Preparation, crystal structures, and magnetic features for a series of dinuclear [NiIILnIII] schiff-base complexes: Evidence for slow relaxation of the magnetization for the DyIII derivative

Article abstract of DOI:10.1021/ic2004276

A series of dinuclear [Ni^IILn^III] Schiff-base complexes (using a Schiff-base dicompartmental ligand derived from o-vanillin [H₂valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]) with Ln = La, Ce, Pr, Nd, Sm, E

Full text of DOI:10.1021/ic2004276

ARTICLE
pubs.acs.org/IC
Preparation, Crystal Structures, and Magnetic Features for a Series of
Dinuclear [Ni Ln ] Schiff-Base Complexes: Evidence for Slow
II III
III
Relaxation of the Magnetization for the Dy Derivative
†
,‡,§
†
‡,§,||
Traian D. Pasatoiu, Jean-Pascal Sutter,* Augustin M. Madalan, Fatima Zohra Chiboub Fellah,
‡
,§
,†
Carine Duhayon, and Marius Andruh*
†
University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Str. Dumbrava Rosie nr. 23, 020464-Bucharest,
Romania
‡
CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse, France
§
Universit ꢀe de Toulouse, UPS, INPT, LCC, F-31077 Toulouse, France
Department of Chemistry, Faculty of Science, University Aboubaker Belkaid, BP 119, 13000 Tlemcen, Algeria
S Supporting Information
b
ABSTRACT:
II III
A series of dinuclear [Ni Ln ] Schiff-base complexes (using a Schiff-base dicompartmental ligand derived from o-vanillin [H valpn =
2
1
,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]) with Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and a hydroxo-
II III
bridged tetranuclear [Ni Yb ] are reported. The crystal structures have been solved for 10 dinuclear complexes revealing four
arrangements for the dinuclear units, which are modulated by the coordinated solvent molecules and the nitrato-anion interactions.
II
III
The magnetic behaviors have been investigated, and the nature of the Ni ꢀLn exchange interaction has been emphasized by
II III
comparison with the behavior of the related [Zn Ln ] derivatives. This allowed for establishing that the interaction within these
III
compounds is antiferromagnetic with the 4f ions of the beginning of the Ln series and turns ferromagnetic from Gd toward the end of
the series. AC susceptibility investigations clearly show the occurrence of slow relaxation processes of the magnetization close to 2 K for
II III
the dinuclear [Ni Dy ] complex.
’
INTRODUCTION
which exhibit hysteresis in the absence of long-range magnetic
order. These are the so-called single-molecule magnets (SMMs)
4
The combination of different paramagnetic metal ions within
and single-chain magnets (SCMs). Their design requires the
use of lanthanides exhibiting a high anisotropy, of which the
the same molecular entity leads to a wide variety of magnetic
1
properties of the polynuclear complexes. Among these, 3dꢀ4f
III
7
III
6
III 5
best candidates are Tb ( F ), Dy ( H15/2), and Ho ( H ).
complexes are a special case and have been intensively studied in
order to reveal the factors governing the nature and magnitude of
the exchange interaction between a 3d metal ion and various 4f
6
8
Interestingly, a compound as simple as a dinuclear [CuꢀTb]
complex was found to exhibit SMM behavior, yet at very low
5
2
temperature.
metal ions. Lanthanide ions bring large and, in some cases,
An important breakthrough in the study of 3dꢀ4f complexes
highly anisotropic magnetic moments. The interest for 3dꢀ4f
heteronuclear complexes grew rapidly after Gatteschi et al.’s
report on the ferromagnetic interaction between the adjacent
3
was realized by Costes et al., who developed a general synthetic
6
route leading to strictly dinuclear complexes. This strategy is
II
III
II
III
II
Cu and Gd ions within trinuclear Cu Gd Cu complexes.
Nowadays, we are facing a revival of the 3dꢀ4f combined chem-
Received: March 2, 2011
Published: June 02, 2011
istry that is due to the discovery of molecular nanomagnets,
r 2011 American Chemical Society
5890
dx.doi.org/10.1021/ic2004276
|Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
based upon the use of bicompartmental Schiff base ligands with a
Scheme 1. Synthetic Pathway for [Ni(valpn)(H O) ]
2 2
N O coordination site, hosting the 3d ion, and an open O O
2
2
2 2
coordination site, able to accommodate the large 4f metal ions.
The synthesis of such complexes is a stepwise process, in which
the 3d ion is first introduced before the resulting complex is used
as a ligand to coordinate the 4f ion.
II
III
The magnetic studies of polynuclear Cu Gd complexes
II
III
proved that the exchange interaction within the Cu ꢀGd pair
III
7
II
is, in most cases, ferromagnetic. The peculiarity of the Cu ꢀG-
d
coupling raised further questions concerning the nature of
III
the magnetic exchange interactions between (i) Gd and other
II
III
paramagnetic 3d metal ions, (ii) Cu and the other Ln cations,
and (iii) more generally Ln(III) ions with other spin carriers.
To address these questions, numerous 3dꢀ4f complexes, mainly
behaviors have been obtained, an evaluation of the gain that
II III
results from such arrays of exchange coupled [Ni Tb ] and
II III
7
[Ni Dy ] units was hindered by the absence of information for
dinuclear, have been synthesized and investigated. Several bime-
nþ
3þ
8
2þ
the simple bimetallic compounds. Herein, we report on the AC
tallic complexes containing M ꢀGd pairs, such as VO
ꢀ
III
3
þ 9
þ 13
2þ
3þ 10
2þ
3þ 11
3þ
3þ 12
2þ/3þ
susceptibility behaviors for [Ni(valpn)Ln(NO ) ] with Ln = Tb
Gd , Ni ꢀGd
,
Co ꢀGd
,
Cr ꢀGd
,
Fe
3 3
III
3
and Dy (valpn = 1,3-propanediyl-bis(2-iminomethylene-6-
ꢀ
Gd , were studied. Both ferro- and antiferromagnetic in-
methoxy-phenol); Scheme 1). Moreover, the rather facile
growth of crystals for the whole series of Ln ions (except
radioactive promethium) allowed for solving of the structures
for 10 complexes revealing differences only in solvent content
and/or nitrato-anion coordination. The magnetic behaviors for
all of the complexes have been investigated. The availability of
teractions have been observed; moreover, geometrical factors have
been found to influence the nature of the exchange coupling.
nþ
3þ
Although the M ꢀGd magnetic interaction was found to be
ferromagnetic in many cases, examples in which this interaction is
8,14
antiferromagnetic are known as well.
Kahn investigated the magnetic interaction in oxamato-
II
III
II III
the homologous [Zn (valpn)Ln ] derivatives (see preceding
paper in this issue) prompted us to compare the magnetic data
for the two families of compounds in order to emphasize the
bridged Cu Ln complexes by comparison with their analogues
containing a diamagnetic 3d metal ion. This led to the conclusion
II
III
II
III
II
III
II
II
II
that M ꢀGd , M ꢀTb , and M ꢀDy (M = Ni , Cu )
II
III
15,16
nature of magnetic interaction between Ni and the Ln ions
in this ligand set.
interactions are ferromagnetic.
