can be of high
environmental concern. This may involve solid phase extraction,
notably with polymeric materials designed as metal sequestering
agents. Some recent works deal, for example, with chitosan grafted
with 8-hydroxyquinolein groups,2 polystyrene grafted with 6-mer-
captopurinylazo3 or aminosulfonyl4 groups, amidoxime-, amidraz-
one- or oxazoline-derivatives of polyacrylonitrile,5 Merrifield or
poly(glycidylmethacrylate) resins grafted with various pyridyl
derivatives6 or silica-gel coated with terpyridine-norbornene
block-copolymers.7 Polymers supporting pre-organised complex-
ing units have also been studied. For example, glycidyl(polymeth-
tred properties.11 Some of these contributions are devoted to
polymerised or polymer-grafted calixarene derivatives. For the lat-
ter, recent examples deal with covalent attachment of various ca-
lix[4]arene podands for preconcentration/separation of various
metal ions: including copper and zinc, on chitosan;12 including
copper but not zinc, on Merrifield resin derivatives,13 polysty-
rene,14 chitosan,15 cellulose,16 dextran17 and silica-gel.18
It has been shown that calixarene derivatives integrating two
2,20-bipyridine chelating units in alternate positions of the lower
rim gave tetrahedral mononuclear complexes with Cu(I) salts and
zinc triflate, and a dinuclear species with zinc chloride.19 With
the objective of developing extracting polymers incorporating such
calixarene-bipyridyl units, we describe in the present report (i) the
synthesis of a new bifunctional calix[4]arene species, aimed at
complex ions with tetrahedral coordination geometry and
incorporating for this purpose two 6-methylene-[60-methyl-2,20-
bipyridine]yl arms in alternate position of the lower rim, and a
p-aminoethyl-phenoxypropyl attachment group on one of the
two residual phenol units; (ii) the grafting of this compound on
Wang-benzaldehyde resin; and (iii) the simultaneous evaluation
of grafting efficiency and some complexation properties towards
copper(I) and zinc(II) species of the new materials, using UV/visible
spectrophotometry and ionic chromatography.
acrylates
incorporating
carboxymethylated
pentaethylene
hexamine,8 or various polyaza/thia/oxa-crown ethers9 have been
recently described. Aza-crowns were also attached to silica-gel
for similar purpose.10
Due to the possibilities they offer in terms of structural and
functional modifications, the calixarene platforms are subjected
to intense investigations in particular for the building of highly
organised metal chelators, with objectives of separation, purifica-
tion, waste depollution and evaluation/use of various metal-cen-
The bis-bipyridyl calix[4]arene 1, prepared according to the lit-
erature,20 was reacted with (p-boc-aminoethyl)phenyl-(3-bromo-
propyl)ether21 in dry DMF and NaH, to give the podand 2 with a
yield of 80%. The Boc-protective group was removed by treatment
* Corresponding author. Tel.: +33 3 8368 2315; fax: +33 3 8368 2345.
E-mail address: jean-bernard.regnouf@pharma.uhp-nancy.fr (J.-B. Regnouf-de-
Vains).
0040-4039/$ - see front matter Ó 2009 Published by Elsevier Ltd.
doi:10.1016/j.tetlet.2009.07.131

5794
Y. de Gaetano et al. / Tetrahedron Letters 50 (2009) 5793–5797
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
of 2 with TFA in CH2Cl2, to give the salt 3 with a yield of 90%
(Scheme 1).
0.8
The two new intermediates 2 and 3 gave satisfactory analyses,
in accordance with the proposed formulas. 1H and 13C NMR
showed that they are in the cone conformation, the necessary con-
dition for exhibiting the expected complexation properties.22 The
functional polymer 4 was prepared by stirring the Wang benzalde-
hyde resin, the amine salt 3 and NEt3 in toluene at 50 °C under ar-
gon, during 48 h. The time of reaction was evaluated by the
observation of colouration of an aliquot of resin after treatment
by a Cu(I) salt.
The grafting yield was first appreciated by elemental analysis.
Taking into account the concentration of CHO groups available in
commercial Wang benzaldehyde resin (3.0 ꢀ 10ꢁ3 mol gꢁ1), its
general formula was evaluated to be C69.8H66.2O6, resulting in cal-
culated proportions of 83.70% C, 6.60% H and 0.00% N. The combus-
tional analysis afforded approaching values, with 83.20% C, 6.65% H
and 0.00% N. The polymer 4 gave in this case 80.71% C, 6.36% H and
0.58% N. The grafting was confirmed by the presence of N, the pro-
portion of which corresponds at least to 41.4 ꢀ 10ꢁ3 mol of N, or to
8.3 ꢀ 10ꢁ3 mol (5 available N atoms), that is, 9.8 g of calixarene
subunit (free base of 3, MW = 1189.7) in 100.0 g of 4. The mass
of corresponding starting polymer was thus evaluated at 90.2 g.
