New ferro-and antiferromagnetic complexes of tridentate azomethines with copper

Article abstract of DOI:10.1134/S0036023608100082

Tridentate azomethine ligands with N₂O₄ and N ₃donor atoms and their copper complexes were synthesized and characterized. The dimeric structure of copper(II) chelates was confirmed by EXAFS studies. Complexes based on 2-to

Full text of DOI:10.1134/S0036023608100082

ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2008, Vol. 53, No. 10, pp. 1566–1572. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.S. Burlov, V.N. Ikorskii, S.A. Nikolaevskii, Yu.V. Koshchienko, V.G. Vlasenko, Ya.V. Zubavichus, A.I. Uraev, I.S. Vasil’chenko, D.A. Garnovskii, G.S.
Borodkin, A.D. Garnovskiia, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1677–1683.
COORDINATION
COMPOUNDS
New Ferro- and Antiferromagnetic Complexes of Tridentate
Azomethines with Copper
A. S. Burlova, V. N. Ikorskiib,†, S. A. Nikolaevskiia, Yu. V. Koshchienkoa, V. G. Vlasenkoc,
Ya. V. Zubavichusd, A. I. Uraeva, I. S. Vasil’chenkoa, D. A. Garnovskiie,
G. S. Borodkina, and A. D. Garnovskiia
a Research Institute of Physical and Organic Chemistry, Southern Federal University,
pr. Stachki 194/2, Rostov-on-Don, 344090 Russia
b International Tomography Center, Siberian Branch, Russian Academy of Sciences,
ul. Institutskaya 3A, 630090 Novosibirsk, Russia
c Research Institute of Physics, Southern Federal University, pr. Stachki 194, Rostov-on-Don, 344090 Russia
d Kurchatov Institute Russian Research Center, pl. Kurchatova 1, Moscow, 123182 Russia
e Southern Scientific Center, Russian Academy of Sciences, ul. Chekhova 11, Rostov-on-Don, 344006 Russia
Received September 10, 2007
Abstract—Tridentate azomethine ligands with N2O4 and N3 donor atoms and their copper complexes were
synthesized and characterized. The dimeric structure of copper(II) chelates was confirmed by EXAFS studies.
Complexes based on 2-tosylaminobenzaldehyde azomethines tend to undergo ferromagnetic exchange,
whereas similar salicylaldehyde derivatives have antiferromagnetic exchange.
DOI: 10.1134/S0036023608100082
As a development of studies dealing with targeted synthe- ligands [1–4], we synthesized for the first time the tridentate
sis of ferro- and antiferromagnetic complexes of azomethine Schiff bases (I) with various aldehyde and amine fragments
NO2
R
XH
N
YH
R
X
N
N
X
Y
Y
Cu
Cu
R
O2N
I
R
II X = NTs
O2N
O2N
N
Y
X
X
Y
X = NTs, Y = NCH3, R = H (‡);
X = NTs, Y = NC2H5, R = Br (b);
X = NTs, Y = NC3H7-n, R = H (c);
X = O, Y = NPhCF3-m, R = H (d);
X = O, Y = NC2H5, R = Br (e);
X = O, Y = NC3H7-n, R = Me (f);
X = O, Y = NPh, R = H (g)
Cu
Cu
N
NO2
III X = O
R
†
Deceased
1566

NEW FERRO- AND ANTIFERROMAGNETIC COMPLEXES OF TRIDENTATE AZOMETHINES
1567
These compounds were used to prepare copper(II) magnetic moment as a function of temperature was cal-
complexes for which structures with different metal– culated as follows [10, 11]:
metal bridges are possible (II and III).
µeff(T) =
χT 1/2 ≈ (8χT)1/2
,
3k
⎛
⎝
⎞
---------
2
⎠
Nβ
EXPERIMENTAL
where N, k, and β are the Avogadro number, the Boltz-
IR spectra were recorded on a Nicolet Impact 400
spectrophotometer for mineral oil mulls. H NMR
mann constant, and the Bohr magneton, respectively.