Costes et al. observed with
II
III
Schiff-base complexes that the Cu ꢀLn interaction is anti-
III
III
III
III
III
III
ferromagnetic for Ln = Ce , Nd , Sm , Tm , and Yb and
III
III
III
III
III
III 17
ferromagnetic for Ln = Gd , Tb , Dy , Ho , and Er ,
while Okawa et al. came to the conclusion that the interaction is
antiferromagnetic for Ln = Ce , Pr , and Sm and ferro-
’
EXPERIMENTAL SECTION
III
III
III
III
General Procedures and Materials. The chemicals used, i.e.,
III
III
III
III
III
III 18
magnetic for Ln = Gd , Tb , Dy , Ho , and Er . Mohanta
3 2 3 3 2
o-vanillin, 1,3-diaminopropane, Ni(NO ) 6H O, and Ln(NO ) xH O,
3
3
II
II
et al. studied a series of heterodinuclear Cu ꢀLn complexes
as well as all of the solvents (THF, acetonitrile) were of reagent grade and
were purchased from commercial sources.
III
and stated that there is a ferromagnetic interaction for Ln =
III
III
III
III
III
III
III
III
Gd , Tb , Dy , Ho , Tm , and Yb , while for Ln = Ce ,
Synthesis of [Ni(valpn)(H
0 mmol) was added dropwise to a solution of o-vanillin (3.04 g; 20
mmol) in THF (50 mL), followed by NEt (2.79 mL, 20 mmol). After
0 min, an aqueous solution (50 mL) containing Ni(NO3)2 6H O
2 2
O) ]. 1,3-Diaminopropane (0.83 mL,
III
III
1
Nd , and Sm the magnetic exchange interaction is antiferro-
magnetic. Matsumoto et al.’s investigations of tetranuclear
1
9
3
3
complexes also showed that the magnetic interaction between
3
2
II
III
III
III
20
(2.91 g, 10 mmol) was added, and the resulting mixture was stirred for 1
Cu and Gd , Tb , and Dy ions is ferromagnetic.
The situation for other 3d metal ions is much less docu-
h, while pouring in 200 mL of H O. A pale green solid was obtained,
2
2
1
II
III
which was vacuum filtered and dried in the air (m = 2.83 g, Y = 65%).
Elemental analyses were used to characterize the starting material.
mented. The exchange interaction in the Ni ꢀLn pair has
II
III
not been studied as extensively as that of the Cu ꢀLn pair,
III
II
Synthesis of [Ni(valpn)Ln ] Complexes. Ln(NO ) xH O
3
3
3
2
because many of the Ni 3dꢀ4f complexes contained a square-
II
22
(4 mmol) in MeCN (10 mL) was added to a suspension of [Ni
(valpn)(H O) ] (0.17 g; 4.0 mmol) in MeCN (20 mL). The reaction
planar Ni ion which is diamagnetic. However, for Schiff-based
II
III
2
2
complexes, the Ni ꢀLn exchange interaction seems to follow
II
III
mixture was stirred for about 30 min. Crystals of the desired compounds
were obtained in high yields through the slow evaporation of the solvent
over a period of a few days. This technique yielded crystals suitable for
X-ray diffraction studies.
Crystallography. X-ray diffraction data for the crystals were
collected on an IPDS II STOE diffractometer (compounds 1, 3, and
the same trend as the Cu ꢀLn one, i.e., antiferromagnetic for
1
ꢀ5
7ꢀ9
23
the 4f
ions and ferromagnetic for the 4f
ions.
Besides model compounds to investigate magnetic phenom-
ena, bimetallic 3dꢀ4f Schiff-base complexes are interesting
molecular modules for the construction of supramolecular
2
4
II III
II III
systems. We have been using such [Cu Ln ] and [Ni Ln ]
4
), on a Bruker Apex2 diffractometer (compounds 2, 5, 11, and 12), on
units for the preparation of polynuclear architectures by assem-
an IPDS I STOE diffractometer (compounds 7, and 8), or on an
Xcalibur Oxford Diffraction diffractometer (compound 9), using gra-
3
ꢀ
blage with paramagnetic cyanometallate linkers (i.e., {Fe(CN) } ,
6
3ꢀ
3ꢀ 25
8
{
Mo(CN) } , {W(CN) } ). One of the aims of that approach
ꢀ
8
phite-monochromated Mo KR radiation sources (λ = 0.71073 Å).
was the construction of SMMs and SCMs by taking advantage of
Multiscan absorption corrections were applied. The structures were
solved by direct methods using SHELXS-97, SIR92, or SUPERFLIP and
refined by means of least-squares procedures using the programs of
the PC version of CRYSTALS or SHELXL-97. Atomic scattering fac-
tors were taken from the international tables for X-ray crystallog-
raphy. Hydrogen atoms were included but not refined. Drawings of
III
both the anisotropy of the Ln ions and the significant exchange
interaction that may take place between the 3d ion of the Schiff-
base complex and the cyanometallate. In this respect, the
II III
[
Ni Ln ] units appeared well suited because of the significant
V V 26
ferromagnetic exchange with Mo and W . While SMM
5
891
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
Table 1. Crystal Data and Refinement for the Compounds 1ꢀ13
compound
1
2
3
4
5
formula
C
23
H
26
N
7
O
13NiLa
C
48
H
63
N
15
O
30Ni
2
Ce
2
C
23
H
26
N
7
O
13NiPr
C
46
H
53
N
14
O
27.5Ni
2
Nd
2
25 31 8
C H N O14NiSm
ꢀ1
M (g mol
temp (K)
)
806.13
293(2)
0.71073
1727.77
180
808.13
293(2)
0.71073
1647.90
293(2)
0.71073
876.68
295
wavelength (Å)
cryst syst
space group
a (Å)
0.71073
0.71073
orthorhombic
P2
monoclinic
P2 /n
monoclinic
P2 /c
monoclinic
P2 /n
orthorhombic
Pbca
1
1
1
1 1 1
2 2
9.8448(3)
17.4207(7)
18.2862(5)
90.00
17.9538(6)
11.3152(4)
9.8353(3)
17.3914(7)
18.1987(6)
90.00
18.4138(5)
19.6726(3)
35.2354(8)
90.00
12.5639(5)
14.7667(6)
19.3364(9)
90.00
b (Å)
c (Å)
32.2403(11)
90.00
R (deg)
β (deg)
γ (deg)
91.570(2)
90.00
90.983(3)
90.00
91.811(3)
90.00
90.00
90.00
90.00
90.00
3
V (Å )
3134.97(18)
4
6548.7(4)
4
3111.33(19)
4
12763.9(5)
8
3587.4(3)
4
Z
D
c
1.708
1.752
1.725
1.711
1.623
ꢀ1
μ (mm
F(000)
)
2.017
2.028
2.225
2.273
2.217
1608
3472
1616
