Synthesis, characterization and electrochemical properties of two new calix[4]arene derivatives bearing two ferrocene imine or ferrocene amine units at the upper rim

Article abstract of DOI:10.1016/j.tet.2010.02.056

A novel calix[4]arene derivative with two ferrocenyl Schiff-base groups at the upper rim 3 has been synthesized from 5,17-diformyl-25,27-dipropoxy-26,28-dihydroxy calix[4]arene and 4-ferrocenylaniline via condensation reaction. Reduction of 3 with sodium borohydride led to calix[4]arene derivative 4 with two amino ferrocenyl groups at the upper rim. The ferrocenyl Schiff-base calix[4]arene and its corresponding reduced amine have been purified and characterized by elemental analysis,¹H NMR, FTIR, Mass and UV-vis spectral data. Electrochemical properties of compounds 3 and 4 have been investigated. Cyclic voltammograms of 3 and 4 show reversible redox couples of ferrocene/ferrocinium at E_1/2=0.401 V and 0.346 V, respectively. Electrochemical studies show these redox active compounds electrochemically recognize trivalent lanthanides La³⁺ and Ce³⁺ and divalent Pb²⁺ and Cu²⁺cations. With ferrocenyl Schiff-base calix[4]arene 3 an anodic shift as large as 130 mV is observed on addition of one equivalent of Ce³⁺ ion. Also extraction properties of compound 4 towards some metal cations have been described. It has been observed that compound 4 has a good selectivity for metal cations Fe³⁺, Cu²⁺, Pb²⁺ and Cd²⁺ against Ni²⁺ and Co²⁺.

Full text of DOI:10.1016/j.tet.2010.02.056

Tetrahedron 66 (2010) 3259–3264
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis, characterization and electrochemical properties of two new
calix[4]arene derivatives bearing two ferrocene imine or ferrocene amine
units at the upper rim
*
Behrouz Shaabani , Zohreh Shaghaghi
Research Laboratory of Synthesis of Inorganic Compounds, Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 13 July 2009
Received in revised form 4 January 2010
Accepted 15 February 2010
Available online 23 February 2010
A novel calix[4]arene derivative with two ferrocenyl Schiff-base groups at the upper rim 3 has been
synthesized from 5,17-diformyl-25,27-dipropoxy-26,28-dihydroxy calix[4]arene and 4-ferrocenylaniline
via condensation reaction. Reduction of 3 with sodium borohydride led to calix[4]arene derivative 4 with
two amino ferrocenyl groups at the upper rim. The ferrocenyl Schiff-base calix[4]arene and its corre-
sponding reduced amine have been purified and characterized by elemental analysis,1H NMR, FTIR, Mass
and UV–vis spectral data. Electrochemical properties of compounds 3 and 4 have been investigated.
Cyclic voltammograms of 3 and 4 show reversible redox couples of ferrocene/ferrocinium at E1/2¼0.401 V
and 0.346 V, respectively. Electrochemical studies show these redox active compounds electrochemically
recognize trivalent lanthanides La3þ and Ce3þ and divalent Pb2þ and Cu2þcations. With ferrocenyl Schiff-
base calix[4]arene 3 an anodic shift as large as 130 mV is observed on addition of one equivalent of Ce3þ
ion. Also extraction properties of compound 4 towards some metal cations have been described. It has
been observed that compound 4 has a good selectivity for metal cations Fe3þ, Cu2þ, Pb2þ and Cd2þ
Keywords:
Calix[4]arene
Ferrocenyl Schiff-base
Cyclic voltammetry
Cation extraction
Cation recognition
against Ni2þ and Co2þ
.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
potential ligands for fluorescent studies8 and for cation recognition,
particularly with transition metals.9
Calix[n]arenes are macrocyclic compounds in which phenolic
units are linked via methylene bridging groups at their ortho po-
sition. The smallest in the series is where four phenolic units make
up the macrocyclic backbone (n¼4). Calixarenes and their de-
rivatives can be used as synthetic receptors to selectively bind
a wide variety of guest molecules/ions forming host–guest com-