1
spectra were recorded in CDCl3 on a Varian Unity-300
spectrometer (300 MHz) with the internal deuterium
lock.
Synthesis of Anilines
2,4-Dinitro-N-methylaniline. Methylamine hydro-
chloride (7.43 g, 0.11 mol) was added to a suspension
of 2,4-dinitrochlorobenzene (20.26 g, 0.1 mol) and
CH3COONa · 3H2O (29.94 g, 0.22 mol) in ethanol
(50 mL). The mixture was refluxed for 2 h and cooled,
and the precipitate was filtered off and washed with water
and ethanol. Yield, 14.98 g (76%); mp 178–179°ë (from
ethanol), which is consistent with the literature data
[12].
CuK-edge X-ray absorption spectra were recorded
in the transmission mode on an EXAFS spectrometer at
the structural materials science station of the Kurchatov
Synchrotron Center (Moscow). The electron beam
energy used as the X-ray synchrotron radiation source
was 2.5 GeV at a current of 80–100 mA.A double-crys-
tal Si(111) monochromator was used for X-ray mono-
chromatization.
The spectra were processed by standard procedures
including background removal, normalization to the
ä-edge jump, and subtraction of the atomic absorption
µ0 [5]. Then, the resulting EXAFS (χ) spectra were sub-
jected to Fourier transform in the range of photoelec-
tron wave vectors k from 2.6 to 12.6 Å–1 with the weight
function k3. The threshold ionization energy E0 was
chosen from the maximum of the first derivative of the
K edge and was subsequently varied during fitting.
The exact values for the parameters of the local
environment structure of copper atoms were found by
nonlinear fitting of the parameters of corresponding
coordination spheres by comparing the calculated
EXAFS signal with that isolated from the full EXAFS
spectrum by Fourier filtration. The nonlinear fitting was
performed by using the IFFEFIT-1.2.5 software [6].
The phases and amplitudes of photoelectron wave scat-
tering needed to simulate the spectrum were calculated
with the FEFF7 software [7]. The single crystal X-ray
diffraction data for C22H22Cu2N2O4, acetylacetone-
mono(Ó-hydroxyanil)copper(II) dimer (ACHANC) [8],
which are deposited at the Cambridge Crystallographic
Data Centre [9], were taken as the initial atomic coor-
dinates needed to calculate the scattering phases and
amplitudes and for the subsequent fitting.
2-Methylamino-5-nitroaniline. A suspension of
N-methyl-2,4-dinitroaniline (19.71 g, 0.1 mol) in etha-
nol (40 mL) was added to a warm solution of Na2S ·
9H2O (48.01 g, 0.2 mol) and crystalline sulfur (6.41,
0.2 mol) in water (63 mL). The mixture was refluxed
for 2 h, diluted with water (30 mL), and cooled. The
precipitate was filtered off and washed with warm
water. Yield, 12.37 g (74%); dark red crystals, mp =
177°ë (from ethanol), which is consistent with the lit-
erature data [13].
2,4-Dinitro-N-propylaniline. Propylamine (7.39 g,
0.125 mol) was added to a suspension of 2,4-dinitrochlo-
robenzene (20.26 g, 0.1 mol) and CH3COONa · 3H2O
(29.94 g, 0.22 mol) in ethanol (40 mL). The mixture was
refluxed for 4 h and cooled, and the precipitate was filtered
off and washed with water and ethanol. Yield, 21.17 g
(94%); yellow crystals, mp 95°ë (from ethanol), which is
consistent with the literature data [14].
2-Propylamino-5-nitroaniline was prepared sim-
ilarly to 2-methylamino-5-nitroaniline except that the
reaction mixture was refluxed for 4 h. Yield, 67%; dark
red crystals, mp = 117–118°ë (from benzene), which is
consistent with the literature data [15].
2,4-Dinitro-N-(m-trifluoromethylphenyl)aniline
was prepared similarly to 2,4-dinitro-N-propylaniline
from 2,4-dinitrochlorobenzene and m-trifluoromethy-
laniline. Yield, 68%; yellow crystals, mp 123–124°C
(from ethanol).