6552
1748
goodness of fit
refinement on
1.109
1.104
1.073
1.047
1.020
2
2
2
F
F
F
F
F
final R
I > nσ(I)]
, wR (all data)
1
, wR
2
0.0433, 0.0766
n = 2
0.0429, 0.0381
n = 3
0.0480, 0.0942
n = 2
0.0655, 0.1605
n = 2
0.0355, 0.0357
n = 3
[
R
1
2
0.0698, 0.0834
0.369, ꢀ1.140
0.0694, 0.0448
2.12, ꢀ0.83
0.0772, 0.1028
0.519, ꢀ1.790
0.0945, 0.1854
1.349, ꢀ1.336
0.0502, 0.0391
2.88, ꢀ0.71
ꢀ3
largest diff. peak and hole (eÅ
compound
)
7
8
9
11
12
formula
C
25
H
29
8
N O
13NiGd
C
23
H
36
N
7
O
18NiTb
C
23
H
36
N
7
O18NiDy
C
25
H
29
8
N O
13NiEr
38 58 8 2 2
C H N O30Ni Yb
ꢀ1
M (g mol
)
865.52
180
916.22
180
919.79
180
875.52
180
1570.40
180
temp (K)
wavelength (Å)
cryst syst
space group
a (Å)
0.71073
monoclinic
P2 /a
0.71073
monoclinic
P2 /c
0.71073
monoclinic
P2 /c
0.71073
monoclinic
P2 /c
0.71073
monoclinic
P2 /c
1
1
1
1
1
23.8100(17)
10.4107(8)
13.2080(10)
90.00
13.5488(11)
10.4531(6)
24.351(2)
90.00
13.5166(2)
10.4131(2)
24.2996(5)
90.00
13.1659(4)
10.4172(3)
23.6189(6)
90.00
11.1489(4)
17.1833(7)
15.3045(7)
90.00
b (Å)
c (Å)
R (deg)
β (deg)
γ (deg)
89.727(9)
90.00
98.710(10)
90.00
98.669(2)
90.00
91.1440(10)
90.00
108.659(2)
90.00
3
V (Å )
3273.9(4)
4
3409.0(5)
4
3381.1(1)
4
3238.73(16)
4
2777.9(2)
2
Z
D
c
1.756
1.785
1.806
1.795
1.877
ꢀ1
μ (mm
F(000)
)
2.658
2.696
2.837
3.230
4.100
1724
1840
1844
1740
1556
goodness of fit
refinement on
1.060
0.896
1.111
1.097
1.086
2
2
F
F
F
F
F
final R
I > nσ(I)]
, wR (all data)
largest diff. peak and hole (eÅ
1
, wR
2
0.0457, 0.1238
n = 2
0.0244, 0.0480
n = 2
0.0241, 0.0232
n = 3
0.0251, 0.0236
n = 3
0.0307, 0.0318
n = 2
[
R
1
2
0.0552, 0.1300
1.14 ꢀ 2.07
0.0378, 0.0501
0.66, ꢀ1.03
0.0301, 0.0244
1.13, ꢀ1.37
0.0425, 0.0323
1.07, - 0.73
0.0578, 0.0578
2.06, - 0.79
ꢀ3
)
the molecule were performed with the program Diamond 3. A summary
of the crystallographic data and the structure refinement parameters is
given in Table 1. CCDC reference numbers are as follows: 813327 (2),
Magnetic Studies. Magnetic data were obtained with a Quantum
Design MPMS-5 SQUID susceptometer. All samples consisted of
crushed crystals dispersed in grease to avoid orientation in the field.
Magnetic susceptibility measurements were performed in the 2ꢀ300 K
temperature range in a 0.1 T applied magnetic field; diamagnetic
813328 (5), 813329 (7), 813330 (8), 813331 (9), 813332 (11), 815089
(
1), 815090(3), 815091(4), and 815749(12).
5
892
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
2
7
corrections were applied by using Pascal’s constants. Isothermal
magnetization measurements were performed up to 5 T at 2 K. The
magnetic susceptibilities have been computed by exact calculations of
the energy levels associated with the spin Hamiltonian through diag-
onalization of the full matrix with a general program for axial and
Ln(NO ) . All, except the Yb derivative, are the anticipated
3
3
III
III
bimetallic [Ni(valpn)Ln(NO ) ] complexes (Ln = La ꢀEr ,
3
3
1ꢀ11), the formulas of which are completed by solvent molecules.
For Yb, a tetranuclear compound, [Ni(H O) (valpn)Yb(NO )
2
2
3
(
μ -OH)] (NO ) (12), was obtained. The structures for all of the
2 2 3 2
28
rhombic symmetries. Least-squares fittings were accomplished with an
adapted version of the function-minimization program MINUIT.
compounds have been confirmed by X-ray diffraction studies.
Crystal Structures. Six different structure types have been
identified from the crystal data for the dinuclear compounds
2
9
1
ꢀ11. The structures’ determinations revealed four different
’
RESULTS AND DISCUSSION
II III
organizations for the bimetallic moieties. They are modulated
mainly by the involvement of different solvent molecules (H O,
MeCN) and by the linkages of the NO3 anions. Below, they
A series of 13 [Ni Ln ] complexes was synthesized by the
reaction of stoichiometric amounts of [Ni(valpn)(H O) ] and
2
ꢀ
2
2
have been classified as types IꢀIV, corresponding each to a given
structure for the bimetallic unit. Type I is subdivided in three
parts to reflect the solvent molecules found in the crystal lattice.
Type I.1. [Ni(CH CN) (valpn)Ln(NO ) ]: La (1), Pr (3)
3
2
3 3
Type I.2. [Ni(CH CN) (valpn)Ln(NO ) ] CH CN 2H O:
3
2
3 3
3
3
3
2
Sm (5)
Type I.3. [Ni(CH CN) (valpn)Ln(NO ) ] CH CN: Eu
3
2
3 3
3
3
(
6), Gd (7), Er (11)
Type II. [Ni(CH CN) (valpn)Ce(NO ) (H O)][Ni(CH C
3
2
3 3
2
3
N)(H O)(valpn)Ce(NO ) (H O)] NO 2CH CN: Ce (2)
2
3 2
2
3
3
3
3 3
3
Type III. [Ni(CH CN) (valpn)Nd(NO ) ][Ni(CH CN)-
3
2
3
(
H O)(valpn)Nd(NO ) ] CH CN 0.5H O: Nd (4)
2 3 3 3 2
3
3
Type IV. [Ni(CH CN)(H O)(valpn)Ln(NO )(H O) ]
3
2
3
2
3
3
2
NO CH CN H O: Tb (8), Dy (9)
3 3 2
3
3
Compounds 1, 3, 5ꢀ7, and 11 belong to type I and possess the
same structural organization for the bimetallic unit. They differ
only by the solvent molecules found in the lattice. Compound 1
will be briefly described as representative. The geometrical
features for the other compounds are given in Tables S1 and
S2 from the Supporting Information section.
3 2
Figure 1. View of the molecular structure for [Ni(CH CN)
(
valpn)La(NO ) ], 1. Selected bond lengths (Å): Ni1ꢀN1 = 2.020(2),
3
3
Ni1ꢀN2 = 2.040(2), Ni1ꢀO2 = 2.053(2), Ni1ꢀO3 = 2.032(2) Å,
Ni1ꢀN6 = 2.120(3), Ni1ꢀN7 = 2.139(2) Å, La1ꢀO1 = 2.701(2),
La1ꢀO2 = 2.412(2), La1ꢀO3 = 2.4394(2), La1ꢀO4 = 2.645(2) Å,
La1ꢀO5 = 2.641(2), La1ꢀO6 = 2.576(2), La1ꢀO8 = 2.631(2),
La1ꢀO9 = 2.570(2), La1ꢀO11 = 2.685(2), La1ꢀO12 = 2.632(2).
