Synthesis of calix[4]arene-bis(tin(IV)porphyrins) and supramolecular complexes on their basis

Article abstract of DOI:10.1134/S0036023612030187

Selective substitution of one of the two trans hydroxy groups of calix[4]arene-bis(porphyrinato-tin(IV)) resulted in supramolecular tetramer assemblies based thereon with parallel and perpendicular arrangement of tetrapyrrole macrocyclic rings, which were characterized by UV spectroscopy, ¹H NMR, and elemental analysis data.

Full text of DOI:10.1134/S0036023612030187

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2012, Vol. 57, No. 3, pp. 390–397. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © G.M. Mamardashvili, N.V. Chizhova, N.Zh. Mamardashvili, 2012, published in Zhurnal Neorganicheskoi Khimii, 2012, Vol. 57, No. 3, pp. 443–451.
COORDINATION COMPOUNDS
Synthesis of Calix[4]areneꢀbis(tin(IV)porphyrins)
and Supramolecular Complexes on Their Basis
G. M. Mamardashvili, N. V. Chizhova, and N. Zh. Mamardashvili
a Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya 1, Ivanovo, 153045 Russia
eꢀmail: gmm@iscꢀras.ru
Received April 27, 2010
Abstract—Selective substitution of one of the two trans hydroxy groups of calix[4]areneꢀbis(porphyrinatoꢀ
tin(IV)) resulted in supramolecular tetramer assemblies based thereon with parallel and perpendicular
arrangement of tetrapyrrole macrocyclic rings, which were characterized by UV spectroscopy, 1H NMR, and
elemental analysis data.
DOI: 10.1134/S0036023612030187
According to [1–3], zinc(II) and ruthenium(II) seconds, whereas it takes 30 min for the complex with
porphyrinates containing amino or pyridyl substituꢀ
ents in the macrocyclic ring are able to selfꢀassemble.
The corresponding monomeric porphyrin units are
combined into dimeric, trimeric, tetrameric, and
other oligomeric supramolecular assemblies. These
processes are underlain by donor–acceptor interacꢀ
tion of the metal cation of the porphyrinate reaction
site with the nitrogen atom of the amino group or
pyridyl moiety of the substrate molecule. This process
propionic acid to be formed [7]. Benzoic acid mainly
forms dicarboxylate complexes with monomeric
tin(IV) porphyrinates [7].
O
+
is controllable equilibrium since the Мn –N bond is
O
Ph
relatively labile in organic solvents (it is rapidly and
reversibly broken and formed again at room temperaꢀ
ture). As compared with the pentacoordinated Zn
porphyrin complexes, Ru porphyrins have a hexacoorꢀ
dinated geometry and form more stable complexes.
No less interesting for design of supramolecular
porphyrin assemblies are tin(IV) porphyrinates. The
large multicharged Sn4+ cation can enter the porphyꢀ
rin cavity, without disturbing the planarity of the macꢀ
rocyclic ligand [4]. Sn(IV) porphyrins preferably bind
oxygenꢀcontaining ligands (as a rule, carboxylates and
phenolates) and are hexacoordinated complexes with
transꢀdiaxial coordination of anionic or neutral
ligands [4–8]. The latter, as in the case of amines coorꢀ
dinated to zinc porphyrinates, can be selectively
replaced by other substrates.
N
N
N
Sn
Ph
Ph
N
Ph
O
O
I
The stability of the carboxylate complexes of
Sn(IV) porphyrinates depends not only on the acidity
of the carboxylate but also on the existence of addiꢀ
tional (π–πꢀ or donor–acceptor) interactions that
can arise in the complex and on the conformation
rigidity of an oxygenꢀcontaining ligand (a ligand with
a more rigid carbon skeleton forms a more stable
complex). The Sn(IV) porphyrin complexes with
Carboxylate complexes of Sn(IV) porphyrins can
be synthesized by mixing a carboxylic acid excess
with dihydroxyporphyrinatotin(IV). The rate and
degree of substitution (mono or diꢀ) depend on the
acidic properties of organic acids. Dicarboxylate
complexes SnP(R)2 (I) are formed by strong acids
and when the acid concentration is twice as large as
the porphyrinate concentration. For example, the
phenols and
rins are formed by refluxing that latter with trans
dichloroporphyrinatotin(IV) in benzene or pyridine
nꢀhydroxyphenylꢀsubstituted porphyꢀ
ꢀ
complex with dichloroacetic acid is formed in a few for several hours [6].
