Synthesis, IR and NMR characterization and ion extraction properties of tetranonylcalix[4]resorcinol bearing acetylhydrazone groups

Article abstract of DOI:10.1016/j.tet.2008.10.008

A series of new calix[4]resorcinarenes (rccc-isomer) and resorcinols functionalized by acetylhydrazone binding fragments have been synthesized. The IR and NMR data and stereochemical behaviour of hydrazones are reported and compared with the results of ea

Full text of DOI:10.1016/j.tet.2008.10.008

Tetrahedron 65 (2009) 408–417
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis, IR and NMR characterization and ion extraction properties of
tetranonylcalix[4]resorcinol bearing acetylhydrazone groups
*
Sergey N. Podyachev , Nadezda E. Burmakina, Viktor V. Syakaev, Svetlana N. Sudakova,
Roald R. Shagidullin, Alexander I. Konovalov
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences, Arbuzov str. 8, 420088, Kazan, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of new calix[4]resorcinarenes (rccc-isomer) and resorcinols functionalized by acetylhydrazone
binding fragments have been synthesized. The IR and NMR data and stereochemical behaviour of hy-
drazones are reported and compared with the results of earlier investigations. The barriers of rotation of
hydrazone fragments for some octahydrazone derivatives of calix[4]resorcinarenes and their resorcinol
analogues have been determined by NMR-measurements. The complexing behaviour of bis- and octa-
hydrazones has been studied by liquid–liquid extraction towards the s-metal ions (Liþ, Naþ, Kþ, Csþ and
Received 9 July 2008
Received in revised form 18 September
2008
Accepted 2 October 2008
Available online 10 October 2008
Ca2þ), p-metal ions (Pb2þ), d-metal ions (Co2þ, Ni2þ, Cu2þ, Zn2þ, Cd2þ and Hg2þ) and f-metal ions (La3þ
,
Keywords:
Gd3þ and Lu3þ). The stoichiometry of complexes and the extraction constants have been determined. It
has been established that octahydrazones do not extract alkali metal cations but show excellent selec-
tivity towards transition and soft heavy metal cations (especially Hg2þ or Pb2þ).
Ó 2008 Elsevier Ltd. All rights reserved.
Calix[4]arene
Calix[4]resorcinarene
Hydrazone
Metal cations
Extraction
Conformation
1. Introduction
synthesis of spatially-organized structures, particularly, calixar-
enes.5–8 The parent compounds are readily available and can be
Chelating systems are widely used in coordination chemistry as
a class of ligands forming predominantly five- and six-membered
metal rings.1 In order to enhance the binding efficiency and selec-
tivity of the designed ligands complementary matching between
the interacting sites is usually optimized. Another approach of
modification of chelating system properties is the synthesis of
three-dimensional polydentate ligands with ligating groups fixed
on a suitable molecular skeleton. The presence of several such
groups in a molecule can be used for creating new architecture
compounds with unusual properties. The resulting nanometre-
scale structures are normally capable of simultaneously binding
two or more metal ions located in defined positions relative to each
other. On the other hand, the cooperative effect of closely located
binding centres can increase the yield of more kinetically and
thermodynamically stable metal complexes than their monomer
acyclic analogues.2–4
functionalized both at the phenolic OH groups and at the para
positions of phenol rings into numerous of derivatives. By variation
of the number and type of aromatic fragments (usually phenol,
resorcinol and pyrogallol fragments are widely used) the required
coordinating capacity of supramolecular receptor can be reached.
The use of a template approach in the case of calix[4]phenol, the
choice of suitable condensing agent for the calix[4]resorcinol syn-
thesis allows as a rule to fix the desired molecular configuration at
the initial stages of their synthesis. In this connection, calixarenes
are appealing macrocyclic platforms for the preorganization of
chelating groups and can be considered as ‘multivalent scaffolds’.9
Multivalency is the ability of a particle to bind another particle via
multiple simultaneous noncovalent interactions. The valency is
therefore the number of ‘ligating functionalities of the same or
similar types connected to each of these entities’.9
The calixarenes, as parent compounds, have been transformed
into their ethers,7,8,10 which are suitable precursors for the sub-
sequent synthesis of polydentate ligands. By the hydrazinolysis of
these ethers, a series of hydrazide derivatives of calix[4]phenols,
calix[4]resorcinols and calix[4]pyrogallols have been synthesized.11
The high extraction ability and selectivity of calix[4]phenols with
acetylhydrazide groups towards a series of transition metal ions
have been established.11,12 By the interaction of calix[4]phenol
In the last decade, the interest in polychelate compounds has
notably increased due to the further development of supramolec-
ular chemistry and especially the chemistry directed to the
* Corresponding author. Fax: þ07 843 2731872.
E-mail address: spodyachev@iopc.knc.ru (S.N. Podyachev).
0040-4020/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2008.10.008

S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
409
acetylhydrazides with aldehydes, new hydrazone derivatives pos-
sessing interesting conformations and dynamic behaviour have
been obtained.13,14 Hydrazone compounds are attractive not only
due to their potential antibacterial, bactericidal, fungicidal and
antitumoral properties,15–17 or the ability to control the release of
volatile aldehydes and ketones,18 but also due to their effective
extraction properties towards transition metal ions.19–21 Acetylhy-
drazone complexes with metal cations are well studied in co-
ordination chemistry, which is also explained by their unique
physico-chemical properties and physiological activity.19,22 The
presence of donor oxygen and nitrogen atoms in hydrazone mol-
ecules provides them with the ability to coordinate hard as well as
soft transition metal ions. The incorporation of hydrazone groups in
calixarenes will help to maintain the corresponding metal deriva-
tive’s integrity under a variety of conditions. Such types of com-
pound are very promising for liquid extraction procedure with the
aim of recovery, separation and concentration of transition metal
ions.
In this paper, we present details of the synthesis, IR and NMR
characterization of a new family of hydrazonesdderivatives of
calix[4]resorcinol and their structural units. The investigation of
the receptor properties of this family of calixarenes towards alkali,
alkali-earth and transition metals has been carried out. Their
binding properties have been investigated by the liquid–liquid
extraction method by using the aqueous solutions of metal picrates.
The extraction efficiency and selectivity, stoichiometry of com-
plexes and extraction constants for transition metals have been
established.
[4]pyrogallol, the corresponding esters have been obtained. Then,
by the subsequent treatment with an excess of hydrazine hydrate,
the esters were transformed into hydrazides 1 and 3 according to
a procedure described by us earlier.11 Condensation of compound 1
or 3 with an excess of appropriate aldehyde (or acetone) has
resulted in the conversion of all acetylhydrazide groups to ace-
tylhydrazone. The hydrazones 2a–f and 4b–f have been obtained
with yields in the range 52–92%. The composition and the structure
of synthesized compounds 2a–f and 4b–f have been proven by the
elemental analysis, HRMS (EI) and MALDI-TOF mass spectrometry,
NMR and IR spectroscopy data.
Recently we have also reported the synthesis of tetrathiaca-
lix[4]phenols functionalized by acetylhydrazone fragments.13,14
However, the desired product of complete substitution has
been obtained only by using picolinaldehyde as a reagent. The re-
action of tetrathiacalix[4]arene acetylhydrazide with an excess of
4-nitrobenzaldehyde leads to the preferential formation of an
unconventional tetrathiacalix[4]arene with two acetylhydrazone
fragments and the additional formation of N,N0-diacetylhydrazine
bridge in the 1,3-positions. Though for the 1,3-alternate conformer
of calix[4]phenol as well as for calix[4]resorcinol and resorcinol
derivatives in our case such a phenomenon did not take place.