Relating the number of calixarene subunits to the number of ini-
tially available CHO sites gave a grafting yield of 3.1%.
A mass gain of 0.073 g was observed with a 0.5 g Wang resin
sample. The latter, treated in similar conditions but without 3
and NEt3, lost 0.021 g of the substance. Considering this loss to
be recurrent, the mass of grafted calixarene in polymer 4 was eval-
uated to be 0.094 g, corresponding to a grafting yield of 5.5%.
Before extraction experiments, the complexation abilities of the
calixarene subunit were evaluated in solution by UV/visible spec-
troscopy with the organosoluble derivative 2, expecting a similar
behaviour in polymer 4. By analogy with similar ligands,19 2 should
give tetrahedral mononuclear complexes with Cu(I) salts and zinc
triflate, and a dinuclear species with zinc chloride. As shown in
Figure 1, the addition of Cu(MeCN)4PF6 to a solution of 2 in CH2Cl2
resulted in the bathochromic shift of the bipyridyl transitions from
290 nm to 302 nm, with an isosbestic point at 296 nm, and the
appearance of the expected MLCT (Metal-to-Ligand Charge Trans-
fer) band at ca. 445 nm; the evolution of the spectrum was
0.75
a
b
c
f
0.7
0.65
0.6
0.55
0.5
0.45
0.4
280
285
290
295
300
305
240
290
340
390
440
λ (nm)
490
540
590
Figure 1. UV/vis titration of 2 by Cu(MeCN)4PF6 in CH2Cl2. [2] = 1.6 ꢀ 10ꢁ5 M,
[Cu(I)] = 3.85 ꢀ 10ꢁ4 M, Valiquot = 12.4
(f)): 2 + 0.4–1.0 equiv Cu(I).
lL. (a) Free 2; (b) 2 + 0.1 equiv Cu(I); (c) to
completed at 1 equiv of metal salt, confirming the expected ML
stoichiometry.
The addition of ZnCl2 to a solution of 2 in CH2Cl2 resulted in the
bathochromic shift of the bipyridyl transitions from 291 nm to 309
and 320 nm, with two isosbestic points at 299 nm then at 301 nm;
the evolution of the spectrum was completed at 2 equiv of metal
salt, resulting in the expected M2L stoichiometry (Fig. 2).19
Finally, and as shown in Figure 3, the addition of Zn(OTf)2 to a
solution of 2 in CH2Cl2 showed a similar bathochromic shift from
291 nm to 308 nm, with one isosbestic point at 302 nm; the evolu-
tion of the spectrum was completed at 1 equiv of metal salt, result-
ing as expected in an ML stoichiometry.19
Taking into account that these stoichiometries should be con-
served with polymer 4, the extraction experiments were carried
out against CH2Cl2 solutions of Cu(MeCN)4PF6, Zn(CF3SO3)2 and
ZnCl2 salts. The evaluation of the grafting yield, ion extraction capac-
ity and extraction kinetic was performed by direct metal-extraction
method, followed by quantification of residual metal salt. This was
done by UV/visible-monitored complexation by 6,60-dimethyl-2,20-
bipyridine (dmbp) for Cu(I) and Zn(II), and by ionic chromatography
for Zn(II). In these conditions, no uptake of copper or zinc salts was
observed with the commercial Wang resin. The typical experiment
and calculation mode are presented hereafter.
UV/visible titration by 6060-dimethyl-2,20-bipyridine (dmbp): A
fixed volume of a CH2Cl2 salt solution, at a defined concentration,
was mixed to a known mass of polymer 4, and shaken in a gas-tight
vial. A fixed volume of supernatant (0.3 mL for Cu(I) and 0.1 mL for
(i)
O
O
Boc
NH
OH
HOO
HOO
N
O
O
N
N
N
N
N
1
N
N
0.9
a
a
0.56
0.53
(ii)
1
2
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
k
0.5
0.47
299
300
301
302
grafting
(iii)
O
O
P
O
O
HOO
N
HOO
O
O
NH2
N
k
4 CF3COOH
N
N
N
N
N
N
N
3
240
260
280
300
320
340
360
380
4: P = Wang benzaldehyde resin
(nm)
λ
Scheme 1. Reagents and conditions: (i) NaH, (p-boc-aminoethyl)phenyl-(3-bro-
mopropyl)ether, DMF, 80%; (ii) TFA, CH2Cl2, 90%; (iii) Wang benzaldehyde resin,
NEt3, toluene, 50 °C.