390

SYNTHESIS OF CALIX[4]ARENEꢀBIS(TIN(IV)PORPHYRINS)
391
R
O
OH
O
N
N
N
N
N
O
O
O
Sn
O
O
O
Sn
N
N
N
N
O
O
O
O
OH
OH
O
O
OH
OH
O
O
O
O
N
N
N
Sn
Sn
N
N
N
N
OH
O
O
II
III
R
In the present work, selectively substituting for one
Individual compounds were separated using colꢀ
of the two hydroxy groups at the Sn(IV) cation in the umn chromatography on neutral alumina. Organic
synthesized calix[4]areneꢀbis(porphyrinatotin(IV)) solvents were purified by known procedures [11]. The
(Sn2D(OH)4, II), we obtained for the first time two course of the reaction was monitored by thinꢀlayer
new supramolecular tetrameric assemblies with paralꢀ chromatography (TLC) on Silufol UVꢀ254 plates. The
lel and perpendicular arrangement of the tetrapyrrole 1H NMR spectra of solutions in deuterated chloroꢀ
macrocyclic rings and characterized them by UV form (TMS as an internal reference) were recorded on a
1
spectroscopy, H NMR, and elemental analysis data. Bruker VCꢀ500 spectrometer operating at 500.17 MHz.
The approximate arrangement of the porphyrinate The electronic absorption spectra were recorded on a
moieties in the Sn2D(OH)4 dimer prevents bulky subꢀ Varian Caryꢀ100 spectrophotometer.
strates, such as benzoic (L1) and 4ꢀpyridinecarboxylic
Calix[4]areneꢀbis(transꢀdichloroꢀ
β
ꢀoctaalkylporꢀ
(
L2) acid molecules, from entering the interporphyrin
phyrinatotin(IV)). Compound
V (0.40 g) was dissolved
complexing cavity of the dimer. Therefore, unlike the
described methods of synthesis of supramolecular assemꢀ
blies based of tin(IV) porphyrinates, the method sugꢀ
gested by us affords the addition of substrate molecules
only on one “outer” side of the porphyrinate moieties,
which results in both the (Sn2D(OH)2(O2СR)2 comꢀ
plexes (III) and more complex porphyrin assemblies.
in pyridine, and a 1.5ꢀfold excess of SnCl2 · 2H2O was
added to the solution. The reaction mixture was
refluxed for 8 h. The reaction course was monitored by
observing the changes in the visible absorption spectra.
After cooling, the solution was filtered, the solvent was
vacuumꢀdistilled off, and the residue was recrystalꢀ
lized from a dichloromethane–hexane (2 : 1) mixture.
The yield was 0.44 g (92%). Rf 0.73 (Al2O3, elution
with СН2Cl2–С6Н14, 1 : 2).
EXPERIMENTAL
1H NMR (CDCl3,
7.91 (m, 8H, ArꢀHporph + calixarene), 7.60 (m, 8H, Arꢀ
porph + calixarene), 7.24 (t, 2H, ArꢀHporph), 7.06 (t, 2H,
δ, ppm): 9.95 (s, 4H, msꢀH),
5ꢀ(4ꢀHydroxyphenyl)ꢀ10,15,20ꢀtriꢀ(4ꢀmethylpheꢀ
H
nyl)porphyrin (IV) was synthesized as described in [9],
the calix[4]areneꢀbis(βꢀoctaalkylporphyrin) ligand
ArꢀHcalixarene), 4.41 (s, 6H, OCH3), 4.03 (d, 4H,
ArCH2Ar), 3.84 (q, 16H, СН2СН3), 3.40 (d, 4H,
ArCH2Ar), 2.39 (s, 24H, CH3), 1.35 (t, 24H,
(V) was synthesized as in [10], and tin tetraphenylporꢀ
phyrinate (SnP(OH)2 (VI) was synthesized by the
method [8].