plexes or supramolecular species, and have been applied success-
fully to various areas of science and technology. It is also noted that
the calixarene platform can be selectively functionalized both at
the phenolic OH groups (lower rim or narrow rim)1 and at the para
positions of the phenol rings (upper rim or wide rim), which pro-
vides unique possibilities to organize several binding sites appro-
priately for complexation of potential guests.2 For example, these
molecules are capable of alkali, alkaline earth and heavy metal ion
recognition.3–5
Molecular sensors are required for the efficient detection of
charged and neutral pollutant species within organic and aqueous
effluents. Particularly, redox-active molecular receptors have been
designed to sense target guest species via means of an electro-
chemical response. For example, ferrocene-containing ligands have
previously been shown electrochemically to sense alkali, alkali-
earth and transition metal ions.10,11
Metallocene containing calixarenes have already been studied
to sense or activate molecular level processes. Beer has been a pi-
oneer in making metallocene appended calixarene for analytical
purposes and investigating electrochemical interactions between
multi-redox architectures.12–14 Tuntulani and co-workers have
synthesized calix[4]arene derivatives containing amide ferrocene
units at the wide rim and ethyl ester groups at the narrow rim and
investigated their anion-binding and sensing properties.15,16 Kaifer
and co-workers have reported a redox controlled dissociation of
a self-assembled dimer.17 Recently Pellet and co-workers reported
the syntheses and conformational analyses of similar artificial re-
ceptors associating calixarene as molecular platform and ferrocene
redox-active fragments.18
The attachment of N-ligating groups through imine bond
formation has been successful at the upper6 and lower7,8 rims of
calixarenes. This has resulted calix[4]arene Schiff bases, which are
In the present work, we report the synthesis and characteriza-
tion of new calix[4]arene ligands containing two Schiff base
* Corresponding author. Tel./fax: þ98 411 3393144.
E-mail address: shaabani_b@yahoo.com (B. Shaabani).
0040-4020/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.02.056

3260
B. Shaabani, Z. Shaghaghi / Tetrahedron 66 (2010) 3259–3264
Table1
1H NMR chemical shifts of diformylcalix[4]arene 1, 3 and 4 (400 MHz)
No
Solvent
Lower rim
Calixarene core
Upper rim
OH
OPr
OCH2
CH2
CH3
CH2
CH2
ArH
ArH
ArH
ArH
ArH
CHO
HCN
NH
NCH2
ferrocene ArH
1
3
4
CDCl3
DMSO-d6
CDCl3
9.32
9.46
d
4.02
3.99
3.98
2.04–2.13
1.98–2.04
2.04–2.13
1.34
1.30
1.33
4.30
4.19
4.32
3.51
3.65
3.38
6.81
6.83
6.79
6.98
7.11
6.95
7.64
7.80
7.07
d
d
9.78
d
d
d
d
d
7.62
7.32
7.21
6.59
9.74
d
d
d
4.79,4.37,4.01
4.23,4.15.4.03
d
8.52
4.54
ferrocenyl 3 and amino ferrocenyl groups 4 at the upper rim and
two ether groups at the lower rim and investigate their electro-
chemical behaviour in the presence of La3þ, Ce3þ, Cu2þ and Pb2þ
metal ions. We also report a study of extraction ability of compound
4 towards metal cations (Ni2þ, Co2þ, Fe3þ, Pb2þ, Cu2þ and Cd2þ).
mass and elemental analysis and investigated with UV–vis spec-
trometry and cyclic voltammetry. Also we studied extraction
properties of compound 4 towards some metal cations. We applied
compounds 3 and 4 electrochemically for cation recognition to-
wards some metal ions.
2.2. IR spectra
2. Results and discussion
2.1. Synthesis
The major difference in the IR spectrum of 1 compared to 3 is the
presence of an aldehyde peak at 1679 cmꢀ1 in 1. The formation of
diimine derivative of calix[4]arene 3 was confirmed by the ap-
pearance of the characteristic imine peak at 1655 cmꢀ1 in its IR
spectra. Also, perfect reduction of compound 3 to diamine cal-
ix[4]arene derivative 4 was confirmed by the absence of the peak at
1655 cmꢀ1 in its IR spectra.