The quality of fit Q, which was minimized when
determining the structure parameters of the local envi-
ronment, was calculated by the formula
[kχexp(k) – kχtheor(k)]2
For C13H8F3N3O4 anal. calcd. (%): C, 47.72; H,
2.46; N, 12.84.
∑
--------------------------------------------------------------
Q(%) =
⋅ 100%.
[kχexp(k)]2
∑
Found (%): C, 47.66; H, 2.52; N, 12.90.
1H NMR, δ, ppm: 7.18 (d, 1H, Jo = 9.5 Hz, CAr–H),
7.51–7.66 (m, 4H, CAr–H), 8.25 (dd, 1H, Jo = 9.5 Hz,
Jm = 2.6 Hz, CAr–H), 9.20 (d, 1H, Jm = 2.6 Hz, CAr–H),
9.98 (br.s 1H, NH).
The magnetic measurements of the complexes were
carried out on a Quantum Design SQUID magnetome-
ter in the temperature range of 2–300 K in a 5-Oe mag-
netic field. In calculations of the paramagnetic compo-
nent of the magnetic susceptibility χ, the additive dia-
magnetic contributions of ions were taken into account
2-(m-Trifluoromethylphenyl)amino-5-nitroaniline
in conformity with the Pascal constants. The effective was prepared similarly to 2-propylamino-5-nitroaniline.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008

1568
BURLOV et al.
Yield, 55%; dark red crystals, mp = 167–168°C (from eth-
Ib. Yield 70%. Yellow-orange crystals, mp = 176–
177°C.
anol).
For C13H10F3N3O2 anal. calcd. (%): C, 52.53; H,
3.39; N, 14.14.
For C22H21BrN4O4S anal. calcd. (%): C, 51.07; H,
4.09; N, 10.83, S, 6.20.
Found (%): C, 52.46; H, 3.45; N, 14.21.
Found (%): C, 51.27; H, 3.96; N, 11.02, S, 6.39.
1H NMR, δ, ppm: 3.82 (br.s, 2H, NH2), 5.79 (br.s,
1H, NH), 7.15–7.28 (m, 4H, CAr–H), 7.43 (t, 1H, Jo =
7.9 Hz, CAr–H), 7.69–7.73 (m, 2H, CAr–H).
1H NMR, δ, ppm: 1.42 (t, 3H, J = 7.1 Hz,
3
CH2−CH3), 2.37 (3H, Ò, CH3), 3.39–3.43 (m, H, CH2–
CH3), 5.53 (t, 1H, 3J = 4.9 Hz, NH–C2H5), 6.67–8.17 (m,
11H, CAr–H), 8.65 (s, 1H, CH=N), 12.47 (s, 1H, NH).
2,4-Dinitro-N-phenylaniline. Freshly distilled
aniline (10.25 g, 0.11 mol) was added to a suspension
of 2,4-dinitrochlorobenzene (20.26 g, 0.1 mol) and
CH3COONa · 3H2O (13.61 g, 0.1 mol) in ethanol (50 mL).
The mixture was refluxed for 1 h and cooled, and the pre-
cipitated red-orange crystals were filtered off and washed
with water and ethanol. Yield, 24.88 g (96%); mp = 156–
157°ë (from ethanol), which is consistent with the lit-
erature data [16].
2-Phenylamino-5-nitroaniline. A suspension of
N-phenyl-2,4-dinitroaniline (25.92 g, 0.1 mol) in etha-
nol (60 mL) was added to a warm solution of Na2S ·
9H2O (48.01 g, 0.2 mol) and crystalline sulfur (6.41,
0.2 mol) in water (60 mL). The mixture was refluxed
for 2 h, diluted with water (30 mL), and cooled. The
precipitate was filtered off and washed with warm
water. Yield, 19.5 g (85%); dark brown crystals, mp =
125°ë (from ethanol), which is consistent with the lit-
erature data [17].