Figure 2. UV/vis titration of
2
by ZnCl2 in CH2Cl2. [2] = 1.76 ꢀ 10ꢁ5 M,
lL. (a) Free 2; (b) to (k) 2 + 0.2–2 equiv ZnCl2.
[Zn(II)] = 4.8 ꢀ 10ꢁ4 M, Valiquot = 11

Y. de Gaetano et al. / Tetrahedron Letters 50 (2009) 5793–5797
5795
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
4.5
4
a
3.5
3
k
2.5
2
0
20
40
60
80
100
120
140
160
180
time (mn)
240
260
280
300
320
340
360
380
Figure 4. Complexation kinetics of Cu(I) on polymer 4. Titration of residual
Cu(MeCN)4PF6 by UV/vis spectroscopy (dmbp 4.95 ꢀ 10ꢁ4 mol Lꢁ1 in
CH2Cl2,455 nm). Image: polymer 4 before addition of Cu(I) salt (left) and at the
end of extraction (right).
(nm)
λ
Figure 3. UV/vis titration of
2
by Zn(OTf)2 in CH2Cl2. [2] = 1.6 ꢀ 10ꢁ5 M,
[Zn(II)] = 3.85 ꢀ 10ꢁ4 M, Valiquot = 12.4
lL. (a) Free 2; (b) to (k) 2 + 0.1–1 equiv
Zn(TfO)2.
was used and calibration was performed on aqueous solutions of
Zn(TfO)2 or ZnCl2 ranging from 1.0 to 6.0 ꢀ 10ꢁ4 M (r2 >0.99).
The Zn(II) ion was detected in these conditions with a retention
time of 4.1 min. The working solutions were the same as those
used for Zn(II) UV/visible titration experiments. A fixed volume
of supernatant (0.2 mL) was collected at regular times, and was
evaporated to dryness. The residue was dissolved in water
(0.2 mL) before injection. A typical chromatogram for ZnCl2 is gi-
ven in Figure 5A, showing the water and chloride void volume peak
Zn(II)) was collected at regular times, and was diluted by addition of
CH2Cl2 (2.0 mL) before UV/visible data collection. The final metal
concentration in the UV cell was about 5.0 ꢀ 10ꢁ5 M for Cu(I), and
about 2.8 ꢀ 10ꢁ5 M for Zn(II), in order to respect the Beer–Lambert
law (absorbance <1) at the selected wavelength (455 nm for Cu(I)
and 320 nm for Zn(II)). The concentration of residual metal salt
was evaluated by titration with a 4.95 ꢀ 10ꢁ4 M solution of dmbp,
on the assumption of the formation of an M:(dmbp)2 complex with
CuPF6 (survey at 455 nm, MLCT, = ca. 5800 molꢁ1 L cmꢁ1 23,24
and
)
Zn(TfO)2 (survey at 320 nm) and an MCl2:dmbp complex with ZnCl2
(survey at 320 nm).25 This titration was done for each sampling, un-
til stabilisation of the residual metal concentration occurred (ca.
100–240 min).
The amount of fixed metal ion was thus deduced, giving, on the
assumption of ML and M2L stoichiometries extrapolated from Fig-
ures 1–3, the amount of grafted calixarene ligand. From this step,
the calculation mode of grafting yield was similar to the one em-
ployed with the elemental analysis. The results obtained for the
three salts of the study are given in Table 1. The UV/visible kinetics
of extraction of CuPF6, Zn(CF3SO3)2 and ZnCl2 extractions are illus-
trated in Figures 4 and 6.
a
20
18
A
B
16
12
8
b
14
10
6
c
4
0
d
-4
3.5
4.5
5.5
2
Time (min.)
-2
0
1
2
3
4
5
Ion chromatography titration was performed with indirect
spectrophotometric detection (k = 220 nm) on a Zorbax 300 SCX
Time (min.)
Figure 5. (A) Typical ionic chromatogram obtained with
a
ZnCl2 solution
column (5
l
m, 250 ꢀ 4.6 mm), using
a 2.0 mM CuSO4 water
(5.7 ꢀ 10ꢁ4 M), and (B) decrease of the Zn(II) peak as a function of the contact
time with polymer 4 (a, b, c and d: 0, 15, 30 and 240 min).