In this work, to synthesis the new compounds 3 and 4; we used
diformyl calix[4]arene 1 and 4-ferrocenylaniline 2 as the pre-
cursors. Diformyl calix[4]arene 119 and 4-ferrocenylaniline20,21
were synthesized according to the reported literature procedure.
The synthetic route is shown in Scheme 1. Compound 1 was
refluxed with 4-ferrocenylaniline 2 in anhydrous THF and a cata-
lytic amount of p-toluenesulfonic acid to give the corresponding
imine derivative of calix[4]arene 3 in 81% yield. Compound 4 was
achieved by reduction of compound 3 with NaBH4 in anhydrous
THF in 66% yield. The new compounds 3 and 4 containing two
Schiff-base and two amino groups, respectively, at the upper rim of
calix[4]arene were characterized by a combination of IR, 1H NMR,
2.3. 1H NMR spectra
The structures of 3 and 4 were fully characterized using 1H NMR
spectroscopy. Table 1 shows the 1H NMR chemical shifts for aro-
matic protons, bridging methylene protons and chain methylene
and methyl proton signals for 1, 3 and 4. 1H NMR data showed that
Scheme 1. Preparation steps of 3 and 4. (i) AlCl3/phOH, Toluene, 1 h, rt (ii) PrI, K2CO3, CH3CN, Refluxed for 24 h, (iii) Cl2CHOCH3, SnCl4, CHCl3, T¼ꢀ15 ꢁC, (iv) 4-nitroaniline, water,
concentrated hydrochloric acid, sodium nitrite, hexadecyltrimethylammonium bromide, ethyl ether, (v) palladium on charcoal, sodium borohydride, water and methanol, room
temperature, 2 h, (vi) p-toluenesulfonic acid catalyst, THF, refluxed for 24 h, (vii) sodium borohydride, THF, Refluxed for 3 h.

B. Shaabani, Z. Shaghaghi / Tetrahedron 66 (2010) 3259–3264
3261
compounds 3 and 4 have a cone conformation. A typical AB pattern
corresponding to n/
p* transition (non-bonding electrons of ni-
was observed for the methylene bridge ArCH2Ar protons at 3.65
and 4.19 (J¼13 Hz) for 3 and 3.38 and 4.32 (J¼12.8 Hz) for 4.
The high field doublets at 3.65 for 3 and 3.38 for 4 were assigned
to the equatorial protons of methylene groups, whereas the low
field signals at 4.19 for 3 and 4.32 for 4 were assigned to the axial
protons.
The formation of the imine 3 was established by the loss of the
signal due to the aldehyde group of 1 at 9.78 in the 1H NMR spectra
and the appearance of the signal at 9.74, depending on the sub-
stituent attached to the imine nitrogen atom. The formation of the
amine 4 was determined by the loss of the signal due to the imine
group of 3 at 9.74 in the 1H NMR spectra and the appearance of the
signal at 8.25 for the amine protons and 4.54 for the –NCH2– groups
depending on the reduction of imino groups to the amine groups
(–HCN– to –CH2NH–).
trogen to p* orbital of imine) and a weak band at 468 nm corre-
sponding to the d–d transition for the iron of ferrocene. Also,
compound 4 was determined to show a strong absorption at
297 nm apparently corresponding to p/p* transition of aromatic
rings and a weak band at 450 nm corresponding to the d–d transi-
tion of ferrocene. The absence of a shoulder in compound 4 com-
pared to compound 3 was ascribed to the reduction of the imine
groups and the formation of amine derivative 4 (the disappearance
of p* orbital of imine).
2.5. Electrochemical analysis
The electrochemical properties of compounds 3 and 4 were
studied by cyclic voltammetry. Cyclic voltammetry (CV) was per-
formed using solutions of 3 and 4 (1ꢂ10ꢀ3 M) prepared in DMSO
with 0.1 M LiClO4 as a supporting electrolyte and using a glassy
carbon working electrode, a Hg/Hg22þ reference electrode, and a Pt
wire counter electrode. The potential was scanned in the range of 1
to ꢀ1 V at 100 mV/s potential scan rate. Cyclic voltammograms of 3
and 4 showed reversible redox couples of ferrocene/ferricinium at
E1/2¼0.401 V and 0.346 V, respectively, as shown in Figure 2 and
Table 2. The observation of only one redox wave for both iron
centers in compounds 3 and 4 indicates no interaction between the
ferrocene units.
