Iron(III) complexes on the basis of azomethine derived from 4,4′-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxybenzaldehyde

Article abstract of DOI:10.1134/S1070363210100130

This work deals with the synthesis and investigation of phase behavior of iron(III)-containing complexes of linear azomethine derived from 4,4′-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxybenzaldehyde with NO ₃ ^-, PF ₆ ^-, Cl^-, and BF ₄ ^- counterions. All semiproducts and target substances are characterized by TLC, elemental analysis, IR and NMR spectroscopy, and melting points. It is established that the reaction of Schiff base with metal salts at room temperature leads to the formation of complexes having presumably the linear structure. Phase behavior of the compounds obtained depending on the nature of counterion was studied.

Full text of DOI:10.1134/S1070363210100130

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 10, pp. 1954–1962. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © U.V. Chervonova, M.S. Gruzdev, A.M. Kolker, N.G. Manin, N.E. Domracheva, 2010, published in Zhurnal Obshchei Khimii, 2010,
Vol. 80, No. 10, pp. 1643–1651.
Iron(III) Complexes on the Basis of Azomethine Derived
from 4,4'-Dodecyloxybenzoyloxybenzoyl-4-oxy-2-
hydroxybenzaldehyde
U. V. Chervonovaa, M. S. Gruzdeva, A. M. Kolkera, N. G. Manina, and N. E. Domrachevab
a Institute of the Solution Chemistry, Russian Academy of Sciences,
ul. Akademicheskaya 1, Ivanovo, 153045 Russia
b Kazan Physicotechnical Institute, Kazan Scientific Center,
Russian Academy of Sciences, Kazan, Tatarstan, Russia
Received November 19, 2009
Abstract―This work deals with the synthesis and investigation of phase behavior of iron(III)-containing
complexes of linear azomethine derived from 4,4'-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxybenzal-
dehyde with NO3–, PF6–, Cl–, and BF4– counterions. All semiproducts and target substances are characterized by
TLC, elemental analysis, IR and NMR spectroscopy, and melting points. It is established that the reaction of
Schiff base with metal salts at room temperature leads to the formation of complexes having presumably the
linear structure. Phase behavior of the compounds obtained depending on the nature of counterion was studied.
DOI: 10.1134/S1070363210100130
Designing magnetic and paramagnetic organic
substances is one of the main problems of modern
chemistry in the course of several decades. Systems of
such type with the controlled magnetic moment and
permitting the controlled spin variation of the magnetic
and paramagnetic species are used as model systems
for the investigation of processes taking place in living
nature and for the analysis of intermolecular
interactions in artificial media. First successful works
[1] dealing with the synthesis of the spin-variable
Fe(III) complexes were connected with the variation of
the effect of counterion (NO3–, PF6–, BPh4–) in the outer
sphere and variation in the position of substituents (H,
OCH3) in the structure of the complex. Later
sophisticated magnetic systems appeared [2–4] based
on the complex compounds exhibiting the meso-
morphic behavior and high relaxation time of the
magnetic moment of the complex-forming ion. Iron
and rare earth metal ions were used as complex
formers [5]. Specific feature of such compounds is the
dependence of magnetic behavior on the nature of
counterion [4]. Several years ago data on the magnetic
properties of dendrimer compounds on the basis of
porphyrins were reported [6, 7]. Such compounds were
used as model systems for investigation of behavior of
hemoglobin and cytochrome [8]. Diederich et al.
suggested that the magnetic properties varied due to
the changes in the branched structure [7, 8]. Hence,
combining the principles of creating organic
substances with the properties varied under the action
of magnetic field and the synthetic strategies used for
the controlled synthesis of dendrimer macromolecules
[9] it is possible to obtain new materials with desired
characteristics. They may combine the controlled
structure with the predicted behavior in the magnetic
field. It is also possible to analyze phase behavior of
compounds considering the variation and the effect of
outer counterion in metal complexes.
The aim of this work was the synthesis of iron(III)-
containing complexes of linear azomethine derived
from 4,4'-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hyd-
roxybenzaldehyde playing the role of ligand with
different counterions (NO3–, PF6–, Cl–, BF4– ).