Obviously this is caused by the relative ordering of functional
groups.
2.2. IR characterization in solid
IR spectra of 4b–f in solid state are practically similar to the
spectra of 2a–f and earlier reported data for 4-tert-butylphenoxy-
acetylhydrazones23 that is caused by the similarity of their struc-
2. Results and discussion
2.1. Synthesis
tural blocks (Table 1). The absorption band n(C]N) appeared as
a shoulder in the region of w1640–1660 cmꢀ1 and only for com-
pound 2a registered as a weak single peak with the maximum at
1640 cmꢀ1. At the same time IR spectra of 4b–f in comparison with
their acyclic analogues spectra have broader absorption bands. The
The synthesis of hydrazones 2a–f and 4b–f is shown in Figure 1.
By the reaction of ethyl bromoacetate with resorcinol or calix-
Figure 1. Synthesis of the hydrazones 2a–f and 4b–f and atomic numbering scheme.

410
S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
w1550 cmꢀ1 (Amid II
d(NH)). The absorbance of dNH is the most
Table 1
a
The frequencies of characteristic vibrations (
conformational composition of acetylhydrazones 2a–f and 4b–f
n
, cmꢀ1
)
in IR spectra and cis/trans
characteristic attribute of trans-form, because it is not observed for
cis-amide conformers in the above mentioned region of spectrum.
The absorption bands for cis-amide form appear in the regions:
Compound
Vibration, assignment (Nujol)
(NH) (NH)
Conformational
composition
w3200 (
n
NH); w3100 cmꢀ1 (composite tone
(C]O); w1490–1440 cmꢀ1
n
(C]O)þ
d(NH)) and
n
d
N(C]O)
w1650 cmꢀ1
n
d(NH). In conformity
2a
2b
3221br
3054br
3237sh
3215
3073br
3187
1556
1683
cis/transb
cis/trans
with this point of view, the spectra of 4-tert-butylphenoxy-
acetylhydrazones have been interpreted earlier.23 In agreement
with these data the specific spectral characteristics for hydrazones
2a–f and 4b–f allowed their conformation composition in the solid
to be established (Table 1).
1556
1687
1675sh
2c
d
1685
1675
cis/d
3088
3067sh
3191br
3062
3294
3090br
3061
The trans-amide conformation of hydrazone fragment in the in-
vestigated molecules is revealed in a pair of absorption bands
2d
2e
1565
1696
1667
1705sh
1698
cis/trans
n
NH>3200 and 2
frequency and intensity. An additional specific criterion of trans-
amide conformation is the presence of peak
NHz1540 cmꢀ1
A similar picture is observed in the spectra of compounds 2e, 2f.
The cis-amide conformation is characterized by the vibrations
(NH)<3200 cmꢀ1 and composite tone
(NH)z3070
d
NHz3070 cmꢀ1, where the first peak has a higher
1530
cis/transb
d
.
2f
3311
1546
1702
1683
cis/transb
3219br
3163br
3218br
3062br
3214br
3250br
3205br
3055
n
n
(C]N)þ
d
4b
1534
1695br
cis/transb
cmꢀ1. Therewith the first component in this pair of bands has the
lower than for trans-conformer frequency and the lower intensity
of absorption compared to its partnerdcomposite tone. This situ-
ation is clearly illustrated by the spectrum of compound 2c and is
rather sophisticated for 2d due to Fermi resonance, which was
observed earlier for the 4-tert-butylphenoxyacetylhydrazone
analogue.23
4c
4d
4e
1533
(d)a
1531
1695br
1698br
1697br
cis/transb
cis/transb
cis/transb
4f
3331
3213br
1549
1531
1704br
cis/transb
a
Additional characteristics of absorption bands: shdshoulder; brdbroad; vbrd
very broad. The maxima of rather intensive bands of signals are italicized. The
maxima of weak intensive bands of signals are in bold.
In the most of cases the picture of spectrum is complicated by
the presence of both cis- and trans-conformer simultaneously and
by the influence of functional groups. In general the total content
of trans-form in solid state of investigated compounds increased
under going from mono-23 to bishydrazones 2a–f and octahy-
drazones 4b–f. Apparently, the fixing of a large number of
hydrazone fragments on a molecule prevents the formation of cis-
H-dimers owing to steric hindrance. Most of the calix[4]resorcinols
4b–f prefer the trans-conformation of amide fragments, obviously,
due to the possibility of formation of unhindered trans-H-polymer
chains.
b
The trans-conformer dominated.
occurrence of four resorcinol fragments in compounds 4b–f leads
to a variety of conformational states and the appearance of addi-
tional intra- and intermolecular interactions.
The structural characteristics of hydrazones are determined by
the presence of cis/trans conformers about C(O)–N bond and E/Z
geometrical isomers respect to the C]N double bonds (Fig. 2). The
ZN–N conformer is not realized because of steric hindrance. IR, 1H,
13C NMR and X-ray analysis have shown the cis/trans-amide con-
formers only. The EC]N/ZC]N isomerization is registered only for
the 4-tert-butylphenoxyacetylhydrazone of picolinaldehyde in
special conditions in CDCl3.24
2.3. NMR characterization in solution
1H NMR spectra of calix[4]resorcinols 4b–g in DMSO at 303 K
show broad overlapping signals. With increasing temperature, the
spectra are simplified and at temperatures above 373 K only single
signals corresponding to the aromatic protons of upper (H1) and
lower (H4) rim are observed. Compounds 4b–g have been syn-
thesized from the calixarenes having rccc-configuration. The in-
vestigation of unsubstituted calix[4]resorcinols and the compounds
with functionalized hydroxyl groups has shown that even at high
temperatures the rccc-isomer does not transform into another
isomer.26,27 Taking these facts into consideration, it may be con-
cluded that at ambient temperature compounds 4b–g adopt an
rccc-configuration.
According to the literature data25 the absorption bands of trans-
amide forms are revealed in the regions: w3300 cmꢀ1
n
(NH);
(NH)); w1680–
1630 cmꢀ1 (high intensive absorption band Amid I
(C]O)) and
w3100 cmꢀ1 (weak absorption of overtone 2
d
n
In contrast to 4-tert-butylphenoxyacetylhydrazones24 inves-
tigated by us earlier compounds 2a–f and especially 4b–f can adopt
much more spatial forms. Thus, there are at least two groups of
signals in NMR spectra of compounds 2a–f in DMSO-d6 at 303 K.
This is explained by the presence of three spatial forms of mole-
cules where pairs of acetylhydrazone fragments can exist in cis/cis,
cis/trans or trans/trans conformations. The presence of eight
acetylhydrazone fragments in calix[4]resorcinol molecules of 4b–f
leads to an additional multiplicity of spatial forms as compared to
model compounds. Moreover, a large number of polar groups (C(O),
NH etc.) favourable to intra-and intermolecular hydrogen bonds,
which are stable even in such polar solvent as DMSO, result in the
broadening of signals and the overlapping of multiplets in the NMR
spectra. For this reason it was impossible in most of the cases to
Figure 2. The isomer forms of acetylhydrazone fragment.

