Calix[4]arene-porphyrin molecular receptors for selective binding of ethylenediamines

Article abstract of DOI:10.1134/S1070328407100119

A new zinc calix[4]arene-bis-porphyrinate was synthesized and its 1 : 1 and 1 : 2 complexation reaction with ehtylenediamine, diethylenediamine, and triethylenediamine in toluene at 298 K was studied by spectrophotometric titration and ¹H NMR.

Full text of DOI:10.1134/S1070328407100119

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2007, Vol. 33, No. 10, pp. 774–778. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © G.M. Mamardashvili, I.A. Shinkar’, N.Zh. Mamardashvili, O.I. Koifman, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 10,
pp. 787−791.
Calix[4]arene-Porphyrin Molecular Receptors
for Selective Binding of Ethylenediamines
G. M. Mamardashvili, I. A. Shinkar’, N. Zh. Mamardashvili, and O. I. Koifman
Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, 153045 Russia
Received May 24, 2006
Abstract—A new zinc calix[4]arene-bis-porphyrinate was synthesized and its 1 : 1 and 1 : 2 complexation
reaction with ehtylenediamine, diethylenediamine, and triethylenediamine in toluene at 298 K was studied by
spectrophotometric titration and 1H NMR.
DOI: 10.1134/S1070328407100119
Among numerous interactions of the substrate–
CHO
HO
CHO
receptor type, the processes of complex formation of
porphyrins and related chromophores with the nitro-
gen-containing organic molecules of different nature
occupy special place [1, 2]. With two and more elec-
tron-donor N atoms in the molecules of bases, the
ligand can coordinate several Zn-porphyrin frag-
ments. If the bidentate ligand concentration does not
exceed the porphyrin concentration, then the coordi-
nation of two tetrapyrrole macrocycles is observed
with the formation of 1 : 2 complexes. At the higher
ligand concentrations, complexes of the composition
1 : 1 are formed [3].
O
O
+ 4
+ 2
N
N
(II)
(III)
HO
CHO
H+, [O], Zn2+
(I)
N
N
N
N
HO
Zn
Zn
The coordination of bidentate ligands by cyclo-
phane dimeric porphyrins can give both the internal
complexes (when the ligand molecule penetrates the
interporphyrin complex forming cavity due to its geo-
metric conformity and occupies the place between
two porphyrin fragments of a dimer) and the internal
complexes (when the ligand molecules cannot pene-
trate the cavity and are arranged outside the tetrapyr-
role macrocycles). Depending on the nature of a
bridge, which holds the porphyrin fragments of the
dimer at a definite distance, and the mutual arrange-
ment, the constant of the dimeric porphyrin binding
with the bindentate ligand according to a two-center
scheme can be 2–5000 times as high as the corre-
sponding value for the monomeric analog [3–5].
O
O
N
N
N
N
HO
(IV)
X(CH2CH2O)CH2CH2Y
Cs2CO3
N
N
N
N
O
Zn
Zn
O
O
O
The aim of this work was to study the complexing
properties of zinc bisporphyrinate toward the bidentate
nitrogen-containing ligands of different nature. We
used the above scheme and synthesized zinc porphyri-
nate dimers, where the spatial preorganization of the
porphyrin fragments occurs due to the presence of
calixarene platform.
O
O
N
N
N
N
O
O
(V)
774

CALIX[4]ARENE-PORPHYRIN MOLECULAR RECEPTORS
775
EXPERIMENTAL
vents were distilled in vacuum, porphyrinate was
recrystallized from the ëç2ël2–Cç3éç mixture (1 : 1).
The yield was 29.59 mg (87%), Rf 0.54 (Al2O3, the 1 : 2
ëç2Cl2–ë6ç14 mixture as eluent).
