Helical 1D coordination polymers - Structure and magnetic properties of catena-poly[chloro(μ-({2-[(hydroxyimino)methyl]phenoxy}acetato-N,O,O, O′)copper(II)]

Article abstract of DOI:10.1002/1099-0682(200212)2002:12<3313::AID-EJIC3313>3.0.CO;2-K

A new compound [CuHLCl]_n, where H₂L is the product of the condensation reaction between 2-formylphenoxyacetic acid and hydroxylamine, has been synthesized and its crystal structure determined. The copper(Il) atom is in an O₃NCl coordination environment and the helical chains of the complex are formed by square-pyramidal copper(II) ions bridged by anti-anti carboxylate ligands in basal-apical positions. The chloride ion acts as monodentate ligand and is involved in intramolecular hydrogen bonding to the oxime group. The results of magnetic susceptibility and EPR measurements performed on the polycrystalline sample over a wide temperature range are presented. The magnetic susceptibility data have been fitted by use of the linear chain model and J = -2.5 cm^-1 as the value of antiferromagnetic interaction. The value of the exchange exceeds the Zeeman energy difference for two adjacent magnetically nonequivalent copper centers, and signals of these centers are averaged out. The temperature dependence of the EPR spectra shows increases in the linewidth and the shifts of the signals as the temperature decreases, indicating a short-range-order effect in the chain. Shifts of the EPR signals in the Q-band were discovered for the orientations perpendicular to the chain direction as the temperature decreased below 10 K. The nature of this shift is discussed. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Full text of DOI:10.1002/1099-0682(200212)2002:12<3313::AID-EJIC3313>3.0.CO;2-K

FULL PAPER
Helical 1D Coordination Polymers ؊ Structure and Magnetic Properties of
catena-Poly[chloro(µ-({2-[(hydroxyimino)methyl]phenoxy}acetato-
N,O,O,OЈ)copper(II)]
Sergiu Shova,*[a] Ghenadie Novitchi,[b] Maria Gdaniec,[c] Andrea Caneschi,[d]
Dante Gatteschi,[d] Ludmila Korobchenko,[e] Violeta K. Voronkova,[e] Yurii A. Simonov,[a] and
Constantin Turta[f]
Keywords: Copper / EPR spectroscopy / Magnetic properties / N ligands / O Ligands
A new compound [CuHLCl]n, where H2L is the product of the
condensation reaction between 2-formylphenoxyacetic acid
−2.5 cm−1 as the value of antiferromagnetic interaction. The
value of the exchange exceeds the Zeeman energy differ-
and hydroxylamine, has been synthesized and its crystal ence for two adjacent magnetically nonequivalent copper
structure determined. The copper(II) atom is in an O3NCl co-
ordination environment and the helical chains of the complex
are formed by square-pyramidal copper(II) ions bridged by
anti-anti carboxylate ligands in basal-apical positions. The
chloride ion acts as monodentate ligand and is involved in
intramolecular hydrogen bonding to the oxime group. The
results of magnetic susceptibility and EPR measurements
performed on the polycrystalline sample over a wide temper-
ature range are presented. The magnetic susceptibility data
have been fitted by use of the linear chain model and J =
centers, and signals of these centers are averaged out. The
temperature dependence of the EPR spectra shows increases
in the linewidth and the shifts of the signals as the temper-
ature decreases, indicating a short-range-order effect in
the chain. Shifts of the EPR signals in the Q-band were
discovered for the orientations perpendicular to the chain
direction as the temperature decreased below 10 K. The na-
ture of this shift is discussed.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
isting in crystals in the form of a helical polymeric chain
of formula [Cu(HL)Cl]n, where H2L is the product of the
condensation reaction between 2-formylphenoxyacetic acid
and hydroxylamine. There is currently renewed interest in
copper() complexes with carboxylic ligands[8Ϫ13] because
carboxylic groups can exhibit several different coordination
modes to the central atom, giving rise to compounds with
ferromagnetic or antiferromagnetic properties[14,15] de-
pending on the copper magnetic orbitals involved in bond-
ing and the coordination mode of the carboxylic group.
Studies of structure and magnetic exchange interactions in
this type of compounds are aimed at understanding of the
structural and chemical features determined by the magni-
tude and sign of the exchange interaction.