solution at 3.0 mL/min as mobile phase. A 100 lL injection loop
Table 1
Data collection for the evaluation of the grafting yield in resin 4, and determination of its extraction capabilities towards Cu(I) and Zn(II) salts
Titration method
Metal salt
UV/visible
Zn(TfO)2
Ionic chromatography
CuPF6
ZnCl2
6
5.80
20.0
3.50
240
4.60
2.30
2.73
15.60
17.5
12.87
3.86
6.0
Zn(TfO)2
ZnCl2
6
Figures
4
6
6
[M]0 (10ꢁ4 mol Lꢁ1
Volume (10ꢁ3 L)
)
3.96
10.0
2.14
180
1.82
1.82
2.16
10.40
20.8
8.24
2.47
7.4
6.20
10.0
4.70
240
1.50
1.50
1.79
9.60
18.6
7.81
2.34
6.4
5.70
5.70
20.0
3.48
240
10.0
4.30
240
[M]final (10ꢁ4 mol Lꢁ1
Time (min)
)
Number of fixed metal ions (10ꢁ6 mol)
Number of fixed ligand units (10ꢁ6 mol)
Mass of fixed ligand (10ꢁ3 g)a
Mass of polymer 4 (10ꢁ3 g)
1.40
1.40
1.67
9.60
4.44
2.22
2.64
15.60
16.9
12.96
3.89
5.7
Mass ratio—loading amount (%)
Mass of original polymer (10ꢁ3 g)
Initial number of CHO groups (10ꢁ5 mol)
Grafting yield (%)
17.5
7.93
2.38
6.9
Mass (g) of metal/kg polymer 4
Mass (g) of salt/kg polymer 4
Moles of salt/kg polymer 4
11.0
36.4
0.174
10.2
56.7
0.156
19.3
40.2
0.295
9.5
53.0
0.146
18.6
38.9
0.285
a
Molecular weight of 3, free base form: 1189.7.

5796
Y. de Gaetano et al. / Tetrahedron Letters 50 (2009) 5793–5797
6.5
6
to 5.5% calculated from mass gain evaluation, but is the double
of the one obtained by elemental analysis (3.1%); taking into ac-
count the low amount of nitrogen measured here (0.58%) and the
precision of the combustional method ( 0.2% by element), we have
to consider that the elemental analysis is not pertinent enough for
polymer 4.
We have prepared a new polymer including a bis-bipyridyl-cal-
ixarene chelating agent aimed at complex metal ions with a tetra-
hedral coordination geometry. Its demonstrated chelating
properties are currently explored in separation studies involving
various metal ions of economical or environmental interest.
5.5
5
4.5
4
3.5
3
Acknowledgements
0
40
80
120
160
200
240
We thank the Ministère de la Recherche et de l’Enseignement
Supérieur, particularly Y. De Gaetano for a PhD grant, the CNRS
and the Région Lorraine for financial support and SAFAS (Monaco)
for UV facilities. We also thank Mr Eric Dubs for synthesis of start-
ing materials, and Mrs. N. Marshall for correcting the manuscript.
time (mn)
Figure 6. Complexation kinetics of ZnCl2 (broad line) and Zn(OTf)2 (thin line) on
functionalised Wang resin 4. Titration of residual ZnCl2 and Zn(OTf)2 by ionic
chromatography (
at 320 nm (O)).
D
) and UV/vis spectroscopy (dmbp 4.95 ꢀ 10ꢁ4 mol Lꢁ1 in CH2Cl2,
References and notes
at 1.0 min and the expected Zn(II) peak at 4.1 min. The decrease of
the residual Zn(II) peak after contact with the grafted polymer 4 is
illustrated in Figure 5B from 0 to 240 min (curves a–d).
The concentration of residual Zn(II) ion was directly evaluated
from the corresponding peak surface. The calculations were similar
to UV/visible titration experiments (Table 1). The ion chromatogra-
phy kinetics of extraction of Zn(CF3SO3)2 and ZnCl2 extractions are
illustrated in Figure 6.
1. For example: (a) Arnold, R. Integr. Environ. Assess. Manage. 2005, 1, 333–342; (b)
Ludwig, T.; Jekel, M. Vom Wasser 2007, 105, 15–19; (c) Kraft, U.; Goldschmidt,
R.; Freese, D. Wasser, Luft und Boden 2007, 51, 40–42; (d) Hullmann, H.; Kraft, U.
Metall 2002, 56, 125–130.
2. Carletto, J. S.; Di Pietro Roux, K. C.; Maltez, H. F.; Martendal, E.; Carasek, E. J.
Hazard. Mater. 2008, 157, 88–93.
3. Mondal, B. C.; Das, D.; Das, A. K. J. Trace Elem. Med. Biol. 2002, 16, 145–148.
4. Jeragh, B. J. A.; Elassar, A-Z. A.; El-Dissouki, A. J. Appl. Polym. Sci. 2005, 96, 1838–
1846.