IR (cm–1): 3640 (w, NH), 1620 (s, C=N), 1349 (vs,
νasSO2), 1164 (Ó.Ò, νsSO2), 1164 (vs, νsSO2).
Ic. Yield 45%. Red-brown crystals, mp = 153–
154°ë.
For C23H24BrN4O4S anal. calcd. (%): C, 61.05; H,
5.35; N, 12.38, S, 7.09.
Found (%): 61.16; H, 5.46; N, 12.64, S, 7.16.
3
1H NMR, δ, ppm: 1.06 (t, 3H, J = 7.4 Hz, CH2–
3
CH2–CH3), 1.78–1.85 (m, 2H, J = 7.4 Hz, CH2–CH2–
CH3), 2.39 (s, 3H, CH3), 3.30–3.37 (m, 2H, CH2–CH2–
CH3), 5.54 (t, 1H, 3J = 5.3 Hz, NH), 6.68 (d, 1 H, Jo =
9.2 Hz, CAr–H), 7.12–8.12 (m, 10H, CAr–H), 8.68 (s, 1H,
CH=N), 12.44 (s, 1H, NH). IR (cm–1): 3455 (w, NH),
1620 (s, C=N), 1351 (vs, νasSO2), 1165 (vs, νsSO2).
Id. Yield 94%. Yellow crystals, mp = 179–180°ë.
For C20H14F3N3O3 anal. calcd. (%): C, 59.85; H,
3.52; N, 10.47.
Found (%): C, 60.01; H, 3.45; N, 10.56.
Synthesis of Azomethines I
1ç NMR, δ, ppm: 6.81 (s, 1H, NH), 7.03–8.13 (m,
2-Tosylaminobenzaldehyde and 5-bromo-2-tosy-
laminobenzaldehyde were prepared by a known proce-
dure [18].
11H, CAr–H), 8.79 (s, 1H, CH=N), 11.48 (s, 1H, OH).
IR (cm–1): 3400 (w, NH), 1614 (s, C=N), 1276 (m, Ph–O).
Ie. Yield 73%. Orange crystals, mp = 182–183°ë.
Compounds Ia–Ig (general procedure). A solution
of 2-methyl- (ethyl-, propyl-, phenyl-, m-trifluorome-
thyl)amino-5-nitroaniline (0.01 mol) in toluene (50 mL)
was added to a solution of 2-tosylamino- or 5-bromo-2-
tosylaminobenzaldehyde, salicylaldehyde, 5-bromo- or
5-methylsalicylaldehyde (0.01 mol) in toluene (30 mL),
and the mixture was refluxed with a Dean–Stark trap
under argon until water was completely removed (4 h).
After completion of the reaction, the solvent was dis-
tilled off on a rotary evaporator to 1/4 of the initial vol-
ume. The precipitates formed after cooling were fil-
tered off and recrystallized from an ethanol–chloro-
form mixture (2 : 1).
For C15H14BrN3O3 anal. calcd. (%): C, 49.47; H,
3.87; N, 11.54.
Found (%): C, 49.52; H, 3.89; N, 11.64.
3
1ç NMR, δ, ppm: 1.35 (t, 3H, J = 7.2 Hz, CH3),
3.31–3.40 (m, 2H, CH2), 5.01 (s, 1H, NH), 6.65 (d, 1H,
Jo = 9.1 Hz, CAr–H), 6.93–8.16 (m, 5H, CAr–H), 8.64
(s, 1H, CH=N), 12.32 (s, 1H, OH). IR (cm–1): 3400
(w, NH), 1615 (s, C=N), 1277 (m, Ph–O).
If. Yield 65%. Brown crystals, mp = 160–161°ë.
For C17H19N3O3 anal. calcd. (%): C, 65.16; H, 6.11;
N, 13.41.
Ia. Yield 68%. Yellow-orange crystals, mp = 135–
136°C.
For C21H20N4O4S anal. calcd. (%): C, 59.42; H,
4.75; N, 13.20, S, 7.55.