In the first stage of this work the intermediate
compounds for formation of the coordination sphere
around the iron ion were synthesized and studied (see
Scheme 1). Several procedures for preparing alkyl
alkoxybenzoates are published having both advantages
and drawbacks. A classical procedure includes the
formation of acid chloride by treating the acid with the
chlorine-containing reagent (SOCl2, POCl3, PCl5) and
1954

IRON(III) COMPLEXES ON THE BASIS OF AZOMETHINE
1955
CH2Cl
Na2CO3
DMF
O
O
O
+
HO
HO
OH
CH2
I
DCC, DMAP
CH2Cl2, −25°C
O
O
O
C12H25O
O
O
CH2
C12H25
O
OH
II
1,4-dioxane
O
40°C
O
C12H25O
O
5% PdC
H2
OH
III
DCC, DMAP
CH2Cl2, −25°C
O
O
O
O
C12H25O
O
H
O
H
HO
OH
IV
Scheme 1. Synthesis of 4,4'-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxybenzaldehyde. (DCC) dicyclohexyl-
carbodiimide and (DMAP) 4-(dimethylamino)piridine.
the subsequent acylation of phenol fragment and
elongation of molecule in the presence of pyridine or
triethanolamine or in their medium [10]. This method
has several faults (Scheme 1).
In the course of synthesis of the liquid crystalline
4,4'-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxy-
benzaldehyde IV and its Schiff base we have at first
prepared benzyl 4-hydroxybenzoate I necessary as the
protective group in the course of esterification. This
compound was obtained by alkylation of p-hyd-
roxybenzoic acid with benzyl chloride in dry DMF
[12]. The ester I was used for preparing the elongated
ester of p-dodecyloxybenzoic acid II [11] with the
subsequent removal of the protective benzyl group by
hydrogenation into toluene. On the basis of the
obtained ester of p-dodecyloxybenzoyloxybenzoic acid
III the aldehyde IV was prepared.
The main problem is that in the course of
performing the esterification in the organic base
medium tarring can occur decreasing the yield and
requiring the purification of compounds synthesized.
Since the beginning of nineteen nineties publications
appeared describing the possibility of the ester
fragment formation by the reaction of carboxy and
phenol groups in the presence of dicyclohexyl-
carbodiimide (DCC) in methylene chloride, chloro-
Syntheses of the target products were carried out
according to Scheme 2 directly through the formation
of Schiff base without isolation of the ligand from the
solution and the subsequent complex formation with
the salt of iron(III) (Scheme 2).
form, or DMF using
a
catalytic amount of
dimethylaminopyridine [11]. This method permits to
prepare compounds of high purity in a significant yield
and also to use protective groups for the controlled
increase in the dimensions of the organic molecule.
The significant fault of this method is the necessity to
use palladium on activated carbon and gaseous
hydrogen what increases the net cost of the product.
In order to check the purity and individuality of the
compounds obtained the electron absorption spectra of
complexes V–VIII in dry THF were taken. Data on the
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

1956
CHERVONOVA et al.
IV
.
Fe(NO3)3 9Η2Ο
H2N
N
H
CH3
.
Fe(NO3)3 9Η2Ο, KPF6
FeCl3
EtOH, 25°C
.
Fe(NO3)3 9H2O, NaBF4
+
NO3−
PF6−
Cl−
O
C12H25
O
CH3
O
N
NH2
2
BF4−
O
Fe
Scheme 2. Synthesis of the compounds under study.
maxima positions and the absorption intensities are
presented in Table 1.
azomethine group. It leads to the formation of H-bond
(Fig. 2) characterized by the broad band of medium
intensity at 3179 cm–1. The formation of the ligand
takes place in the course of the reaction between the
aldehyde and the amino group directly in solution as
confirmed by the presence of a strong band at 1639
cm–1 characteristic of the HC=N bond [14]. It lies close
to the absorption band of carbonyl group (C=O) of the
ester fragment at 1738–1734 cm–1 [15]. IR spectra
contain also the absorption bands of counterions.
Vibrations of nitrate in compound V are located at
1383 cm–1, hexafluorophosphate in the substance VI
gives two bands at 844 and 556 cm–1, chloride ion of
compound VII gives two bands at 543 and 215 cm–1,
while the vibrations of tetrafluoroborate from the
complex VIII are observed at 1032, 534, and 522 cm–1
[15, 16]. The presence of the coordinated Fe(III) ion is
confirmed by the absorption bands in the far IR range.