The lanthanum derivative crystallizes in the P2 /n monocli-
1
nic space group and consists of neutral [Ni(CH CN) (valpn)
3
2
La(NO ) ] entities (Figure 1). The nickel ion displays an
3
3
þ
3 2 3 3 2 3 2 3 2 2 2
Figure 2. View of the molecular structure for (a) [Ni(CH CN) (valpn)Ce(NO ) (H O)] and (b) [Ni(CH CN)(H O)(valpn)Ce(NO ) (H O) ]
entities of 2. Selected bond lengths (Å): (a) Ni2ꢀN51 = 2.032(2), Ni2ꢀN52 = 2.049(2), Ni2ꢀN56 = 2.113(2), Ni2ꢀN57 = 2.150(3), Ni2ꢀO52 =
2
2
.0477(18), Ni2ꢀO53 = 2.0302(18), Ce2ꢀO12 = 2.520(2), Ce2ꢀO51 = 2.6568(17), Ce2ꢀO52 = 2.4656(17), Ce2ꢀO53 = 2.4164(18), Ce2ꢀO54 =
.6037(18), Ce2ꢀO55 = 2.610(2), Ce2ꢀO56 = 2.676(2), Ce2ꢀO58 = 2.565(2), Ce2ꢀO61 = 2.582(2), Ce2ꢀO62 = 2.644(2), Ce2ꢀO64 = 2.479(2) Å.
(
b) Ni1ꢀN1 = 2.027(2), Ni1ꢀN2 = 2.043(2), Ni1ꢀN5 = 2.116(2), Ni1ꢀO2 = 2.0382(17), Ni1ꢀO3 = 2.0263(17), Ni1ꢀO13 = 2.1329(19),
Ce1ꢀO1 = 2.6692(18), Ce1ꢀO2 = 2.4169(17), Ce1ꢀO3 = 2.4624(18), Ce1ꢀO4 = 2.6738(18), Ce1ꢀO5 = 2.625(2), Ce1ꢀO6 = 2.632(2), Ce1ꢀO8 =
2
.589(2), Ce1ꢀO9 = 2.691(2), Ce1ꢀO11 = 2.505(2) Å.
5
893
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
Figure 3. View of the molecular structure for the (a) [Ni(CH
3
CN)
2
(valpn)Nd(NO
3
)
3
] and (b) [Ni(CH
3
CN)(H
2
O)(valpn)Nd(NO
3
)
3
] molecular
units of 4. Selected bond lengths (Å): (a) Ni1ꢀN1 = 2.028(4), Ni1ꢀN2 = 2.046(4), Ni1ꢀN11 = 2.128(4), Ni1ꢀN12 = 2.163(5), Ni1ꢀO2 = 2.036(3),
Ni1ꢀO3 = 2.017(3), Nd1ꢀO1 = 2.619(3), Nd1ꢀO2 = 2.401(3), Nd1ꢀO3 = 2.397(3), Nd1ꢀO4 = 2.579(3), Nd1ꢀO5 = 2.583(4), Nd1ꢀO6 =
2
.508(5), Nd1ꢀO8 = 2.565(4), Nd1ꢀO9 = 2.644(4), Nd1ꢀO11 = 2.524(4), Nd1ꢀO12 = 2.571(4). (b) Ni2ꢀN6 = 2.018(4), Ni2ꢀN7 = 2.037(4),
Ni2ꢀN13 = 2.167(4), Ni2ꢀO15 = 2.041(3), Ni2ꢀO16 = 2.034(3), Ni2ꢀO27 = 2.120(4), Nd2ꢀO14 = 2.545(3), Nd2ꢀO15 = 2.396(3), Nd2ꢀO16 =
2
.386(3), Nd2ꢀO17 = 2.557(3), Nd2ꢀO18 = 2.592(5), Nd2ꢀO19 = 2.590(5), Nd2ꢀO21 = 2.563(4), Nd2ꢀO22 = 2.570(5), Nd2ꢀO24 = 2.604(4),
Nd2 ꢀ O25 = 2.574(4).
donor atoms of the Schiff-base ligand and two apical acetonitrile
ligands. The cerium ion is surrounded by 10 oxygen atoms
comprising two phenolato and two methoxy oxygen atoms from
the Schiff-base, four oxygen atoms arising from the two chelating
nitrato anions, the oxygen atom of one terminal nitrato ligand,
and the oxygen atom from one aqua ligand.
Within the monocationic [Ni(CH CN)(H O)(valpn)Ce
3
2
þ
(
NO ) (H O)] unit, the hexacoordinated nickel ion is sur-
3 2 2
rounded by the organic ligand in the equatorial positions and
in apical positions by one MeCN and one H O ligand. As for
2
the neutral unit, the cerium ion is 10-coordinated with the four
oxygen atoms of the Schiff-base ligand, four oxygen atoms be-
longing to two chelating nitrato anions, and by two H O ligands.
2
The third structural type is represented by the neodymium
derivative, [Ni(CH CN) (valpn)Nd(NO ) ][Ni(CH CN)(H O)-
3
2
3 3
3
2
Figure 4. View of the molecular structure for [Ni(CH CN)(H O)-
(valpn)Nd(NO ) ] CH CN 0.5H O (4) that crystallizes in
3
2
3 3 3 2
3
3
(
2
valpn)Tb(NO )(H O) ], 8. Selected bond lengths (Å): NiꢀN1 =
3
2
3
the Pbca orthorhombic space group. Two neutral dinuclear [Ni-
valpn)Ln(NO ) ] units are found in the crystal lattice, together
.030(3), NiꢀN2 = 2.021(3), NiꢀN6 = 2.114(3), NiꢀO2 = 2.025(2),
(
3
3
NiꢀO3 = 2.027(2), NiꢀO14 = 2.168(2), TbꢀO1 = 2.488(2), TbꢀO2 =
.307(2), TbꢀO3 = 2.318(2), TbꢀO4 = 2.487(2), TbꢀO5 = 2.509(2),
TbꢀO6 = 2.469(2), TbꢀO8 = 2.452(2), TbꢀO9 = 2.351(2), TbꢀO10 =
.436(2).
with solvent molecules. The complexes differ by the nature of the
ligands in apical positions of the Ni centers, i.e., two MeCN or one
2
MeCN and one H O, respectively (Figure 3).
2
2
Within the [Ni(CH CN) (valpn)Nd(NO ) ] units, the nick-
3
2
3 3
el ion shows an octahedral environment, with a N O tetragonal
octahedral environment, with a N O equatorial plane built by
2 2
2
2
base formed by the donor atoms of the organic ligand, and two
the donor atoms of the organic ligand and two apical acetonitrile
ligands. The lanthanum ion is located in the open compartment,
being surrounded by 10 oxygen atoms. Two phenolato and two
methoxy oxygen atoms arise from the Schiff base, and two oxygen
atoms arise from each of the three chelating nitrato ions.
III
apical acetonitrile ligands. The Nd ion fills the open compart-
ment, and it is coordinated by the 10 oxygen atoms from the
Schiff-base and from the three chelating nitrato anions. The
[
Ni(CH CN)(H O)(valpn)Nd(NO ) ] entity has a similar
3 2 3 3
II
Compound 2 has a type II structure and crystallizes in the P2 /c
structure but with the Ni ion coordinated by an aqua ligand
and by an acetonitrile molecule in apical positions.