Synthesis of 5,17-bis-(zinc meso-phenylporphyri-
nate)-25,27-dimethoxy-26,28-dihydroxycalix[4]arene
(IV). Diformylcalix[4]arene (I) (0.2 g, 0.37 mmol),
4,4'-dimethyl-3,3'-diethyldipyrrolylmethane (II) (0.36 g,
1.48 mmol), and benzaldehyde (III) (0.08 g,
0.74 mmol) were dissolved in a mixture of 60 ml aceto-
nitrile and 100 ml dichloromethane. After the addition
of a solution of trichloroacetic acid (95.4 mg,
0.59 mmol) in 10 ml acetonitrile, the mixture was
stirred in the atmosphere of argon for 3 h and oxidized
with a solution of tetrachlorobenzoquinone-1,2 (1.46 g,
6.1 mmol) in 20 ml dichloromethane. The content of a
flask was stirred for 2 h, the solvent was evaporated to
a volume of 30 ml, and the residue was washed with a
10% ammonia solution. The precipitate was dried, dis-
solved in 100 ml dichloromethane, and a saturated solu-
tion of zinc acetate in 10 ml methanol was added to the
mixture obtained. The solution was stirred for 30 min
and filtered. The solvent was removed from the filtrate
to a volume of 10 ml, and the residue was chromato-
graphed on aluminium oxide, Rf 0.76 (Al2O3, with 1 : 2
ëç2Cl2–ë6ç14 mixture as eluent).The yield was
38.4 mg (6%).
The electronic absorption spectrum (ëç2ël2),
λmax, nm (logε ): 420.1 (4.91), 551.5 (3.98), 588 (3.74).
The 1H NMR of porphyrinate V, δ, ppm: 10.11 s (4 ç,
ms-ç), 7.92 m (4 + 4H, Arortho, porph + calixarene), 7.65–7.46
m (4 + 4H, Armeta, porph + calixarene), 7.28 t (2H, Arpara, porph),
7.08 t (2H, Arpara, calixarene), 4.45 s (6H, OCH3), 4.00 d
(4H, ArCH2Ar), 3.80 q (8H, CH2CH3), 3.78 m (8H,
CH2CH3), 3.71 s (4H, OCH2CH2O), 3.66 m (16H,
OCH2CH2O), 3.39 d (4H, ArCH2Ar), 2.08 s (12H,
CH3), 2.20 s (12H, CH3), 1.01 t (12H, CH2CH3), 0.90 t
(12H, CH2CH3). Mass spectrum, m/e (Irel, %): 1774.97
(69), M+.
For C122H143N8Zn2O8
anal. calcd. (%): C, 74.00;
Found (%): C, 73.97;
H, 7.28;
H, 7.24;
N, 5.66.
N, 5.63.
The 1H NMR spectrum of complex V-EDA (1 : 2),
δ, ppm: 10.13 s (4 ç, ms-ç), 7.93 m (4 + 4H, Arortho,
porph + calixarene), 7.66-7.47 m (4 + 4H, Armeta, porph + calix-
arene), 7.30 t (2H, Arpara, porph), 7.09 t (2H, Arpara, calixarene),
4.47 s (6H, OCH3), 4.03 d (4H, ArCH2Ar), 3.82 q (8H,
CH2CH3), 3.79 m (8H, CH2CH3), 3.73 s (4H,
OCH2CH2O), 3.69 m (16H, OCH2CH2O), 3.41 d (4H,
ArCH2Ar), 2.52 s (4H, NH2CH2CH2NH2), 2.11 s (12H,
CH3), 2.21 s (12H, CH3), 1.02 t (12H, CH2CH3), 0.91 t
(12H, CH2CH3), 0.01 s (4H, NH2CH2CH2NH2).
The 1H NMR spectrum of complex V-DEDA (1 : 1),
δ, ppm: 10.10 s (4 ç, ms-ç), 7.91 m (4 + 4 H, Arortho,
porph + calixarene), 7.63-7.45 m (4 + 4H, Armeta, porph + calix-
arene), 7.28 t (2H, Arpara, porph), 7.06 t (2H, Arpara, calixarene),
4.45 s (6H, OCH3), 4.01 d (4H, ArCH2Ar), 3.08 q (8H,
CH2CH3), 3.77 m (8H, CH2CH3), 3.71 s (4H,
OCH2CH2O), 3.66 m (16H, OCH2CH2O), 3.40 d (4H,
ArCH2Ar), 1.80 s (12H, CH3), 2.10 s (12H, CH3), 1.01
t (12H, CH2CH3), 0.90 t (12H, CH2CH3), –3.67 s (8H,
NH(CH2CH2)2NH).