S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
411
determine the coupling constants. The assignment of spatial forms
was performed by using mainly the differences in chemical shifts
on the basis of criteria described in our previous works.14,24 In ac-
cordance with these criteria, 1H signal of CH2–C(O) group for cis-
conformer should be shifted in downfield by w0.5 ppm as com-
pared with trans-conformer. The 13C chemical shift of carbonyl
group of the cis-conformer should be also downfield shifted by 5–
6 ppm relatively to the signal for trans-conformer. The results of
conformational assignment for investigated compounds 2a–f and
4b–f are represented in Tables 2 and 3. The O–CH2 group signals are
the most sensitive to the conformational change, which allowed the
quantitative evaluation of relative population of all spatial forms for
bishydrazones 2a–f (Table 4). Whereas, the calix[4]resorcinols 4b–f
have essentially more complicated conformational composition,
only the relative content of cis/trans-conformers has been
determined.
The percentage of trans-amide form for resorcinols 2a–b equals
38–45% and is practically similar to the conformational composi-
tion for corresponding 4-tert-butylphenoxyacetylhydrazones.24
Under going to calix[4]resorcinols 4b–f the percentage of trans-
form increases by 8–18%. A similar phenomenon has been ob-
served under going from 4-tert-butylphenoxyacetylhydrazone of
picolinaldehyde (40%) to tetrathiacalix[4]arene functionalized by
the identical hydrazone fragments (55%).14 It is in agreement with
IR spectroscopy data indicating an increase of trans-form per-
centage for octahydrazones 4b–f as compared with bishydrazones
2a–f in the solid state. The attachment of acetylhydrazone sub-
stituents to the calixarene unit obviously prevents their intra-
molecular interaction, which is observed in cyclic H-dimers and
leads to the stabilization of cis-conformers.23,24 Whereas, the for-
mation of hydrogen bonds between NH/C(O) groups of neigh-
bouring acetylhydrazone fragments having trans-configuration is
less spatially hindered and promotes the generation of trans-H-
polymer chains.
The E/Z isomerization relative to the C]N double bonds has not
been revealed in most of the investigated cases. Our previous in-
vestigations14,24 have shown that the irradiation of hydrazones in
CDCl3 by UV light only in the case of 4-tert-butylphenoxy-
acetylhydrazone of picolinaldehyde resulted in the partial conver-
sion of the EC]N into the ZC]N isomer. A thermally induced
isomerization was not found for all hydrazone compounds studied
by us earlier.
A similar situation has been also observed for compounds 2 and
4. The irradiation and keeping of samples at 373 K for 2 h did not
lead to the appearance of any new peaks in their NMR spectra, with
the exception of compound 2e. Under heating of a DMSO-d6 solu-
tion of this resorcinol for 2 h the conversion of EC]N into the ZC]N
isomer (9%) was observed. When the solution was heated for 12 h
the ZC]N isomer content had increased to 21% and practically did
not change on further keeping this solution at this temperature
(Fig. 3a and b).
The signals attributed to the trans ZC]N form (24%) are presented
in the spectrum of compound 2e in CDCl3 immediately after dis-
solution (Fig. 3c). Irradiating a solution of compound 2e by UV light
(254 nm) for half an hour in a quartz dish increases the amount of
the ZC]N isomer to 66% (trans ZC]N: 64%; cis ZC]N: 2%) (Fig. 3d). The
high percentage of trans ZC]N form may be provided by the par-
ticipation of the amide hydrogen atom of the hydrazone fragment
in the formation of bifurcated H-bonds with the ether (–OCH2)
group and nitrogen of the pyridine atom.
The DG values depend only slightly on imine group substituents
in 4-tert-butylphenoxyacetylhydrazones.24 On going to resorcinols
2b, 2e and particularly to calix[4]resorcinols 4b, 4e the values of
the energy barriers increase by 2.8–5.3 kJ/mol (Table 4). This is
probably due to a large number of intra-molecular hydrogen
bonds.

Table 3
13C chemical shifts (ppm) of trans-(cis-) amide conformers of 2a–f and 4b–f in DMSO-d6
Carbon no. Chemical shift (ppm)
2a
2b
2c
2d
2e
2f
4b
4c
4d
4e
4f
1
2
3
101.37(101.61) 101.66 (101.91)
159.00 (159.30) 158.88a; 158.81b
101.46a; 102.03b
(101.86c)
101.86a; 102.05b
(101.27c)
101.97a; 101.70b
101.65a; 102.00b
(101.95c)
100.43 (d)g
100.5 (d)g
100.83 (d)g
100.79 (d)g
100.83 (d)g
158.79a; 158.85b
158.83a; 158.88b
(159.27;c 159.33d)
107.63 (107.1)
158.81a; 158.88b 158.83a; 158.89b
(159.27;c 159.31d) (159.30;c 159.36d)
154.04 (d)g
127.32 (d)g
154.36 (d)g
126.50 (d)g
154.06 (d)g
127.02 (d)g
154.02 (d)g
127.32 (d)g
154.06 (d)g
126.62 (d)g
(159.29;c 159.36d) (159.26;c 159.33d)
107.16 (106.72) 107.44a; 107.55b
107.44a; 107.55b
107.64a; 107.55b
107.65, 107.58
(106.84;c 106.93d) (106.84;c 106.93d)
(106.94;c 107.02d) (107.02)
4
5
6
7
139.94 (129.71) 130.00 (129.91)
130.05 (129.87)
129.99 (129.84)
129.93 (d)g
130.16b (129.96)
125.77 (d)g
35.2 (d)g
127.21 (d)g
35.2 (d)g
127.61 (d)g
34.95 (d)g
34.72 (d)g
22.07; 27.62;
28.78; 29.21;
29.48; 31.32
13.82 (d)g
124.51 (d)g
34.87 (d)g
127.38 (d)g
34.77 (d)g
34.58 (d)g
21.96; 27.58;
28.67; 29.07;
29.82; 31.19
13.74 (d)g
34.23 (d)g
21.98; 27.61;
28.70; 29.13;
29.35; 31.22
13.75 (d)g
68.4 (67.7)
34.32 (d)g
34.36 (d)g
22.05; 27.62;
28.75; 29.17;
29.39; 31.29
13.83 (d)g
22.00; 27.67;
28.73; 29.13;
29.36; 31.24
13.80 (d)g
8
9
d
66.06 (64.83)
66.59 (64.69)
66.56 (64.66 ;c64.74
164.18 (168.89)
146.68 (142.57)
133.33 (133.16)
128.68 (128.88)
131.66 (131.71)
123.30 (123.03)
)
66.57 (64.82;c 64.69d)
164.69 (169.34)
145.52 (141.48)
140.37 (140.18)
128.05 (127.82)
66.60 (64.69)
66.56 (64.75)
68.27 (66.40)
67.21 (65.03)
68.64 (65.86)
68.39 (66.33)
10
12
13
14
15
16
17
164.07 (168.83) 164.07 (168.83)
157.56 (151.36) 147.94 (143.77)
24.89e (25.11f) 134.3 (133.87)
17.49e (16.95f) 127.03 (126.81)
128.72 (128.69)
164.46 (169.09)
148.13 (144.24)
152.98 (152.75)
149.45 (149.37)
164.73 (169.39)
145.63 (141.43)
140.29 (141.10)
121.06 (120.88)
150.23 (150.20)
164.26; (169.20) 164.71 (169.5) 166.33 (168.39) 164.82 (169.49) 164.88 (169.70)
148.18 (143.31) 146.94 (142.29) 145.52 (141.48) 148 (144.52)
133.98 (133.87) 133.5 (131.27)
140.37 (140.18) 149.1 (d)g
127.04 (126.72) 129.06 (128.64) 127.80 (127.40) 149.4 (d)g
145.78 (141.18)
140.87 (d)g
120.93 (120.58)
149.98 (d)g
123.97 (123.89;c123.94d) 124.41 (124.22)
147.93 (147.70;c 147.75d) 136.79 (136.73)
119.93 (119.77)
128.49 (d)g
132.7 (d)g
123.57 (123.54) 126.3 (d)g
130.05 (129.83)
129.94 (129.52) 123.52 (123.07) 147.93 (147.75) 136.5 (d)g
119.94 (d)g
a
For trans-amide conformation of hydrazone fragment when neighbouring group has cis-conformation.