1
monoclinic space group. One neutral [Ni(CH CN) (valpn)
3
2
Ce(NO ) ] complex (Figure 2a) and one monocationic [Ni
Complexes 8 and 9 belong to the type IV structures with the
general formula [Ni(CH CN)(H O)(valpn)Ln(NO )(H O) ]-
3
3
þ
(
CH CN)(H O)(valpn)Ce(NO ) (H O) ] bimetallic unit
Figure 2b) are found in the crystal lattice together with an
3 2 2 2 2 2
3
2
3
2
3
(
(NO ) (CH CN)(H O). They crystallize in the P2 /c monoclinic
3 2 3 2 1
uncoordinated nitrate ion and solvent molecules.
space group. The terbium derivative, 8, consists of a cationic [Ni-
2
þ
Within the neutral entity, the nickel ion has an octahedral
environment consisting of a N O equatorial plane formed by the
(CH CN)(H O)(valpn)Tb(NO )(H O) ] unit, two uncoor-
3 2 3 2 3
dinated nitrate anions, one H O, and one MeCN molecule (Figure 4).
2
2
2
5
894
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
2 2
Figure 5. View of the molecular structure for [Ni(H O) (valpn)Yb
(
NO
3
)(μ
2
-OH)]
2
. Selected bond lengths (Å): NiꢀN1 = 2.026(3),
NiꢀN2 = 2.029(3), NiꢀO2 = 2.026(2), NiꢀO3 = 2.0160(19), Niꢀ
O9 = 2.120(2), NiꢀO10 = 2.114(2), Yb1ꢀO1 = 2.440(2), Yb1ꢀO2 =
2
2
2
.2484(19), Yb1ꢀO3 = 2.2541(19), Yb1ꢀO4 = 2.419(2), Yb1ꢀO5 =
Figure 6. Experimental and calculated temperature dependence of
0
.159(2), Yb1ꢀO5 = 2.199(2), Yb1ꢀO6 = 2.431(3), Yb1ꢀO7 =
χ
M
T for compounds 1ꢀ6. The red line represents the calculated
0
.438(2) ( = 1 ꢀ x, ꢀy, ꢀz).
behavior for 1.
II
The Ni center has an octahedral surrounding with an acetoni-
III
trile and an aqua ligand in the apical positions. The Tb ion is
surrounded by nine oxygen atoms arising from the Schiff-base
ligand, from the chelating nitrato ion, and from three aqua ligands.
III
Surprisingly, the Yb derivative, 12, is not strictly a dinuclear
III
complex, such as those obtained with the other Ln ions, but
a dimer of hydroxo-bridged bimetallic units. This compound
crystallizes in the monoclinic space group P2 /c and consists of
1
2þ
tetranuclear [Ni(H O) (valpn)Yb(O NO)(μ -OH)]
units,
2
2
2
2
2
two uncoordinated nitrate ions, and lattice H O molecules.
2
A view of the tetranuclear aggregate is given in Figure 5.
The centrosymmetric teranuclear cationic units are con-
structed by connecting two {Ni(H O) (valpn)Yb(NO )} frag-
2
2
3
ments via two hydroxo bridges. Within each fragment the nickel
ions are hexacoordinated, the apical positions being occupied
by the aqua ligands. Each ytterbium ion is eight-coordinated by
four oxygen atoms arising from the organic ligand, the chelat-
ing nitrato, and the two hydroxo bridges. The intramolecular
Yb Yb distance is 3.549 Å.
3
3 3
Selected bond distances for compounds 1ꢀ5, 7ꢀ9, 11, and 12
Figure 7. Temperature dependence of χ T for compounds 7ꢀ12.
M
are given in the Supporting Information.
For 7, the red line corresponds to the calculated behavior (see text).
Comparison of the structures found for 1ꢀ12 shows that
whereas the coordination sphere of the Ni ions remains the same,
the surroundings of the Ln ions show some degree of change
from La to Yb. This can be ascribed to the size of the ions, which
decreases from the left to the right of the Ln series, hence the
Magnetic Properties. The molar magnetic susceptibility, χ ,
M
for compounds 1ꢀ12 has been recorded in the temperature
range 2ꢀ300 K (Figures 6 and 7). Let us start with the simple
cases of the La and Gd derivatives, 1 and 7. For these compounds,
the deviation from Curie behavior is due to the ZFS associated
2
ꢀ
tendency of replacing η -coordinated NO3 anions with steri-
II
cally less demanding H O ligands. However, it can be noticed
with Ni (for 1) and to the exchange interaction operative
2
ꢀ
II
III
that the structure with three NO3 ’s coordinated to the Ln
applies over the whole first half of the series (i.e., for 4f to 4f
ions). This surrounding was also found for the 4f ion Er,
suggesting that the ionic radii may not be the only parameter to
direct the coordination preferences.
between Ni and Gd for 7. For both compounds, these
0
7
parameters can be easily evaluated by modeling the magnetic
1
1
behaviors. The temperature dependence of χ
T for 1 is repre-
M
3
sented in Figure 6. At 300 K, the value of χ
T is 1.22 cm
II
M
ꢀ
1
mol K, in agreement with the contribution of one Ni ion. This
value remains unchanged down to ca. 30 K and decreases below
The access to the bimetallic complexes with the almost whole
II III
3
ꢀ1
series of Ln ions, and the availability of their [Zn Ln ] homo-
to reach 0.42 cm mol K at 2 K. For Gd derivative 7 (Figure 7),
the value of χ
3
ꢀ1
logues, suggested the possibility of gathering information on
T at 300 K is 9.0 cm mol K, in good agreement
M
II III
II
III
the exchange interaction operative between Ni and Ln ions
for a large set of complexes with very similar structures. There-
fore, the magnetic properties for compounds 1ꢀ12 have been
investigated.
with the contribution of noninteracting Ni and Gd centers. This
3
ꢀ1
value steadily increases as T islowered to reach 11.40 cm mol
K
II
III
at 5 K revealing a ferromagnetic Ni ꢀGd interaction. These
magnetic behaviors have been modeled (see the Experimental
5
895
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
contribution. However, rather facile access to qualitative informa-
tion on the exchange interaction is possible by simple com-
parisonofthe magneticbehaviors for the exchange coupled system
III
and for a homologous complex with Ln as the only para-
8
c,15,17,31
magnetic component.
II
The nature of the exchange interaction between Ni , in our
case, and lanthanides displaying spinꢀorbit coupling can be
emphasized by the general procedure that consists of represent-
ing the temperature dependence of the difference Δχ T =
M
χ T
ꢀ χ T
, where the intrinsic magnetic behavior
(ZnLn)
II III
M
(NiLn)
M
of the lanthanide ions, as found within the dinuclear [Zn Ln ]
complexes (see preceding paper in this issue), is subtracted from
the one measured for the [Ni Ln ] complexes. In Figures 8 and
II III
III
9
are shown the results obtained by this procedure for the Pr
III
and Er derivatives, examples for antiferromagnetic and ferro-
magnetic [Ni Ln ] interactions, respectively. The temperature
II III
dependences of χMT(NiLn), χMT(ZnLn), and Δχ T for all of the
M
Figure 8. Temperature dependence of χ T
χ T(ZnPr) (blue 9), for the [Ni Pr ] and [Zn Pr ] complexes, and
M
(black 9) and
M
(NiPr)
II III
II III
other compounds can be found in the Supporting Information.