Found (%): C, 65.26; H, 6.15; N, 13.52.
3
1ç NMR, δ, ppm: 1.03 (t, 3H, J = 7.3 Hz, CH3),
1.72–1.77 (m, 2H, CH2), 2.35 (s, 3H, CH3), 3.27 (quint,
2H, 3J = 6.6 Hz, CH2), 5.17 (s, 1H, NH), 6.63 (d, 1H, Jo =
9.1 Hz, CAr–H), 6.93–8.14 (m, 5H, CAr–H), 8.64 (s, 1H,
CH=N), 12.12 (s, 1H, OH). IR (cm–1): 3400 (w, NH),
Found (%): C, 59.55; H, 4.65; N, 13.83, S, 7.39.
1H NMR, δ, ppm: 2.38 (s, 3H, NH–CH3), 3.08 (s,
3H, CH3), 5.62 (s, 1H, NH–CH3), 6.61–8.21 (m, 11H,
CAr–H), 8.68 (s, 1H, CH=N), 12.53 (s, 1H, NH). IR (cm–1): 1615 (s, C=N), 1276 (m, Ph–O).
3640 (w, NH), 1620 (s, C=N), 1350 (vs, νasSO2), 1165
(vs, νsSO2).
Ig. Yield 80%. Yellow needle crystals, mp = 206–
207°ë.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008

NEW FERRO- AND ANTIFERROMAGNETIC COMPLEXES OF TRIDENTATE AZOMETHINES
1569
For C19H15N3O anal. calcd. (%): C, 68.46; H, 4.54;
N, 12.61.
Found (%): C, 54.58; H, 4.62; N, 11.32; Cu, 17.12.
IR (cm–1): 1605 (s, C=N), 1330 (m, Ph–O).
IIg. Yield 81%. Brown powder, mp > 250°ë.
Found (%): C, 68.46; H, 4.54; N, 12.61.
3
1ç NMR, δ, ppm: 1.35 (t, 3H, J = 7.2 Hz, CH3),
For C38H26N6O6Cu2 anal. calcd. (%): C, 57.79; H,
3.32; N, 10.64; Cu, 16.09.
3.31–3.40 (m, 2H, CH2), 5.02 (s, H, NH), 6.65 (d, 1H,
Jo = 9.1 Hz, CAr–H), 6.93–8.16 (m, 5H, CAr–H), 8.64 (s,
Found (%): C, 57.82; H, 3.45; N, 10.72; Cu, 16.35.
1H, CH=N), 12.32 (s, 1H, OH). IR (cm–1): 3400 (w, NH),
1617 (s, C=N), 1276 (m, Ph–O).
RESULTS AND DISCUSSION
Synthesis of Copper Complexes II
Complexes II and III were obtained by the direct
reaction of ligand I (LH2) with copper acetate monohy-
drate [19, 20]:
Compounds IIa–IIg (general procedure). A solu-
tion of copper acetate monohydrate (0.199 g, 0.001 mol)
in ethanol (20 mL) was added to a solution of azome-
thine Ia–g (0.001 mol) in ethanol (50 mL). The mixture
was refluxed for 4 h under argon. The finely crystalline
precipitates of the complexes were filtered off, washed
with boiling ethanol (3 × 5 mL), and dried in a vacuum
drying chamber at 150°C.
IIa. Yield 75%. Red-brown powder, mp > 250°C.
For C42H36N8O8S2Cu2 anal. calcd. (%): C, 51.89; H,
3.73; N, 11.53; S, 6.60; Cu, 13.08.
2LH2 + Cu2(CH3COO)4 ⋅ 2H2O
Cu2L2 + 4CH3COOH + 2H2O.
According to elemental analysis, complexes II have
the composition M2L2. The chelate structure follows
from analysis of their IR spectra. The C=N stretching fre-
quency at 1600–1620 cm–1 decreases by 10–20 cm–1, the
νs(SO2) and νas(SO2) frequencies at 1350 and 1165 cm–1
decrease by 50 and 30 cm–1, respectively, and the
stretching bands for XH and YH acidic protons (3300–
3450 cm–1) disappear [21, 22].