5. de Santa Maria, L. C.; Amorim, M. C. V.; Aguiar, M. R. M. P.; Guimaraes, P. I. C.;
Costa, M. A. S.; Palermo de Aguiar, A.; Rezende, P. R.; Souza de Carvalho, M.;
Barbosa, F. G.; Andrade, J. M.; Ribeiro, R. C. C. React. Funct. Polym. 2001, 49, 133–
143.
6. (a) Greig, J.; Hancock, R.; Lindsay, D. WO 8702273.; (b) Lindsay, D.; Sherrington,
D.; Greig, J.; Hancock, R. Chem. Commun. 1987, 1270–1272.
7. Glatz, I.; Mayr, M.; Hoogenboom, R.; Schubert, U. S.; Buchmeiser, M. R. J.
Chromatogr., A 2003, 1015, 65–71.
8. Kagaya, S.; Maeba, E.; Inoue, Y.; Kamichatani, W.; Kajiwara, T.; Yanai, H.; Saito,
M.; Tohda, K. Talanta 2009, 79, 146–152.
9. (a) van de Water, L. G. A.; Driessen, W. L.; Glenny, M. W.; Reedijk, J.; Schröder,
M. React. Funct. Polym. 2002, 51, 33–47; (b) van de Water, L. G. A.; Driessen, W.
L.; Reedijk, J.; Sherrington, D. C. Eur. J. Inorg. Chem. 2002, 221–229; (c) van de
Water, L. G. A.; ten Hoonte, F.; Driessen, W. L.; Reedijk, J.; Sherrington, D. C.
Inorg. Chim. Acta 2000, 303, 77–85.
10. Bradshaw, J. S.; Krakowiak, K. E.; Tarbet, B. J.; Bruening, R. L.; Biernat, J. F.;
Bochenska, M.; Izatt, R. M.; Christensen, J. J. Pure Appl. Chem. 1989, 61, 1619–
1624.
One can observe that the amount of complexed ZnCl2 is approx-
imately the double of Zn(OTf)2, in accordance with the expected
M2L and ML stoichiometries. This corresponds, depending on the
ligand behaviour of counter-anion (Clꢁ: coordinating; TfOꢁ: non-
coordinating), to an extraction capacity of 0.29–0.15 mmol by
gram (or 20 to ca. 10 g of pure metal ion by kilogram) for 4. The lat-
ter appears thus less efficient than the N-sulfonylpolyamine resins
described by Jeragh et al. (0.85 mmol gꢁ1)4 or than the 6-mercapto-
purinylazo resin of Mondal et al. (0.52 mmol gꢁ1),3 but equivalent
to or better than poly-(O-,S-)glycidylmethacrylate resins incorpo-
rating N,O,S- (0.05–0.13 mmol gꢁ1),9a N,O- (0.05 mmol gꢁ1 9b
N,S-crown ethers (0.10–0.15 mmol gꢁ1 9c
described by Driessen
and coll.
)
or
)
As shown in Figure 6, the complexation of zinc salts by resin 4 is
achieved between 40 min and 1 h of contact, close to the 14 min
described for a 50% uptake by 6-mercaptopurinylazo resin,3 or
20 min for a 100% uptake by the N-sulfonylpolyamine resins men-
tioned above.4 No kinetic data were available for the above men-
tioned crown ether-derived polymers, except a contact time of
48 h.
11. (a) Calixarenes for Separations; Lumetta, L. G., Rogers, R. D., Gopalan, A. S.,
Eds.ACS Symposiums Series 757; American Chemical Society, 2000; (b)
Calixarenes 2001; Asfari, Z., Böhmer, V., Horrowfield, J., Vicens, J., Eds.;
Kluwer Academic: Dordrecht, 2001.
12. Gong, S.; Hu, C.; Wang, W.; Liu, Q. Wuhan Daxue Xuebao, Yixebueban 2004, 50,
458–462. CA 143: 175016.
13. (a) Gungor, O.; Memon, S.; Yilmaz, M.; Roundhill, D. M. React. Funct. Polym.
2005, 63, 1–9; Case of thiacalixarene: (b) Tabakci, B.; Beduk, A. D.; Tabakci, M.;
Yilmaz, M. React. Funct. Polym. 2006, 66, 379–386; (c) Alexandratos, S. D.;
Natesan, S. Macromolecules 2001, 34, 206–210.
14. Memon, S.; Akceylan, E.; Sap, B.; Tabakci, M.; Roundhill, D. M.; Yilmaz, M. J.
Polym. Environ. 2003, 11, 67–74.
15. (a) Tabakci, M.; Yilmaz, M. Bioresour. Technol. 2008, 99, 6642–6645; Tang, X.;
Zhang, A.; Zhou, S.; Xiong, J. Huaxue Yanjiu Yu Yingyong 2003, 15, 274–275. CA
141: 227134.
