Lanthanide triangles sandwiched by tetranuclear copper complexes afford a family of hendecanuclear heterometallic complexes [LnIII 3CuII8] (Ln = La-Lu): Synthesis and magnetostructural studies

Article abstract of DOI:10.1021/ic4009015

Reaction in ethanol of 3-hydroxymethylen-5-methylsalicylaldoxime (H ₃L) with CuCl₂·2H₂O and LnCl ₃·xH₂O [Ln = La (1), Ce (2), Pr (3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), Lu (11), Ho (12)] allowed the synthesis of a family of hendecanuclear heterometallic copper(II)- lanthanide(III) clusters with general formula [Ln^III ₃Cu^II₈(HL)₆(μ₄-O) ₂Cl₆(H₂O)₈]Cl₃ (1-12). According to the single-crystal X-ray diffraction investigation, the complexes are isomorphous and crystallize in the trigonal R32 group. The hendecanuclear cluster is formed by two tetrahedral μ₄-oxo {Cu₄} clusters assembled by three lanthanide ions sandwiched in between. Along the family, the separation between the {Cu₄} moieties increases linearly from Lu to La in good correlation with ionic radius of the lanthanide ions. A comparative analysis of the magnetic data for the lanthanum (1) and lutetium (11) compounds shows the presence of ferromagnetic and antiferromagnetic interactions within the μ₄-oxo {Cu₄} moieties. For the gadolinium (6) and terbium (7) compounds, the magnetic interactions between the lanthanide and the copper ions are found to be ferromagnetic. The dysprosium (8) compound exhibits single-molecule magnet behavior.

Full text of DOI:10.1021/ic4009015

Article
pubs.acs.org/IC
Lanthanide Triangles Sandwiched by Tetranuclear Copper
Complexes Afford a Family of Hendecanuclear Heterometallic
Complexes [LnIII CuII ] (Ln = La−Lu): Synthesis and Magnetostructural
3
8
Studies
Olga Iasco,† Ghenadie Novitchi,*,†,‡ Erwann Jeanneau,† and Dominique Luneau*,†
†Laboratoire des Multimater
Villeurbanne cedex, France
‡Laboratoire National des Champs Magnet
́
iaux et Interfaces (UMR 5615), Universite
́
Claude Bernard Lyon 1, Campus de la Doua, 69622
́
iques Intenses-CNRS, 38042 Grenoble Cedex 9, France
S
* Supporting Information
ABSTRACT: Reaction in ethanol of 3-hydroxymethylen-5-methylsalicylaldox-
ime (H3L) with CuCl2·2H2O and LnCl3·xH2O [Ln = La (1), Ce (2), Pr (3), Nd
(4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), Lu (11), Ho (12)]
allowed the synthesis of a family of hendecanuclear heterometallic copper(II)−
lanthanide(III) clusters with general formula [LnIII3CuII8(HL)6(μ4-
O)2Cl6(H2O)8]Cl3 (1−12). According to the single-crystal X-ray diffraction
investigation, the complexes are isomorphous and crystallize in the trigonal R32
group. The hendecanuclear cluster is formed by two tetrahedral μ4-oxo {Cu4}
clusters assembled by three lanthanide ions sandwiched in between. Along the
family, the separation between the {Cu4} moieties increases linearly from Lu to
La in good correlation with ionic radius of the lanthanide ions. A comparative
analysis of the magnetic data for the lanthanum (1) and lutetium (11)
compounds shows the presence of ferromagnetic and antiferromagnetic
interactions within the μ4-oxo {Cu4} moieties. For the gadolinium (6) and
terbium (7) compounds, the magnetic interactions between the lanthanide and the copper ions are found to be ferromagnetic.
The dysprosium (8) compound exhibits single-molecule magnet behavior.
In this paper, we present the synthesis and magnetostructural
studies of a new family of Cu/Ln heterometallic clusters that
INTRODUCTION
■
One major concern of coordination chemistry is currently the
synthesis and investigation of polynuclear heterometallic
coordination compounds possessing slow relaxation of the
magnetization.1−7 Along this line, the use of lanthanides for the
modulation and enhancement of the magnetic properties of
transition metal single-molecule magnets has become common
in recent years.8−17 This is because the magnetic anisotropy of
some lanthanides can induce an increase of the blocking
temperature for reversal of magnetization.18−20 The funda-
mental understanding regarding the factors that can favor a
high value of the resulting ground-state spin and the associated
required negative anisotropy is an important prospect of
researchers working in the field. In this regards, the study of a
large family of compounds, where magnetostructural correla-
tions can be established in a systematic way, contributes to a
better understanding of the relationships between the structure
and the magnetic interaction or magnetic anisotropy.21−28
Thus, during the last two decades, several series of original
heterometallic polynuclear systems have been reported
particularly with respect to their single-molecule magnet
properties. We can mention here the different series of
heterometallic systems, Cr/Ln,14,29 Mn/Ln,8,9,19,30−35 Fe/
Ln,36−41Co/Ln,17,33,42−45 Ni/Ln,23,46−51 and Cu/Ln.15,52−67
are hendecanuclear with general formula [LnIII3CuII (HL)6(μ4-
8
O)2Cl6(H2O)8]Cl3 (1−12) where LnIII = La (1), Ce (2), Pr
(3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10),
Lu (11), and Ho (12) and H3L = 3-hydroxymethylen-5-
methylsalicylaldoxime. The clusters may be viewed as a triangle
of lanthanide ions sandwiched between two classical tetrahedral
μ4-oxo Cu4 clusters,68−75 to afford an original hendecanuclear
cluster with C3 molecular symmetry.
EXPERIMENTAL SECTION
■
Materials. All chemicals and solvents were purchased from Aldrich
and used without further purification. Manipulations were performed
under aerobic conditions using chemicals and solvents as received.
Synthesis. H3L (3-Hydroxymethylen-5-methyl-salicylaldoxime).
Hydroxylamine hydrochloride (0.84g, 12.1 mmol) and sodium
hydroxide (0.48 g, 12.1 mmol) were dissolved in 15 mL of water.
The obtained solution was added to 2-(hydroxymethyl)-6-carbalde-
hyde-4-methylphenol76 (2g, 12.1 mmol) dissolved in ethanol (20 mL).