The aromatic proton signals of the phenyl rings of calixarene
core appear as a singlet, a triplet and a doublet in the case all of the
compounds 1, 3 and 4 at
of the phenyl rings attached to ferrocene appear as two doublets for
compound 3 at ¼6.59 and 7.32
¼7.21 and 7.62 (J¼8.4 Hz) and 4 at
d
¼6.79–7.80. The aromatic proton signals
d
d
(J¼8.5 Hz). The ferrocene proton signals appear as three singlets in
the case both compounds 3 and 4 at
d
¼4.01–4.79.
2.4. The UV–vis spectra
In the next step, cyclic voltammetry was used to investigate the
electrochemical response of the ferrocene units in compounds 3
The UV–vis spectra for 3 and 4 in DMSO solvent at 200–650 nm
are shown in Figure 1. Compound 3 was determined to show
a strong absorption at 294 nm apparently corresponding to p/p*
and
4 in the presence of varying concentrations from 0.1
(1ꢂ10ꢀ4 M) to 2.0 equiv (2ꢂ10ꢀ3 M in DMSO) of metal ions (La3þ
,
Ce3þ, Cu2þ and Pb2þ). Table 3 shows that in all cases addition of
metal ions (La3þ, Ce3þ and Pb2þ) cause significant anodic shifts in
the respective ferrocene-ferrocenium redox couple of 3 and 4, ad-
dition of Cu2þ cation causes a cathodic shift in the respective
ferrocene-ferrocenium redox couple of 3, and for 4, after adding
1 equiv of Cu2þ cation, disappear oxidation and reduction waves
(Figs. 3 and 4). For metal ions (La3þ, Ce3þ and Pb2þ) Schiff-base li-
gand 3 shows greater potential shifts than compound 4. Thus
compound 3 exhibits generally greater anodic perturbations (Table
3). Compound 3 and 4 give a shift increasing from 125 mV for La, to
130 mV for Ce and 20 mV for La, to 64 mV for Ce, respectively. The
smaller, more charge dense Ce3þ cation, perturbs the ferrocene
oxidation more than the La3þ ion (Table 3).
transition of aromatic rings and a shoulder at 336 nm apparently
Titration of 3 and 4 with metal ions (La3þ, Ce3þ and Pb2þ) dis-
play a progressive appearance of a new reduction wave at the less
positive potential and a progressive disappearance of the initial
reduction (after adding 0.1 equiv of La3þ ion, ligand 4 only shows
Figure 2. Cyclic voltammogram of ferrocene, compounds
DMSO).
3
and
4
(1ꢂ10ꢀ3 M in
Figure 1. UV–vis spectrum of 3 (a) and 4 (b) (1ꢂ10ꢀ4 M in DMSO).

3262
B. Shaabani, Z. Shaghaghi / Tetrahedron 66 (2010) 3259–3264
Table 2
addition of cation disappear oxidation and reduction wave)
(Figs. 3d and 4d).
Electrochemical data recorded by cyclic voltammetry for ferrocene,
dissolved in DMSO
3 and 4
Epa(mV)
Epc(mV)
E1/2(mV)
D
Ep(mV)
DEp/2(mV)
2.6. Two phase solvent extraction
Ferrocene
3
4
528
457
397
417
346
296
472
401
346
111
111
101
55.5
55.5
50.5
The extraction data with diferrocenylamine calix[4]arene de-
rivative 4 has been investigated for various cations and compared
with 2 (a simple non-calixarene compound) in Table 4 and Figure 5.