16. Tabakci, M.; Erdemir, S.; Yilmaz, M. J. Hazard. Mater. 2007, 148, 428–435.
17. Engrand, P.; Regnouf-de-Vains, J.-B. Tetrahedron Lett. 2002, 43, 8863–8866.
18. Tabakci, M.; Yilmaz, M. J. Hazard. Mater. 2008, 151, 331–338.
19. Dalbavie, J.-O.; Regnouf-de-Vains, J.-B.; Lamartine, R.; Perrin, M.; Lecocq, S.;
Fenet, B. Eur. J. Inorg. Chem. 2002, 4, 901–909. and references cited therein.
20. Regnouf de Vains, J.-B.; Lamartine, R. Helv. Chim. Acta 1994, 77, 1817–1825.
21. Mourer, M., Regnouf-de-Vains J.-B., unpublished results.
Even if copper(I) is much less abundant than copper(II), we
found interesting to compare, in the limits of their different coor-
dination chemistry, the copper capacities of 4 and other complex-
ing polymers, involving here, a contrario to Zn, polymers appended
calixarene derivatives. We found that polymer 4 displays a copper
capacity of 0.17 mmol gꢁ1 (i.e., 11 g of pure metal by kilogram), far
from the 6-mercaptopurinylazo resin of Mondal et al.
(1.48 mmol gꢁ1),3 from the N-sulfonylpolyamine resins described
by Jeragh et al. (1.00 mmol gꢁ1),4 or from a chitosan-appended
nitrilocalixarene described by Tabakci et al. (1.00 mmol gꢁ1),15b
but close to the poly-(O-,S-)glycidylmethacrylate resins incorporat-
22. Compound 2:
A
mixture of bis-bipyridyl calix[4]arene
1
(0.85 g,
0.84 ꢀ 10ꢁ3 mol) and NaH (0.034 g at 60% in oil, 0.84 ꢀ 10ꢁ3 mol) in dry DMF
(20 mL) was stirred at rt under Ar during 15 min. The p-(bromopropyl)-(N-
Boc)-tyramine (0.288 g, 0.84 ꢀ 10ꢁ3 mol) was then added, and stirring was
continued during 24 h. The solvent was evaporated to dryness under high
vacuum, and the resulting solid was dissolved in CH2Cl2 (50 mL); the solution
was washed with H2O (25 mL), dried over Na2SO4 and concentrated for
ing N,O,S- (0.13–0.36 mmol gꢁ1),9a N,O- (0.00–0.36 mmol gꢁ1 9b
)
or
N,S-crown ethers (0.24–0.36 mmol gꢁ1).9c
Finally, we observe that the grafting yield values obtained from
extraction experiments are similar, whatever the metal ion or the
titration method be, approaching 6.5%. This average value is close

Y. de Gaetano et al. / Tetrahedron Letters 50 (2009) 5793–5797
5797
chromatography (Al2O3, hexane/CH2Cl2 1/1). Compound 2 (0.94 g; 87%). White
powder. Mp: 103–104 °C. IR: 1717.9 (COO), 1575.9 (C@N). UV/vis (CH2Cl2):
289 (46910). 1H NMR (400 MHz; CDCl3): 0.81 (s, 18H, Me3C b); 1.29 (s, 9H,
Me3C a or c); 1.30 (s, 9H, Me3C c or a); 1.39 (s, 9H, Me3CO); 2.25 (quint,
J = 7.6 Hz, 2H, CH2CH2CH2); 2.58 (s, 6H, Mebpy); 2.60 (m, 2H, CH2CH2N); 3.28
(m, 4H, CH2CH2N + CH2CH2CH2O-Ar d); 3.85 (t, J = 7.8 Hz, 2H, CH2CH2CH2O-Ar
c); 3.09–4.33 (‘q’, AB, JAB = 13.2 Hz, 4H, Ar-CH2-Ar); 3.24–4.48 (‘q’, AB,