СН2СН3). UV (СН2Сl2, nm (logε)): 406 (4.96), 521
(3.41), 559 (3.97), 599 (3.80).
For C116H122N8O8Sn2Cl4 anal. calcd. (%): C,
65.24; H, 5.72; N, 5.25.
NH
N
O
O
O
NH
N
O
O
Found (%): C, 65.99; H, 5.69; N, 5.33.
O
O
Calix[4]areneꢀbis(transꢀdihydroxyꢀβꢀoctaalkylporphyꢀ
rinatotin(IV)) (II). Compound VI (0.30 g, 0.13 mmol)
and potassium carbonate (0.21 g, 1.50 mmol) were
dissolved in 100 mL of tetrahydrofuran and 25 mL of
water, and the reaction mixture was refluxed for 4 h.
The solution was concentrated to 30 mL by rotary
evaporation and left overnight in a refrigerator. The
O
NH
N
HN
N
V
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 3 2012

392
MAMARDASHVILI et al.
precipitated crystals were filtered off, washed with cold alumina with chloroform. The yield was 0.044 g (73%).
water, and vacuumꢀdried. The yield was 0.24 g (85%). Rf 0.81 (elution with chloroform–ethanol, 20 : 1).
1H NMR (CDCl3,
8.05 (d, 8H, ArꢀHortho), 8.21 (t, 8H, ArꢀHmeta), 7.70 (t,
4H, ArꢀHpara). UV (CHCl3, nm (log
490 (3.66), 529 (4.30).
For C45H32N4O2Ru anal. calcd. (%): C, 66.09; H,
3.92; N, 6.85.
δ
, ppm): 8.65 (d, 8H, CHpyrrole),
1H NMR (DMSO,
δ
, ppm): 9.92 (s, 4H, msꢀH),
7.93 (m, 8H, ArꢀHporph + calixarene), 7.63 (m, 8H, Arꢀ
porph + calixarene), 7.25 (t, 2H, ArꢀHporph), 7.09 (t, 2H,
ε)): 411 (5.31),
H
ArꢀHcalixarene), 4.44 (s, 6H, OCH3), 4.01 (d, 4H,
ArCH2Ar), 3.88 (q, 16H, СН2СН3), 3.32 (d, 4H,
ArCH2Ar), 2.33 (s, 24H, СН3), 1.30 (t, 24H,
СН2СН3), –6.34 (s, 4H, OH). UV (СН2Сl2, nm
Found (%): C, 66.01; H, 3.89; N, 6.81.
(5,10,15,20ꢀTetraphenylporphyrinato)ruthenium
RuP(CO)(L3)) (VIIIa). Compound VII (0.03 g,
0.045 mmol) and pyridine (0.007 g, 0.045 mmol) were
kept in dichloromethane for 1 h. The solvent was evapꢀ
orated, and the resulting crystals were washed with
water and vacuumꢀdried.
(
logε)): 408 (4.90), 522 (3.30), 558 (3.57), 598 (3.59).
For C116H126N8O12Sn2 anal. calcd. (%): C, 67.59;
H, 6.12; N, 5.44.
Found (%): C, 67.21; H, 6.18; N, 5.66.
Calix[4]areneꢀbis(transꢀ(hydroxy,L1)ꢀ
βꢀoctaalkylꢀ
1H NMR (CDCl3,
δ, ppm): 8.67 (d, 8H, CHpyrrole),
8.02 (d, 8H, ArꢀHortho), 8.17 (t, 8H, ArꢀHmeta), 7.69 (t,
4H, ArꢀHpara), 4.55 (t, 1H, Pypara), 4.29 (d, 2H,
Pymeta), 3.12 (d, 2H, Pyortho).