For trans-amide conformation of hydrazone fragment when neighbouring group has trans-conformation.
For cis-amide conformation of hydrazone fragment when neighbouring group has cis-conformation.
For cis-amide conformation of hydrazone fragment when neighbouring group has trans-conformation.
Methyl group at Z position to N11.
b
c
d
e
f
Methyl group at E position to N11.
Signal not assigned as it was covered by other signals or due to low concentration of conformer.
g

S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
413
Table 4
The presence of the lone electron pair on the nitrogen atom in
hydrazone molecules provides their basic properties. The pro-
tonation of these compounds in acid conditions leads to the for-
mation of an ion-pair complex with the Picꢀ anion and, as a result,
to the transfer of picric acid from the aqueous to the organic phase
even without metal ion participation (Fig. 4). The nitrogen atom of
the pyridine fragment in resorcinol derivatives 2e, 4e and 4f con-
tributes additionally to the efficiency of HPic transfer, obviously,
providing the more basic properties of these compounds as com-
pared with 2b, 4b and 4c. It is interesting to notice, when going from
bishydrazones 2b and 2e to octahydrazone analogues 4b and 4e the
HPic transfer notably increases, though the effective concentrations
of hydrazone groups in these experiments remain equal.
Increasing the pH of the aqueous phase would obviously prevent
the protonation process. Therefore for correct comparison of ex-
traction data and simplicity of complex stoichiometry and extrac-
tion constant calculations the liquid–liquid extraction experiments
were carried out at pH¼6.0 with buffer using. Under such condi-
tions, the transfer of picric acid from aqueous to organic phase was
The distribution of spatial forms cis/cis, trans/trans and cis/trans of hydrazone frag-
ments, the percentage of trans-amide conformers, the coalescence temperatures
and the energy barrier values for the conformational conversion of compounds 2a–f
and 4b–f as determined by NMR data (DMSO-d6)
Compound
trans, %
Distribution of spatial forms, %
Tc, K
DG, kJ/mol
trans/trans
cis/cis
trans/cis
2a
2b
2c
2d
2e
2f
4b
4c
4d
4e
4f
45
43
41
39
42
38
55
51
47
64
48
(d)a
18
(d)a
31
(d)a
51
(d)b
385
(d)b
74.5
17
36
47
(d)b
(d)b
371
(d)b
(d)b
71.6
15
37
48
13
37
50
14
39
47
(d)b
388
(d)b
75.0
(d)b
(d)b
73.4
(d)b
(d)b
(d)b
383
(d)b
Percent was not determined due to overlapping of signals in 1H spectrum.
Value was not determined.
a
b
2.4. Extraction studies
only observed for 4f (aw0.1 see Fig. 4). Higher values of pH usually
lead to undesirable hydrolysis of metal ions. Under these conditions,
the extraction of metal cations accompanied by z picrate anions and
n neutral organic ligands (L) can be described by Eq. 1:
Liquid–liquid extraction experiments were performed to ex-
amine the efficiency and selectivity of hydrazones 2b, 2e, 4b, 4c, 4e
and 4f in transferring s-metal ions (Liþ, Naþ, Kþ, Csþ and Ca2þ),
p-metal ions (Pb2þ), d-metal ions (Co2þ, Ni2þ, Cu2þ, Zn2þ, Cd2þ and
Hg2þ) and f-metal ions (La3þ, Gd3þ and Lu3þ) from aqueous phase
into chloroform. Unfortunately, some of the synthesized hydra-
zones have insufficient solubility in the organic phase. The con-
centrations of picric acid (HPic) and metal cations in aqueous phase
were identical in all experiments.
D
D
MzaqDzPicaLqDnLorg$½Mz LnPicLzꢁorg
(1)
where Mzþ, Picꢀ, L, [MzþLnPicꢀz] denote the metal ion, picrate an-
ion, ligand, ion-pair metal complex and the subscripts aq and org
mean that the species exist in the aqueous or organic phase. As-
sumptions are made that the partition of the ligand to the aqueous
Figure 3. The assignment of –OCH2C(O)– signals in 1H spectrum of compound 2e to spatial forms of acetylhydrazone fragments (the spatial form of neighbouring group is shown in
parentheses): (a) in DMSO-d6 at 303 K; (b) sample (a) after keeping at 373 K at 24 h; (c) in CDCl3 at 303 K; (d) sample (c) after irradiating by UV light for half an hour.

414
S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
On going from bishydrazones 2 to calix[4]resorcinol derivatives
4, the extraction yield was dramatically increased. The profiles of
extraction selectivity of 4b and 4c are similar. However, the ex-
traction efficiency of 4b towards Hg2þ is much higher in compari-
son with other transition metals.
The introduction of pyridine as a substituent into the hydrazone
fragments of compounds 4e and 4f leads to the substantial increase
of extraction efficiency towards transition metal ions. All these data
indicate that the sp2-nitrogen pyridine atoms are involved into
coordination with metal ions. However, the coordinating ability of
2-pyridine substituted compounds is higher than that for the 4-
pyridine substituted analogues. The extraction of Cu2þ ion and
heavy metal ions Cd2þ, Hg2þ and Pb2þ by 4e is almost quantitative
(94–97%). A high extraction yield was observed for Lu3þ, having the
smallest radius among lanthanides. Obviously, it may be due to
the geometrically favourable position of the nitrogen atom in the
molecule 4e leading to the O,N,N0-tri-dentate binding site forma-
tion. According to NMR data, the conformational equilibrium for
amide fragments is shifted to the trans-conformer in nonpolar
solvents and this also promotes the formation of a thermodynam-
ically more effective binding site under the extraction conditions.
The increase of extraction efficiency in the case of calix[4]resorcinol
4f is essentially higher than the transfer contribution of free picric
acid. This increase is probably connected with an additional co-
ordination of sp2-nitrogen pyridine atoms of neighbouring hydra-
zone fragments with metal ions.
Figure 4. Effect of pH on a degree of transfer of HPic in the systems containing ex-
tractants 2b,e and 4b,c,e,f; [HPic]¼2.5ꢂ10ꢀ4 M; [L2]¼2ꢂ10ꢀ3 M; [L4]¼0.5ꢂ10ꢀ3 M.
phase is negligible ([L]aqw0). The presence of [MzþPicꢀ
]
in the
z org
organic phase is also negligible. This was confirmed by blank con-
trol experiments.