II III
II III
the difference Δχ
M
T (red b).
The χ T for both the [Ni Pr ], 3, and [Zn Pr ] derivatives
M
steadily decreases when T is lowered. The difference, Δχ T =
M
χ T
ꢀ χ T(ZnPr), is characterized by a value that remains
M
(NiPr)
M
unchanged between 300 and 30 K and in agreement with the
contribution of solely one Ni . Below this temperature, a sharp
II
decrease of Δχ T is observed, revealing the occurrence of an
M
II
III
antiferromagnetic interaction between Ni and Pr for com-
pound 3. A related feature is found for the other paramagnetic Ln
ions of the first half of the 4f series, indicating that antiferromag-
II
III
netic interactions take place between Ni and Ln for Ln = Ce ꢀ
Sm, i.e., compounds 2ꢀ5.
For compounds 7ꢀ9, the increase exhibited by χ T at low
M
temperatures unambiguously reveals the existence of ferromag-
II
III
netic interactions between Ni and the Ln ions. Such a feature
is not found for Ho and Er derivatives 10 and 11; for these
III
III
compounds, χ T steadily decreases with T. As mentioned above,
M
such behavior does not allow for a conclusion on the exchange
interaction taking place between the metal centers. Indeed, the
intrinsic contribution of these ions might simply compensate the
1
5b
increase of χ T resulting from a ferromagnetic interaction.
Figure 9. Temperature dependence of χ
M
T
(NiEr) (black 9) and
M
II III
II III
This is exactly what occurs for 11, as shown in Figure 9. When the
contribution of the Er ion, χMT(ZnEr), is subtracted from the
χ
M
T(ZnEr) (blue 9), for the [Ni Er ] and [Zn Er ] complexes, and
III
the difference Δχ T (red b).
M
χ T
behavior of 11, the ferromagnetic interaction between
M
(NiEr)
II
III
Ni and Er is clearly revealed by the temperature dependence
of Δχ T. The same has been found for the Ho derivative 10.
ꢀ
1
III
Section), with the best fit yielding for 1 D = 8.6 cm and g = 2.21
M
ꢀ1
and, for 7, JNiGd = 2.3 cm (based on isotropic Hamiltonian
This qualitative evaluation of the exchange interactions estab-
ꢀ1
0
ꢀ1
II
III
H = ꢀJS S ), D = 7.5 cm , g = 2.0, and zJ = ꢀ0.11 cm ,
Ni
3
Gd
lished between Ni and paramagnetic Ln ions clearly
shows that antiferromagnetic interactions take place with the ions
0
where J and J are the intra- and intermolecular exchange coupling
parameters, respectively. The value of the ferromagnetic interac-
tion, JNiGd, is close to the one reported by Costes et al. for a
III
III
with less than half-filled 4f orbitals, i.e., for Ce to Sm , whereas the
interaction is ferromagnetic for the ions of the second half, from
ꢀ1
10c
III
III
dinuclear complex with a similar ligand (þ3.6 cm ). The
Gd to Er . These results are in agreement with earlier reports on
II
III
II III 23
exchange interaction between phenoxo-bridgedNi and Gd ions
was found to be ferromagnetic with several other complexes, the
[Ni Ln ] Schiff-base complexes. They also follow the trend
II III
15ꢀ20
established for related [Cu Ln ] compounds.
ꢀ
1 10,23,25
values of the J parameter spanning from ∼0.2 to ∼5 cm .
For the other complexes, the magnetic properties are more
complicated because of the intervening first-order angular
The χ T behavior for the tetranuclear compound 12 was also
M
3
investigated (Figure 7). At 300 K, the value for χ T is 7.22 cm
M
ꢀ
1
III
mol K, in agreement with the contributions of two Yb
III
3
ꢀ1
II
momentum and crystal field effect for the Ln ions. For these
(2.57 cm mol K) and two Ni ions. This value gradually
diminishes for lower temperatures with a sharp decrease below
compounds, the variation of the magnetic behavior arises from the
superpositionoftwo phenomena. One isthe result of the exchange
3
ꢀ1
20 K to reach 3 cm mol K for 2 K. Unfortunately, the
homologous tetranuclear [Zn Yb ] derivative was not available
II
III
II III
interaction between the Ni and Ln ions. The second is intrinsic
III
to the Ln ion and originates from the thermal popu-
for performing the qualitative evaluation of the exchange inter-
action between Ni and Yb .
Finally, AC susceptibility measurements have been performed
for derivatives 8, 9, and 10 in order to investigate the possible
30
II
III
lation of the so-called Stark levels. This phenomenon is modu-
lated by the crystal field and the symmetry of the compound, and
there is no easy-to-handle analytical model to account for this
5
896
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
ARTICLE
II
III
II
The AC susceptibility for the [Ni (valpn)Tb ] and [Ni (valpn)-
III
Dy ] complexes reveals that slow relaxation of their magnetiza-
tion can already be observed around 2 K for these strictly dinuclear
compounds. The holmium derivative, 10, does not show frequency
dependent in-phase and out-of-phase magnetic susceptibilities.
’
ASSOCIATED CONTENT
S
Supporting Information. Synthetic and experimental de-
b
tails, crystallographic data, and supplementary magnetic data. AC
magnetic susceptibility measurements for compound 8. This
material is available free of charge via the Internet at http://pubs.
acs.org
’
AUTHOR INFORMATION
Corresponding Author
*
E-mail: sutter@lcc-toulouse.fr, marius.andruh@dnt.ro.
0
Figure 10. Temperature dependence of the in-phase (χ ) and out-of-
M
0
0
) signals for 9, at different frequencies of the oscillating field
phase (χ
DC = 1 kOe).
M
’
ACKNOWLEDGMENT
(
H
Financial support from the CNCSIS (grant IDEI 506/2009)
and the Agence Universitaire de la Francophonie (grant to FZC)
are gratefully acknowledged.
slow relaxation of their magnetization. In the absence of an
applied field, no signal was found for the imaginary part of the
magnetic susceptibility down to 2 K. However, with an applied
’
REFERENCES
0
0
static field of HDC = 1000 Oe, the onset of a χM signal is
(1) (a) Kahn, O. Struct. Bond. (Berlin) 1987, 68, 89. (b) Kahn, O.
III
observed with the Tb derivative 8 above 2 K (Supporting
Adv. Inorg. Chem. 1995, 43, 179.
III
00
Information). For the Dy derivative 9, χM deviates from zero
(2) (a) Kahn, O. Molecular Magnetism; VCH: New York, 1993. (b)
Kahn, O.; Galy, J.; Journaux, Y. J. Am. Chem. Soc. 1982, 104, 2165. (c)
Pei, Y.; Verdaguer, M.; Kahn, O.; Sletten, J.; Renard, J.-P. J. Am. Chem.
Soc. 1986, 108, 428.