The 1H NMR spectrum of complex V-DEDA (1 : 2),
δ, ppm: 10.10 s (4 ç, ms-ç), 7.91 m (4 + 4 H, Arortho,
porph + calixarene), 7.63-7.45 m (4 + 4 H, Armeta, porph + calix-
arene), 7.28 t (2H, Arpara, porph), 7.06 t (2H, Arpara, calixarene),
4.45 s (6H, OCH3), 4.01 d (4H. ArCH2Ar), 3.80 q (8H,
CH2CH3), 3.77 m (8H, CH2CH3), 3.71 s (4H,
OCH2CH2O), 3.66 m (16H, OCH2CH2O), 3.40 d (4H,
ArCH2Ar), 2.52 s (8H, NH(CH2CH2)2NH), 2.09 s
(12H, CH3), 2.18 s (12H, CH3), 1.01 t (12H, CH2CH3),
0.90 t (12H, CH2CH3), 0.19 s (8H, NH(CH2CH2)2NH).
The electronic absorption spectrum (ëç2ël2),
max, nm (logε ): 422 (5.01), 552 (4.11), 587 (3.89). The
λ
1H NMR spectrum of porphyrinate IV, δ, ppm: 10.17 s
(4 ç, ms-ç), 7.96 m (4 + 4H, Arortho, porph + calixarene), 7.68-
7.49 m (4 + 4H, Armeta, porph + calixarene), 7.31 t (2H, Ar para,
porph), 7.11 t (2H, Arpara, calixarene), 4.47 s (6H, OCH3),
4.01 d (4H, ArCH2Ar), 3.97 q (8H, CH2CH3), 3.89 s
(2H, OH), 3.86 m (8H, CH2CH3), 3.42 d (4H,
ArCH2Ar), 2.41 s (12H, CH3), 2.25 s (12H, CH3), 1.03 t
(12H, CH2CH3), 0.92 t (12H, CH2CH3). Mass spec-
trum, m/z (Irel, %): 1746.57 (73), M+.
For C110H120N4Zn2O4
anal. calcd. (%): C, 75.59;
Found (%): C, 75.54;
H, 6.86;
H, 6.82;
N, 6.41.
N, 6.38.
Synthesis of 5,17-bis-(zinc meso-phenylporphyri-
nate)-25,
27-dimethoxy-26,28-crown[6]-
calix[4]arene (V). Compound IV (30 mg, 0.017 mmol)
was dissolved in a mixture of dimethylformamide and
9 ml acetonitrile (1 : 2 v/v). Then, in the atmosphere of
argon, cesium carbonate (32.51 mg, 0.10 mmol) and
pentaethylene glycol di(p-toluenesulfonate) (16.38 mg,
0.03 mmol) were added to the solution obtained. The
reaction mixture was heated with stirring for 24 h. the
solvents were distilled off in vacuum, and the residue
was extracted with dichloromethane (30 ml) containing
5 ml of a 10% hydrochloric acid solution. The organic
The 1H NMR spectrum of complex V-TEDA 91 : 1)
layer was separated and washed with water twice. The δ, ppm: 10.06 s (4 H, ms-H), 7.89 m (4 + 4 H, Arortho,
dichloromethane solution was dried with sodium sul- porph + calixarene), 7.61-7.42 m (4 + 4 H, Armeta, porph + calix-
fate, the solvent was evaporated to a volume 20 ml, and arene), 7.25 t (2H, Arpara, porph), 7.01 t (2H, Arpara, calixarene),
the residue was chromatographed on aluminium oxide 4.40 s (6H, OCH3), 3.93 d (4H, ArCH2Ar), 3.73 q (8H,
with the 1 : 1 ëç2ël2–ë6ç14 mixture as eluent. The sol- CH2CH3), 3.71 m (8H, CH2CH3), 3.65 s (4H,
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

776
MAMARDASHVILI et al.