The results of extraction show that compound 4 presents a low
affinity towardsFe3þ, Pb2þ, Cu2þ and Cd2þ and no affinity for Ni2þ and
Co2þ, when the concentration of 4 and the concentration of cation are
same([ligand]/[cation]¼1). But, when the concentration of 4 to the
concentration of metal cation solution increases ten times, it presents
a good affinity towards Fe3þ, Pb2þ, Cu2þ and Cd2þ and no affinity for
Ni2þ and Co2þ. In this case, compound 4 presents a very good selec-
tivity for Fe3þ, Pb2þ, Cu2þ and Cd2þ in the comparison with Ni2þ and
Co2þ. Thus, when large amount of compound 4 contributes in the
extraction, the extractabilities for Fe3þ, 7.6, Pb2þ, 4.27, Cd2þ, 2.5 and
Cu2þ, 3.5 times increase and affinity for Ni2þ and Co2þ does not
change. While, in the same conditions (when large amount of non-
calix[4]arene compound 2 contributes in the extraction) affinity for
Fe3þ, Cu2þ and Ni2þ does not increase, for Cd2þ and Co2þ shows minor
increase and for Pb2þ is similar to compound 4 (Fig. 5 and Table 4).
Generally, the extractability of 4 for Fe3þ, Cu2þ and Cd2þ is six,
four and near to two times greater than 2, respectively. The affinity
of 4 for Pb2þ is 48.78, that is, a little more in the comparison with 2,
the extraction properties of compounds 2 and 4 are similar for Ni2þ
and finally unlike ligand 4, 2 shows approximately a good affinity
for Co2þ (Fig. 5b).
Epa (anodic peak potential), Epc (cathodic peak potential), E1/2¼(EpaþEpc)/2,
Ep¼EpaꢀEpc.
D
Table 3
Electrochemical data and metal ions electrochemical recognition results
Compound Ea
D
Eb
1/2
1/2
La3þ
Ce3þ
Pb2þ
Cu2þ
3
4
401 125, 115 130, 125 124, 119 45, 45
346
20, 20
64, 59
9, 53 The disappearance of
oxidation and reduction wave
a
Obtained in DMSO solution with LiClO4.
Anodic shifts (for Cu2þ, cathodic shift) of respective ferrocene/ferrocenium
b
couple produced by 1 and 2 equiv of metal cations.
a potential shift of initial reduction wave) and a potential shift of
oxidation wave (with Ce3þ ion, compound 3 shows a progressive
appearance of a new oxidation wave at a less positive potential and
a progressive decreasing of the initial oxidation wave). Titration of 3
and 4 with Cu2þ cation reveal a potential shift of oxidation and
reduction wave with a progressive decreasing of intensity of the
oxidation and reduction wave (for compound 4, after 1 equiv
Figure 3. Titration of 3 and metal ions (La3þ, Ce3þ, Cu2þ and Pb2þ) in DMSO with 0.1 M LiClO4 and a scan rate of 100 m V/s: (a) La3þ, (b) Ce3þ, (c) Pb2þ, (d) Cu2þ
.

B. Shaabani, Z. Shaghaghi / Tetrahedron 66 (2010) 3259–3264
3263
Figure 4. Titration of 4 and metal ions (La3þ, Ce3þ, Cu2þ and Pb2þ) in DMSO with 0.1 M LiClO4 and a scan rate of 100 m V/s: (a) La3þ, (b) Ce3þ, (c) Pb2þ, (d) Cu2þ
.
3. Conclusion
and used without further purifications. THF solvent was distilled
and dried before use and other solvents were used without purifi-
cations. All operations were performed under an oxygen free dry
dinitrogen atmosphere using standard Schlenk techniques. NMR
spectra were recorded on Bruker Avance 400 in CDCl3 and DMSO-d6
solvent with SiMe4 as internal standard at room temperature. Ele-
mental analyses were performed on Elementar Vario EL III. IR
spectra were recorded on a FT-IR Spectrometer Bruker Tensor 27 in
the region 4000–400 cmꢀ1 using KBr pellets. Electronic absorption
spectra in the UV–vis region were recorded with an Analytick Jena
Spectrod 40. Mass spectrometries were performed on LC/MS 500
ion trap Varian at Klinikum rechts der Isar, Technische Universita¨t
Mu¨nchen, Department of Nuclear Medicine. Melting points were
obtained with an Electrothermal 9100 and are uncorrected.