Introduction
The quasi-one-dimensional magnetic systems of trans-
ition metal ions (metallopolymers) are of particular interest
for physicists and chemists because of their special proper-
ties resulting from the nature of the magnetic ions. On the
other hand, one-dimensional polymeric helical motifs are
also attracting increased attention in supramolecular
chemistry,[1Ϫ4] which certainly originates from the observed
importance of these motifs in biological systems and enanti-
oselective catalysis.[5Ϫ7]
This paper reports the synthesis, crystal structure, and
magnetic properties of an anhydrous copper() complex ex-
[a]
Institute of Applied Physics, Academy of Sciences of Moldova,
Results and Discussion
Moldavian State University
Mateevicistr. 60, Chisinau, MD 2009 Moldova
[b]
Synthesis
Faculty of Chemistry, State University of Moldova,
MD2009 Chisinau, Moldova
[c]
The template synthesis of the copper() coordination
compound was carried out according to Scheme 1.
Copper() chloride and acetate were used for the reac-
tion, but the yield was less when the acetate was used in-
stead of the chloride. The compound [Cu(HL)Cl] was also
formed when copper() chloride reacted directly with the
oxime.
Faculty of Chemistry, A. Mickiewicz University,
60-780 Poznan, Poland
[d]
Department of Chemistry, University of Florence,
50019 Florence, Italy
[e]
Zavoisky Physical-Technical Institute of the Russian Academy
of Sciences,
42009 Kazan, Russia
[f]
Institute of Chemistry, Academy of Sciences of Moldova,
MD2028 Chisinau, Moldova
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318  2002 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 1434Ϫ1948/02/1212Ϫ3313 $ 20.00ϩ.50/0 3313

S. Shova et al.
FULL PAPER
˚
along the chain, 5.845 A, is longer than those observed in
similar helical chains but with the syn-anti carboxylate co-
ordination mode.[12] The H-atom of the oxime group is in-
volved in intramolecular hydrogen bonding [O(4)···Cl 3.058
˚
˚
A, H···Cl 2.34 A, OHCl 150°], closing a five-membered
ring. No intermolecular hydrogen bonds are formed in this
crystal; however, there is some overlap of the aromatic rings
belonging to adjacent helical chains, with the distances be-
Scheme 1
˚
tween the ring atoms being in the 3.22Ϫ3.62 A range, sug-
gesting that π-π interactions may be of some importance in
stabilizing this crystal structure (Figure 1). In the lattice,
right- and left-handed helices alternate, resulting in an op-
tically inactive racemic crystal, spontaneous resolution of
two isomers being rare.[11,12]
IR Spectra
The IR spectrum of [Cu(HL)Cl]n does not contain ab-
sorption bands attributable to the vibration of the aldehyde
group of 2-formylphenoxyacetic acid [ν(CHϭO): ν˜ ϭ 1754,
1712 cmϪ1], but it does show the vibration bands of the
coordinated imino group [ν(CϭN): ν˜ ϭ 1604 cmϪ1], indic-
ating that the template reaction is accompanied by con-
densation between 2-formylphenoxyacetic acid and hy-
droxylamine.[16] In addition, the IR spectrum of the com-
plex shows the characteristic absorption bands of the carb-
oxyl group of the formylphenoxyacetic fragment
[νas(COOϪ): ν˜ ϭ 1570 cmϪ1; νs(COOϪ): ν˜ ϭ 1414cmϪ1],
which were assigned according to ref.[17] The 156 cmϪ1 dif-
ference in the wavenumbers of the absorption bands
νas(COOϪ) and νs(COOϪ) suggests the bidentate bridge
mode of coordination. The shift of the νs(CϪOϪC) absorp-
tion band (1164 cmϪ1) of the ether group by 52 cmϪ1 in the
lower wavenumber range and of the νas(CϪOϪC) band
(1244 cmϪ1) by 4 cmϪ1 in the higher wavenumber range
(relative to their counterparts in 2-formylphenoxyacetic
acid) confirm the participation of the ether oxygen atom in
Magnetic Susceptibility
The temperature dependence of the magnetic susceptibil-
ity and χT is presented in Figure 2. The value of χT (see a
in Figure 2) decreases as the temperature decreases, indicat-
ing antiferromagnetic behavior. The Hamiltonian appropri-
ate for a Heisenberg linear chain of S ϭ 1/2 spins is given
by Equation (1).