Spectra of all complexes contain the same set of
absorption bands related to Fe(III) ion. They include
the bands at 511 cm–1 (bond vibrations of Fe–N bond),
These data show the absence of unreacted Fe(NO3)3·
9H2O indicating the purity and individuality of each
complex. Only λ3 and λ4 values characterizing the
location of the iron ion inside the coordination sphere
and the effect of outer counterion vary significantly.
Analysis of spectra of complexes V–VIII in the
near IR range confirms the presence of Schiff base
formed by N-ethylethylenediamine. Bands at 5850–
5838 and 5709–5703 cm–1 belong to the secondary and
tertiary amine groups respectively [13] (see Fig. 1). In
the range 2921–2851 cm–1 the vibration bands of CH2
groups from the alkyl fragments are observed, 3800–
2600 cm–1. The absorption bands of aromatic ring
protons νH–Ph at 3071 cm–1 have significantly lower
intensity. For the complexes containing strongly
electronegative PF6– and BF4– ions in the outer
coordination sphere the latter characteristically interact
with the proton of the cation, probably of the
Table 1. Electron absorption spectra of complexes V–VIII and Fe(NO3)3·9H2Oa
Comp. no.
Compound
λ1, nm
λ2, nm
λ3, nm
λ4, nm
C37H58N5O20Fe
256 (2.92)
290 (1.09)
310 (0.89)
483 (0.06)
V
C37H48N3O9FeP2F12
C37H48N2O6FeCl3
C37H50N3O10FeB3F12
Fe(NO3)3·9H2O
260 (2.34)
262 (1.97)
262 (1.86)
240 (1.37)
289 (0.76)
289 (0.54)
289 (0.57)
293 (0.81)
351 (0.31)
314 (0.28)
316 (0.34)
–
388 (0.18)
393 (0.11)
387 (0.12)
–
VI
VII
VIII
a Absorption band intensities are given in brackets.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

IRON(III) COMPLEXES ON THE BASIS OF AZOMETHINE
1957
Transmission
VIII
VII
Transmission
3179
VI
V
3071
νH–Ph
V
3424
νOH
VI
VII
VIII
2851
ν(CH3–Alk)
2921
7500 7000 6500 6000 5500 5000 4500 4000
3800 3600
3400 3200
3000 2800 2600
ν, cm–1
ν, cm–1
Fig. 2. IR spectra of complexes V–VIII in the range 3800–
Fig. 1. IR spectra of complexes V–VIII in the near IR
range.
2600 cm–1.
at 471 cm–1 (Fe ion vibrations), at 420 cm–1 (Fe–O
bond vibrations), at 323, and 279 cm–1 (metal–anion
bond vibrations).
made by the nature of counterion in the coordination
sphere of complex. For nitrate complex V, the pre-
cursor of compounds VI, VII, the melting point was
found to be 141.75°C, and its exothermic decom-
position takes place at about 180°C. In the case of
chloride complex the melting was not observed, and
the exothermic decomposition of the complex takes
place near 200°C (see Fig. 4). In the case of complexes
with PF6– and BF4– counterions the simultaneous
melting of the associate formed by the intermolecular
interaction of the H-bond type and probably of the
complex itself is observed. The presence of two phase
transitions in the range 98–114°C can probably be
attributed to the crystal–crystal or crystal–mesophase
transformations.
In Fig. 3 the IR spectra of the target compound V,
of the Fe(III) nitrate nanohydrate, and of Fe(III)
chloride in the range 680–170 cm–1 are present. These
salts were used as complex formers and the location of
characteristic bands of Fe(III) ion and its interaction
with counterions are clearly registered. Hence, for the
iron nitrate crystal hydrate three main absorption
bands are observed at 444, 353, and 323 cm–1.
They characterize the vibrations of Fe3+ ion and of the
Fe3+–O bond. In the case of iron(III) chloride metal
vibrations are located at 474 cm–1, and Fe3+–Cl bond is
characterized by two bands at 348 and 276 cm–1 [17].
The presence of vibrations of the coordinate metal-
counterion bond in this range was reported previously
[17, 18]. Absorption bands characteristic of the Me–X
bonds (X = NO3–, PF6–, BF4–, Cl–) are also observed in
the IR spectra of complexes confirming the presence
of iron as the complex forming ion in the composition
of complex (see Fig. 3).