The final compound was isolated by precipitation from water. Yield
70−75%. IR/cm−1: νmax 3384 (O−H), 2916, 2864 (C−H), 1620,
Received: April 11, 2013
© XXXX American Chemical Society
A
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Table 1. Crystal Data and Structure Refinement Parameters for Series of Heterometallic Clusters [LnIII3CuII (HL)6(μ4-
8
O)2Cl6(H2O)8]Cl3 (1−11)
[La3Cu8] (1)
[Ce3Cu8] (2)
[Pr3Cu8] (3)
[Nd3Cu8] (4)
C54H70Cl19Cu8
Nd3N6O28
2511.33
trigonal
R32
[Eu3Cu8] (5)
[Gd3Cu8] (6)
C54H70Cl19Cu8
Gd3N6O28
2550.36
trigonal
R32
formula
C54H70Cl19Cu8
La3N6O28
C54H70Cl19Cu8
Ce3N6O28
C54H70Cl19Cu8
Pr3N6O28
C54H70Cl19Cu8
Eu3N6O28
fw
2495.34
trigonal
2498.97
trigonal
R32
2501.34
trigonal
R32
2534.52
trigonal
R32
cryst syst
space group R32
a (Å)
b (Å)
c (Å)
22.086(2)
22.186(3)
22.186(3)
20.947(2)
90
22.132(3)
22.132(3)
20.854(3)
90
22.135(3)
22.135(3)
21.038(3)
90
22.086(2)
22.086(2)
20.661(2)
90
22.1460(10)
22.1460(10)
20.699(2)
90
22.086(2)
20.661(2)
90
α (deg)
β (deg)
γ (deg)
V (Å3)
Z
90
90
90
90
90
90
120
120
120
120
120
120
8728.0(14)
3
8929.2(19)
3
8846(2)
3
8927(2)
3
8728.0(14)
3
8791.7(10)
3
ρcalcd
1.424
1.394
1.407
1.401
1.447
1.445
(g/cm3)
μ (mm−1
)
2.765
2.773
2.880
2.935
3.280
100(2)
3.349
T (K)
100(2)
0.0667
0.1235
100(2)
0.0748
0.1373
100(2)
0.0646
0.1545
100(2)
0.0507
0.0803
100(2)
a
R
0.0583
0.0565
b
Rw
0.0998
0.0994
[Tb3Cu8] (7)
[Dy3Cu8] (8)
[Er3Cu8] (9)
[Yb3Cu8] (10)
[Lu3Cu8] (11)
formula
fw
C54H70Cl19Cu8Tb3 N6O28
C54H70Cl19Cu8Dy3 N6O28
C54H70Cl19Cu8Er3 N6O28
C54H70Cl19Cu8Yb3 N6O28
C54H70Cl19Cu8Lu3 N6O28
2603.52
trigonal
R32
2566.11
trigonal
R32
2580.39
trigonal
R32
2597.73
trigonal
R32
2603.52
trigonal
R32
cryst syst
space group
a (Å)
22.126(2)
22.126(2)
20.559(2)
90
22.089(2)
22.089(2)
20.674(3)
90
22.291(2)
22.291(2)
20.550(2)
90
22.145(2)
22.145(2)
20.554(2)
90
22.1950(10)
22.1950(10)
20.4840(10)
90
b (Å)
c (Å)
α (deg)
β (deg)
γ (deg)
V (Å3)
Z
ρcalcd (g/cm3)
μ (mm−1
90
90
90
90
90
120
120
120
120
120
8716.4(14)
3
8735.9(17)
3
8843.0(14)
3
8729.3(14)
3
8738.9(7)
3
1.488
1.463
1.454
1.482
1.484
)
3.491
13.993
100(2)
0.0803
0.1866
3.777
4.074
4.203
T (K)
100(2)
0.0576
100(2)
0.0421
0.0862
100(2)
0.0422
0.0699
100(2)
0.0401
0.0708
a
R
b
Rw
0.1063
a
b
2
2
R1 = ∑||Fo| − |Fc||/∑|Fo|. Rw2 = {∑[w(Fo − Fc2)2]/[(w(Fo )2]}1/2 and I > 2σ(I).
(CN), 1599, (CC), 1402, 1469, 1296 (C−H), 1236 (C−OH),
989 (CH). NMR-H1/ppm and intensities: (DMSO-d6) 11.47 (1sH),
10.10 (1sH), 8.30 (1dH), 7.16 (1dH), 7.05 (1 H), 4.50 (2 H), 2.22 (3
H).
(%) for C54H70Cl9Cu8Ce3N6O28: C, 25.95; H, 2.82; N, 3.36. Found
(%): C, 25.75; H, 2.90; N, 3.41.
[Pr3Cu8] (3). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), PrCl3 (0.12 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33 mmol),
and Et3N (0.2 mL). Yield: 25% (based on Cu). Anal. Calcd (%) for
C54H70Cl9Cu8Pr3N6O28: C, 25.93; H, 2.82; N, 3.36. Found (%): C,
25.97; H, 2.88; N, 3.34.
[Nd3Cu8] (4). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), NdCl3·6H2O (0.18 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 27% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Nd3N6O28: C, 25.83; H, 2.81; N, 3.35. Found
(%): C, 25.76; H, 2.80; N, 3.51.
[Eu3Cu8] (5). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), EuCl3·6H2O (0.18 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 31% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Eu3N6O28: C, 25.59; H, 2.78; N, 3.32. Found
(%): C, 25.60; H, 2.83; N, 3.30.
[Gd3Cu8] (6). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), GdCl3·H2O (0.13 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 24% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Gd3N6O28: C, 25.43; H, 2.77; N, 3.30. Found
(%): C, 25.54; H, 2.80; N, 3.41.
[LnIII3CuII (HL)6(μ4-O)2Cl6(H2O)8]Cl3 (1−12). To a stirred solution of
8
3-hydroxymethyl-5-methylen-salicylaldoxime (1 mmol) in absolute
ethanol (20 mL), the solid LnCl3 (Ln = La (1), Ce (2), Pr (3), Nd
(4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), Lu (11), Ho
(12); 0.5 mmol) and CuCl2·2H2O (1.33 mmol) were added. Finally,
the triethylamine (2 mmol) was added to the reaction mixture. The
resulting dark green solution was stirred for 10 min and then was left
undisturbed to concentrate slowly by evaporation. After 2−4 days,
green cube-shaped crystals of 1−12 were collected by filtration and
washed with a small amount of absolute ethanol. Specific details of
each reaction are given below.
[La3Cu8] (1). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), LaCl3·7H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 30% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8La3N6O28: C, 25.99; H, 2.83; N, 3.37. Found
(%): C, 25.98; H, 2.86; N, 3.42.
[Ce3Cu8] (2). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), CeCl3·7H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 29% (based on Cu). Anal. Calcd
B
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[Tb3Cu8] (7). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), TbCl3·6H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 29% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Tb3N6O28: C, 25.38; H, 2.76; N, 3.29. Found
(%): C, 25.45; H, 2.71; N, 3.34.
[Dy3Cu8] (8). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), DyCl3·6H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 32% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Dy3N6O28: C, 25.27; H, 2.75; N, 3.28. Found
(%): C, 25.36; H, 2.72; N, 3.35.
[Er3Cu8] (9). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18 g,
1 mmol), ErCl3·6H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 24% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Er3N6O28: C, 25.13; H, 2.73; N, 3.26. Found
(%): C, 25.20; H, 2.68; N, 3.24.
[Yb3Cu8] (10). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18
g, 1 mmol), YbCl3·6H2O (0.19 g, 0.5 mmol), CuCl2·2H2O (0.23 g,
1.33 mmol), and Et3N (0.2 mL). Yield: 28% (based on Cu). Anal.