H ϭ JΣSi·Siϩ1
(1)
The experimental data for the variation of susceptibility
with temperature can be satisfactorily fitted into the ana-
lytic expression introduced to represent the BonnerϪFisher
model[18] for a uniformly spaced Heisenberg chain of spins
with S ϭ 1/2 [Equation (2)].[19]
coordination. The presence of the absorption band of the
Ϫ1
˜
stretching frequency ν(OH) at ν ϭ 3100Ϫ3300 cm testi-
(2)
fies to the presence of the protonated aldoxime group.
Structure
The solid line in Figure 2 (part b) is the curve calculated
The crystal of the complex [Cu(HL)Cl]n consists of infi- according to Equation (2) with J ϭ 2.5 cmϪ1, g ϭ 2.15.
nite helical chains directed along the b axis. Two antiparallel It shows good agreement between experimental data and
enantiomorphic helices in the crystal are shown in Figure 1, calculated χ(T). Although the decrease in χ(T) in the tem-
together with the atom-labeling scheme. The monomeric perature range studied is not observed experimentally, the
units of the [Cu(HL)Cl]n chain are sequentially bridged by measured values of χ(T) in the low-temperature range (inset
anti-anti carboxylate groups. The monodeprotonated HLϪ in part b of Figure 2) would allow the presence of the max-
anion acts as a tridentate ligand towards one copper() ion imum in this range. We considered the one-dimensional
and as a monodentate ligand towards another copper() model, neglecting the interaction between the chains, as the
center. The copper() ions each exist in distorted square- distances between the paramagnetic copper centers in adja-
˚
pyramidal coordination with the O3NCl atom-donor set. cent chains (R ϭ 9.50 A) exceed the intrachain copper dis-
˚
The basal coordination sites are occupied by three donor tance (R ϭ 5.85 A) and there are no channels for indirect
atoms of the ligand [CuϪO(1) 2.089(3), CuϪO(2) 1.908(3) exchange between neighboring chains. Hence the antiferro-
˚
and CuϪN(1) 1.966(3) A] and the chlorine atom [CuϪCl magnetic interaction is produced only inside the chains.
˚
2.245(1) A], whereas the carboxylate O(3) atom of the li-
It should be noted that the given data are in good agree-
gand from the adjacent monomeric unit along the chain ment with a model chain of equally spaced copper() ions.
˚
resides in the apical position [CuϪO(3)Ј 2.189(3) A]. Thus, In fact, the bridging fragments between the copper com-
each anti-anti carboxylate group is located in the basal-ap- plexes in the chains coincide completely, although the chain
ical positions of the coordination polyhedra and bridges is built up of magnetically nonequivalent copper centers:
˚
two copper() ions. The Cu atom is displaced by 0.208 A square-pyramidal copper() polyhedra CuClNO3 are ro-
from the OONCl plane toward the axially coordinated tated with respect to each other along the direction of the
O(3)Ј atom. The distance between the nearest Cu atoms chain. This chain structure results in a small value for the
3314
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318

Helical 1D Coordination Polymers
FULL PAPER
Figure 2. Temperature dependence of the experimental values of
χT (a) and measured (black triangles) and calculated (solid line) of
the values χ(T) (b); the inset presents the low-temperature range of
χ(T) on a larger scale
overlap of the magnetic orbitals according to the
GoodenoughϪKanamori rule.[20Ϫ22]
EPR Investigation
EPR spectra of the polycrystalline sample are shown in
Figures 3 and 4. The spectrum is typical for the state S ϭ
1/2 with the rhombic symmetry of the {g} tensor. The tem-
perature dependence of the spectra at the Q-band indicates
the change of the values of the {g} tensor: g1 ϭ 2.239 Ϯ
0.002, g2 ϭ 2.159 Ϯ 0.002, g3 ϭ 2.060 Ϯ 0.002 at T ϭ
293 K; g1 ϭ 2.236 Ϯ 0.002, g2 ϭ 2.129 Ϯ 0.002, g3 ϭ 2.044
Ϯ 0.002 at T ϭ 4.2K.