JAB = 13.2 Hz, 4H, Ar-CH2-Ar); 4.99 (‘q’, AB, JAB = 12.4 Hz, 4H, OCH2bpy); 5.87
(s, 1H, OH); 6.42 (d, J = 8.4 Hz, 2H, ArH d); 6.53 (br d, 4H, ArH b); 6.84 (d,
J = 8.4 Hz, 2H, ArH d); 7.10–7.19 (d + s + s, 6H, H(5’)bpy + ArH a + ArH c); 7.53
(t, J = 8.0 Hz, 2H, H(40)bpy); 7.62 (t, J = 7.6 Hz, 2H, H(4)bpy), 7.67 (d, 2H,
H(5)bpy); 8.13 (d, J = 8.0 Hz, 2H, H(30)bpy); 8.26 (d, J = 7.6 Hz, 2H, H(3)bpy). 13C
NMR (CDCl3): 24.63 (Mebpy); 28.42 (OCMe3); 29.61 (CH2–CH2–CH2); 31.01
(Me3C Ar b); 31.19 (Ar-CH2-Ar); 31.66, 31.75 (Me3C Ar a and c); 33.70 (Me3C Ar
b) 33.86, 34.12 (Me3C Ar c and a); 35.13 (CH2CH2NH); 41.89 (CH2CH2NH);
65.44 (CH2OAr d); 71.99 (CH2OAr c); 78.78 (OCH2bpy and Me3CO); 114.35 (Co
Ar d); 118.33 (C(30)bpy); 120.02 (C(3)bpy); 122.70 (C(5)bpy); 123.19
(C(50)bpy); 124.87 (Cm Ar a or c); 125.08 (Cm Ar b); 125.59 (Cm Ar a or c);
129.30, 128.32 (Co Ar a and Cm Ar d); 129.45 (Cp Ar d); 131.82 (Co Ar b); 132.48,
135.85 (Co Ar b and Co Ar c); 137.06 (C(40)); 137.08 (C(4)); 137.35 (C(4));
141.59, 145.72 (Cp Ar a and c); 145.60 (Cp Ar b); 150.82 (Ci Ar a); 151.15 (Ci Ar
b); 154.02 (Ci Ar c); 155.46, 157.69 (C(20), C(60)); 155.84, 156.58 (C(2), C(6));
157.65 (COO); 157.72 (Ci Ar d). Anal. Calcd for C85H103N5O7, 0.5 H2O (1314.79):
C, 77.59; H, 7.97; N, 5.32. Found: C, 77.53; H, 7.60; N, 5.44. ES-MS (negative
mode): 1288.7 [MꢁH]ꢁ; (positive mode): 1290.7 [M+H]+, 1312.7 [M+Na]+,
CH2CH2CH2O-Ar c); 3.85 (br s, 3H, NH3þ); 4.97 (q, J = 11.4 Hz, 4H, OCH2bpy);
6.29 (d, J = 8.4 Hz, 2H, ArH d); 6.53 (s, 4H, ArH b); 6.86 (d, J = 8.4 Hz, 2H, ArH d);
7.05 (s, 2H, ArH a or c); 7.09 (s, 2H, ArH c or a); 7.13 (d, J = 7.6 Hz, 2H, H(5) of
bpy); 7.62–7.65 (m, 6H, H(4), H(40) and H(50) of bpy); 8.16–8.20 (m, 7H, H(3),
H(30) of bpy and 3H pyridinium). 13C NMR (CDCl3): 23.54 (Mebpy); 29.44 (CH2–
CH2–CH2); 31.00 (Me3C Ar b); 31.14 (Ar b-CH2-Ar c); 31.43 (Ar a-CH2-Ar b);
31.64, 31.73 (Me3C Ar a and Ar c); 32.62 (CH2CH2N); 33.71 (Me3C Ar b); 33.86
(Me3C Ar a); 34.12 (Me3C Ar c); 41.11 (CH2CH2N); 65.10 (CH2OAr d); 71.64
(CH2OAr c); 78.60 (OCH2bpy); 114.40 (Co Ar d); 119.33, 120.60, 123.29, 137.68,
138.73 (C(3), C(4), C(5), C(30), C(40)); 124.02 (C(50)); 125.08 (Cm Ar b); 125.14
(Cm Ar a); 125.63 (Cm Ar c); 127.67 (Cp Ar d); 129.41 (Cm Ar d); 131.82 (Co Ar b);
132.41, 135.72 (Co Ar a and c); 141.67 (Cp Ar a or c); 145.75 (Cp Ar b); 145.84
(Cp Ar a or c); 150.62 (Ci Ar a); 151.07 (Ci Ar b); 154.04 (Ci Ar c and (C(6) or
C(60)); 154.28 (C(60) or C(6)); 156.66, 157.19 (C(2), C(20)); 157.83 (Ci Ar d). Anal.
Calcd for C79H91N5O5, 4 CF3COOH, 2H2O (1682.72): C, 62.10; H, 5.93; N, 4.16.