EXPERIMENTAL
All the reagents and solvents were of “chemically
pure” grade. They were used without the additional
purification. IR spectra were recorded on a Bruker
Vertex 80V instrument in the ranges 7500–370 cm–1
and 670–190 cm–1 in KBr and CsBr pellets. NMR
spectra were taken on
a
Bruker Avance-500
According to the differential scanning calorimetry
data (Fig. 4) all four target substances exhibit several
endothermic phase transitions. Values of temperatures
and enthalpies of phase transitions are listed in Table 2.
Considering that the organic part of the metal complex
molecule in all cases remains the same, and only the
anion alters, it can be suggested that the prevailing
contribution to the phase behavior of compounds is
spectrometer [500.17 MHz (1H) and 125.76 MHz
(13C)]. Elemental analysis of crystalline compounds
was carried out on a FlashEA 1112 analyzer.
Chromatograms and mass spectra were registered on a
Chromatek DSQ-II mass spectrometric instrument
using Kristall 5000.2 gas chromatograph. It was
equipped with a quartz TR-5MS capillary column
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

1958
Transmission
CHERVONOVA et al.
279
323
FeCl3
V
VI
VII
418
471
Fe(NO3)3·9H2O
V
VIII
–50
0
50
100
150
T, °C
600
500
400
300
200
ν, cm–1
Fig. 3. IR spectra of compound V, of iron(III) nitrate
crystal nanohydrate, and of Fe(III) chloride in the range
680–170 cm–1.
Fig. 4. Differential scanning calorimetry curves for the
complexes V–VIII in the cycle of heating.
(15000×0.25 mm). Injector temperature was 280°C,
detector temperature was 290°C, initial and final
temperature of oven varied from 59 to 260°C at a rate
10 deg min–1, helium carrier gas, injecting sample
volume 1 µl. The analysis was carried out at a constant
gas flow rate. The mass selective detector operated in
an electron impact regime (70 eV). The thermo-
gravimetric analysis was carried out on a NETZCH TG
209 F1 analyzer, 20 ml min–1 argon flow, heating rate
10°C/min. Differential scanning calorimetry was
carried out on a NETZCH DSC 204 F1 instrument in
aluminum capsules, mass of the probe ~10 mg, heating
rate 10°C/min under nitrogen. TLC was performed on
a PolyGRAM, Sil G/UV 254 plates, elution with
chloroform, development in the 254 nm UV light.
12.54 ml, was added under constant stirring. The
reaction mixture was stirred for 12 h at room
temperature. On the next day it was poured in 200 ml
of distilled water and extracted with diethyl ether
(5×25 ml). Combined organic solutions were washed
with water, 3×25 ml, and brine (1×20 ml). The organic
layer was dried over the anhydrous sodium sulfate and
concentrated in a vacuum. The residue was crystallized
from 1:6 CH2Cl2–hexane. Yield 23.04 g (93.7%), mp
121°C. IR spectrum, ν, cm–1: 3497.43 (medium,
intramolecular hydrogen bond), 3388.42 (strong, –OH
vibrations), 3091.40, 3025.06 (strong, aromatic C–H
vibrations), 2948.44 (strong, –CH2 vibrations), 1685.05
(strong, C=O vibrations), 1605.45, 1585.28 (strong,
aromatic C–H vibrations), 856.02 (strong, symmetric
vibrations of the 1,4-substituted aromatic ring), 731.10,
697.73 (strong, symmetric vibrations of mono-
substituted aromatic ring). Mass spectrum. m/z:
calculated M 228.24, found [M+] 228. 1H NMR
Benzyl p-hydroxybenzoate (I). p-Hydroxybenzoic
acid, 15 g, and anhydrous sodium carbonate, 11.55 g
were dissolved in 100 ml of DMF. Benzyl chloride,
Table 2. Temperatures of phase transitions according to the differential scanning calorimetry data in the cycle of heating
Compound
Tp, °С
ΔH, J g–1
Tp1, °С
ΔH1, J g–1
Tp2, °С
ΔH2, J g–1
mp, °С
ΔHm, J g–1
C37H48N5O15Fe·5H2O
–
–
98.11
3.29
114.11
3.92
141.75
19.04
a
C37H48N2O6FeP2F12·2H2O
C37H48N2O6FeCl2·2H2O
C37H48N2O6FeB2F8·9H2O
–
–
–
114.03
99.67
94.13
0.55
135.47
111.34
106.54
142.05
–
5.39a
–
0.61
0.59
–
a
a
74.66
67.13a
136.72
3.34
a Total area of peak under the curve.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

IRON(III) COMPLEXES ON THE BASIS OF AZOMETHINE
1959
spectrum (DMSO-d6, TMS), δ, ppm: 5.28 s (2H, CH2),
6.83 d(2H, H–P), 7.4 m (5H, H–P), 7.82 d (2H, H–P).