The X-band anisotropy of the spectra is not resolved
completely, but computer analysis of the spectra has al-
lowed the temperature dependence of the g factor aniso-
tropy and linewidths to be estimated. The temperature de-
pendence of the linewidth for the high-field signal (Fig-
ure 5) shows that the appreciable changes are already de-
tectable at T ϭ 10 K and that the effect increases as the
Figure 1. Crystal structure of [Cu(HL)Cl]n: ball-and-stick model
showing atom labelling (a); space-filling diagram of two adjacent
enantiomorphic helices (b)
antiferromagnetic interaction between the copper centers in temperature decreases.
the chains.
As we have already noted, the principal axes of g tensors
The value of the isotropic exchange interaction is deter- of the neighboring copper ions are rotated with respect to
mined by the overlap integral between ground-state orbitals, each other. As the exchange interaction exceeds the differ-
which for an indirect exchange is produced through inter- ence of Zeeman energies for two magnetically inequivalent
mediate orbitals of bridging ligands (the ground state of a molecules, collapse of the lines occurs and for this spectrum
2
2
square-pyramidal copper complex is the dx Ϫy orbital). A the temperature dependence of the g tensor is detectable
weak antiferromagnetic coupling is justified by the small due to the merging effect. In principle, the temperature de-
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318
3315

S. Shova et al.
FULL PAPER
Figure 5. The temperature dependence of the linewidth of the high-
field signal at the X-band
The 2γ term is the angle between the gz directions of two
neighboring complexes. It might be expected that this angle
should be equal to the angle between the directions of the
apical CuϪO bonds of two consecutive copper positions.
According to Equation (3), for γ ഠ 36° and typical values
of g|| and gЌ for the square-pyramidal copper complexes it
would be expected that the change in the g2 value due to
possible small structural changes with temperature should
not exceed the change of the g1 value. However, the g1 value
is practically independent of the temperature and the sup-
position about the temperature dependence of the g value
due to the availability of the short-range order effect is pre-
ferable. Analysis of the expressions of Equation (3) indic-
ates that the g1 component corresponds to the orientation
of the magnetic field along the chain and the g2,3 compon-
ents are perpendicular to the chain direction.
Figure 3. Temperature dependence of the EPR spectra of the poly-
crystalline sample of [Cu(HL)Cl]n at the X-band
The temperature dependence of the EPR spectra unequi-
vocally shows that the linewidth for all orientations in-
creases as the temperature decreases, and that the g factors
shift for orientations perpendicular to the direction of the
chain. No shift of the signal relative to the direction of the
magnetic field along the direction of the chain is observed.
The effects of the increase in the linewidth and the shifts of
the signals for quasi-one-dimensional systems as the tem-
perature approaches the value of the exchange interaction
inside a chain have previously been explained in terms of
the availability of the short-range order and the presence of
the preferable direction for antiferromagnetic or ferromag-
netic ordering due to the anisotropy of the
interaction.[24Ϫ26] Changes of different signs were observed
for the g factor, depending on the direction of a magnetic
field: parallel or perpendicular to the direction of the chain.
These experimental data are satisfactorily described by the
assumption that the anisotropy of the interaction has a di-
pole-dipole character.
Figure 4. The EPR spectra at the Q-band at 298 K (a), 77 K (b),
4.2 K (c)
pendence of the positions of the signals may be due to small
structural changes and to short-range order effects in the
chain. Consider the correlation between observed g1, g2, g3
components and molecular {g} tensors. On the assumption
of the axial symmetry of the molecular g tensor (g||, gЌ) the
resulting components of the g tensor are given by Equa-
tion (3).[23]
The [Cu(HL)Cl]n crystal provides an example of a new
type of behavior of magnetic properties close to the temper-
ature T ഠ J. The change in behavior is probably connected
with the change of the nature of the anisotropy of the inter-
action. For [Cu(HL)Cl]n, the distance between the copper
˚
centers in a chain (R ϭ 5.85 A), allows us to assume that
g3 ϭ gЌ
g1 ϭ (g||2 cos2γ ϩ gЌ2 sin2γ)1/2
g2 ϭ (g||2 sin2γ ϩ gЌ2 cos2γ)1/2
(3)
the main role is played by the anisotropy of the exchange
interaction, including the antisymmetric interaction. For
3316
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318

Helical 1D Coordination Polymers
FULL PAPER
EPR and Magnetic Measurements: The measurements were carried
out on the polycrystalline sample of [Cu(HL)Cl]n. The static mag-
netic susceptibility was measured over the 2Ϫ300 K temperature
range. The data were corrected for a diamagnetic contribution by
use of Pascal constants.[29] The magnetization vs. B was recorded
the orientations of the magnetic field in the plane perpen-
dicular to the direction of the chain, as the temperature
decreases in the range T ഠ J, the EPR signals shift to
higher fields.