Calcd (%) for C54H70Cl9Cu8Yb3N6O28: C, 24.97; H, 2.72; N, 3.24.
Found (%): C, 25.01; H, 2.78; N, 3.26.
[Lu3Cu8] (11). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18
g, 1 mmol), LuCl3 (0.14 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 27% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Lu3N6O28: C, 24.91; H, 2.71; N, 3.23. Found
(%): C, 24.98; H, 2.74; N, 3.31.
[Ho3Cu8] (12). 3-Hydroxymethylen-5-methyl-salicylaldoxime (0.18
g, 1 mmol), HoCl3 (0.14 g, 0.5 mmol), CuCl2·2H2O (0.23 g, 1.33
mmol), and Et3N (0.2 mL). Yield: 27% (based on Cu). Anal. Calcd
(%) for C54H70Cl9Cu8Ho3N6O28: C, 24.91; H, 2.71; N, 3.23. Found
(%): C, 24.98; H, 2.74; N, 3.31.
Physical Measurements. NMR spectra were recorded at 300
MHz on a Bruker DRX spectrometer in DMSO-d6 solution. The
chemical shifts were referred to TMS using the residual signals from
the solvent. IR spectra were recorded in the solid state on a NICOLET
spectrophotometer in the 400−4000 cm−1 range. Magnetic suscept-
ibility data (2−300 K) were collected on powdered samples using a
SQUID magnetometer (Quantum Design MPMS-XL), applying
magnetic field of 0.1 T. All data were corrected for the contribution
of the sample holder and the diamagnetism of the samples estimated
from Pascal’s constants.77,78 Magnetic data analyses were carried out
by calculations of energy levels associated with the spin Hamiltonians
presented in the text and with the MAGPACK program package.79 To
take into account the intermolecular interaction, the following
definition of the susceptibility has been used:78,80,81
Table 2. Selected Bond Distances and Angles in [Dy3Cu8]
(8)
N1−Cu1
Cl1−Cu1
O3−Cu1
O5−Cu1
O2−Cu1
Cl1−Cu2
O5−Cu2
O6−Cu2
O1−Dy1
O2−Dy1
O3−Dy1
O4−Dy1
1.947(11)
2.594(5)
1.958(11)
1.938(5)
1.978(11)
2.339(5)
1.931(17)
1.93(3)
Cl1−Cu1−O2
Cl1−Cu1−O3
Cl1−Cu1−N1
Cl1−Cu1−O5
O2−Cu1−O3
O3−Cu1−O5
O5−Cu1−N1
O2−Cu1−N1
Cl1−Cu2−O6
Cl1−Cu2−O5
Cl1−Cu2−Cl1′
94.1(4)
104.7(4)
97.9(4)
84.6(5)
81.1(4)
94.4(3)
93.1(4)
92.1(5)
2.398(13)
2.381(12)
2.347(9)
2.409(14)
87.88(15)
92.12(15)
119.86(2)
ature and under aerobic conditions in 6:3:8 ratio in the
presence of Et3N leads to the formation of deep green cube-
shaped crystals with formula [LnIII3CuII8(HL)6(μ4-
O)2Cl6(H2O)8]Cl3 where Ln = La (1), Ce (2), Pr (3), Nd
(4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), Lu (11),
and Ho (12) and H3L = 3-hydroxymethylen-5-methylsalicy-
laldoxime.
Molecular Structures. The single-crystal X-ray diffraction
data revealed that 1−11 are isomorphous and crystallize in the
trigonal space group R32. The X-ray diffraction data was not
collected for 12 due to the very small size of the single crystals.
However the elementary analytical data, X-ray powder
diffraction patterns, and physical measurements allow us to
suggest similar structure and composition for 12 as for 1−11.
Herein we will describe in detail the structure of dysprosium
complex 8 as an example for the family 1−12.
The crystal structure of [Dy3Cu8] (8) consists of complex
cations [DyIII3CuII (HL)6(μ4-O)2Cl6(H2O)8]3+ crystallizing
8
with chloride anions for charge balance (Figure 1). The
complete architecture of the cation could be described as two
nearly flat {Cu3} fragments located in two parallel planes
(crystallographic ab-planes) formed by coordination of three
double-deprotonated ligands (HL2−, Scheme 1) to three
copper(II) ions in a triangular fashion. A lateral look shows
that the two {Cu3} fragments are bridged together by three
dysprosium(III) ions sandwiched between with Cu1···Dy1
distances of 3.4068(26) Å. The architecture is completed on
the other side by two additional CuII ions Cu(2) bridged to the
copper(II) ions of the two {Cu3} fragments by chloride ions
and a μ4-oxo oxygen atom forming two tetranuclear {Cu4}
moieties with a classical tetrahedral arrangement of the
copper(II) ions (Figure 1 and Figure S1, Supporting
Information). The Cu1···Cu1′ and Cu1···Cu2 distances are
3.2269(34) and 3.0887(38) Å, respectively.
χ0(T)
χ(T) =
⎡
2zJ ′ χ0(T)⎤
1 −
Ng2β2
⎢
⎣
⎥
⎦
X-ray Data Collection and Structure Refinement. Diffraction
data were collected at 100.0(1) K using a Gemini A Ultra
diffractometer from Agilent Technologies Ltd. (Mo Kα graphite-
monochromated radiation, λ = 0.71073 Å) equipped with a CCD
camera and controlled by the CrysAlisPro Software (Agilent
Technologies, version 1.171.34.49). A summary of the crystallographic
data and structure refinement is given in Table 1. An analytical
absorption correction was applied by modeling the crystal habit.82 The
crystals were placed in the cold stream of an Oxford Cryosystems
open-flow nitrogen cryostat with a nominal stability of 0.1 K.83 All the
structures were solved by direct methods using the SIR97 program84
and refined against F2 using the CRYSTALS program.85 All non-
hydrogen atoms were refined anisotropically, whereas the hydrogen
atoms were placed in ideal calculated positions with isotropic thermal
parameters riding on their respective carbon atoms. The graphical
manipulations were carried out with the DIAMOND86 program.
Selected bond distances and angles for 1−11 are listed in Table 2.
As commonly observed with such oximes,7,77−81 within the
{Cu3} fragments, the copper(II) ions are assembled together in
a triangular fashion by an oxo oxygen atom (O5) and by the
bridging oximato groups that are coordinated to one copper(II)
ion by the nitrogen atom and to a second copper(II) ion by the
oxygen atom (Figure 1). The torsion Cu1O3N1Cu1′ angle is
equal 13.09°. Here the oxygen of the oximato groups is also
bridging the dysprosium with copper ions in a μ3-fashion, while
the oxo oxygen atom (O5) is bridging a fourth copper ion
(Cu2) in a μ4-fashion. The copper(II) ions and the
dysprosium(III) ions are also bridged by the deprotonated
phenoxy groups of 3-hydroxymethylen-5-methylsalicylaldox-
RESULTS AND DISCUSSION
The reaction of 3-hydroxymethylen-5-methylsalicylaldoxime
(H3L) with LnCl3·6H2O and CuCl2·2H2O at room temper-
■
C
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oxygen and one oxygen from the oxo group. The apical
position is occupied by a chloride ion. The Cu−O, Cu−N, and
Cu−Cl bond lengths are 1.938−1.968, 1.964, and 2.604 Å,
respectively. The oxo groups (O5, O5′) are located on the R3-
axis and serve as one of the apical positions of the trigonal
bipyramid environment of the Cu2 and Cu2′ copper(II) ions
from the additional {Cu−Cl3H2O} entities. The basal plane of
the bipyramid is an equilateral triangle made of the three
chloride ions that bridge the copper(II) ions of the {Cu3}
fragments, and the second apical position is a coordinated water
molecule (Figure 1 and Figure S1, Supporting Information).