13C NMR spectrum (DMSO-d6, TMS), δC, ppm: 66.60
(–CH2–); 113.96 (CHarom, C4, C6, C10, C14); 121.27
(Carom); 127.88 (Carom); 132.41 (CHarom, C3, C7, C11,
C13); 135.5 (Carom); 165.30 (C=O). Found, %: C 73.06,
H 5.71, O 21.23. C14H12O3. Calculated, %: C 73.67, H
5.3, O 21.03.
[strong, Alk–C–O–C(Ph)]. 1H NMR spectrum (CDCl3,
TMS) δ, ppm: 0.86–0.90 t (3H, CH3), 1.26–1.51 m
(18H, 9CH2), 1.79–1.86 q (2H, Ph–O–CH2–CH2–),
4.03–4.06 t (2H, Ph–O–CH2), 6.97–6.99 d (2H, Ph–H),
7.32–7.35 d (2H, Ph–H), 8.13–8.15 d (2H, Ph–H),
8.18–8.21 d (2H, Ph–H). Found, %: C 73.61, H 8.3.
C26H34O5. Calculated, %: C 73.21, H 8.03.
4,4'-Dodecyloxybenzoyloxybenzoyl-4-oxy-2-hyd-
roxybenzaldehyde (IV). Compound III, 6 g, and 1.94
g of 2,4-hydroxybenzaldehyde were dissolved in 100
ml of CH2Cl2. After that 3.52 g of dicyclohexyl-
carbodiimide was added. The mixture obtained was
stirred until the complete dissolution of solids, and a
catalytic amount of dimethylaminopyridine was added.
After that the reaction mixture was stirred for 12 h,
urea was removed on a glass frit, and the solvent was
distilled off on a rotary evaporator. The yellowish solid
residue was subjected to chromatography on silica gel,
elution with chloroform, and then crystallized from
acetonitrile. Yield 6.18 g (80.5%), mp 172.76°C. IR
spectrum, ν, cm–1: 3450.18 (strong, OH bond vibra-
tions, intramolecular hydrogen bond), 3099, 3053
(strong, aromatic bond vibrations), 2956–2858 [strong,
–(CH2)n–CH3 vibrations], 2771–2625 (weak, –CHO
vibrations), 1731.5 (strong, C=O vibrations), 1415.73,
1393.29 (strong, Ph–CHO), 1285.82–1149.07 [strong,
Alk–C–O–C–(Ph)], 829.26–795.26 (strong, symmetric
vibrations of 1,4-disubstituted aromatic ring). Mass
spectrum, m/e: calculated M 546.65, found [M+] 545.
1H NMR spectrum (CDCl3, TMS), δ, ppm: 0.91 t (3H,
CH3), 1.28 m (18H, CH2–Alk), 1.85 t (2H, CH2), 4.06 t
(2H, O–CH2–Alk), 6.95 m (4H, H–P), 7.01 d (2H, H–
P), 7.62 t (2H, H–P), 8.15 d (2H, H–P), 8.26 d (2H, H–
Ph), 9.9 s (1H, Ph–COH), 11.29 s (1H, Ph–OH). 13C
NMR spectrum (CDCl3, TMS) δC, ppm: 13.66 (–CH3),
14.65 (–CH2–, C32), 21.73 (–CH2–, C31), 22.72 (CH2,
C30–24), 28.64 (–CH2–, C23), 69.4 (–CH2–O, C22), 110.19
(CHarom, C4)113.37 (CHarom, C6), 114.7 (Carom, C19),
Benzyl p-dodecyloxybenzoyloxybenzoate (II). A
mixture of 6.7 g of compound I, 9 g of 4-dode-
cyloxybenzoic acid, a catalytic amount of dimethyl-
aminopyridine, and 100 ml of dry methylene chloride
was stirred for 10 min. After that 6.66 g of dicyclo-
hexylcarbodiimide was added, and the reaction
mixture was left for 12 h at room temperature under
constant stirring. The precipitate formed was filtered
off, and the filtrate was washed in succession with 5%
acetic acid (2×25 ml), ice-cold 5% solution of sodium
hydroxide (2×25 ml), then with water (3×25 ml), and
dried over anhydrous Na2SO4. The solvent was
removed on a rotary evaporator, and the yellowish
solid residue was subjected to chromatography on
silica gel, elution with chloroform. The product was
crystallized from the chloroform–acetonitrile mixture.