In principle, interaction between copper ions of adjacent
chains in the plane perpendicular to the direction of the
chains could give a similar effect. Because of the absence of
the channels for such indirect exchange between copper
ions of neighboring chains, however, this supposition is im-
probable. Measurements on single crystals would be neces-
sary for more detailed investigation, because the spectrum
of the polycrystalline sample contains only the signals cor-
responding to appropriate orientations of the magnetic field
along the principal axes of the g tensor.
Table 1. Crystal data for [Cu(HL)Cl]n
Empirical formula
M
C9H8ClCuNO4
293.15
293(2)
Temperature [K]
˚
Wavelength [A]
1.54178
Space group
P21/c
6.5090(10)
8.311(2)
18.923(4)
94.98(3)
1019.8(4)
4
1.909
5.457
588
˚
a [A]
˚
b [A]
˚
c [A]
β [°]
3
˚
V [A ]
Experimental Section
Z
ρcalcd. [Mg/m3]
µMo [mmϪ1
F(000)
]
Synthesis of [Cu(HL)Cl]n: 2-Formylphenoxyacetic acid (0.9 g, 0.005
mol) was added to CuCl2·2H2O (0.85 g, 0.005 mol) in methanol
(20 mL). A mixture of hydroxylamineϪhydrochloride (0.35 g,
0.005mol) and NaOH (0.4 g, 0.01 mol) in methanol (25 mL) was
then added, with stirring, to the resulting solution. The obtained
solution was heated in a water bath at 50 °C for 30 min. The dark
blue crystals, precipitating after cooling, were filtered, washed with
cold methanol, and dried in air. Yield: 1.025 g, 70%.
C9H8ClCuNO4 (293): calcd. C 36.86, H 2.73, Cl 12.12, Cu 21.67,
N 4.78; found C 36.93, H 2.76, Cl 12.09, Cu 21.78, N 4.80.
Crystal size [mm]
θ range [°]
Index ranges
0.4 ϫ 0.4 ϫ 0.2
4.69Ϫ64.82
Ϫ7 Յ h Յ 7,
Ϫ9 Յ k Յ 9, Ϫ22 Յ l Յ 22
Number of reflections:
measured
unique
2772
1811 [R(int) ϭ 0.048]
147
1.130
Number of refined parameters
GOOF for F2
R factor [I Ͼ 2σ(I)]
R1 ϭ 0.0648, wR2 ϭ 0.1608
R1 ϭ 0.0670, wR2 ϭ 0.1621
1.413, Ϫ1.213
IR Spectra: These were recorded as oil suspensions with a Specorde
M-80 spectrometer in the 4000Ϫ400 cmϪ1 range.
R factor (all data)
3
˚
∆ρmax, ∆ρmin [e A ]
X-ray Crystal Structure Analysis: The crystal used for measure-
ments was a prism of approximate dimensions 0.4 ϫ 0.4 ϫ 0.2 mm.