The extraction percentages of metal picrates at equal effective
concentrations of hydrazone groups are given in Figure 5. It was
observed that the alkali metals ions are not extracted by hydra-
zones (E<3.5%). The more effective apparent extraction of these
metals by compound 4f is really caused by the above mentioned
transfer of free picric acid from water to the organic phase at pH¼6.
Poor extraction was also observed for alkali-earth metal ion Ca2þ
(from w0.3% for 2b to 18.1% for 4e). Bishydrazone 2b only
insignificantly extracts Hg2þ (8.7%) and Lu3þ (11.6%) ions. The
replacement of phenyl substituent in hydrazone fragment with a 2-
pyridine substituent is resulted in an increase of the extraction
yield for transition metal ions. The maxima of extraction for com-
pound 2e were observed for heavy metal ionsdCd2þ (49.2%) and
Hg2þ (83.7%). It is probable that Cu2þ was also extracted by this
compound with high yield, but because of precipitate formation the
extraction yield could not be evaluated correctly.
The sequence (Co2þ<Ni2þ<Cu2þ>Zn2þ) of extraction efficiency
values for compounds 2e and 4f is in accordance with Irving–
Williams order for the relative stability of complexes formed by
first transition series of metal ions.28 However for 4e, this regularity
is disturbed. The Co2þ ion is extracted substantially better than
Ni2þ. The cis-planar coordination of chelate groups of neighbouring
aromatic fragments with metal ions becomes preferable when
binding fragments are fixed at one of the rims of calixarene matrix.
However, for mono-chelate ligands the symmetrical trans-planar
coordination is more typical. Thus, the presence of tri-dentate do-
nor fragments rigidly oriented relative to each other and the non-
typical cis-coordination of chelate groups may be a reason for steric
hindrance leading to the Irving–Williams order deviation.
The stoichiometry of the extracted complexes and the extraction
constants (log Kex) have been determined for some of the metals,
which were most effectively extracted by ligands 2e, 4b, 4c and 4e
(Table 5). The extraction constant (Kex) is evaluated from Eq. 2:
D
ex [ ½Mz LnPicLzꢁorg=½MzDꢁaq½PicL z
n
K
ꢁ
½Lꢁ
(2)
aq
org
The extraction percent (E%) and extraction yield (a) can be cal-
culated from Eq. 3:
D
3100% [ ½Mz LnPicLzꢁorg=ð½PicL
E% [
a
ꢁaq;init=zÞ3100%
(3)
[Picꢀ]aq,init is the initial concentration of the picrate anion in the
aqueous phase.
When MzþLn metal complexes are extracted as an ion-pair with
the picrate anion into the organic phase, then the concentration of
MzþLnPicꢀ in the organic phase is determined by Eq. 4:
z
D
½Mz LnPicLzꢁorg [ ð½PicL
ꢁ
aq;initL½PicLꢁaqÞ=z [
a
½PicL
ꢁaq;init=z (4)
[Picꢀ]aq is the final concentration of the picrate ion in the aqueous
phase.
Substitution of Eq. 4 in Eq. 2 and taking logarithms gives Eq. 5:
z
log Kex [ logð
a
=zð1L
a
Þ ÞLðzL1Þ log½PicLꢁaq;init
Figure 5. Extraction percentage (E%) of cations as a function of the nature of ligands
2b,e and 4b,c,e,f. Percent was not determined due to formation of precipitate.
Llog½MzD
ꢁ
aqLnlog½Lꢁorg
ð5Þ
a

S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
415
Table 5
The extraction constants and stoichiometry of complexes of hydrazones 2e, 4b, 4c
and 4e with metal cations
Cation
Metal/ligand
stoichiometry
log Kex
2e
4b
4c
4e
Co2þ
Ni2þ
Cu2þ
Zn2þ
Cd2þ
Hg2þ
Pb2þ
La3þ
Gd3þ
Lu3þ
1:1
1:1
1:1
1:1
1:1
1:1
1:1
1:1
1:1
1:1
6.5a
9.3ꢃ0.2
7.6a
8.5ꢃ0.2
11.3ꢃ0.4
8.9ꢃ0.2
7.3a
6.8a
7.2a
8.8ꢃ0.2
8.7ꢃ0.4
10.9ꢃ0.3
10.2ꢃ0.3
11.7ꢃ0.4
13.1ꢃ0.3
12.9ꢃ0.4
13.7ꢃ0.4
9.2ꢃ0.2
8.0a
6.6a
7.3a
8.2ꢃ0.1
7.5a
a
The extraction constant was evaluated from extraction yield for proposed
complex stoichiometry 1:1.
The dependence of log Q is described as a function of the Kex and
the concentrations of the picrate anion and the ligand:
log Q [ log KexDðzL1Þ log½PicL
ꢁ
aq;initDlog½MzD
ꢁaqDnlog½Lꢁorg
(6)
where Q¼
If the extraction is very efficient and [L]org,init is less or compa-
rable with [Mzþ] and [Picꢀ
then the final concentration of
a/z(1ꢀ
a
)z.
]
z aq,init
[L]org becomes dramatically lower than [L]org,init The concentration
of [L]org in such a case is determined by Eq. 7:
½Lꢁorg [ ½Lꢁorg;initLn
a
½PicL
ꢁ
aq;init=z
(7)
Under the assumption that [Mzþ
]
]
aqz[Mzþ
]
(in our case
aq,init
[Mzþ
aq,init>[L]org,init and [Picꢀ]aq,init), a plot of log Q vs log[L]org
should be linear with a slope of n, where n indicates the number of
ligands involved per cation in the extracted species. The experi-
mental errors of the extraction yield determination leads to the
very large dispersion of the plotted points in the range of rather
high or low
a. Therefore, for the correct construction of the graph
log Q versus log[L]org we have used only
traction constants Kex are calculated using the intercept values (b)
of the plot with the log Q-axis and Eq. 8:
a
¼0.05O0.95 values. Ex-
b [ log KexDðzL1Þ log½PicL
ꢁ
aq;initDlog½MzDꢁaq
(8)
Figure 6. Log Q versus log[L]org for some metal ions extracted by 4e(a) and 2e, 4b,c
(b) in CHCl3; [HPic]¼2.5ꢂ10ꢀ4 M, [Mzþ]¼1ꢂ10ꢀ2 M, pH¼6.0.
All graphs of extraction dependences (log Q vs log[L]org) for
metal ions have an equal slope (nz1) as well as in the case of excess
and insufficiency of ligand (Fig. 6). This indicates the 1:1 (Mzþ/L)
stoichiometry of the extracted complexes across a wide concen-
tration range. We had earlier shown12 that under excess of
extractant in the case of the tetrahydrazide of classical calix[4]-
arene, the bis-ligand complexes with all transition metal ions are
formed. However, the more flexible conformational analogue
tetrathiacalix[4]arene, having an increased size of the lower rim,
only forms mono-ligand complexes with lanthanide ions. The high
coordinating capacity and large size of calix[4]resorcinols is prob-
ably the reason for formation only mono-ligand complexes.