Yield 13.1 g (86%), mp 62–65°C. IR spectrum, ν, cm–1:
2918 (strong, aromatic C–H vibrations), 2851 [strong,
–(CH2)n–CH3 vibrations], 1732 (strong, C=O vibra-
tions), 1470 (strong, symmetric vibrations of the aro-
1
matic ring), 1292 [strong, Alk–C–O–C(Ph)]. H NMR
spectrum (CDCl3, TMS) δ, ppm: 0.86–0.90 t (3H,
CH3), 1.27–1.50 m (18H, 9CH2), 1.78–1.85 q (2H, Ph–
O–CH2–CH2–), 4.02–4.06 t (2H, Ph–O–CH2), 5.38 s
(2H, O–CH2–Ph), 6.96–6.98 d (2H, Ph–H), 7.28–7.30
d (2H, Ph–H), 7.35–7.46 m (5H, Ph–H), 8.12–8.16 m
(4H, Ph–H). Found, %: C 76.65, H 7.94. C33H40O5.
Calculated, %: C 76.71, H 7.80.
p-Dodecyloxybenzoyloxybenzoic acid (III). Com-
pound II, 13.1 g, was dissolved in 100 ml of 1,4-
dioxane, and 2.7 g of 5% Pd/C catalyst was added. The
mixture obtained was stirred under hydrogen at 40°C,
the reaction progress was monitored by TLC. After the
completion of the process the reaction mixture was
filtered, and the solvent was removed in a vacuum.
The product formed was crystallized from 1,4-
dioxane–petroleum ether (bp 60–80°C) mixture. Yield
9.9 g (92%), mp 220.5°C. IR spectrum, ν, cm–1: 3070,
2972 (strong, aromatic C–H vibrations), 2851 [strong,
(CH2)n–CH3 vibrations], 1732 (strong, C=O vibra-
tions), 1688 [strong, C(O)O], 1261, 1470 (strong,
symmetric vibrations of the aromatic ring), 1292, 1161
115.08 (Carom, C5), 118.66 (Carom, C2), 120.81 (CHarom
,
C11, C13), 126.10 (Carom, C9), 131.31 (CHarom, C10),
131.81 (CHarom, C17, C21), 132.62 (CHarom, C14), 133.11
(CHarom, C18, C20), 134.38 (CHarom, C7), 135.66 (Carom
–
OH), 155.74 (Carom, C16), 157.52 (Carom, C12), 163.19
(Carom, C19), 163.44 (C–O, C8), 164.24 (C=O, C15),
196.21 (HC=O). Found, %: C 71.54, H 7.83, O 20.63.
C33H38O7. Calculated, %: C 72.51, H 7.01, O 20.48.
Fe(III) complex with NO3– counterion (V). Com-
pound IV, 1.28 g, N-ethylethylenediamine, 0.21 g, and
KOH, 0.18 g, were dissolved in 40, 10, and 10 ml of
ethanol respectively and mixed in the course of
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

1960
CHERVONOVA et al.
Table 3. Elemental analysis data of complexes V–VIII
Elemental analysis data
Comp.
Formula
М
found, %
calculated, %
no.