Found (%): C, 51.92; H, 3.83; N, 11.64; S, 6.47; Cu,
13.21.
IR (cm–1): 1603 (vs, C=N), 1285 (vs, νasSO2), 1138
The dimeric structure and the type of ligand envi-
ronment are confirmed by analysis of the EXAFS spec-
tra of complexes II (a, b, d, g).
(vs, νsSO2).
IIb. Yield 83%. Brown powder, mp > 250°ë.
For C44H38Br2N8O8S2Cu2 anal. calcd. (%): C, 45.64;
H, 3.31; N, 9.68; S, 5.54; Cu, 13.80.
Figure 1 shows the Fourier transform magnitudes
(FTMs) of the CuK-edge EXAFS spectra of IIa, IIb,
IId, and IIg. All FTMs consist of two principal peaks
with r of 2.39–2.40 Å and 2.39–2.40 Å, except for the
FTM of IId where the second peak is shifted to greater
distances and has the value r = 2.72 Å. The phases and
amplitudes of photoelectron wave scattering were cal-
culated proceeding from the model for the structure of
these complexes in which two copper ions connected
by two nitrogen bridges form bonds with two ligands
(Cu–O and/or C–N). Multishell nonlinear of the simu-
lated EXAFS spectrum to the experimental one gave
parameters of the coordination sphere (table). As can be
seen from the table, parameters of the first coordination
sphere for all compounds do not differ much, indicating
the same local environment of copper atoms in these
compounds. The coordination number of copper in
these complexes is four, the Cu–O and Cu–N distances
and the Debye–Waller factor have typical values for
this type of bonds. The second FTM peaks with greater
distances are most likely due to short Cu–Cu dis-
tances. The results of nonlinear approximation made it
possible to determine the quantitative characteristics
of the second coordination sphere in the complexes.
The Cu–Cu distances in IIa, IIb, and IIg (table) are in
the range R = 2.70–2.85 Å; for IId, this distance is much
longer (R = 3.02 Å).
Found (%): C, 45.78; H, 3.39; N, 9.62; S, 5.45; Cu,
13.92.
IR (cm–1): 1604 (vs, C=N), 1283 (vs, νasSO2), 1137
(vs, νsSO2).
IIc. Yield 65%. Brown powder, mp 233–234°ë.
For C46H44N8O8S2Cu2 anal. calcd. (%): C, 53.74; H,
4.31; N, 10.90; S, 6.24; Cu, 12.36.
Found (%): C, 53.86; H, 4.46; N, 10.85; S, 6.35; Cu,
12.46.
IR (cm–1): 1605 (s, C=N), 1285 (vs, νasSO2), 1135
(vs, νsSO2).
IId. Yield 75%. Dark brown powder, mp > 250°ë.
For C40H24F6N6O6S2Cu2 anal. calcd. (%): C, 51.90;
H, 2.61; N, 9.08; Cu, 13.73.
Found (%): C, 52.03; H, 2.57; N, 9.15; Cu, 13.92.
IR (cm–1): 1602 (vs, C=N), 1327 (w, Ph–O).
IIe. Yield 72%. Brown powder, mp > 250°ë.
For C30H24Br2N6O6Cu2 anal. calcd. (%): C, 42.32; H,
2.84; N, 9.87; Cu, 14.93.
Found (%): C, 42.38; H, 2.76; N, 9.91; Cu, 15.12.
IR (cm–1): 1604 (s, C=N), 1328 (m, Ph–O).
IIf. Yield 80%. Red-brown powder, mp > 250°ë.
For C34H34N6O6Cu2 anal. calcd. (%): C, 54.46; H,
4.57; N, 11.21; Cu, 16.95.
Thus, EXAFS studies confirm the proposed dimeric
structure of copper complexes II and III.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008

1570
BURLOV et al.