Two new calix[4]arene derivatives containing ferrocenyl units 3
and 4 have been prepared and characterized. These compounds
studied with cyclic voltammetry. Cyclic voltammograms of 3 and 4
showed reversible redox couples of ferrocene/ferrocenium at
E1/2¼0.401 V and 0.346 V, respectively. The observation of only one
redox wave for both iron centers in compounds 3 and 4 indicates no
interaction between the ferrocene units. Electrochemical studies
show these redox-active ligands electrochemically recognize tri-
valent lanthanide (La3þand Ce3þ), and divalent Pb2þ and Cu2þ ions.
According to CV data Schiff-base ligand 3 shows greater potential
shifts than compound 4. With ferrocenyl Schiff-base calix[4]arene 3
an anodic shift as large as 124–130 mV is observed on addition of
one equivalent of La3þ and Pb2þ ions. Compound 3 shows a cathodic
shift for Cu2þ cation and for ligand 4, after adding 1 equiv of Cu2þ
cation, anodic and cathodic waves disappear. Also the investigation
of extraction properties of compound 4 towards some metal cations
4.2. Synthesis of 5,17-bis(4-iminophenylferrocne)-25,27-
dipropoxy-26,28-dihydroxy calix[4]arene 3
show that compound 4 has a good selectivity for metal cations Cu2þ
,
4-Ferrocenylaniline 2 (0.39 g, 1.42 mmol) in THF (30 ml) was
added drop wise, over one hour, to a THF solution (150 ml) of 5,17-
diformyl-25,27-dipropoxy-26,28-dihydroxy calix[4]arene 1 (0.4 g,
0.71 mmol) and a catalytic amount of p-toluenesulfonic acid, im-
mediately the colour of solution changed to dark-violet and pre-
cipitation was formed. The mixture was refluxed for 24 h, then the
mixture was filtrated and residue solid was washed with dry THF
Fe3þ, Pb2þ and Cd2þ against Ni2þ and Co2þ. Extraction data
comparison of 4 with 2, a simple non-calixarene compound, reveals
grater extractability of 4 for Cu2þ, Fe3þ, Pb2þ and Cd2þ
.
4. Experimental
4.1. General
twice and dried in vacuum. Yield: 0.626 g (81%). IR (KBr, cmꢀ1
)
3422b,1655vs,1603vs,1526m,1484w,1431m,1314m,1277m,1174s,
1032m, 910m, 816s, 771s. 1H NMR (400 MHz, DMSO-d6): 9.74 (s,
2H, –HC]N–), 9.46 (s, 2H, –OH), 7.80 (s, 4H, ArH of calixarene core),
7.62 (d, 4H, J¼8.42 Hz, ArH), 7.21 (d, J¼8.42 Hz, 4H, ArH), 7.11 (d,
5,17-Diformyl-25,27-dipropoxy-26,28-dihydroxy calix[4]arene
119 and 4-ferrocenylaniline 20,21 were prepared according to litera-
ture methods. Starting materials were all purchased commercially

3264
B. Shaabani, Z. Shaghaghi / Tetrahedron 66 (2010) 3259–3264
Table 4
NMR (CDCl3, 400 MHz) 8.52 (s, 2H, –NH–), 7.32 (d, J¼8.5 Hz, 4H, Ar–
Extraction percentage of metal nitrates by 2 and 4
H), 7.07 (s, 4H, Ar–H of calixarene core), 6.95 (d, J¼7.5 Hz, 4H, Ar–H of
calixarene core), 6.79 (t, J¼7.5 Hz, 2H, Ar–H of calixarene core), 6.59
(d, J¼8.5 Hz, 4H, Ar–H), 4.54 (s, 4H, –CH2–NH–), 4.32 (d, J¼12.8 Hz,
4H, ArCH2Ar), 4.23 (s, 4H, HFc), 4.15 (s, 4H, HFc), 4.03 (s, 10H, HFc),
3.98(t, J¼6.2 Hz,4H,–OCH2–), 3.38(d, J¼12.8 Hz, 4H,ArCH2Ar), 2.04–
2.13 (m, 4H, –OCH2CH2–),1.33 (t, J¼7.4 Hz, 6H, –OCH2CH2CH3). Elem.