C
H
N
O
C
H
N
O
C37H48N5O15Fe·5H2O
948.89
1024.62
779.14
46.79
6.12
4.69
5.59
4.63
6.09
26.91
46.84
6.16
7.38
33.72
V
C37H48N2O6FeP2F12·2H2O
C37H48N2O6FeCl2·2H2O
C37H48N2O6FeB2F8·9H2O
43.44
55.05
42.31
5.69
2.88
3.43
22.32
16.26
19.13
43.37
57.04
43.86
4.72
6.21
4.97
4.10
3.59
4.15
14.05
12.32
15.79
VI
VII
VIII
1013.12
30 min. After that the ethanol solution of Fe(NO3)2·
9H2O, 0.47 g, was slowly added. Dark brown reaction
mixture was stirred for 2 h, and the precipitate formed
was filtered off through a glass frit. The product is a
solid brown fine powder, yield 0.46 g. Elemental
analysis data are listed in Table 3. IR spectrum, ν, cm–1:
3412.82 (strong, OH bond vibrations), 3075 (strong,
aromatic C–H vibrations), 2921.97, 2852.52 [strong,
(CH2)n–CH3 vibrations], 1738.71 (strong, C=O
vibrations), 1639.46 s, (C=N), 1602.75, 1514.47,
1507.67 (strong, aromatic C–H vibrations), 1472.81
[strong, (CH2)n–CH3 vibrations], 1383.83 (strong, NO3
vibrations), 1312.11 [strong, (CH2)n–CH3 vibrations],
1250.75, 1203.27, 1162.03 [strong, Alk–C–O–C(Ph)
vibrations], 1058.72 (medium, NH vibrations), 845.73,
824.91 (strong, symmetric vibrations of 1,4-
disubstituted aromatic ring), 721.33, 762.79 [strong,
3438.86 (strong, OH bond vibrations), 3182.34,
3068.53 (strong, aromatic C–H vibrations), 2922.93,
2857.06 [strong, (CH2)n–CH3 vibrations], 1735.70
(strong, C=O vibrations), 1626.41 (strong, C=N
vibrations), 1602.42, 1542.0, 1505.57 (strong, aromatic
C–H vibrations), 1469.14 [strong, (CH2)n–CH3
vibrations], 1377.62, 1305.64 [strong, (CH2)n–CH3
vibrations], 1255.58, 1202.57, 1162.03 [strong, Alk–
C–OC(Ph)], 1056.85 (medium, NH vibrations), 845.73
(medium, symmetric vibrations of 1,4-disubstituted
aromatic ring), 844.48, 556.61 (strong, PF6– vibrations),
763.97 [strong, (CH2)n–CH3 vibrations]. 1H NMR
spectrum, CDCl3, TMS), ™, ppm: 0.91 m (6H, CH3),
1.29 m (18H, CH2–Alk), 1.48 t (2H, O–CH2–CH2–
Alk), 1.85 s (2H, CH2), 2.09 d (2H, –CH2–Alk), 3.07 t
(2H, N–CH2–), 3.73 t (2H, N–CH2–CH2-NH), 4.07 s
(2H, O–CH2–Alk). 5.16 s (1H, NH–CH2), 5.89 q (1H,
CH=N), 7.02 m (4H, H–P), 7.48 m (2H, H–P), 7.78 d
(2H, H–P), 8.18 d (1H, H–P), 8.26 d (2H, H–P). 9.90 s
(1H, OH).
Fe(III) complex with Cl– anion (VII). Compound
IV, 1 g, was dissolved in 30 ml of ethanol under
constant stirring and the solutions of 0.16 g of N-ethyl-
ethylenediamine and 0.158 g of potassium hydroxide
in ethanol were added. The resulting mixture was
stirred for 30 min, and then a solution of 0.149 g of
FeCl3 in 40 ml of ethanol was slowly added to it.
Brown solution was stirred for 30 min and the
precipitate was filtered off through a glass frit. Light
brown needle-like crystals were obtained, yield 0.17 g.
Elemental analysis data are listed in Table 3. IR spec-
trum, ν, cm–1: 3420.53 (strong, OH bond vibrations),
3076.26 (strong, aromatic C–H vibrations), 2923.90,
2857.06 [strong, (CH2)n–CH3 vibrations], 1735.70
(strong, C=O vibrations), 1625.91 (strong, C=N),
1603.70, 1535.78, 1510.90 (strong, aromatic C–H
vibrations), 1473.6, 1426.68 [strong, (CH2)n–CH3
vibrations], 1255.58, 1208.13, 1156.32 [strong, Alk–
1
(CH2)n–CH3 vibrations]. H NMR spectrum (CDCl3,
TMS), δ, ppm: 0.91 m(6H, CH3), 1.29 m (18H, CH2–
Alk), 1.48 t (2H, O–CH2–CH2–Alk), 1.85 s (2H, CH2),
2.09 d (2H, –CH2–Alk), 3.01 t (2H, N–CH2), 3.83 t
(4H, N–CH2–CH2–NH), 4.07 s (2H, O–CH2–Alk),
5.16 s (1H, NH–CH2), 5.89 q (1H, CH=N), 7.02 m
(4H, H–P), 7.48 m (2H, H–P), 7.78 d (2H, H–P), 8.18
d (1H, H–P), 8.26 d (2H, H–P). 9.90 s (1H, OH).