For C51H35N4ORu anal. calcd. (%): C, 74.63; H,
4.27; N, 6.83.
porphyrinatotin(IV)) (IIIa). Compound II (0.03 g,
0.014 mmol) and benzoic acid (0.004 g, 0.028 mmol)
were heated in dichloromethane for 30 min. The soluꢀ
tion was cooled, and the solvent was slowly evapoꢀ
rated. The resulting crystals were washed with cold
water and vacuumꢀdried.
1H NMR (DMSO,
7.97 (m, 8H, ArꢀHporph + calixarene), 7.65 (m, 8H, Arꢀ
porph + calixarene), 7.27 (t, 2H, ArꢀHporph), 7.12 (t, 2H,
ArꢀHcalixarene), 4.81 (d, 2H, СНL1), 4.47 (s, 6H,
OCH3), 4.25 (d, 4H, СНL1), 4.03 (d, 4H, ArCH2Ar),
3.90 (q, 16H, СН2СН3), 3.36 (d, 4H, ArCH2Ar), 3.17
(d, 4H, СНL1), 2.31 (s, 24H, CH3), 1.33 (t, 24H,
СН2СН3), –6.30 (s, 2H, OH).
For C130H134N8O14Sn2 anal. calcd. (%): C, 68.80;
H, 5.91; N, 4.94.
δ, ppm): 9.95 (s, 4H, msꢀH),
Found (%): C, 74.58; H, 4.21; N, 6.78.
(5,10,15,20ꢀTetraphenylporphyrinato)ruthenium
RuP(CO)(L2)) (VIIIb). A mixture of compound VII
(0.03 g, 0.045 mmol) and 4ꢀpyridinecarboxylic acid
(0.006 g, 0.045 mmol) in dichloromethane was kept
for 1 h. The solvent was evaporated, and the resulting
crystals were washed with water and vacuumꢀdried.
H
1H NMR (CDCl3,
δ, ppm): 8.62 (d, 8H, CHpyrrole),
8.07 (d, 8H, ArꢀHortho), 8.19 (t, 8H, ArꢀHmeta), 7.71 (t,
4H, ArꢀHpara), 4.19 (d, 2H, CHL2), 3.27 (d, 2H,
CHL2).
For C50H34N5O3Ru anal. calcd. (%): C, 70.34; H,
3.98; N, 8.21.
Found (%): C, 68.48; H, 5.88; N, 4.66.
Calix[4]areneꢀbis(transꢀ(hydroxy,L2)ꢀ
βꢀoctaalkylꢀ
porphyrinatotin(IV)) (IIIb). A mixture of compound II
(0.03 g, 0.014 mmol) and 4ꢀpyridinecarboxylic acid
(0.004 g, 0.028 mmol) was heated in dichloromethane
for 30 min. The solution was cooled, and the solvent
was slowly evaporated. The resulting crystals were
washed with cold water and vacuumꢀdried.
Found (%): C, 70.28; H, 3.89; N, 8.16.
(CO)RuPꢀL2ꢀSn2D(HO)2ꢀL2ꢀRuP(CO) (IX).
A
mixture of compound VIIIb (0.03 g, 0.015 mmol) and
RuP(CO)(H2O) (0.02 g, 0.030 mmol) in dichloꢀ
romethane was kept for 1 h and then slowly evapoꢀ
1H NMR (DMSO,
7.93 (m, 8H, ArꢀHporph + calixarene), 7.64 (m, 8H, Arꢀ and vacuumꢀdried.