FTM, arb. units
N/O
50
Cu
1
2
d
c
40
30
20
10
0
b
‡
0
1
2
3
4
5
6
r, Å
Fig. 1. FTM of the CuK-edge X-ray EXAFS spectra for compounds (a) IIa, (b) IIb, (c) IId, (d) IIg. (1) Experimental FTMs and
(2) simulated spectra.
The magnetochemical measurements for complexes 2-tosylaminebenzaldehyde, ferromagnetic exchange
IIa–IIg in the temperature range 300–2 K have shown coupling is typical (Figs. 2–4), whereas, in the coordi-
(Figs. 2–8) that, for complexes IIa–IIc based on nation compounds of salicylaldehyde and its substi-
tuted derivatives, the exchange coupling is antiferro-
magnetic.
Structural data found from the multishell fitting of the
This result may be attributed to the formation of
EXAFS data (R are interatomic distances, N are the coordi-
structure II with Y = NAlk bridging fragments in the
nation numbers, σ2 is the Debye–Waller factor, Q is the fit-
former case, whereas, in the latter case, oxygen metal–
ting quality function)
metal bridge III (Y = O) with a typical antiferromag-
netic exchange coupling is formed [23].
Com-
pound
N
R, Å
σ2, Å2
Atom
Q, %
The experimental µeff(T) curves for complexes II
(III) are presented in Figs. 2–8 (the solid lines show
theoretical curves). Assuming a dimeric structure of the
complexes, these dependences were theoretically simu-
lated using the Bleaney–Bowers equation for the mag-
netic susceptibility of a dimer [10, 11]
II‡
2
2
1
4
1
4
1
2
2
1
4
1.98
2.07
2.84
1.90
2.70
1.93
3.02
1.95
2.03
2.85
3.19
0.0051
0.0057
0.0089
0.0045
0.0052
0.0028
0.0035
0.0034
0.0033
0.0092
0.010
N
N
5.6
3.8
4.2
Cu
IIb
IId
IIg
Nβ2g2
---------------
3kT
1
3
–2J
---------
kT
–1
⎛
⎝
⎞
⎠
--
1 + exp
χ(Cu–Cu)
=
+ Nα
Cu
with inclusion of the exchange interaction between the
dimers zJ'
Cu
N/O
N/O
Cu
χ(Cu–Cu)
χ' = ---------------------------------------------------------------------
(1 – (2zJ'/Nβ2g2) ⋅ χ(Cu–Cu)
)
6.0
and a possible monomeric impurity p with the spin
S = 1/2:
C
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008

NEW FERRO- AND ANTIFERROMAGNETIC COMPLEXES OF TRIDENTATE AZOMETHINES
1571
µeff, µB
µeff, µB
2.2
3.4
3.3
3.2
3.1
3.0
2.9
2.8
2.7
2.6
2.5
2.4
2.0
1.8
0
50
100 150 200 250 300
0
50 100 150 200 250 300
T, K
T, K
Fig. 2. Temperature dependence of the effective magnetic
moment of IIa.
Fig. 3. Temperature dependence of the effective magnetic
moment of IIb.
µeff, µB
µeff, µB
2.75
2.4
2.2
2.0
1.8
1.6
1.4
2.70
2.65
2.60
2.55
0
50 100 150 200 250 300
0
50 100 150 200 250 300
T, K
T, K
Fig. 4. Temperature dependence of the effective magnetic
moment of IIc.
Fig. 5. Temperature dependence of the effective magnetic
moment of IId.
µeff, µB
2.5
µeff, µB
2.4
2.0
2.2
2.0
1.8
1.6
1.5
1.0
0.5
0
50 100 150 200 250 300
0
50 100 150 200 250 300
T, K
T, K
Fig. 6. Temperature dependence of the effective magnetic
moment of IIe.
Fig. 7. Temperature dependence of the effective magnetic
moment of IIf.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008

1572
BURLOV et al.
2. A. S. Burlov, Yu. V. Koshchienko, V. N. Ikorskii, et al.,
χ, Òm3/mol
Zh. Neorg. Khim. 51 (7), 1143 (2006) [Russ. J. Inorg.