Fe(III) complex with PF6– anion (VI). Compound
IV, 1.5 g, was dissolved in 30 ml of ethanol under
constant stirring. The ethanol solutions of N-
ethylethylenediamine, 0.24 g, and KOH, 0.209 g, were
added, and the resulting mixture was stirred for 30
min. After that a solution of 0.55 g of Fe(NO3)2·9H2O
in 40 ml of ethanol was added slowly. The reaction
mixture was stirred for 30 min and then treated with a
solution of 1.01 g of KPF6 in 10 ml of ethanol. The
reaction mixture was stirred for 2 h and then the
precipitate was filtered off through a glass frit. It was a
dark brown fine powder, yield 1.91 g. Elemental
analysis data are listed in Table 3. IR spectrum, ν, cm–1:
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 10 2010

IRON(III) COMPLEXES ON THE BASIS OF AZOMETHINE
1961
C–O–C(Ph)], 1056.35 (medium, NH vibrations),
845.16 (strong, symmetric vibrations of 1,4-disub-
stituted aromatic ring), 763.48 [strong, (CH2)n–CH3
vibrations], 543.82, 215.02 (medium, Cl– vibrations).
1H NMR spectrum, CDCl3, TMS), δ, ppm: 0.91 m(6H,
CH3), 1.29 m (18H, CH2–Alk), 1.48 t (2H, O–CH2–
CH2–Alk), 1.85 s (2H, CH2), 2.09 d (2H, –CH2–Alk),
3.04 t (2H, N–CH2–), 3.86 t (2H, N–CH2–CH2–NH),
4.07 s (2H, O–CH2–Alk). 5.16 s (1H, NH–CH2), 5.89 q
(1H, CH=N), 7.02 m (4H, H–P), 7.48 m (2H, H–P),
7.78 d (2H, H–P), 8.18 d (1H, H–P), 8.26 d (2H, H–P),
9.90 s (1H, OH).
partially absorbs the traces of some other elements,
which influences the data on the content of the element
analyzed.
ACKNOWLEDGMENTS
The work was carried out with the financial support
of the grant of President of Russian Federation (grant
no. MK-1625.2009.3) and the grant of Russian
Fundation for Basic Research (grant no. 08-03-00513).
REFERENCES
Fe(III) complex with BF4– anion (VIII). Com-
pound IV, 1 g, was dissolved in 30 ml of ethanol and
the solutions of 0.16 g of N-ethylethylenediamine and
0.158 g of potassium hydroxide in 10 ml ethanol were
added. The resulting mixture was stirred for 30 min,
and then a solution of 0.37 g of Fe(NO3)2·9H2O in
40 ml of ethanol was added to it. Dark brown solution
was stirred for 1 h, and then a solution of 0.402 g of
NaBF4 in several drops of water was added. The
reaction mixture was stirred for 1 h, and the precipitate
formed was filtered off through a glass frit to obtain
fine dark brown powder, yield 0.85 g. Elemental
analysis data are listed in Table 3. IR spectrum, ν, cm–1:
3430.18 (strong, OH bond vibrations), 3183.99,
3072.47 (strong, aromatic C–H vibrations), 2922.93,
2854.92 [strong, (CH2)n–CH3 vibrations], 1734.19
(strong, C=O vibrations), 1628.16 (strong, C=N),
1601.46, 1542.56, 1511.14 (strong, aromatic C–H
vibrations), 1468.73 [strong, (CH2)n–CH3 vibrations],
1303.81 [strong, (CH2)n–CH3 vibrations], 1255.70,
1207.99, 1161.61 [strong, Alk–C–O–C(Ph)], 1058.85
(medium, NH vibrations), 1032.51, 534, 522.21
(strong, BF4– vibrations), 846.68 (strong, symmetric
vibrations of 1,4-disubstituted aromatic ring), 764.41
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[strong, (CH2)n–CH3 vibrations]. H NMR spectrum
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