The Kex (Hg2þ) values for acetylhydrazones with N,O-bidentate
chelate center (2e, 4b and 4c) are similar to those for calix[4]arenes
functionalized by hydrazide groups (Kex (Hg2þ)¼108.1–109.1),12 but
in the case of calix[4]resorcinol 4e, having an additional soft ni-
trogen atom in molecule, the Kex (Hg2þ) value is more than one
order of magnitude higher. Calix[4]resorcinol 4b reveals high ex-
traction selectivity towards Hg2þ, which amounts to more than one
and a half or two orders of magnitude Kex in the series of d- and
f-elements, respectively.
(Kex(Cu2þ)/Kex(Co2þ)¼102). The extraction constants for heavy toxic
metals varied from 1010.2 (Hg2þ) to 1011.7 (Pb2þ) (Table 5). It was
interesting to notice that the maximum of extraction efficiency for
this compound shifted from Hg2þ to Pb2þ compared with hydra-
zones 2b, 2e, 4b, 4c and 4f. A similar shift in the maximum of ex-
traction was also observed for tetrathiacalix[4]arene functionalized
by hydrazide groups on going from 1,3-alternate to cone conformer,
which, obviously, possesses more effective local concentration of
donor centres.12 The efficiency of extraction of lanthanide ions by
the tetrahydrazone 2e increased more than one and a half orders of
magnitude (Kex¼1012.9–1013.7) as compared with tetrahydrazide
derivatives of tetrathiacalix[4]arenes.
3. Conclusions
The synthesis and ion extraction abilities of the receptors based
on calix[4]resorcinol derivatives 4b–f and their monomer struc-
tural blocks 2a–f have been studied. The spectroscopic data in-
dicate that the investigated calix[4]resorcinols have the cone (rccc)
The selectivity in the series of d-elements (Co2þ, Ni2þ, Cu2þ
Zn2þ) with compound 4e achieves two orders of magnitude
,

416
S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
conformation. The diagnostically important IR spectral criteria re-
quired for the conformational analysis of polyacetylhydrazones
have been considered. It was established that the population of
trans-amide form of hydrazone fragments in solid state and solu-
tions increased on going from mono-23 to bis- 2a–f and octahy-
drazones 4b–f. The favourable formation of hydrogen bonds
between NH/C(O) groups of neighbouring acetylhydrazone frag-
ments having the less spatially hindered trans-configuration is the
reason of this phenomenon. The irradiating or heating of poly-
hydrazones only in the case of picolinaldehyde bishydrazone 2e
resulted in the partly conversion of the EC]N into the ZC]N isomer.
On going from resorcinols 2b, 2e to calix[4]resorcinols 4b, 4e, the
value of the energy barrier increases, which is probably due to
a formation of a large number of intra-molecular hydrogen bonds.
The solvent extraction data have demonstrated that at equal
efficient concentrations of binding groups, the acetylhydrazones of
calix[4]resorcinol are substantially more effective extractants of
transition and heavy metal ions as compared to their monomer
structural analogues. In spite of the high coordinating capacity of
calix[4]resorcinols, only the metal/ligand 1:1 stoichiometry com-
plexes are realized. The extraction efficiency in the series of metal
ions (Co2þ<Ni2þ<Cu2þ>Zn2þ) for investigated compounds is in
accordance with Irving–Williams order of the relative stability of
complexes. An exception was observed for compound 4e, which
showed better extraction of Co2þ than Ni2þ cation. The Irving–
Williams order deviation has been caused by the steric hindrances.
The presence of rigidly oriented tri-dentate donor centres and non-
typical cis-coordination of chelate groups at complexation may be
a reason for this. The calix[4]resorcinol 4b with benzene as a sub-
stituent in the hydrazone fragments reveals excellent selectivity
towards Hg2þ. Thus, we can conclude that octahydrazones 4b and
4e have potential use in the extraction separation, phase transfer,
recovery of metals and exclusion of toxic heavy metal ions.
4.2. Synthesis
Figure 1 illustrates the successive synthetic steps of the com-
pounds 2a–f and 4b–f. 1H, 13C NMR and IR data are presented in
Tables 1–3.
4.3. 1,3-Bis[(N0-(propan-2-ylidene))-
hydrazinocarbonylmethyloxy]benzene (2a)
To a suspension of 1 (1.02 g, 4 mmol) in water (10 ml) and ac-
etone (20 ml) several drops of acetic acid were added. The reaction
mixture was heated for 2 h at 70 ꢄC. After cooling, the precipitate
was filtered off. The precipitate was washed several times with
acetone and recrystallized from mixture of EtOH and DMFA. Yield:
1.07 g (80%) as a white powder. Mp 223 ꢄC. HRMS (EI), m/z:
334.1639 (calcd for C16H22N4O4 334.1641). Anal. Calcd for
C16H22N4O4 (334.38): C, 57.46; H, 6.64; N, 16.76. Found: C, 57.40; H,
6.80; N, 16.79.
4.4. General procedure for the preparation of hydrazone
derivatives of resorcinol (2b–f)
To a suspension of 1 (1.02 g, 4 mmol) in 45 ml EtOH and 15 ml
DMF under stirring 8.4 mmol of the corresponding aldehyde and
several drops of acetic acid were added. The reaction mixture was
heated for 5 h at 80 ꢄC. After cooling, the formed precipitate was
filtered off. During the synthesis of compounds 2e and 2f no pre-
cipitate was formed. In these cases, the solvent was removed from
the reaction mixture by distillation. The residue was washed sev-
eral times with a mixture of water/EtOH (1:1) and recrystallized
from EtOH and DMFA.
4.4.1. 1,3-Bis[(benzylidene)hydrazinocarbonylmethyloxy]-
benzene (2b)
Prepared similar to the general procedure using benzaldehyde
(0.89 g). Yield: 1.13 g (66%) as a white powder. Mp 208 ꢄC. HRMS
(EI), m/z: 430.1640 (calcd for C24H22N4O4 430.1641). Anal. Calcd for
C24H22N4O4 (430.46): C, 66.97; H, 5.15; N, 13.02. Found: C, 66.98; H,
4.87; N, 13.18.
4. Experimental
4.1. General
All chemicals were used as commercially received without fur-
ther purification. CHCl3 and DMFA were distilled over P2O5. CDCl3
(99.8% isotopic purity) and DMSO-d6 (99.5% isotopic purity) from
Aldrich were used for NMR spectroscopy. The metal salts for ex-
traction experiments were the following chlorides and nitrates:
LiCl, NaCl, NaCl, CsCl, CaCl2, CoCl2$6H2O, NiCl2, CuCl2, ZnCl2,
CdCl2$2.5H2O, Hg(NO3)2$H2O, Pb(NO3)2, LaCl3$7H2O, Gd$6H2O,
LuCl3$6H2O.
4.4.2. 1,3-Bis[(4-bromobenzylidene)hydrazinocarbonyl-
methyloxy]benzene (2c)
Prepared similar to the general procedure using 4-bromo-
benzaldehyde (1.55 g). Yield: 2.2 g (94%) as a white powder. Mp
246 ꢄC. HRMS (EI), m/z: 585.9847 (calcd for C24H20Br2N4O4
585.9851). Anal. Calcd for C24H20Br2N4O4 (588.25): C, 49.00; H,
3.43; Br, 27.17; N, 9.52. Found: C, 49.10; H, 3.43; Br, 30.83; N, 9.52.