Found: C, 62.26; H, 5.70; N, 4.48. ES-MS (positive mode): 1212.7 [M+Na]+,
1190.7 [M+H]+, 606.85 [M+H+Na]2+/2, 595.9 [M+2H]2+/2. Free base of 3: 1H NMR
(400 MHz; CDCl3): 0.77 (s, 18H, Me3C b); 1. 16 (br s, 2H, NH2)1.27 (s, 9H, Me3C a
or c); 1.28 (s, 9H, Me3C c or a); 2.22 (quint, J = 7.1 Hz, CH2CH2CH2); 2.52 (s, 6H,
Mebpy); 2.74 (t, J = 7.1 Hz, 2H, CH2CH2N); 2.99 (t, J = 6.8 Hz, 2H, CH2CH2N);
3.10,4.32 (‘q’, AB, JAB = 12.6 Hz,
4 H, Ar-CH2-Ar); 3.21–3.24 (m, 4 H,
CH2CH2CH2O-Ar d + Ar–CH2-Ar); 3.81 (t, J = 7.1 Hz, 2 H, CH2CH2CH2O-Ar c);
4.46 (d, 2H, Ar-CH2-Ar); 4.95 (q, J = 11.3 Hz, 4 H, OCH2bpy); 5.86 (s, 1H, Ar-OH);
6.35 (d, J = 8.4 Hz, 2H, ArH d); 6.51 (s, 4 H, ArH b); 6.79 (d, J = 8.4 Hz, 2H, ArH d);
7.03 (s, 2H, ArH a or c); 7.05 (s, 2H, ArH c or a); 7.08 (d, J = 7.3 Hz, 2H, H(5) of
bpy); 7.51 (t, J = 7.3 Hz, 2H, H(4) of bpy); 7.56–7,64 (m, 4H, H(40) and H(50) of
bpy); 8.10 (d, J = 7.3 Hz, 2H, H(3) of bpy); 8.18 (d, J = 7.3 Hz, 2H, H(30) of bpy).
1328.7 [M+K]+, 645.8 [M+2 H]2+/2 656.8 [M+H+Na]2+/2
, . Compound 3: The
calixarene 2 (0.5 g, 3.8 ꢀ 10ꢁ4 mol) was dissolved in anhydrous CH2Cl2 (50 mL)
and TFA (1.6 mL) was then added. The resulting yellow mixture was stirred at
rt under Ar during 4 h (TLC monitoring, SiO2, CH2Cl2/MeOH:95/5+1 drop
NH4OH) and the solvent was evaporated to give an oily residue. The latter was
dissolved in H2O (40 mL), and the solution was evaporated again to remove
excess of TFA. The resulting yellow powder was repeatedly dissolved in CH2Cl2
(20 mL) and evaporated, until neutral pH was obtained. Compound 3 (0.41 g;
64%). Light yellow powder. Mp: 145–146 °C. IR: 1513.03 (C@N), 1677.8 (COO).
UV/vis (CH2Cl2): 290 (44500). 1H NMR (400 MHz; CDCl3): 0.81 (s, 18H, Me3C b);
1.28 (s, 9H, Me3C a or c); 1.29 (s, 9H, Me3C c or a); 2.19 (quint, J = 7.3 Hz,
CH2CH2CH2); 2.58 (s, 6H, Mebpy); 2.82 (t, J = 7.3 Hz, 2H, CH2CH2N); 3.07 (t,
J = 6.8 Hz, 2H, CH2CH2N); 3.10–3.14 (m, 4H, CH2CH2CH2O-Ar d + Ar-CH2-Ar);
3.25,4.49 (‘q’, AB, JAB = 13.2 Hz, 4H, Ar-CH2-Ar); 3.77 (t, J = 7.6 Hz, 2H,
Polymer 4: The Wang benzaldehyde resin (3.0 ꢀ 10ꢁ3 mol gꢁ1
;
3
50 mg,
(10 mg,
1.5 ꢀ 10ꢁ4 mol of CHO) was added to
a
solution of calixarene
5.9 ꢀ 10ꢁ6 mol) in toluene (10 mL). Triethylamine (0.1 mL, 1.5 mol) was then
added and the resulting mixture was heated at 50 °C during 48 h. After cooling
to rt, the resin was recovered by filtration, rinsed with CH2Cl2 (2 ꢀ 10 mL) and
MeOH (2 ꢀ 10 mL) and finally dried under vacuum. Anal. Calcd for: C, 80.71; H,
6.36; N, 0.58. For the commercial Wang resin: Anal. Calcd for (C69.8H66.2O6): C,
83.70; H, 6.60; N, 0.0. Found: C, 83.20; H, 6.65; N, 0.0.
23. Parker, W. L.; Crosby, G. A. J. Phys. Chem. 1989, 93, 5692–5696.
24. Kitagawa, S.; Munakata, M.; Higashie, A. Inorg. Chim. Acta 1984, 84, 79–84.
25. Newkome, G. R.; Pantaleo, D. C.; Puckett, W. E.; Ziefle, P. L.; Deutsch, W. A. J.
Inorg. Nucl. Chem. 1981, 43, 1529–1531.