Optical density
1.0
Optical density
0.6
(a)
(b)
0.8
0.6
0.4
0.2
0
0.4
0.2
0
1
2
3
4
5
6
380
400
420
440
TEDA (mol/l)/porphyrinate (mol/l)
Wavelength, nm
Fig. 1. (a) The curve of spectrophotometric titration of V–TEDA in toluene at the increasing wavelength 420 nm (298 K, c
=
porph
−5
–6
6.8 × 10 mol/l) and (b) the spectral changes in the region of the Soret band of V with the TEDA additives from 0 to 8 ×10 mol/l.
OCH2CH2O), 3.59 m (16H, OCH2CH2O), 3.31 d (4H, on the basis of spectrophotometric data at two wave-
lengths (decreasing and increasing) as follows:
ArCH2Ar), 1.75 s (12H, CH3), 2.04 s (12H, CH3), 0.94
t (12H, CH2CH3), 0.86 t (12H, CH2CH3), –3.79 s (12H,
N(CH2CH2)3N).*
[ZnP ⋅ L]
-----------------------
KÛ =
[ZnP][L]
(1)
The electronic absorption spectra of IV, V, and zinc
2,7,12,17-tetramethyl-3,8,13,18-tetraethylporphyrinate
(VI) in toluene were recorded on a Carry 100 spectro-
photometer. The changes in the above spectra on addi-
tion of ethylenediamine (EDA), diethylenediamine
(DEDA), and triethylenediamine (TEDA) are shown in
Figs. 1-4 together with the corresponding titration
∆Di, λ ∆D0, λ
= 1/[L]
(mol/l)–1,
1
2
⎛
⎝
⎞
------------------------------
⎠
∆D0, λ ∆Di, λ
1
2
where λ1 is the decreasing wavelength, λ2 is the increas-
ing wavelength. [L] is the ligand concentration, ∆D0 is
the maximum change in the optical density of a solution
at the given wavelength and concentration [9]. The
curves. The 1H NMR spectra of V were recorded on a error in Kst determination was 7%.
Brucker VC-200 spectrometer at 200 Hz in deutero-
chloroform with TNS as internal standard. The electron
impact mass spectrum of IV and V were measured on a
MX-1310 spectrometrical device at the energy of ioniz-
ing electrons 70 eV and ionization chamber tempera-
ture 150–200°ë. The reaction course was controlled by
the results of a TLC on UV-254 Silufol plates.
Diformylcalixarene (I), dipyrrolylmethane (II), and
zinc porphyrinate (VI) were synthesized by the known
procedures [6, 7]. The individual compounds were iso-
lated by the column chromatography on a neutral alu-
minium oxide with 1 : 1 methylene chloride-haxane
mixture as eluent. The organic solvents were purified
by the standard procedures [8].
RESULTS AND DISCUSSION
The study of the complex formation of V with
TEDA in toluene in a wide range of the ligand concen-
trations (ÒL = 0–8 × 10–5 mol/l) revealed the formation of
a single-type complex only. The spectrophotometric
titration curve for this process (Fig. 1) indicates that the
saturation of the reaction system V-TEDA is observed
at the 1 : 1 molar ratio of reagents, i.e., the obtained
complex has the composition 1 : 1. The formation of
“internal” complex I, where the ligand is located
between the porphyrinate fragments of a dimer and is
coordinated by two zinc atoms, is confirmed by the up-
field signal of the TEDA protons (–3.79 ppm) and the
intensity ratio of the signals due to the porphyrinate
protons and the ligand protons in the 1H NMR spectrum
of I.