Chem. 51 (7), 1065 (2006)].
3. A. S. Burlov, V. N. Ikorskii, A. I. Uraev, et al., Zh.
0.025
0.020
0.015
0.010
0.005
Obshch. Khim. 76 (8), 1337 (2006).
4. A. D. Garnovskii, V. N. Ikorskii, A. I. Uraev, et al.,
J. Coord. Chem. 60 (14), 1493 (2007).
5. D. I. Kochubei, Yu. A. Babanov, K. I. Zamaraev, et al.,
X-ray Spectral Method of Investigation of the Structure
of Amorphous Solids: EXAFS Spectroscopy (Nauka, SO,
Novosibirsk, 1988) [in Russian].
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(1965).
0
50 100 150 200 250 300
T, K
9. F. H.Allen,Acta Crystallogr. Sect. B: Struct. Sci. 58, 380
Fig. 8. Temperature dependence of the magnetic suscepti-
bility of IIg.
(2002).
10. O. Kahn, Molecular Magnetism (Verlag-Chemistry,
New York, 1993).
Nβ2g2S(S + 1)
11. V. T. Kalinnikov andYu. V. Rakitin, Introduction to Mag-
netochemistry. The Static Magnetic Susceptibility
Method (Nauka, Moscow, 1980) [in Russian].
-----------------------------------
χ = χ'(1 – p) +
p.
3k(T – θ)
12. A. N. Lomakin, A. M. Simonov, and V. A. Chigrina, Zh.
Here N, Nα, k, β, J, g, and θ are the Avogadro num-
ber, van Vleck paramagnetism, the Boltzmann con-
stant, the Bohr magneton, the exchange coupling
parameter, the Lande factor, and the Weiss constant,
respectively.
Thus, a change in the nature of the bridging frag-
ment (X, Y) gives rise to dimeric copper complexes
with different types of magnetic exchange: ferromag-
netic (X = NTs) and antiferromagnetic (X = O) types.
Obshch. Khim. 33 (1), 204 (1963).
13. B. A. Porai-Koshits and Ch. Frankovskii, Zh. Obshch.
Khim. 28 (4), 928 (1958).
14. H. Brauniger and K. Spangenberg, Pharmazie 12, 335
(1957).
15. C. Runti, Ann. Chim. (Rome) 46, 406 (1956).
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16 (10), 1667 (1946).
17. R. Nietzki and K. Almenzader, Ber. Dtsch. Chem. Ges.
28 (15), 2969 (1895).
ACKNOWLEDGMENTS
18. N. I. Chernova, Yu. S. Ryabokobylko, V. G. Brudz’, and
This work was supported by the Program of the
Ministry of Science and Education of the Russian Fed-
eration “Development of the Scientific Potential”
(2006–2008) (RNP.2.1.1.1875), by the Program of Pre-
sidium of the Russian Academy of Sciences (project
“Molecular Design of MagneticallyActive Compounds
and Materials (Molecular Magnets)”), the Council for
Grants of the President of the Russian Federation for
State Support of Leading Scientific Schools (grant
no. NSh-363.2008.3), and a Southern Federal Univer-
sity domestic grant.
B. M. Bolotin, Zh. Org. Khim. 7 (8), 1680 (1971).
19. A. D. Garnovskii, I. S. Vasil’chenko, and D. A. Gar-
novskii, Modern Aspects of Synthesis of Metal Com-
plexes. Ligands and Methods (LaPO, Rostov-on-Don,
2000) [in Russian].
20. Synthetic Coordination and Organometallic Chemistry,
Ed. byA. D. Garnovskii and B. I. Kharisov (Marcel Dek-
ker, New York, 2003).
21. A. D. Garnovskii, V. A. Alekseenko, V. A. Kogan, et al.,
Koord. Khim. 3 (4), 500 (1977).
22. K. Nakamoto, Infrared and Raman Spectra of Inorganic
and Coordination Compounds, 5th ed., part B (John Wil-
ley, London, 1997).
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RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 10 2008