porph + calixarene), 7.26 (t, 2H, ArꢀHporph), 7.11 (t, 2H,
δ
, ppm): 9.91 (s, 4H, msꢀH), rated. The resulting crystals were washed with water
1H NMR (DMSO,
δ
, ppm): 9.89 (s, 4H, msꢀH),
H
ArꢀHcalixarene), 4.44 (s, 6H, OCH3), 4.23 (d, 4H,
СНL2), 4.07 (d, 4H, ArCH2Ar), 3.92 (q, 16H,
СН2СН3), 3.33 (d, 4H, ArCH2Ar), 3.19 (d, 4H,
СНL2), 2.30 (s, 24H, CH3), 1.31 (t, 24H, СН2СН3),
8.65 (d, 16H, CHpyrrole), 8.05 (d, 16H, ArꢀHortho), 8.21
(t, 16H, ArꢀHmeta), 7.91 (m, 8H, ArꢀHporph + calixarene),
7.70 (t, 8H, ArꢀHpara), 7.62 (m, 8H, ArꢀHporph + calixarene),
7.21 (t, 2H, ArꢀHporph), 7.11 (t, 2H, ArꢀHcalixarene), 4.42
(s, 6H, OCH3), 4.04 (d, 4H, ArCH2Ar), 3.89 (q, 16H,
СН2СН3), 3.39 (d, 4H, СНL2), 3.28 (d, 4H,
ArCH2Ar), 3.20 (d, 4H, CHL2), 2.31 (s, 24H, CH3),
1.33 (t, 24H, СН2СН3), –6.30 (s, 2H, OH). UV
⎯
6.33 (s, 2H, OH).
For C128H132N10O14Sn2 anal. calcd. (%): C, 67.68;
H, 5.82; N, 6.17.
Found (%): C, 69.13; H, 6.05; N, 6.39.
(
СН2Сl2, nm (logε)): 410 (4.65), 492 (4.32), 528
(5,10,15,20ꢀTetraphenylporphyrinato)ruthenium
RuP(CO)(H2O)) (VII). A mixture of tetraphenylporꢀ
phine (0.05 g, 0.081 mmol) and Ru3(CO)12 (0.03 g,
0.054 mmol) was heated in 5 g of phenol for 1 h. The
melt was cooled and dissolved in 20 mL of dimethylꢀ
formamide, the solution was poured into water, and
(4.08), 560 (3.14), 601 (3.21).
For C218H188N16O16Sn2Ru2 anal. calcd. (%): C,
70.26; H, 5.05; N, 6.02.
Found (%): C, 70.33; H, 5.12; N, 6.07.
P–O–Sn2D(НО)2–O–P (X). A mixture of comꢀ
the precipitate was filtered off and washed with hot pounds II (0.03 g, 0.014 mmol) and IV (0.02,
water. The residue was chromatographed two times on 0.030 mmol) in benzene was refluxed for 3 h. The solꢀ
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 3 2012

SYNTHESIS OF CALIX[4]ARENEꢀBIS(TIN(IV)PORPHYRINS)
393
(а)
(b)
log[(A0
– Ap)/(Ap – Ak)]
A
2.0
1.5
1.0
0.5
1.0
–5.5 –5.0 –4.5 –4.0 –3.5
logcL
–0.5
–1.0
–1.5
–2.0
0.5
420
440
, nm
λ
–6
Fig. 1. (a) Absorption spectra of solutions in the region of the Soret band of compound VI
(
A
c
0
=
)/(
8
A
×
10 mol/L, СН Сl ,
2 2
porph
1
–3
25°
C
) with additions of benzoic acid (
L
) from 0 to
6
×
10 mol/L and (b) the plot of log[(
–
A
–
A
)] vs log
c
.
p
p
k
ligand
vent was evaporated, and the resulting crystals were
washed with water and vacuumꢀdried.