Microanalyses of C, H and N were carried out with a CHN-3
analyser. Melting points of compounds were measured with
a Boetius hotstage apparatus. The purity of the compounds was
monitored by TLC. NMR experiments were performed on a Bruker
AVANCE-600 spectrometer at 303 K equipped of a 5 mm diameter
broadband probe head working at 600.13 MHz in 1H and
150.864 MHz in 13C experiments. Chemical shifts were reported
relative to TMS as an internal standard. Assignment was accom-
plished by means of 2D 1H–13C HSQC and 2D 1H–13C HMBC
methods. The pulse programs of the HSQC and HMBC experiments
were taken from Bruker software library. IR absorption spectra
were recorded on a Vector-22 Bruker FT-IR spectrophotometer with
a resolution of 4 cmꢀ1 as Nujol emulsions and KBr pellets of com-
pounds. The mass spectra (EI) were obtained on a Finnigan MAT-
212 mass spectrometer (resolution was 1000; data were processed
using the MSS MASPEC II data system 32; direct inlet of the sample
into the ion source, programming of the temperature from 20 to
300 ꢄC, the energy of ionizing electrons was 70 eV, the electron
emission current was 1.0 mA). Mass spectra (MALDI) were detected
on a Finnigan MALDI-TOF Dynamo mass spectrometer.
4.4.3. 1,3-Bis[(4-nitrobenzylidene)hydrazinocarbonyl-
methyloxy]benzene (2d)
Prepared similar to the general procedure using 4-nitro-
benzaldehyde (1.27 g, 8.4 mmol). Yield: 1.74 g (83%) as a light yel-
low powder. Mp 253–255 ꢄC. HRMS (EI), m/z: 520.1348 (calcd for
C24H20N6O8 520.1343). Anal. Calcd for C24H20N6O8 (520.46): C,
55.39; H, 3.87; N, 16.15. Found: C, 55.47; H, 3.89; N, 16.26.
4.4.4. 1,3-Bis[(2-pyridinylmethylidene)hydrazinocarbonyl-
methyloxy]benzene (2e)
Prepared similar to the general procedure using picolinaldehyde
(0.89 g). Yield: 1.01 g (58%) as a white powder. Mp 205–207 ꢄC.
HRMS (EI), m/z: 432.1541 (calcd for C22H20N6O4 432.1546). Anal.
Calcd for C22H20N6O4 (432.43): C, 61.10; H, 4.66; N, 19.43. Found: C,
61.07; H, 4.93; N, 19.69.
4.4.5. 1,3-Bis[(4-pyridinylmethylidene)hydrazinocarbonyl-
methyloxy]benzene (2f)
Prepared similar to the general procedure using iso-
nicotinaldehyde (0.89 g). Yield: 1.31 g (75%) as a white powder. Mp

S.N. Podyachev et al. / Tetrahedron 65 (2009) 408–417
417
241 ꢄC. HRMS (EI), m/z: 432.1544 (calcd for C22H20N6O4 432.1546).
4.6. Picrate extraction experiments
Anal. Calcd for C22H20N6O4 (432.43): C, 61.10; H, 4.66; N, 19.43.
Found: C, 61.31; H, 4.74; N, 19.47.
Aqueous metal picrate solution (5 ml), which was buffered at
pH¼6.0 and the solution of extractant (5 ml, 2.5ꢂ10ꢀ5 to 2ꢂ10ꢀ3 M
for 2 and 2.5ꢂ10ꢀ5 to 0.5ꢂ10ꢀ3 M for 4) in CDCl3 were magnetically
stirred in a flask. The extraction equilibrium was reached after
vigorous stirring for 1.5 h at 20 ꢄC. After that, two phases were
allowed to settle for 1 h. The absorbances A1 of the aqueous phase
after extraction and A0 of the aqueous phase before extraction were
measured at 355 nm (the wavelength of maximum absorption of
the picrate ion, lmax¼355 nm). All data were obtained from two
independent experiments. Aqueous metal picrate solutions ([metal
salt]¼1ꢂ10ꢀ2 M; [picric acid]¼2.5ꢂ10ꢀ4 M) were prepared by
stepwise addition of a 2.5ꢂ10ꢀ4 M aqueous picric acid solution to
the calculated amounts of metal salts. The obtained solutions were
stirred at pH¼6.0 with acetic-acetate buffer for 1 h. For alkaline
ions, tris(hydroxymethyl)aminomethane–HCl (0.05 M) was used as
4.5. General procedure for the preparation of hydrazone
derivatives of calix[4]resorcinol (4b–f)
To a suspension of 3 (0.63 g; 0.4 mmol) in EtOH (18 ml) and DMF
(6 ml) under stirring 6.4 mmol of the corresponding aldehyde and
several drops of acetic acid were added. The reaction mixture was
heated for 24 h at 80 ꢄC. The solvent was removed from the reaction
mixture by distillation. Hexane was added to the residue and the
mixture was heated again. After cooling, the precipitate was filtered
off, washed several times with hexane and EtOH, recrystallized
from EtOH and DMFA.
4.5.1. 2,8,14,20-Tetranonyl-4,6,10,12,16,18,22,24-octa[(benzyli-
dene)hydrazinocarbonylmethyloxy]pentacyclo[19,3,1,13,7,19,13,115,19]-
octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-
dodecaene (4b)
a
buffer. The percent of extraction was calculated as ratio
E%¼100ꢂ(A0ꢀA1)/A0. The log Kex and n values were determined
from the plot of log(
/z(1ꢀ
)z) versus log[L]org
a
a
.
Prepared similar to the general procedure using benzaldehyde
(0.68 g). Yield: 0.69 g (76%) as a white powder. Mp 145–147 ꢄC. MS
(MALDI-TOF), m/z: (2297) [MþNa]þ; (2315) [MþK]þ. Anal. Calcd for
C136H160N16O16 (2274.8): C, 71.81; H, 7.09; N, 9.85. Found: C, 72.13;
H, 7.40; N, 9.87.
Acknowledgements
This work is supported by the Russian Fund for Basic Research
(grant 07-03-00325).
References and notes
4.5.2. 2,8,14,20-Tetranonyl-4,6,10,12,16,18,22,24-octa[(4-
bromobenzylidene)hydrazinocarbonylmethyloxy]pentacyclo-
[19,3,1,13,7,19,13,115,19]octacosa-1(25),3,5,7(28),9,11,13(27),-
15,17,19(26),21,23-dodecaene (4c)
Prepared similar to the general procedure using 4-bromo-
benzaldehyde (1.19 g). Yield: 0.75 g (65%) as a white powder. Mp
152 ꢄC. MS (MALDI-TOF), m/z: (2945) [MþK]þ. Anal. Calcd for
C136H152N16O16Br8 (2906.0): C, 56.21; H, 5.27; N, 7.71; Br, 22.00.
Found: C, 56.23; H, 5.28; N, 7.65; Br, 21.72.
1. Skopenko, V. V.; Amirkhanov, V. M.; Sliva, T. Yu.; Vasilchenko, I. S.; Anpilova, E. L.;
Garnovskii, A. D. Russ. Chem. Rev. 2004, 73, 737.
2. Reinhoudt, D. N. Pure Appl. Chem. 1988, 60, 477.
3. Steed, J. W.; Atwood, J. L. Supramolecular Chemistry; Wiley: Chichester, UK,
2000.