(3) Bencini, A.; Benelli, C.; Caneschi, A.; Carlin, R. L.; Dei, A.;
Gatteschi, D. J. Am. Chem. Soc. 1985, 107, 8128.
below 4 K and is frequency dependent (Figure 10). Unfortu-
0
0
nately, a maximum for the χM curves is seen above 2 K only for
the highest frequency investigated, 1490 Hz, which impeded
confirmation of a SMM-type behavior. Nevertheless, the beha-
vior observed for 9 clearly suggests that such a simple bimetallic
II
III
(4) Gatteschi, D.; Sessoli, R.; Villain, J. Molecular Nanomagnets;
Oxford University Press: New York, 2006.
[
Ni Dy ] complex may already behave as a SMM, much like
II III 5a
what has been observed for a related [Cu Tb ] derivative. It is
interesting to recall also that the SMM behavior of compound 9 is
preserved in a tetranuclear complex and in a 1-D coordination
polymer, which result by connecting dinuclear [Ni Dy ] nodes
with dicarboxylato spacers.
(5) (a) Costes, J.-P.; Dahan, F.; Wernsdorfer, W. Inorg. Chem. 2006,
45, 5. (b) Kajiwara, T.; Nakano, M.; Takaishi, S.; Yamashita, M. Inorg.
Chem. 2008, 47, 8604. (c) Costes, J.-P.; Vendier, L.; Wernsdorfer, W.
Dalton Trans. 2010, 39, 4886.
II
III
24d
(6) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg Chem .
Concluding Remarks. Bimetallic 3dꢀ4f Schiff-base com-
plexes are widely used and can be considered as rather common
species, in part due to their facile preparation. Surprisingly, these
are often involved in the construction of more complex molec-
ular architectures with limited information on the physical
properties of the bimetallic unit itself. This knowledge, however,
is particularly important when the goal is to design a system with
improved properties. In this respect, spin ground state, magnetic
anisotropy, and slow relaxation are of prime importance in
magnetic systems. For bimetallic 3dꢀ4f Schiff-base complexes,
1996, 35, 2400.
(7) (a) Bencini, A.; Benelli, C.; Caneschi, A.; Dei, A.; Gatteschi, D.
Inorg. Chem. 1986, 25, 572. (b) Benelli, C.; Caneschi, A.; Gatteschi, D.;
Guillou, O.; Pardi, L. Inorg. Chem. 1990, 29, 1750. (c) Guillou, O.;
Bergerat, P.; Kahn, O.; Bakalbassis, E.; Boubekeur, K.; Batail, P.; Guillot,
M. Inorg. Chem. 1992, 31, 110. (d) Andruh, M.; Ramade, I.; Codjovi, E.;
Guillou, O.; Kahn, O.; Trombe, J. C. J. Am. Chem. Soc. 1993, 115, 1822.
(
(
e) Ramade, I.; Kahn, O.; Jeannin, Y.; Robert, F. Inorg. Chem. 1997, 36, 930.
d) Costes, J.-P.; Dahan, F.; Dupuis, A. Inorg. Chem. 2000, 39, 5994. (e)
Sanz, J. L.; Ruiz, R.; Gleizes, A.; Lloret, F.; Faus, J.; Julve, M. Inorg. Chem.
1996, 35, 7384. (f) Benelli, C.; Gatteschi, D. Chem. Rev. 2002, 102, 2369.
III
these features will hugely vary as a function of the Ln ion. For
(8) (a) Andruh, M.; Costes, J.-P.; Diaz, C.; Gao, S. Inorg. Chem.
II III
the [Ni Ln ] derivatives investigated here, we provided a set of
2009, 48, 3342. (b) Sakamoto, M.; Manseki, K.; Okawa, H. Coord. Chem.
Rev. 2001, 219ꢀ221, 379. (c) Sutter, J.-P.; Kahn, M. L. In Magnetism:
Molecule to materials; Miller, J. S., Drillon, M., Eds.; Wiley-VCH:
Weinheim, Germany, 2005; Vol. 5, p 161.
III
magnetic properties for almost the whole Ln series, i.e., from La
III
to Er , that have allowed for an emphasis on the occurrence of
II
III
III
antiferromagnetic Ni ꢀLn interaction for the Ln ions for the
beginning of the 4f series, and ferromagnetic interactions starting
from gadolinium toward the end of the series.
(9) (a) Costes, J.-P.; Dahan, F.; Donnadieu, B.; Garcia-Tojal, J.;
Laurent, J. P. Eur. J. Inorg. Chem. 2001, 363. (b) Costes, J.-P.; Dupuis, A.;
Laurent, J. P. J. Chem. Soc., Dalton Trans. 1998, 735.
III
Most of the paramagnetic Ln ions are characterized by an
(10) (a) Brechin, E. K.; Harris, S. G.; Parsons, S.; Winpenny, R. E. P.
anisotropic moment, but the strength of this magnetic moment
J. Chem. Soc., Dalton Trans. 1997, 1665. (b) Winpenny, R. E. P. Chem. Soc.
Rev. 1998, 27, 447. (c) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J. P.
Inorg. Chem. 1997, 36, 4284. (d) Lisowski, J.; Starynowicz, P, . Inorg. Chem.
1999, 38, 1351. (e) Costes, J. P.; Vendier, L. Eur. J. Inorg. Chem. 2010, 2768.
at low temperatures varies significantly along the series. The
III
III
strongest moments are found for the Tb and Dy ions, which
make them valuable candidates for the design of nanomagnets.
5
897
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898

Inorganic Chemistry
11) (a) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J. P. C. R. Acad.
Sci., Ser. IIc: Chim. 1998, 1, 417. (b) Brayshaw, P. A.; Bunzli, J.-C. G.;
Froidevaux, P.; Harrowfield, J. M.; Kim, Y.; Sobolev, A. N. Inorg. Chem.
ARTICLE
(
Duhayon, C; Ramasesha, S.; Sutter, J.-P. CrystEngComm. 2009, 11, 2078.
(d) Sutter, J.-P.; Dhers, S.; Rajamani, R.; Ramasesha, S.; Costes, J.-P.;
Duhayon, C.; Vendier, L. Inorg. Chem. 2009, 48, 5820. (e) Gheorghe, R.;
Madalan, A. M.; Costes, J.-P.; Wernsdorfer, W.; Andruh, M. Dalton Trans.
2010, 39, 4734.
(26) Visinescu, D.; Desplanches, C.; Imaz, I.; Bahers, V.; Pradhan,
R.; Villamena, F.; Guionneau, P.; Sutter, J.-P. J. Am. Chem. Soc. 2006,
128, 10202.
1
995, 34, 2068. (c) Rigault, S.; Piguet, C.; Bernardinelli, G.; Hopfgartner,
G. J. Chem. Soc., Dalton Trans. 2000, 4587. (d) Ma, B. Q.; Gao, S.; Bai, O.;
Sun, H. L.; Xu, G. X. J. Chem. Soc., Dalton Trans. 2000, 1003. (e) Costes,
J. P.; Clemente-Juan, J. M.; Dahan, F.; Dumestre, F.; Garcia-Tojal, J.;
Tuchagues, J. P. Chem.—Eur. J. 2002, 8, 5430.
(
12) Sanada, T.; Suzuki, T.; Yoshida, T.; Kaizaki, S. Inorg. Chem.
998, 37, 4712.