The crystal was a non-mesohedral twin with the twin matrix [1 0
0 0 Ϫ1 0 Ϫ0.5 0 Ϫ1]. The data were collected with a Kuma Diffrac-
tion KM4 diffractometer by use of graphite-monochromatized Cu-
Kα radiation. Lattice parameters were obtained from the least-
squares refinement of 27 reflections with 16° Յ 2θ Յ 70°. The
intensities were measured by the ω/2θ scan technique up to 2θmax ϭ
129.6°. The intensities of three reflections were checked every 100
measurements to monitor instrument and crystal stability. Their
intensity variation was within 3%. The structure was solved by dir-
˚
Table 2. Selected bond lengths [A] and angles [°]; symmetry trans-
formations: (Ј): Ϫx, y ϩ 1/2, Ϫz ϩ 1/2; (ЈЈ): Ϫx, y Ϫ 1/2, Ϫz ϩ 1/2
CuϪO(2)
CuϪN
CuϪO(1)
CuϪO(3)Ј
CuϪCl
O(1)ϪC(1)
O(1)ϪC(8)
1.908(3)
1.966(3)
2.089(3)
2.189(3)
2.245(1)
1.374(5)
1.452(5)
1.274(5)
1.223(5)
1.391(5)
167.0(1)
81.9(1)
NϪC(7)
1.293(6)
1.372(6)
1.417(6)
1.406(6)
1.424(6)
1.381(7)
1.364(7)
1.391(6)
1.505(5)
C(1)ϪC(6)
C(1)ϪC(2)
C(2)ϪC(3)
C(2)ϪC(7)
C(3)ϪC(4)
C(4)ϪC(5)
C(5)ϪC(6)
C(8)ϪC(9)
ect methods with SHELXS-86[27] and refined by full-matrix, least O(2)ϪC(9)
squares on F2 with SHELXL-93.[28] Instruction HKLF5 from
SHELXL-93 was used for the refinement, because half of all the
reflections belonged to both twin domains while the second half
belonged to one domain. The non-hydrogen atoms were refined
by the least-squares method in the anisotropic approximation. The
positions of H atoms bonded to C atoms were calculated by assum-
O(3)ϪC(9)
O(4)ϪN
O(2)ϪCuϪN
O(2)ϪCuϪO(1)
NϪCuϪO(1)
O(2)ϪCuϪO(3)Ј
NϪCuϪO(3)
O(1)ϪCuϪO(3)Ј
O(2)ϪCuϪCl
NϪCuϪCl
O(4)ϪNϪCu
120.9(3)
123.0(4)
120.2(4)
116.8(4)
117.2(4)
115.8(4)
127.0(4)
121.8(4)
119.7(4)
120.3(4)
120.8(4)
127.2(4)
109.3(3)
123.9(3)
117.5(4)
118.6(3)
C(6)ϪC(1)ϪO(1)
C(6)ϪC(1)ϪC(2)
O(1)ϪC(1)ϪC(2)
C(3)ϪC(2)ϪC(1)
C(3)ϪC(2)ϪC(7)
C(1)ϪC(2)ϪC(7)
C(4)ϪC(3)ϪC(2)
C(5)ϪC(4)ϪC(3)
C(4)ϪC(5)ϪC(6)
C(1)ϪC(6)ϪC(5)
NϪC(7)ϪC(2)
87.5(1)
96.9(1)
89.6(1)
85.0(1)
˚
ing CϪH distances of 0.96 A. Positional parameters of the oxime
H atom were obtained from difference Fourier syntheses and veri-
fied by the hydrogen bond geometric parameters. Isotropic dis-
placement parameters of H atoms were fixed at 1.2 ϫ Ueq for the
relevant C and O atoms. The main crystallographic parameters and
structure refinement details are summarized in Table 1, bond
lengths and angles in Table 2. CCDC-182198 contains the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge at www.ccdc.cam.ac.uk/conts/retriev-
ing.html or from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK [Fax: (internat.) ϩ 44-
1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].
93.6(1)
94.9(1)
O(1)ϪCuϪCl
O(3)ЈϪCuϪCl
C(1)ϪO(1)ϪC(8)
C(1)ϪO(1)ϪCu
C(8)ϪO(1)ϪCu
C(9)ϪO(2)ϪCu
C(9)ϪO(3)ϪCuЈЈ
C(7)ϪNϪO(4)
C(7)ϪNϪCu
165.42(9)
109.36(9)
117.1(3)
128.8(2)
110.6(2)
118.3(2)
131.5(3)
111.1(3)
127.8(3)
O(1)ϪC(8)ϪC(9)
O(3)ϪC(9)ϪO(2)
O(3)ϪC(9)ϪC(8)
O(2)ϪC(9)ϪC(8)
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318
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S. Shova et al.
FULL PAPER
[12]
[13]
[14]
E. Colacio, M. Ghazi, R. Kivekas, J. M. Moreno, Inorg. Chem.
2000, 39, 2882Ϫ2890.
R. L. Carlin, K. Kopinga, O. Kahn, M. Verdaguer, Inorg.
Chem. 1986, 25, 1786Ϫ1789.
B. S. Tsukerblat, M. I. Belinskii, Magnetochemistry and spectro-
scopy of exchange clusters, Iz. ‘‘Stiinta’’ (in Russ.), Kishinev,
1983.
V. T. Kalinicov, Yu. V. Rakitin, Introduction to magnetochem-
istry Ϫ The static magnetic susceptibility method in chemistry,
Iz. ‘‘Nauka’’ (Russ.), Moscow, 1980.