The isostructurality of the [Ln3Cu8] family gives an
opportunity to track the impact of variation of ionic radius of
lanthanides on structural parameters of clusters. As may be
expected, we found that the distance between the two {Cu3}
fragments that lie in parallel planes increases with the ionic radii
of lanthanides. More remarkably this increases in a linear
fashion as shown in Figure 2. A linear dependence on the ionic
́
Figure 2. {Cu4}···{Cu4} separation distances, d (Å), as a function of
ionic radius of lanthanides in the family of heterometallic clusters
Figure 1. Molecular structure of [Dy3Cu8] (8): the lateral view with
tetrahedral {Cu4} fragment (top) and view along the 3-fold axis
(bottom).
[Ln3Cu8] (1−11). Solid line is a linear correlation (R2 = 0.959).
radii of lanthanides was also found for CuONCu dihedral angle
(β) (Figure S3, Supporting Information). In contrast, the angle
between OCuO and OLnO planes (α), which is known to
strongly affect magnetic interactions, especially for Cu/Gd
heterometallic systems,24−26 has small variation along the series
of complexes 1−11. Its variation is limited by crystallographic
errors in structural determination (Figure S4, Supporting
Information). No strong variation was found in IR spectra
Scheme 1. Mode of Coordination (μ4:η2:η1:η2:η1) of 3-
Hydroxymethylen-5-methylsalicylaldoxime (HL2−) in
Hererometallic Ln3Cu8 (1−12) Clusters
(4000−400 cm−1) of [Ln3Cu8] series, excepted for the ν(CH −O)
2
stretching vibration, which shows strong correlation with the
ionic radius of lanthanides taking values from 1039.4 cm−1 for
La to 1052.2 cm−1 in the case of Lu clusters (Figure S5,
Supporting Information).
Magnetic Properties. The magnetic susceptibility data for
all [Ln3Cu8] series are shown in Figure 3 and Table S2,
Supporting Information.
ime. The hydroxymethylen groups are coordinated to
dysprosium(III) ions but are not deprotonated.
The three dysprosium(III) ions are eight coordinated by
oxygen atoms: two come from the phenoxo groups; two from
the oximato groups; two from the hydroxymethylen groups and
two from water molecules.
The six copper(II) ions (Cu1) from the two {Cu3} fragments
are in a square pyramid environment made up by one nitrogen
and one oxygen atom from the oximato group, one phenoxo
The temperature dependence of the χT product for [La3Cu8]
(1) and [Lu3Cu8] (11) under an applied magnetic field of 0.1 T
is shown in Figure 4. Both compounds give similar evolution of
magnetic susceptibility as a function of temperature. At 300 K,
the χT product is 2.24 and 2.03 cm3 K mol−1 for 1 and 11,
respectively, which is lower than the expected value of 3.00 cm3
K mol−1 for eight noninteracting CuII ions (S = 1/2) with g = 2.
Upon cooling, the χT product continuously decreases down to
90 K (χT =1.69 for 1 and 1.66 cm3 K mol−1 for 11) then it
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Figure 3. χT versus T plots data (a,b) and magnetization curves (c,d) for 2−5, 7−10, and 12.
Hamiltonian describing the isotropic exchange interactions
(Figure 5) can be written as
H = −2J (S1S2 + S1S3 + S1S4) − 2Jb(S2S3 + S3S4 + S2S4)
a
− 2J (S5S6 + S5S7 + S5S8) − 2Jb(S6S7 + S7S8 + S6S8)
a
(1)
Figure 4. χT versus T plots data for [La3Cu8] (1) and [Lu3Cu8] (11).
The black solid lines correspond to the simulation according the
Hamiltonian (eq 1) with parameters described in the text.
Figure 5. Spin topology for clusters [La3Cu8] (1) and [Lu3Cu8](11)
(left) and [Gd3Cu8] (6) (right).
increases to reach the maximal value of 1.79 and 1.73 cm3 K
mol−1 at 20 K for 1 and 11, respectively. Below 20 K, the χT
sharply decreases with temperature and reaches the values of
1.27 and 1.14 cm3 K mol−1 for 1 and 11, respectively, at 2 K.
(Figure 4). This behavior suggests the presence of both
ferromagnetic and antiferromagnetic interactions in 1 and 11.
To understand the magnetic interactions in 1 and 11, we
simulated the temperature dependence of the magnetic
susceptibility. Taking into account the structural parameters
and that 1 and 11 are isostructural, the general spin-
Ja corresponds to the magnetic interaction between the apical
copper(II) ion (Cu2) and each of the three copper(II) ions
(Cu1, Cu1′, Cu1″) of the {Cu3} fragment (Figures 1 and 5). Jb
holds for the magnetic interaction among the three Cu(II)
within the {Cu3} fragments and should be related to the
CuONCu dihedral angle (β) (Figure S3, Supporting
Information). In order to minimize over parametrization and
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considering the 3-fold axis and the symmetry plane on which lie
the molecule, we use only these two constants (Ja and Jb) to
describe the magnetic interactions. We are aware of frustration
phenomena in trinuclear {Cu3} fragments,87,88 as well as in the
tetranuclear68,73,74 units, and our model is oversimplified. The
constants given below are intended to have an estimation of the
strength of interactions between the copper(II) ions within the
{Cu3} trinuclear fragments (Jb) and with apical copper(II) (Ja).
Similar simplifications were previously used.89−92 The best
agreement between the experimental and theoretical data79 was
obtained with parameters Ja(CuCu) = +7.0 cm−1, Jb(CuCu) =
−111.0 cm−1, zJ′ = −0.34 cm−1, and g = 2.08 for [La3Cu8] (1)
and Ja(CuCu) = +9.0 cm−1, Jb(CuCu) = −130.0 cm−1, zJ′ =
−0.38 cm−1, and g = 2.05 for [Lu3Cu8] (11). The relatively
high values of intermolecular terms (zJ′) are well evidenced in
the low temperature range 2−10 K. These can be ascribed to
magnetic interactions between the two tetrahedral Cu4 clusters
occurring through the noninnocent diamagnetic ions as has
been suggested elsewhere11,93−96 or to interactions operating
via the π−π stacking89,92,97 that is evidenced in the structures of
1 and 11. The strong antiferromagnetic interaction (Jb) within
the {Cu3} fragments found for 1 and 11, which may operate
through the oximato groups and oxo oxygen atom, is consistent
with previously reported examples of clusters with similar
bridging mode.7 The ferromagnetic interaction (Ja) between
apical Cu2 ion and {Cu3} oxime fragment is also consistent
with previous findings in [Cu4OCl6L] complexes.68,74,98 It has
been shown that magnetic interaction in such complexes is
sensitive to small modifications of geometrical parameters in μ4-
O and μ2-Cl bridging ligands68,74,98 and affected by strong
Jahn−Teller effect75 characteristic for CuII ions (d9).
range 300−70 K suggests the presence of antiferromagnetic
interactions within the [Gd3Cu8] core, while the increase below
60 K suggests the presence of a ferromagnetic exchange
interaction.