RESULTS AND DISCUSSION
According to the literature data [5–8], the comꢀ
plexation of monomeric tin(IV) porphyrinates with
aromatic carboxylic acids occurs by the equation
1H NMR (DMSO,
δ, ppm): 9.90 (s, 4H, msꢀH),
9.34 (d, 16H, CHpyrrole), 8.60 (d, 12H, ArꢀHortho2), 8.21
(t, 16H, ArꢀHmeta), 7.92 (m, 8H, ArꢀHporph + calixarene), 7.89
(d, 4H, ArꢀHortho1), 7.61 (m, 8H, ArꢀHporph + calixarene), 7.26
(t, 2H, ArꢀHporph), 7.10 (t, 2H, ArꢀHcalixarene), 4.46
(s, 6H, OCH3), 4.03 (d, 4H, ArCH2Ar), 3.90 (q, 16H,
СН2СН3), 3.30 (d, 4H, ArCH2Ar), 2.74 (s, 18H, Arꢀ
CH3), 2.35 (s, 24H, CH3), 1.33 (t, 24H, СН2СН3),
SnР(OH) + 2HL
2
SnР(L) + 2H O,
2
(2)
ꢀ
2
i.e., carboxylate groups are substituted for both trans
hydroxyl groups. This process is equilibrium estabꢀ
lished in a few minutes.
ꢀ
Figure 1 shows typical changes in the UV spectra
⎯
2.65 (s, 4H, NHpyrrole), –6.30 (s, 2H, OH). UV
caused by the formation of complex I. Studying the
(
СН2Сl2, nm (log )): 409 (4.88), 414 (4.92), 521
ε
complexation of monomeric tin tetraphenylporphyriꢀ
nate VI with L1 showed that, in a wide ligand concenꢀ
(3.32), 559 (3.54), 599 (3.49), 650 (3.20).
tration range (cligand = 0–5.3
×
10–4 mol/L), spectral
For C210H194N16O12Sn2 anal. calcd. (%): C, 74.83;
H, 5.76; N, 6.65.
changes in the course of reaction occur with retention
of one family of isosbestic points. The titration curve
has one step, which is evidence of the formation of one
Found (%): C, 74.87; H, 5.69; N, 6.61.
type of complex; the slope of the log[(A0
k)] versus log ligand plot is 2, which indicates that the
resulting complex has the 1 : 2 composition (Fig. 1b).
In the 1H NMR spectrum of complex
, the proton
– Ap)/(Ap –
The stability constants (Ks) of the 1 : 1 porphyrin
receptor (A)–substrate (B) complexes were calculated
by the equation
A
c
I
signals of the ligand are shifted upfield with respect to
the proton signals of the free ligand. The largest shift is
observed for the ligand protons located closer to the
porphyrin macrocyclic ring in the complex and, thus,
subjected to the stronger shielding effect of its ring
current.
⎛
⎜
⎝
⎞
⎟
⎠
ΔAi,λ ΔAo,λ
Ks =
= 1 [B]
(mol L)−1,
(1)
[AB]
[A][B]
1
2
ΔAo,λ ΔAi,λ
1
2
where λ1 is the decreasing wavelength, λ2 is the
increasing wavelength, [A] is the porphyrinate conꢀ
centration, [B] is the substrate concentration,
the maximal change in the solution absorbance at a
given wavelength, Аi is the change in the solution
absorbance at a given wavelength at a given concentraꢀ
tion [12].
ΔАo is
Studying the complexation of II with benzoic acid
by spectrophotometric titration in dichloromethane
showed that spectral changes in the course of spectroꢀ
photometric titration of II with L1 in a wide ligand
Δ
concentration range (cligand = 0–5.3
×
10–4 mol/L)
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 3 2012

394
MAMARDASHVILI et al.
(а)
(b)
A
log[(A0
– Ap)/(Ap – Ak)]
1.0
1.0
0.5
0.5
–5.5 –5.0 –4.5 –4.0 –3.5
logcL
–0.5
–1.0
420
, nm
400
λ
–6
Fig. 2. (a) Absorption spectra of solutions in the region of the Soret band of compound II
(
A
c
0
=
8
A
×
10 mol/L, СН Сl ,
2 2
porph
1
–3
25°
C
) with additions of benzoic acid (
L
) from 0 to
5
×
10 mol/L and (b) the plot of log[(
–
A
)/(
–
A
)] vs log
c
.