13) (a) Costes, J.-P.; Dupuis, A.; Laurent, J. P. Eur. J. Inorg. Chem.
998, 1543. (b) Edder, C.; Piguet, C.; Bunzli, J.-C. G.; Hopfgartner, G.
(27) Pascal, P. Ann. Chim. Phys. 1910, 19, 5.
(28) Boudalis, A. K.; Clemente-Juan, J.-M.; Dahan, F.; Tuchagues,
J.-P. Inorg. Chem. 2004, 43, 1574.
(29) James, F.; Roos, M. Comput. Phys. Commun. 1975, 10, 343.
(30) B €u nzli, J. C. G.; Chopin, G. R. In Lanthanide Probes in Life,
Chemical, and Earth Sciences: Theory and Practice; Elsevier: Amsterdam,
1989.
1
(
1
Chem.—Eur. J. 2001, 7, 3014. (c) Costes, J. P.; Clemente-Juan, J. M.;
Dahan, F.; Dumestre, F.; Tuchagues, J. P. Inorg Chem. 2002, 41, 2886.
(14) (a) Costes, J. P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg
Chem . 2000, 39, 169. (b) Stoian, S. A.; Paraschiv, C.; Kiritsakas, N.;
Lloret, F.; Munck, E.; Bominaar, E. L.; Andruh, M. Inorg. Chem. 2010,
(31) Sutter, J.-P.; Kahn, M. L.; M €o rtl, K. P.; Ballou, R.; Porcher, P.
Polyhedron 2001, 1593.
49, 3387. (c) Costes, J. P.; Vendier, L. C. R. Chim. 2010, 13, 661. (d)
Lescop, C.; Luneau, D.; Belorisky, E.; Fries, P.; Guillot, M.; Rey, P. Inorg.
Chem. 1999, 38, 5472. (e) Caneschi, A.; Dei, A.; Gatteschi, D.; Sorace,
L.; Vostrikova, K. Angew. Chem., Int. Ed. 2000, 39, 246. (f) Figuerola, A.;
Diaz, C.; Ribas, J.; Tangoulis, V.; Granell, J.; Lloret, F.; Mahia, J.;
Maestro, M. Inorg. Chem. 2003, 42, 641.
(15) (a) Kahn, M. L.; Mathoniere, C.; Kahn, O. Inorg. Chem. 1999,
3
1
8, 3692. (b) Sutter, J.-P.; Kahn, M. L.; Kahn, O. Adv. Mater. 1999,
1, 863. (c) Kahn, M. L.; Sutter, J.-P.; Golhen, S.; Guionneau, P.;
Ouahab, L.; Kahn, O.; Chasseau, D. J. Am. Chem. Soc. 2000, 122, 3413.
16) (a) Kahn, M. L.; Lecante, P.; Verelst, M.; Mathoniere; Kahn, O.
(
Chem. Mater. 2000, 12, 3073. (b) Kahn, M. L.; Ballou, R.; Porcher, P.;
Kahn, O.; Sutter, J.-P. Chem.—Eur. J. 2002, 8, 525.
(17) (a) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg.
Chem. 1997, 36, 4284. (b) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent,
J.-P. Chem.—Eur. J. 1998, 4, 1616.
(
(
18) Shiga, T.; Ohba, M.; Ohkawa, H. Inorg. Chem. 2004, 43, 4435.
19) Koner, R.; Lin, H.-H.; Wei, H.-H.; Mohanta, S. Inorg. Chem.
2
005, 44, 3524.
20) Kido, T.; Ikuta, Y.; Sunatsuki, Y.; Ogawa, Y.; Matsumoto, N.;
Re, N. Inorg. Chem. 2003, 42, 398.
21) (a) Yamaguchi, T.; Costes, J.-P.; Kishima, Y.; Kojima, M.;
(
(
Sunatsuki, Y.; Br ꢀe fuel, N.; Tuchagues, J.-P.; Vendier, L.; Wernsdorfer,
W. Inorg. Chem. 2010, 49, 9125. (b) Costes, J.-P.; Garcia-Tojal, J.;
Tuchagues, J.-P.; Vendier, L. Eur. J. Inorg. Chem. 2009, 3801.
(
c) Chandrasekhar, V.; Pandian, B. M.; Azhakar, R.; Vittal, J. J.; Cl ꢀe rac,
R. Inorg. Chem. 2007, 46, 5140.
22) (a) Lisowski, J.; Starynowicz, P. Inorg. Chem. 1999, 38, 1351.
b) Sanada, T.; Suzuki, T.; Kaizaki, S. J. Chem. Soc., Dalton Trans.
998, 959.
23) (a) Bayly, S. R.; Xu, Z.; Patrick, B. O.; Rettig, S. J.; Pink, M.;
(
(
1
(
Thompson, R. C.; Orvig, C. Inorg. Chem. 2003, 42, 1576. (b) Barta,
C. A.; Bayly, S. R.; Read, P. W.; Patrick, B. O.; Thompson, R. C.; Orvig,
C. Inorg. Chem. 2008, 47, 2280. (c) Shiga, T.; Ito, N.; Hidaka, A.; Okawa,
H.; Kitagawa, S.; Ohba, M. Inorg. Chem. 2007, 46, 3492. (d) Yamaguchi,
T.; Sunatsuki, Y.; Ishida, H.; Kojima, M.; Akashi, H.; Re, N.; Matsumoto,
N.; Pochaba, A.; Mrozinski, J. Inorg. Chem. 2008, 47, 5736. (e)
Chandrasekhar, V.; Pandian, B. M.; Boomishankar, R.; Steiner, A.; Vittal,
J. J.; Houri, A.; Cl ꢀe rac, R. Inorg. Chem. 2008, 47, 4918. (f) Costes, J. P.;
Yamaguchi, T.; Kojima, M.; Vendier, L. Inorg. Chem. 2009, 48, 5555.
(
24) (a) Andruh, M. Pure Appl. Chem. 2005, 77, 1685. (b) Andruh,
M. Chem. Commun. 2007, 2565. (c) Andruh, M. Chem. Commun. 2011,
7, 3025. (d) Pasatoiu, T. D.; Etienne, M.; Madalan, A. M.; Andruh, M.;
4
Sessoli, R. Dalton Trans. 2010, 39, 4802. (e) Madalan, A. M.; Avarvari,
N.; Fourmigu ꢀe , M.; Cl ꢀe rac, R.; Chibotaru, L. F.; Clima, S.; Andruh, M.
Inorg. Chem. 2008, 47, 940. (f) Gheorghe, R.; Cucos, P.; Andruh, M.;
Costes, J.-P.; Donnadieu, B.; Shova, S. Chem.—Eur. J. 2006, 12, 187.
(25) (a) Sutter, J.-P.; Dhers, S.; Costes, J.-P.; Duhayon, C. C. R.
Chim. 2008, 11, 1200. (b) Visinescu, D.; Madalan, A. M.; Andruh, M.;
Duhayon, C.; Sutter, J.-P.; Ungur, L.; Van den Heuvel, W.; Chibotaru,
L. F. Chem.—Eur. J. 2009, 15, 11808. (c) Dhers, S.; Sahoo, S.; Costes, J.-P.;
5
898
dx.doi.org/10.1021/ic2004276 |Inorg. Chem. 2011, 50, 5890–5898