The magnetic interaction in [Gd3Cu8] (6) can be described
by Hamiltonian (see Figure 5 for spin topology):
H = −2J (S1S2 + S1S3 + S1S4) − 2Jb(S2S3 + S3S4 + S2S4)
a
− 2J (S5S6 + S5S7 + S5S8) − 2Jb(S6S7 + S7S8 + S6S8)
a
− 2J (S2S9 + S8S9 + S4S10 + S6S10 + S3S11 + S7S11)
c
(2)
In comparison with compounds 1 and 11, the Jc exchange
parameter was added to take into account the magnetic
interaction between the gadolinium(III) ions and the copper-
(II) ions within the {Cu3} fragment of the [Gd3Cu8] (6)
cluster. As evident from the crystal structure, the molecular
structure of 6 is similar to all other [Ln3Cu8] clusters
investigated in this work. According to structural data, the
bond lengths and angles for [Gd3Cu8] are close and between
those found for the lanthanum (1) and lutetium (11) analogue
compounds. To simulate the magnetic susceptibility for 6, we
took the values Ja and Jb obtained from the magnetic analysis of
1 and 11 as limits for those in 6 (+7.0 ≤ Ja ≤ +9.0 cm−1
;
−130.0 ≤ Jb ≤ −110.0 cm−1).
Assuming that magnetic interaction between 3d and 4f metal
centers are approximately 1 order of magnitude lower than 3d−
3d interactions and using medium values of magnetic
interactions for Ja and Jb obtained from [La3Cu8] (1) and
[Lu3Cu8] (11), the best agreement between experimental and
theoretical values of magnetic susceptibility (Figure 6) was
obtained considering a ferromagnetic interaction between
gadolinium(III) ions and the copper(II) ions Jc(CuGd) =
+1.4 cm−1 with Ja(CuCu) = +9.0 cm−1 and Jb(CuCu) = −130.0
cm−1 with g = 2.0. The value Jc found for the CuGd interaction
is lower than the one that may be calculated via two phenoxo
bridges as a function of angle between planes OCuO and
OLnO (α) (Figure S4, Supporting Information) from reported
magnetostructural correlations.24−26,66,67 One explanation is
that in compound 6 one phenoxo bridge is replaced by an
oximate bridge, which could give an antiferromagnetic
contribution to the overall interaction. The values obtained
for the exchange parameters from the simulation of the
temperature dependence of magnetic susceptibility (0.1 T) for
6 were used to simulate the magnetization curves (0−5.0 T; g =
2.0) using the same Hamiltonian (eq 2) (Figure 5). This gave a
good agreement between experimental and theoretical data,
which suggests the reliability of Ja Jb, and Jc values estimated
from our magnetic analysis of 1, 6, and 11. For 6, a very small
constant zJ′ = −0.003 cm−1 was found for intermolecular
interaction. This small value is consistent with the crystal
packing of compounds 1−12 that results in well isolated
[Ln3Cu8] molecules. This has not to be compared with those
found for 1 and 11 where the intermolecular term in our model
takes also into account the “intramolecular” interaction
between the two {Cu4} moieties via three diamagnetic
lanthanides La and Lu (vide infra).
The temperature dependence of the χT product for the
[Gd3Cu8] compound 6 decreases upon cooling from 26.07 cm3
K mol−1 at 300 K down to 25.36 cm3 K mol−1 at 65 K. Then it
increases up to the maximum value 26.21 cm3 K mol−1 at 13 K
(Figure 6) and finally sharply falls to reach the value of 13.52
cm3 K mol−1 at 2 K. The value at 300 K is slightly lower than
the expected value for eight noninteracting CuII (S = 1/2) and
three GdIII (S = 7/2) ions (3.0 + 23.625 = 26.625 cm3 K mol−1)
with g = 2. The decrease of the χT product in the temperature
[Gd3Cu8] (6) and [Tb3Cu8] (7) show the signature (Figure
3) of Cu/Ln ferromagnetic interaction that is not observed with
the other lanthanides (2−5, 8−10, 12). All compounds are
strongly affected by dominant antiferromagnetic exchange
Figure 6. χT versus T plots data for [Gd3Cu8] (6). Insert shows
magnetization curves for [Gd3Cu8] (6) at 2 and 5 K. The black solid
lines correspond to the simulation according the Hamiltonian (eq 2)
with parameters described in the text.
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interactions in the Cu4OCl3 core and spin orbital components
of anisotropic lanthanides.
application of a small dc field in the range 0.01−0.2 T does not
change the ac signal profile, suggesting that the slow magnetic
relaxation (at 2 K) is not influenced by tunnelling effects. The
presence of a slow magnetic relaxation in the [Dy3Cu8] (8)
compound suggests a single-molecule magnet (SMM) behav-
ior.8,10,32,45−57,92−97
The ac susceptibility has been measured at zero and 0.1 T dc
fields for all compounds, and only in the case of [Dy3Cu8]
complex, the frequency dependence of slow magnetic relaxation
was detected (Figure 7). In the case of the strongly anisotropic
[Tb3Cu8] (7) compound with an evident ferromagnetic
interaction at low temperature, we did not detect any ac signal.
CONCLUSION
■
An original series of hendecanuclear heterometallic clusters
based on the 3-hydroxymethylen-5-methylsalicylaldoxime
(H3L) with general formula [LnIII3CuII8(HL)6(μ4-
O)2Cl6(H2O)8]Cl3 (1−12) where Ln = La (1), Ce (2), Pr
(3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10),
Lu (11), and Ho (12) have been synthesized. According to
single-crystal X-ray investigations, the complexes are isomor-
phous and crystallize in the trigonal R32 group. The
hendecanuclear cluster is formed by two tetrahedral μ4-oxo
Cu4 clusters connected by three lanthanide ions. Along the
family, the separation between the {Cu4} moieties increases
linearly from Lu to La. Comparative analysis of magnetic data
shows the presence of ferromagnetic (Ja) and antiferromagnetic
(Jb) interactions within the μ4-oxo Cu4 clusters (Figure 4). In
the case of diamagnetic ions, La(1) and Lu(11), our analysis
suggested long-distance antiferromagnetic intramolecular inter-
actions. For the isotropic gadolinium and anisotropic terbium
compounds, [Gd3Cu8] (6) and [Tb3Cu8] (7), the magnetic
studies evidence ferromagnetic interactions (Jc) between the
lanthanide ions and the copper ions. Only the [Dy3Cu8] (8)
compound exhibits SMM behavior as suggested from the
temperature dependence and frequency sweeping of out of
phase susceptibility that shows strong frequency dependence.