p
p
k
ligand
also occur with retention of one family of isosbestic
points. The titration curve has one step; however, the one. i.e., carboxyl groups are substituted only for the
slope of the log[(A0 p)/(Ap k)] versus logcligand hydroxy groups on the outer side of the porphyrinate
The conclusion that complex IIIb is the “external”
–
A
– A
plot is 1, which is evidence that the resulting receptor– moieties of dimer II, is supported by the splitting of
substrate complex has the 1 : 1 composition (Fig. 2). the signals of the corresponding ligand protons. When
Thus, the formation of complex III from II involves “internal” complexes are formed and the ligand is in
two parallel independent reactions at each of the two the field of two tetrapyrrole macrocyclic rings (soꢀ
tetrapyrrole moieties:
called sandwich structure of the complex), the orthoꢀ
and metaꢀprotons of the ligand become equivalent and
give rise to one 1H NMR signal [10].
Studying the complexation of ruthenium tetrapheꢀ
nylporphyrinate (VII) with pyridine (L3) (the organic
substrate molecule is substituted for one water moleꢀ
cule in the inner coordination sphere of ruthenium
porphyrinate) by spectrophotometric titration in
dichloromethane showed that the visible absorption
spectrum of the reaction mixture also displays one
SnP(OH) + HL
2
The processes with 4ꢀpyridinecarboxylic acid (L2
SnP(OH)ꢀL + H O.
2
(3)
ꢀ
)
are analogous. The spectrophotometric titration data
enable us to calculate the stability constants of comꢀ
plexes IIIa and IIIb by a common procedure using
Eq. (1): they are estimated at 1.2
benzoic acid and 1.4
×
104 (mol/L)–1 for
×
104 (mol/L)–1 for 4ꢀpyridineꢀ
carboxylic acid.
The elemental analysis data for the complexes family of spectral curves with its set of isosbestic points
obtained by slow crystallization of the reaction mixꢀ
(Fig. 3a). The titration curve has one step, which is
ture from dichloromethane at the reagent molar ratio evidence that complexation is a oneꢀstep process
corresponding to the inflection point on the titration resulting in the 1 : 1 receptor–substrate complex
curve confirm that the molecular complexes contain
two carboxylate moieties and two hydroxy groups. The
characteristics of the H NMR spectra of the comꢀ
(VIIIa) by the equation
R
1
plexes are consistent with these data: (1) the ligand sigꢀ
nals are shifted upfield as compared with the signals of
the free ligands; (2) the closer the ligand protons to the
porphyrin macrocyclic ring, the larger the shift of the
corresponding signals (i.e., each ligand in the complex
is in the shielding field of one porphyrin macrocyclic
ring); (3) the intensity of the OH signals in the
1H NMR spectrum of the complex is twice as low as
N
Ph
N
N
N
Ru
Ph
Ph
N
Ph
CO
the intensity of the OH signals in the spectrum of II
.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 3 2012

SYNTHESIS OF CALIX[4]ARENEꢀBIS(TIN(IV)PORPHYRINS)
395
A
(а)
(b)
Δ
A
1.0
0.2
0.1
530
550
570
λ
, nm
0
0.5
с
1.0
L, mol/L/сRuP(CO), mol/L
1.5
2.0
–5
Fig. 3. (a) Changes in the visible absorption spectra of solutions of compound VII
(
c
= 10 mol/L, 25°C) in dichloꢀ
porph
3
–5
romethane caused by additions of pyridine (L ) from 0 to
3 × 10 mol/L; (b) the titration curve of VII with pyridine at the
“decreasing” and “increasing” wavelengths.
tons of the substrate molecule). Analogous shifts of the
proton signals are observed for 4ꢀpyridinecarboxylic
acid.
RuP(CO)(H O) + L
2
RuP(CO)ꢀL + H O. (4)
2
ꢀ
The equilibrium constants characterizing process
(4) calculated by a common procedure from the specꢀ
trophotometric titration data by Eq. (5) are 3.5
107 (mol/L)–1 for VIIIa and 3.1 107 (mol/L)–1 for
VIIIb
×
Ruthenium and tin porphyrinates in the presence
of 4ꢀpyridinecarboxylic acid are able to selfꢀorganize
into different supramolecular assemblies [13, 14]. We
×
.