The stability constants (Kst) of porphyrinate com-
plexes with the corresponding ligands were calculated
In the presence of TEDA, the up-filed shift of the pro-
ton signals of all porphyrin substituents is observed. The
maximum shift is observed for the protons of the methyl
groups (~0.33 ppm). The stability constant of I is equal
to 670000 l/mol, which is 3.4 times as high as the corre-
sponding value of the complex of monomeric zind por-
phyrinate VI with TEDA (198000, see in the table).
The stability constants of the complexes of monomeric and
dimeric zinc porphyrinate with EDA, DEDA, TEDA in tolu-
ene at 298 K
Kst (l/mol)
DEDA
Compound
EDA
TEDA
V
30600
150000
97000
82000
670000
The reaction of complex formation of V with EDA
in toluene was also studied in a wide interval of the
VI [10]
31000
198000
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

CALIX[4]ARENE-PORPHYRIN MOLECULAR RECEPTORS
Optical density
777
Optical density
0.6
(a)
1.5
(b)
0.4
0.2
1.0
0.5
0
410
420
430
440
0
20
40
60
80
100
Wavelength, nm
TEDA (mol/l)/porphyrinate (mol/l)
Fig. 2. (a) The curve of spectrophotometric titration of V–EDA in toluene at the increasing wavelength 420 nm (298 K, c
=
porph
–4
–6
8.7 × 10 mol/l) and (b) the spectral changes in the region of the Soret band of V with the EDA additives from 0 to 8 × 10 mol/l.
ligand concentrations ÒL = 0–8 × 10–4 mol/l and was field signal of the DEDA protons (–3.67 ppm) and the
ratio of the signal intensities of porphyrinate and ligand
protons in the spectrum of the complex V-DEDA sug-
gest the formation of the “internal” complex of the
composition 1 : 1, where the bidentate ligand is located
between the porphyrinate fragments of a dimer. The
stability constant of the above complex calculated by
the standard procedure is equal to 150000 l/mol, which
is higher than the corresponding value for the complex
of monomeric zinc porphyrinate VI wirh DEDA
(82000, see in the table).
found to give a single-type complex as well (Fig. 2).
The down-field signals of the EDA protons (2.52 and
0.01 ppm) and the intensity ratio of the signals of the
1
porphyrinate protons and the ligand protons in the H
NMR of the complex V-EDA confirm the formation of
the “external” complex II of the composition 1 : 2,
where the ligand molecules cannot penetrate the com-
plex forming cavity between porphyrins and are located
outside the tetrapyrorle macrocycles, each ligand mol-
ecule being coordinated by one zinc atom. The stability
constant of the complex under consideration calculated
by Eq. (1) is equal to 36 000 l/mol, which is comparable
with the corresponding value of the complex of mono-
meric zinc porphyrinate with EDA (31000, see in the
table).
The spectrophotometric titration curve (Fig. 3) for
interaction of VI with DEDA also contains a pro-
nounced step in the region of the higher ligand concen-
trations (at the reagent molar ratio 1 : (0.5–10.0)). In the
spectrum of the porphyrinate–ligand complex, in the
region of the reagent concentration, corresponding to
the system saturation, the signals of the DEDA protons
lie in a weak field (2.52 and -0.19 ppm). The decreasing
screening effect of the π-electron systems of the tet-
rapyrrole chromophores on the ligand protons and the
intensity ratio of the signals of the porphyrinate and
ligand protons indicate the formation of the “external”
complex VI-DEDA (1 : 2), which consists of one
dimeric porphyrinate molecule and two DEDA mole-
cules. At the ligand excess, the 1 : 1 complex is likely
to transform to the 1 : 2 complex. In this case, the biden-
tate ligand molecules are bonded with the reaction cen-
ters of the porphyrinate fragments from the external
side and are less screened by the latter. The stability
constant of the 1 : 2 complex is equal to 970000 l/mol
and is comparable with the corresponding value for the
complex of monomeric zinc porphyrinate VI with
DEDA (82000 l/mol, see in the table).
The complexation reaction of the dimeric porphyri-
nate V with EDA is likely to proceed in two stages:
V + EDA = V-EDA, K1st = [V-EDA]/[V] [EDA] (2)
V-EDA + EDA = EDA-V-ùÑÄ,
(3)
K2st = [EDA-V-EDA]/[V-EDA] [EDA].