ASSOCIATED CONTENT
* Supporting Information
■
S
Crystallographic refinement details and magnetic results for 1−
12. This material is available free of charge via the Internet at
http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: ghenadie.novitchi@lncmi.cnrs.fr, dominique.luneau@
univ-lyon1.fr.
■
Figure 7. Frequency dependence (top) and temperature dependence
(bottom) of the out-of-phase (χ″) ac susceptibility component for
[Dy3Cu8] (8).
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The [Dy3Cu8] (8) compound shows slow magnetic
relaxation (Figure 7) and merits to be additionally mentioned.
The product of χT for compound [Dy3Cu8] (8) at H = 0.1 T
decreases from 44.51 cm3 K mol−1 at room temperature to
23.39 cm3 K mol−1 at 2.0 K (Figure S6, Supporting
Information). The value at room temperature is close to the
expected value of 45.51 cm3 K mol−1 for three DyIII (6H15/2, L =
5, g = 4/3) and eight CuII (S = 1/2, g = 2.0) ions.99,100 The
experimental value for the field dependence of magnetization at
2 K for 8 is typical and indicates the presence of anisotropy in
compound 8 (Figure 3). The ac magnetic susceptibility
measurements for compound 8 were performed in a 1.8−4 K
range using a 2.7 G ac field oscillation in a 1−1400 Hz
frequency range (Figure 7). The temperature dependence and
frequency sweeping of out of phase susceptibility shows strong
frequency dependence without maxima as a result of either a
low energy barrier of magnetic relaxation or tunnelling. The
O.I. thanks the “French Ministry of Education” for a Ph.D.
grant. G.N. thanks the Marie Curie Actions (FP7-People-IIF)
for financial support. The Diffraction center Henri Long-
chambon at Universite Claude Bernard Lyon 1 is acknowledged
́
for X-ray diffraction measurements.
REFERENCES
■
(1) Sessoli, R.; Powell, A. K. Coord. Chem. Rev. 2009, 253, 2328−
2341.
(2) Winpenny, R. E. P. Chem. Soc. Rev. 1998, 27, 447−452.
(3) Andruh, M.; Costes, J. P.; Diaz, C.; Gao, S. Inorg. Chem. 2009, 48,
3342−3359.
(4) Andruh, M. Chem. Commun. 2011, 47, 3025−3042.
(5) Timco, G. A.; Faust, T. B.; Tuna, F.; Winpenny, R. E. P. Chem.
Soc. Rev. 2011, 40, 3067−3075.
(6) Mezei, G.; Zaleski, C. M.; Pecoraro, V. L. Chem. Rev. 2007, 107,
4933−5003.
G
dx.doi.org/10.1021/ic4009015 | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
(7) Chaudhuri, P. Coord. Chem. Rev. 2003, 243, 143−190.
(8) Zaleski, C. M.; Depperman, E. C.; Kampf, J. W.; Kirk, M. L.;
Pecoraro, V. L. Angew. Chem., Int. Ed. 2004, 43, 3912−3914.
(9) Mishra, A.; Wernsdorfer, W.; Parsons, S.; Christou, G.; Brechin,
E. K. Chem. Commun. 2005, 2086−2088.
(10) Aronica, C.; Pilet, G.; Chastanet, G.; Wernsdorfer, W.; Jacquot,
J. F.; Luneau, D. Angew. Chem., Int. Ed. 2006, 45, 4659−4662.
(11) Aronica, C.; Chastanet, G.; Pilet, G.; Le Guennic, B.; Robert, V.;
Wernsdorfer, W.; Luneau, D. Inorg. Chem. 2007, 46, 6108−6119.
(12) Mereacre, V. M.; Ako, A. M.; Clerac, R.; Wernsdorfer, W.; Filoti,
G.; Bartolome, J.; Anson, C. E.; Powell, A. K. J. Am. Chem. Soc. 2007,
129, 9248−9249.
(13) Novitchi, G.; Wernsdorfer, W.; Chibotaru, L. F.; Costes, J. P.;
Anson, C. E.; Powell, A. K. Angew. Chem., Int. Ed. 2009, 48, 1614−
1619.
(14) Rinck, J.; Novitchi, G.; Van den Heuvel, W.; Ungur, L.; Lan, Y.
H.; Wernsdorfer, W.; Anson, C. E.; Chibotaru, L. F.; Powell, A. K.
Angew. Chem., Int. Ed. 2010, 49, 7583−7587.
(15) Iasco, O.; Novitchi, G.; Jeanneau, E.; Wernsdorfer, W.; Luneau,
D. Inorg. Chem. 2011, 50, 7373−7375.
(16) Borta, A.; Jeanneau, E.; Chumakov, Y.; Luneau, D.; Ungur, L.;
Chibotaru, L. F.; Wernsdorfer, W. New J. Chem. 2011, 35, 1270−1279.
(17) Mondal, K. C.; Sundt, A.; Lan, Y. H.; Kostakis, G. E.;
Waldmann, O.; Ungur, L.; Chibotaru, L. F.; Anson, C. E.; Powell, A. K.
Angew. Chem., Int. Ed. 2012, 51, 7550−7554.
(18) Holynska, M.; Premuzic, D.; Jeon, I. R.; Wernsdorfer, W.;
Clerac, R.; Dehnen, S. Chem.Eur. J. 2011, 17, 9605−9610.
(19) Mereacre, V.; Ako, A. M.; Clerac, R.; Wernsdorfer, W.; Hewitt,
I. J.; Anson, C. E.; Powell, A. K. Chem.Eur. J. 2008, 14, 3577−3584.
(20) Ako, A. M.; Mereacre, V.; Clerac, R.; Wernsdorfer, W.; Hewitt,
I. J.; Anson, C. E.; Powell, A. K. Chem. Commun. 2009, 544−546.
(21) Gomez, V.; Vendier, L.; Corbella, M.; Costes, J. P. Inorg. Chem.
2012, 51, 6396−6404.
(22) Cremades, E.; Gomez-Coca, S.; Aravena, D.; Alvarez, S.; Ruiz, E.
J. Am. Chem. Soc. 2012, 134, 10532−10542.
(23) Colacio, E.; Ruiz, J.; Mota, A. J.; Palacios, M. A.; Cremades, E.;
Ruiz, E.; White, F. J.; Brechin, E. K. Inorg. Chem. 2012, 51, 5857−
5868.
(37) Abbas, G.; Lan, Y.; Mereacre, V.; Wernsdorfer, W.; Clerac, R.;
Buth, G.; Sougrati, M. T.; Grandjean, F.; Long, G. J.; Anson, C. E.;
Powell, A. K. Inorg Chem 2009, 48, 9345−9355.