D(OH) and
The elemental analysis data for the complexes found experimentally that the Sn2
4
obtained by slow crystallization of the reaction mixꢀ Sn2D(OH)2(L2)2 complexes can be used as building
ture from dichloromethane at the reagent molar ratio blocks for producing heterometallic porphyrin oligoꢀ
corresponding to the inflection point on the titration mers. In particular, slow evaporation of the reaction
curve (Fig. 2b) indicate that the molecular complexes mixture consisting of Sn2D(OH)4 and RuP(CO)(L2)
contain one pyridine moiety and one CO group. The (1 : 2.5 molar ratio) or of Sn2D(OH)2(L2)2 and
characteristics of the 1H NMR spectra of the complex RuP(CO)(H2O) (1 : 2 molar ratio) resulted in the
are well consistent with these data: the ligand signals same complex, which, according to elemental analyꢀ
are shifted upfield as compared with the signals of free sis, can be represented as supramolecular assembly IX
pyridine (by 5.5 ppm for the orthoꢀprotons, 3.0 ppm consisting of four porphyrin units with orientation
for the metaꢀprotons, and 1.1 ppm for the paraꢀproꢀ close to the cyclophane one.
O
O
O
O
O
O
N
O
O
Ph
Ph
N
N
Sn
N
N
Ph
N
N
N
N
Sn
OHHO
O
O
O
N
N
Ph
OC
Ru
CO
Ph
Ru
N
N
N
N
N
O
N
N
Ph
Ph
Ph
IX
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 3 2012

396
MAMARDASHVILI et al.
1
In the H NMR spectrum of complex IX, the sigꢀ can be represented as supramolecular assembly
X, in
nals of pyridinecarboxylic acid are equally shifted which one hydroxyporphyrin is coordinated to each
upfield from their positions for the free acid. This is
evidence that the protons experience the same shieldꢀ
ing effect of two porphyrin macrocyclic rings. The parꢀ
allel arrangement of the tetrapyrrole moieties in comꢀ
plex IX is also supported by the broadening of the
Soret band and the decrease in its intensity as comꢀ
pared with the absorption spectra of Sn2D(OH)4 and
RuP(CO)(L2).
porphyrinate moiety of the dimer on the outer side of
the tetrapyrrole macrocyclic rings. In the H NMR
spectrum of complex X, the largest upfield shifts are
observed for the orthoꢀprotons of the 4ꢀhydroxypheꢀ
nyl moiety of porphyrin IV. These protons are located
closer to the tetrapyrrole macrocyclic rings of dimer II
than the orthoꢀprotons of the tolyl moieties and, thus,
experience the strongest shielding effect of the macroꢀ
cycles. In the electronic absorption spectrum of comꢀ
1
Slow evaporation of the cooled reaction mixture
obtained by longꢀterm heating under reflux of a mixꢀ
plex X, the Soret band is split, which is typical of oliꢀ
ture of Sn2D(OH)4 and IV (1 : 2.1 molar ratio) yielded gomeric porphyrin systems with nonꢀcyclophane
a complex that, according to elemental analysis data, mutual arrangement of the porphyrin moieties.
O
O
O
O
O
O
N
O
O
N
N
Sn
N
NH
N
N
NH
N
N
Sn
OHHO
O
O
NH
NH
N
N
N
N
X
Thus, we synthesized new tin(IV) porphyrinates and Important Chemical Reactions and Processes” of the
supramolecular complexes based thereon and characꢀ Division of Chemistry and Materials Science of the
terized them by UV spectroscopy, 1H NMR, and eleꢀ RAS.
mental analysis. The use, as the key compound, of
calix[4]areneꢀbis(porphyrinatotin(IV)) with a fixed
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3. G. M. Mamardashvili, N. Zh. Mamardashvili, and
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