The corresponding titration curve (Fig. 2) contains
only one step, which indicates that the constants Ks1t
and K2st are very close and reactions (2) and (3) practi-
cally merge into one total reaction. The spectral
changes shown in Fig. 2 correspond exactly to this total
process, while äst ~ K1st ~ Ks2t .
The study of the complexation reaction between V
and DEDA in toluene revealed two steps on the corre-
sponding titration curve (Fig. 3a). At the low ligand
concentrations (up to the reagent molar ratio 1 : (0–0.5)),
the spectral changes during the reaction occur with the
The above data indicate that the selectivity of bis-
porphyrin-calixarene conjugate in the processes of
retention of isosbestic point (Fig. 3b, 3c, 3d). The up- complexation with the bidentate nitrogen-containing
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

778
MAMARDASHVILI et al.
Optical density
(b)
1
2
Optical density
0.8
(a)
0.6
0.4
0.2
0
0
2
1
10
20
30
EDA (mol/l)/porphyrinate (mol/l)
(d)
(c)
2
1
0
0
410
420
430
440
410
420
430
440
450
Wavelength, nm
Wavelength, nm
Fig. 3. (a) The curve of spectrophotometric titration of V–DEDA in toluene at the increasing wavelength 420 nm (298 K, c
=
porph
–4
–6
8 × 10 mol/l) and the spectral changes in the region of the Soret band of V with the DEDA additives (b) from 0 to 8 × 10 mol/l,
–6
–6
–4
(c) from 0 to 8 × 10 mol/l, and (d) from 8 × 10 to 8 × 10 mol/l.
3. Mamardashvili, G.M., Mamardashvili, N.Zh., and Koif-
ligands is determined by the conformity of the geomet-
ric parameters of the substrate molecule to those of the
complex forming cavity of a receptor.
man, O.I., Usp. Khim., 2005, vol. 74, no. 8, p. 839.
4. Anderson, H.L., Hunter, C.A., Meah, M.N., et al., J. Am.
Chem. Soc., 1990, vol. 112, no. 15, p. 5780.
5. Hunter, C.A., Meah, M.N., and Sanders, J.K.M., J. Am.
Chem. Soc., 1990, vol. 112, no. 15, p. 5773.
ACKNOWLEDGMENTS
This work was supported by the Russian Foundation
for Basic Research (RFBR project nos. 05-03-32055
and 06-03-81001-Bel-a) and Program 7 of the Division
of Chemistry and Materials Science of the Russian
Academy of Sciences “Chemistry and physical chemis-
try of supramolecular systems and clusters”.
6. Mamardashvili, N.Zh. and Golubchikov, O.A., Usp.
Khim., 2000, vol. 69, no. 4, p. 337.
7. Arimura, T., Ide, S., Sugihara, H., et al., New J. Chem.,
1999, vol. 23, p. 977.
8. Weissberger, A. and Proskauer, E.S., Organic Solvents.
Physical Properties and Methods of Purification, Rid-
dick, J.A. and Toops, E.E., Eds., NewYork: Interscience,
1955.
9. Meites, L., An Introduction to Chemical Equilibrium and
Kinetics, New York: Pergamon, 1981.
10. Mamardashvili, N.Zh., Abstracts of Papers, XXV nauch-
naya sessiya vseross. seminara po khimii porfirinov i ikh
analogov (XXV Scientific Session of All-Russian Semi-
nar on the Chemistry of Porphyrins and Their Analogs),
Ivanovo, 2004, p. 13.
REFERENCES
1. Ogoshi, H., Mizutani, T., Hayashi, T., et al., The Porphyrin
Handbook, Kadish, K.M., Smith, K.M., and Guilard, R.,
Eds., NewYork: Academic, 2000, vol. 6, p. 280.
2. Sanders, J.K.M., The Porphyrin Handbook, Kadish, K.M.,
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