(38) Ferbinteanu, M.; Kajiwara, T.; Choi, K. Y.; Nojiri, H.;
Nakamoto, A.; Kojima, N.; Cimpoesu, F.; Fujimura, Y.; Takaishi, S.;
Yamashita, M. J. Am. Chem. Soc. 2006, 128, 9008−9009.
(39) Zaleski, C. M.; Kampf, J. W.; Mallah, T.; Kirk, M. L.; Pecoraro,
V. L. Inorg. Chem. 2007, 46, 1954−1956.
(40) Schray, D.; Abbas, G.; Lan, Y. H.; Mereacre, V.; Sundt, A.;
Dreiser, J.; Waldmann, O.; Kostakis, G. E.; Anson, C. E.; Powell, A. K.
Angew. Chem., Int. Ed. 2010, 49, 5185−5188.
(41) Baniodeh, A.; Lan, Y.; Novitchi, G.; Mereacre, V.; Sukhanov, A.;
Ferbinteanu, M.; Voronkova, V.; Anson, C. E.; Powell, A. K. Dalton
Trans. 2013, 42, 8926−8938.
(42) Chandrasekhar, V.; Pandian, B. M.; Vittal, J. J.; Clerac, R. Inorg.
Chem. 2009, 48, 1148−1157.
(43) Costes, J. P.; Vendier, L.; Wernsdorfer, W. Dalton Trans. 2011,
40, 1700−1706.
(44) Yamaguchi, T.; Costes, J. P.; Kishima, Y.; Kojima, M.; Sunatsuki,
Y.; Brefuel, N.; Tuchagues, J. P.; Vendier, L.; Wernsdorfer, W. Inorg.
Chem. 2010, 49, 9125−9135.
(45) Costes, J. P.; Clemente-Juan, J. M.; Dahan, F.; Dumestre, F.;
Tuchagues, J. P. Inorg. Chem. 2002, 41, 2886−2891.
(46) Chandrasekhar, V.; Pandian, B. M.; Boomishankar, R.; Steiner,
A.; Viftal, J. J.; Houri, A.; Clerac, R. Inorg. Chem. 2008, 47, 4918−4929.
(47) Dhers, S.; Sahoo, S.; Costes, J. P.; Duhayon, C.; Ramasesha, S.;
Sutter, J. P. CrystEngComm 2009, 11, 2078−2083.
(48) Sutter, J. P.; Dhers, S.; Rajamani, R.; Ramasesha, S.; Costes, J.
P.; Duhayon, C.; Vendier, L. Inorg. Chem. 2009, 48, 5820−5828.
(49) Pasatoiu, T. D.; Etienne, M.; Madalan, A. M.; Andruh, M.;
Sessoli, R. Dalton Trans. 2010, 39, 4802−4808.
(50) Yamaguchi, T.; Sunatsuki, Y.; Ishida, H.; Kojima, M.; Akashi, H.;
Re, N.; Matsumoto, N.; Pochaba, A.; Mrozinski, J. Inorg. Chem. 2008,
47, 5736−5745.
(51) Costes, J. P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg. Chem.
1997, 36, 4284−4286.
(52) Novitchi, G.; Costes, J. P.; Tuchagues, J. P.; Vendier, L.;
Wernsdorfer, W. New J. Chem. 2008, 32, 197−200.
(53) Costes, J. P.; Shova, S.; Wernsdorfer, W. Dalton Trans. 2008,
1843−1849.
(54) Costes, J. P.; Dahan, F.; Wernsdorfer, W. Inorg. Chem. 2006, 45,
5−7.
(24) Rajaraman, G.; Totti, F.; Bencini, A.; Caneschi, A.; Sessoli, R.;
Gatteschi, D. Dalton Trans. 2009, 3153−3161.
(25) Cirera, J.; Ruiz, E. C. R. Chim. 2008, 11, 1227−1234.
(26) Costes, J. P.; Dahan, F.; Nicodeme, F. Inorg. Chem. 2001, 40,
5285−5287.
(55) Osa, S.; Kido, T.; Matsumoto, N.; Re, N.; Pochaba, A.;
Mrozinski, J. J. Am. Chem. Soc. 2004, 126, 420−421.
(56) Baskar, V.; Gopal, K.; Helliwell, M.; Tuna, F.; Wernsdorfer, W.;
Winpenny, R. E. P. Dalton Trans. 2010, 39, 4747−4750.
(57) Kajiwara, T.; Takahashi, K.; Hiraizumi, T.; Takaishi, S.;
Yamashita, M. CrystEngComm 2009, 11, 2110−2116.
(58) Kajiwara, T.; Nakano, M.; Takaishi, S.; Yamashita, M. Inorg.
Chem. 2008, 47, 8604−8606.
(27) Dreiser, J.; Pedersen, K. S.; Piamonteze, C.; Rusponi, S.; Salman,
Z.; Ali, M. E.; Schau-Magnussen, M.; Thuesen, C. A.; Piligkos, S.;
Weihe, H.; Mutka, H.; Waldmann, O.; Oppeneer, P.; Bendix, J.;
Nolting, F.; Brune, H. Chem. Sci. 2012, 3, 1024−1032.
(28) Waldmann, O. Inorg. Chem. 2007, 46, 10035−10037.
(29) Birk, T.; Pedersen, K. S.; Thuesen, C. A.; Weyhermuller, T.;
̈
(59) Okazawa, A.; Nogami, T.; Nojiri, H.; Ishida, T. Chem. Mater.
2008, 20, 3110−3119.
Schau-Magnussen, M.; Piligkos, S.; Weihe, H.; Mossin, S.; Evangelisti,
M.; Bendix, J. Inorg. Chem. 2012, 51, 5435−5443.
(60) Okazawa, A.; Nogami, T.; Nojiri, H.; Ishida, T. Inorg. Chem.
2008, 47, 9763−9765.
(30) Stamatatos, T. C.; Teat, S. J.; Wernsdorfer, W.; Christou, G.
Angew. Chem., Int. Ed. 2009, 48, 521−524.
(61) Okazawa, A.; Nogami, T.; Nojiri, H.; Ishida, T. Inorg. Chem.
2009, 48, 3292−3292.
(31) Mishra, A.; Tasiopoulos, A. J.; Wernsdorfer, W.; Moushi, E. E.;
Moulton, B.; Zaworotko, M. J.; Abboud, K. A.; Christou, G. Inorg.
Chem. 2008, 47, 4832−4843.
(62) Costes, J. P.; Vendier, L.; Wernsdorfer, W. Dalton Trans. 2010,
39, 4886−4892.
(32) Bhunia, A.; Gamer, M. T.; Ungur, L.; Chibotaru, L. F.; Powell,
A. K.; Lan, Y. H.; Roesky, P. W.; Menges, F.; Riehn, C.; Niedner-
Schatteburg, G. Inorg. Chem. 2012, 51, 9589−9597.
(33) Liu, Y.; Chen, Z.; Ren, J.; Zhao, X. Q.; Cheng, P.; Zhao, B. Inorg.
Chem. 2012, 51, 7433−7435.