4. Dam, H. H.; Reinhoudt, D. N.; Verboom, W. Chem. Soc. Rev. 2007, 36, 367.
5. Bo¨hmer, V. Angew. Chem., Int. Ed. Engl. 1995, 34, 713.
6. Gutsche, C. D. In Calixarenes Revisited; Stoddart, J. F., Ed.; The Royal Society of
Chemistry: Cambridge, 1998.
7. Calixarenes 2001; Asfary, Z., Bo¨hmer, V., Harrowfield, J., Vicens, J., Eds.; Kluwer
Academic: Dordrecht, 2001.
8. Sliwa, W.; Zujewska, T.; Bachowska, B. Pol. J. Chem. 2003, 77, 1079.
9. Baldini, L.; Casnati, A.; Sansone, F.; Ungaro, R. Chem. Soc. Rev. 2007, 36, 254.
10. Podyachev, S. N.; Sudakova, S. N.; Syakaev, V. V.; Burmakina, N. E.; Shagidullin,
R. R.; Avvakumova, L. V.; Konovalov A. I. Russ. Chem. Bull., in press.
11. Podyachev, S. N.; Syakaev, V. V.; Sudakova, S. N.; Shagidullin, R. R.; Osyanina, D.
V.; Avvakumova, L. V.; Buzykin, B. I.; LatypovSh, K.; Habicher, V. D.; Konovalov,
A. I. J. Inclusion Phenom. 2007, 58, 55.
12. Podyachev, S. N.; Sudakova, S. N.; Syakaev, V. V.; Galiev, A. K.; Shagidullin, R. R.;
Konovalov, A. I. Supramol. Chem. 2008, 20, 479.
13. Podyachev, S. N.; Sudakova, S. N.; Syakaev, V. V.; Shagidullin, R. R.; Galiev, A. K.;
Konovalov, A. I. Mendeleev Commun. 2006, 6, 297.
4.5.3. 2,8,14,20-Tetranonyl-4,6,10,12,16,18,22,24-octa[(4-
nitrobenzylidene)hydrazinocarbonylmethyloxy]pentacyclo-
[19,3,1,13,7,19,13,115,19]octacosa-1(25),3,5,7(28),9,11,13(27),-
15,17,19(26),21,23-dodecaene (4d)
Prepared similar to the general procedure using 4-nitro-
benzaldehyde (0.96 g). Yield: 0.93 g (87%) as a yellow powder. Mp
162–163 ꢄC. MS (MALDI-TOF), m/z: (2636) [MþH]þ; (2658)
[MþNa]þ. Anal. Calcd for C136H152N24O32 (2634.8): C, 62.00; H,
5.81; N, 12.76. Found: C, 61.71; H, 5.91; N, 12.38.
14. Syakaev, V. V.; Podyachev, S. N.; Gubaidullin, A. T.; Sudakova, S. N.; Konovalov,
A. I. J. Mol. Struct. 2008, 885, 111.
15. Amr, A. E.-G. E.; Mohamed, A. M.; Ibrahim, A. A. Z. Naturforsch. 2003, 58b, 861.
16. Todeschini, A. R.; Miranda, A. L. P.; Silva, K. C. M.; Parrini, S. C.; Barreiro, E. J. Eur.
J. Med. Chem. 1998, 33, 189.
17. Cunha, A. C.; Figueiredo, J. M.; Tributino, J. L. M.; Miranda, A. L. P.; Castro, H. C.;
Zingali, R. B.; Fraga, C. A. M.; Souza, M. C. B. V.; Ferreira, V. F.; Barreiro, E. J.
Bioorg. Med. Chem. 2003, 11, 2051.
18. Levrand, B.; Ruff, Y.; Lehn, J.-M.; Herrmann, A. Chem. Commun. 2006, 2965.
19. Kogan, V.; Zelentsov, V.; Larin, G.; Lukov, V. In Complexes of Transition Metals
with Hydrazones; Tsivadze, A. Y., Ed.; Nauka: Moscow, 1990.
20. Carcelli, M.; Mazza, P.; Pelizzi, C.; Pelizzi, G.; Zani, F. J. Inorg. Biochem.1995, 57, 43.
21. Samanta, B.; Chakraborty, J.; Shit, S.; Batten, S. R.; Jensen, P.; Masuda, J. D.;
Mitra, S. Inorg. Chim. Acta 2007, 360, 2471.
4.5.4. 2,8,14,20-Tetranonyl-4,6,10,12,16,18,22,24-octa[(2-
pyridinylmethylidene)hydrazinocarbonylmethyloxy]-
pentacyclo[19,3,1,13,7,19,13,115,19]octacosa-1(25),3,5,7(28),-
9,11,13(27),15,17,19(26),21,23-dodecaene (4e)
Prepared similar to the general procedure using picolinaldehyde
(0.68 g). Yield: 0.48 g (52%) as a white powder. Mp 145 ꢄC. MS
(MALDI-TOF), m/z: (2305) [MþNa]þ; (2327) [Mþ2Na]þ; (2368)
[Mþ2NaþK]þ. Anal. Calcd for C128H152N24O16 (2282.73): C, 67.35; H,
6.71; N, 14.73. Found: C, 67.32; H, 6.96; N, 14.37.
22. Rodrıguez-Arguelles, M. C.; Ferrari, M. B.; Bisceglie, F.; Pelizzi, C.; Pelosi, G.;
Pinelli, S.; Sassi, M. J. Inorg. Biochem. 2004, 98, 313.
23. Podyachev, S. N.; Litvinov, I. A.; Shagidullin, R. R.; Buzikin, B. I.; Bauer, I.;
Osyanina, D. V.; Avvakumova, L. V.; Sudakova, S. N.; Habicher, V. D.; Konovalov,
A. I. Spectrochim. Acta, Part A 2007, 66, 250.
4.5.5. 2,8,14,20-Tetranonyl-4,6,10,12,16,18,22,24-octa[(4-
pyridinylmethylidene)hydrazinocarbonylmethyloxy]-
pentacyclo[19,3,1,13,7,19,13,115,19]octacosa-1(25),3,5,7(28),-
9,11,13(27),15,17,19(26),21,23-dodecaene (4f)
24. Syakaev, V. V.; Podyachev, S. N.; Buzykin, B. I.; LatypovSh, K.; Habicher, V. D.;
Konovalov, A. I. J. Mol. Struct. 2006, 788, 55.
Prepared similar to the general procedure using iso-
nicotinaldehyde (0.68 g). Yield: 0.84 g (92%) as a white powder. Mp
158–162 ꢄC. MS (MALDI-TOF), m/z: (2285) [MþH]þ. Anal. Calcd for
C128H152N24O16 (2282.73): C, 67.35; H, 6.71; N, 14.73. Found: C,
67.08; H, 7.18; N, 14.11.
25. Colthup, N. B.; Daly, L. H.; Wiberley, S. E. Introduction to Infrared and Raman
Spectroscopy; Academic: New York, NY, London, 1964.
26. Abis, L.; Dalcanale, E.; Du Vosel, A.; Spera, S. J. Chem. Soc., Perkin Trans. 2 1990,
2075.
27. Fransen, J. R.; Dutton, P. J. Can. J. Chem. 1995, 73, 2217.
28. Irving, H.; Williams, R. J. P. J. Chem. Soc. 1953, 3192.