Anal. Calcd for C68H66O4N2Fe2$1.5CH2Cl2: C, 68.73; H, 5.68; N, 2.31.
Found: C, 68.67; H, 5.84; N, 2.76. ESIMS: m/z 1086.3. Decomp.: 215 ꢁC.
No
2
[L]/[cation]
Ni2þ
Co2þ
Fe3þ
Pb2þ
Cu2þ
Cd2þ
1
10
1
4.46
1.27
<1
16.48
23.52
<1
5.81
5.24
3.96
8.88
44.2
10.44
48.78
11.77
11.77
13.47
47.37
8.75
29.88
15.88
40.12
4
10
<1
<1
30.47
4.4. Solvent extraction
A solution of compound 4 (2.5 ml, 1ꢂ10ꢀ3 M) in CH2Cl2 and an
aqueous solution containing nitrate salt of metal cations Cu2þ, Fe3þ
,
Pb2þ, Ni2þ, Cd2þ and Co2þ (5 ml, 1ꢂ10ꢀ3 M) were mixed and shaken
in a stoppered glass tube with a magnetically stirred in a thermo-
static water bath at 25 ꢁC for 2 h and finally left standing for an
additional 15 min. Then, the aqueous phase was separated and the
concentration of metal ion remaining in the aqueous phase was
determined by atomic absorption. The extraction percentage (E%)
was calculated by the following expression:
A0 ꢀ A
ðE%Þ ¼
ꢂ 100
A0
where A0 and A are the initial and final absorbance of the metal ion
before and after the extraction in aqueous phase, respectively. The
extraction was repeated with compound 4 (3ꢂ10ꢀ3 M) in CH2Cl2
(2 ml) and 10 ml aqueous solution containing 3ꢂ10ꢀ4 M nitrate
salts of metal Cations Cu2þ, Fe3þ, Pb2þ, Ni2þ, Cd2þ and Co2þ
.
Acknowledgements
We are grateful to University of Tabriz Research Council for the
financial support of this research.
References and notes
1. (a) Gutsche, C. D. Calixarenes revisited. In Monographs in Supramolecular
Chemistry; Stoddart, J. F., Ed.; The Royal Society of Chemistry: Cambridge, UK,
1998; (b) Collins, E. M.; Mckervey, M. A.; Madigon, E.; Maran, M. B.; Owens, M.;
Ferguson, G.; Harris, S. J. Chem. Soc., Perkin Trans. 1 1991, 3137–3142; (c) Bo, Z.;
Li, Y. Z.; Lu, X. F.; Lu, G. Y. Chem. Crystall. 2005, 35, 281–284.
2. (a) Gutsche, C. D.; Nam, K. C. J. Am. Chem. Soc. 1988, 110, 6153–6162; (b)
Kanamathareddy, S.; Gutsche, C. D. J. Org. Chem. 1996, 61, 2511–2516.
3. Memon, S.; Yilmaz, M. J. Mol. Struct. 2001, 595, 101–109.
4. Dumazet-Bonnamour, I.; Halouani, H.; Oueslati, F.; Lamartine, R. J. Compt. Rend.
Chim. 2005, 8, 881–891.
5. Deligoz, H.; Erdem, E. J. Hazard. Mater. 2008, 154, 29–32.
6. Liang, Z.; Liu, Z.; Gao, Y. Spectrochim. Acta Part A 2007, 68, 1231–1235.
7. Zhang, W. C.; Huang, Z. T. Synthesis 1997, 1073–1076.
8. Mahon, M. F.; McGinley, J.; Rooney, A. D.; Walsh, J. M. D. Tetrahedron 2008, 64,
11058–11066.
Figure 5. Extraction percentage of the metal nitrates with 2 and 4 at 25 ꢁC: (a) [L]/
[cation]¼1, (b) [L]/[cation]¼10 (L¼2 and 4).