(34) Feltham, H. L. C.; Clerac, R.; Powell, A. K.; Brooker, S. Inorg.
Chem. 2011, 50, 4232−4234.
(35) Colacio, E.; Ruiz, J.; Lorusso, G.; Brechin, E. K.; Evangelisti, M.
Chem. Commun. 2013, 49, 3845.
(63) Gheorghe, R.; Madalan, A. M.; Costes, J. P.; Wernsdorfer, W.;
Andruh, M. Dalton Trans. 2010, 39, 4734−4736.
(64) Novitchi, G.; Pilet, G.; Ungur, L.; Moshchalkov, V. V.;
Wernsdorfer, W.; Chibotaru, L. F.; Luneau, D.; Powell, A. K. Chem.
Sci. 2012, 3, 1169−1176.
̀ ́
(65) Chandrasekhar, V.; Dey, A.; Das, S.; Rouzieres, M.; Clerac, R.
Inorg. Chem. 2013, 52, 2588−2598.
(66) Costes, J. P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg. Chem.
2000, 39, 169−173.
(36) Akhtar, M. N.; Mereacre, V.; Novitchi, G.; Tuchagues, J. P.;
Anson, C. E.; Powell, A. K. Chem.Eur. J. 2009, 15, 7278−7282.
(67) Costes, J. P.; Dahan, F.; Dupuis, A. Inorg. Chem. 2000, 39,
5994−6000.
H
dx.doi.org/10.1021/ic4009015 | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
(68) Atria, A. M.; Vega, A.; Contreras, M.; Valenzuela, J.; Spodine, E.
Inorg. Chem. 1999, 38, 5681−5685.
(69) Teipel, S.; Griesar, K.; Haase, W.; Krebs, B. Inorg. Chem. 1994,
33, 456−464.
(70) Reim, J.; Griesar, K.; Haase, W.; Krebs, B. J. Chem. Soc., Dalton
Trans. 1995, 2649−2656.
(71) Reim, J.; Werner, R.; Haase, W.; Krebs, B. Chem.Eur. J. 1998,
4, 289−298.
(72) Dickinson, R. C.; Helm, F. T.; Baker, W. A.; Black, T. D.;
Watson, W. H. Inorg. Chem. 1977, 16, 1530−1537.
(73) Jones, D. H.; Sams, J. R.; Thompson, R. C. J. Chem. Phys. 1983,
79, 3877−3887.
(74) Jones, D. H.; Sams, J. R.; Thompson, R. C. Inorg. Chem. 1983,
22, 1399−1401.
(75) Polinger, V. Z.; Chibotaru, L. F.; Bersuker, I. B. Mol. Phys. 1984,
52, 1271−1289.
(76) Carlsson, H.; Haukka, M.; Bousseksou, A.; Latour, J. M.;
Nordlander, E. Inorg. Chem. 2004, 43, 8252−8262.
(77) Pascal, P. Ann. Chim. Phys. 1910, 19, 5.
(78) Kahn, O. Molecular Magnetism; VCH Publishers, Inc.: New
York, Weinheim, Cambridge, 1993.
(79) Borras-Almenar, J. J.; Clemente-Juan, J. M.; Coronado, E.;
Tsukerblat, B. S. J. Comput. Chem. 2001, 22, 985−991.
(80) O′Connor, C. J. Prog. Inorg. Chem. 1982, 29, 203.
(81) Myers, B. E.; Berger, L.; Friedberg, S. A. J. Appl. Phys. 1969, 40,
1149−1151.
(82) Clark, R. C.; Reid, J. S. Acta Crystallogr. 1995, A51, 887−897.
(83) Cosier, J.; Glazer, A. M. J. Appl. Crystallogr. 1986, 19, 105−107.
(84) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.;
Giacovazzo, C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.;
Spagna, R. J. Appl. Crystallogr. 1999, 32, 115−119.
(85) Betteridge, P. W.; Carruthers, J. R.; Cooper, R. I.; Prout, K.;
Watkin, D. J. J. Appl. Crystallogr. 2003, 36, 1487.
(86) DIAMOND; Crystal Impact GbR, Brandeburg and Putz, Bonn,
Germany, 2000.
(87) Ferrer, S.; Lloret, F.; Pardo, E.; Clemente-Juan, J. M.; Liu-
Gonzal
(88) Ferrer, S.; Lloret, F.; Bertomeu, I.; Alzuet, G.; Borras
Granda, S.; Liu-Gonzalez, M.; Haasnoot, J. G. Inorg. Chem. 2002, 41,
5821−5830.
́
ez, M.; García-Granda, S. Inorg. Chem. 2012, 51, 985−1001.
́
, J.; García-
́
(89) Karmakar, S.; Das, O.; Ghosh, S.; Zangrando, E.; Johann, M.;
Rentschler, E.; Weyhermuller, T.; Khanra, S.; Kanti Paine, T. Dalton
Trans. 2010, 39, 10920−10927.
(90) Wenzel, M.; Forgan, R. S.; Faure, A.; Mason, K.; Tasker, P. A.;
Piligkos, S.; Brechin, E. K.; Plieger, P. G. Eur. J. Inorg. Chem. 2009,
2009, 4613−4617.
(91) Kamiyama, A.; Kajiwara, T.; Ito, T. Chem. Lett. 2002, 980−981.
(92) Maity, D.; Mukherjee, P.; Ghosh, A.; Drew, M. G. B.; Diaz, C.;
Mukhopadhyay, G. Eur. J. Inorg. Chem. 2010, 807−813.
́
(93) Costes, J.-P.; Duhayon, C.; Vendier, L.; Colacio, E.; Avila, A. J.
M.; Varela, J. S. Inorg. Chem. 2012, 51, 1011−1019.
(94) Schmidt, S.; Prodius, D.; Novitchi, G.; Mereacre, V.; Kostakis,
G. E.; Powell, A. K. Chem. Commun. 2012, 48, 9825−9827.
(95) Wang, H. L.; Liu, T.; Wang, K.; Duan, C. Y.; Jiang, J. Z. Chem.
Eur. J. 2012, 18, 7691−7694.
(96) Coronado, E.; Gimenez-Saiz, C.; Recuenco, A.; Tarazon, A.;
Romero, F. M.; Camon, A.; Luis, F. Inorg. Chem. 2011, 50, 7370−
7372.
(97) Novitchi, G.; Shova, S.; Caneschi, A.; Costes, J. P.; Gdaniec, M.;
Stanica, N. Dalton Trans. 2004, 1194−1200.
(98) Wong, H.; Tomdieck, H.; Oconnor, C. J.; Sinn, E. J. Chem. Soc.,
Dalton Trans. 1980, 786−789.
(99) Sorace, L.; Benelli, C.; Gatteschi, D. Chem. Soc. Rev. 2011, 40,
3092−3104.
(100) Benelli, C.; Gatteschi, D. Chem. Rev. 2002, 102, 2369−2387.
I
dx.doi.org/10.1021/ic4009015 | Inorg. Chem. XXXX, XXX, XXX−XXX