S. Shova, G. Novitski, M. Gdaniec, Yu. A. Simonov, K. Turte,
Russ. J. Inorg. Chem. 2000, 45, 1193Ϫ1200.
K. Nakamoto, Infrared and Raman Spectra of Inorganic Com-
pounds, New York, Wiley, 1988.
J. C. Bonner, M. E. Fisher, Phys. Rev. 1964, A135, 640Ϫ658.
W. E. Hatfield, J. Appl. Phys. 1981, 52, 1985Ϫ1990.
J. B. Goodenough, Phys. Rev. 1955, 100, 564Ϫ573.
J. B. Goodenough, J. Phys. Chem. Solids 1958, 6, 287Ϫ297.
J. Kanamori, J. Phys. Chem. Solids 1959, 10, 87Ϫ98.
B. J. Hathaway, D. E. Billing, Coordin, Chem. Rev. 1970, 5,
143Ϫ207.
A. Bencini, D. Gatteschi, Electron Paramagnetic Resonance of
Exchange Coupled Systems, Springer Verlag, Berlin, 1990.
K. Nagata, Yu. Tazuke, J. Phys. Soc. Jpn. 1972, 32, 337Ϫ345.
K. Nagata, Yu. Tazuke, K. Tsushima, J. Phys. Soc. Jpn. 1972,
32, 1486Ϫ1492.
at 2.5 and 4.5 K. EPR spectra were recorded at the X-band in the
temperature range from room temperature to 4 K and at the Q-
band at T ϭ 298, 77, 4.2 K.
Acknowledgments
[15]
We acknowledge INTAS financial support, Projects 2000-00565,
and the Russian Foundation for Basic Research, Project 01-03-
32270.
[16]
[17]
[1]
C. Piguet, G. Bernardinelli, G. Hopfgarther, Chem. Rev. 1997,
97, 2005Ϫ2062.
[2]
[18]
[19]
[20]
[21]
[22]
[23]
J.-M. Lehn, Supramolecular Chemistry: Concept and Perspect-
ives, VCH, Weinheim, 1995.
J. W. Steed, J. L. Atwood, Supramolecular Chemistry, John
[3]
Wiley and Sons, Ltd. Chichester, New York, 2000.
L. Plasseraud, H. Maid, F. Hampel, R. W. Saalfrank, Chem.
[4]
Eur. J. 2001, 7, 4007Ϫ4011.
[5]
E. J. Corey, C. L. Cymin, M. C. Noe, Tetrahedron Lett. 1994,
[24]
35, 69Ϫ72.
[6]
K. Maruoka, N. Murase, H. Yamamoto, J. Org. Chem. 1993,
58, 2938Ϫ2939.
L. Stryer, Biochemistry, W. H. Freeman and Co., New York,
[25]
[26]
[7]
1988.
[8]
[27]
[28]
[29]
E. Colacio, J. M. Dominguez-Vera, J. P. Costes, R. Kivekas, J.
SHELX86: G. M. Sheldrick, Acta Crystallogr., Sect. A 1990,
46, 467Ϫ473.
P. Laurent, J. Ruiz, M. Sundberg, Inorg. Chem. 1992, 31,
774Ϫ778 and references therein.
L. S Long, S. P. Yang, Y. X. Tong, Z. W. Mao, X. M. Chen,
G. M. Sheldrick, SHELXL-93, Program for the refinement of
crystal structure, University of Göttingen, Germany, 1993.
E. König, G. König, Magnetic Properties of Coordination and
Organometallic Transition Metal Compounds (Eds: K. H.
Hellwege, A. M. Hellwege), Springer-Verlag, Berlin, 1976.
Received March 22, 2002
[9]
L. N. Ji, J. Chem. Soc., Dalton Trans. 1999, 1999Ϫ2004.
R. W. Saalfrank, H. Maid, F. Hampel, K. Peters, Eur. J. Inorg.
[10]
Chem. 1999, 1859Ϫ1867 and references therein.
K. K. Nanda, A. W. Addison, E. Sinn, L. K. Thompson, Inorg.
[11]
Chem. 1996, 35, 5966Ϫ5967.
[I02152]
3318
Eur. J. Inorg. Chem. 2002, 3313Ϫ3318