J¼7.6 Hz, 4H, ArH of calixarene core), 6.83 (t, J¼7.6 Hz, 2H, ArH of
calixarene core), 4.79 (s, 4H, HFc), 4.37 (s, 4H, HFc), 4.19 (d, J¼13 Hz,
4H, ArCH2Ar), 4.01 (s, 10H, HFc), 3.99 (d, J¼6.2 Hz, 4H, –OCH2–),3.65
(d, J¼13 Hz, 4H, ArCH2Ar), 1.98–2.04 (m, 4H, –OCH2CH2–), 1.30 (t,
J¼7.28 Hz, 6H, –OCH2CH2CH3). Elem. Anal. Calcd for C68H62O4N2
-
Fe2$3CHCl3: C, 59.14; H, 4.51; N, 1.94. Found: C, 58.83; H, 5.01; N,
2.26. ESIMS: m/z 1083.2. Decomp.: 235 ꢁC.
9. Liu, Y.; Zhang, N.; Zhao, B. T.; Zhang, H. Y. Spectrochim. Acta Part A 2002, 58,
2889–2895.
10. (a) Chen, Z.; Pilgrim, A. J.; Beer, P. D. Electroanal. Chem. 1998, 444, 209–217; (b)
Beer, P. D.; Chen, Z.; Drew, M. G. B.; Johnsona, A. O. M.; Smith, D. K.; Spencer, P.
Inorg. Chim. Acta 1996, 246, 143–150; (c) Beer, P. D.; Smith, D. K. J. Chem. Soc.,
Dalton Trans. 1998, 417–423; (d) Beer, P. D.; Bernhardt, P. V. J. Chem. Soc., Dalton
Trans. 2001, 1428–1431.
4.3. Synthesis of 5,17-bis(4-aminophenylferrocne)-25,27-
dipropoxy-26,28-dihydroxy calix[4]arene 4
11. Hall, C. D.; Sachsinger, N.; Nyburg, S. C.; Steed, J. W. Organomet. Chem. 1998, 561,
209–219.
12. Matthews, S. E.; Beer, P. D. Supramol. Chem. 2005, 17, 411–435.
13. Gale, P. A.; Chen, Z.; Drew, M. G. B.; Heath, J. A.; Beer, P. D. Polyhedron 1998, 17,
405–412.
14. Brindley, G. D.; Fox, O. D.; Beer, P. D. J. Chem. Soc., Dalton Trans. 2000, 4354–4359.
15. Tomapatanaget, B.; Tuntulani, T. Tetrahedron Lett. 2001, 42, 8105–8109.
16. Tomapatanaget, B.; Tuntulani, T.; Chailapakul, O. Org. Lett. 2003, 5,
1539–1542.
17. Moon, K.; Kaifer, A. E. J. Am. Chem. Soc. 2004, 126, 15016–15017.
18. Metay, E.; Duclos, M. C.; Pellet-Rostaing, S.; Lemaire, M.; Kannappan, R.; Bucher,
C.; Saint-Aman, E.; Chaix, C. Tetrahedron 2009, 65, 672–676.
19. Arduini, A.; Fabbi, M.; Mantovani, M.; Pochini, A.; Mirone, L.; Secchi, A.; Ungaro,
R. J. Org. Chem. 1995, 60, 1454–1457.
To a stirred suspension of compound 3 (0.700 g, 0.646 mmol) in
THF (250 ml) under dry N2 gas was added NaBH4 (0.123 g,
3.23 mmol) in three steps at room temperature. Then, the reaction
mixture was refluxed for 3 h. During the reflux, the colour of 3 dis-
appeared slowly and finally an orange solution was obtained. The
solution was filtrated and the filtrate was evaporated under reduce
pressure. The residue was dissolved in CH2Cl2 (50 ml) and to the
solution was added NaOH 1 M. The organic phase was separated and
dried over MgSO4. Afterevaporation of the solvent, the crude product
was recrystalized in MeOH–CH2Cl2 and an orange product was
obtained. Yield: 0.467 g (66%). IR (KBr, cmꢀ1) 3382b, 3086w, 2960w,
1612s, 1530s, 1459s, 1315w, 1259s, 1200w, 1090s, 809 Vs, 488s. 1H
20. Hu, P.; Zhao, K. Q.; Xu, H. B. Molecules 2001, 6, M249.
21. Lanez, T.; Pauson, P. L. J. Chem. Soc., Perkin Trans. 1 1990, 2437–2442.