Cobalt complexes supported by salicylichydrazono derivative ligands and various coordination solvents

Article abstract of DOI:10.1016/j.crci.2010.02.005

We report the synthesis and molecular solid-state structures of five novel Co^II and Co^III mononuclear complexes supported by the 2-salicyloylhydrazono-1,3-dithiolane (L1) and 2-salicyloylhydrazono-1,3-dithiane (L2) ligands. Moreover,

Full text of DOI:10.1016/j.crci.2010.02.005

C. R. Chimie 13 (2010) 343–352
Contents lists available at ScienceDirect
Comptes Rendus Chimie
www.sciencedirect.com
´
Full paper/Memoire
Cobalt complexes supported by salicylichydrazono derivative ligands and
various coordination solvents
a
b
a,
*
´
Clement Toussaint , Chahrazed Beghidja , Richard Welter
a UMR CNRS 7177, laboratoire Decomet, universite´ de Strasbourg, 4, rue Blaise-Pascal, 67070 Strasbourg cedex, France
b Laboratoire de chimie mole´culaire du controˆle de l’environnement et des mesures physicochimique (LACMOM), universite´ Mentouri de Constantine,
route Ain El-bey, 25000 Constantine, Algeria
A R T I C L E I N F O
A B S T R A C T
We report the synthesis and molecular solid-state structures of five novel CoII and CoIII
Article history:
Received 1 October 2009
Accepted after revision 9 February 2010
mononuclear complexes supported by the 2-salicyloylhydrazono-1,3-dithiolane (L1) and
2-salicyloylhydrazono-1,3-dithiane (L2) ligands. Moreover, one novel diamagnetic
dinuclear CoIII complex [CoIII2(HL)4(
-O)2] supported by the ligand L1 was stabilized and
characterized. Crystal structure of the supporting ligand L2 was also determined.
m-oxo
m
Keywords:
Coordination chemistry
Cobalt complexes
Crystal structure
Hydrogen bonds
ß 2010 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved.
1. Introduction
MnIII–MnIII interaction [4]. On this basis, we have been
working on slight modifications of its organic peripheral
Control of magnetic coupling, in addition to the
possibility of inducing a spin-state modification at the
molecular scale, are among the most challenging themes in
the field of molecular magnetism. Considering a large
variety of magnetically interesting molecules [1], special
attention has been paid in our lab to exchange coupled
multinuclear transition metal paramagnetic complexes
[2–4]. Systems presenting a lower nuclearity are of interest
at least as versatile building blocks for cooperatively
associated magnetic systems [5]. Due to the dependence of
coupling pathways on the structure and symmetry of the
organic ligands, dinuclear molecular systems offer inter-
esting possibilities to tune metal-to-metal interactions by
subtle structural changes within the organic periphery.
We earlier reported on an interesting dinuclear MnIII
backbone as well as on using other metal centers. The
peculiarity of the [Mn2(HL)4( -OCH3)2] solid-state struc-
m
ture arises from an unsymmetrical arrangement of the
ligands, a feature most likely responsible for its ferromag-
netic ground state. Recent work in our lab clearly
established that the latter ferromagnetic MnIII complex
only exists in the solid state [6]. A similar observation was
made for the analogous FeIII complex supported by the
same H2L ligand) that features, as expected, an antiferro-
magnetic exchange coupling behavior [7].
In an effort to gain more insight into the structural
factors controlling and influencing the formation and the
stabilization of both mono- and/or dinuclear complexes in
the crystalline state (with possible impact on their
magnetic behavior), the original H2L ligand (named L1
in this work) was modified at specific positions (in this
complex [Mn2(HL)4(m-OCH3)2] (H2L is 2-salicyloylhydra-
zono-1,3-dithiolane) which was found to exhibit the
work the ligand 2-salicyloylhydrazono-1,3-dithiane –
largest J value (J = +19.7 cmꢀ1) reported so far for a
named L2 – was synthesized). Moreover, the chemistry
of other transition metals has been investigated system-
atically. In the present article, we report on the synthesis
and structural characterization of novel CoII and CoIII
compounds supported by these two benzoic hydrazide
ligands.
* Corresponding author.
E-mail addresses: welter@chimie.u-strasbg.fr, welter@unistra.fr
(R. Welter).
1631-0748/$ – see front matter ß 2010 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.crci.2010.02.005

344
C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
2. Results and discussion
strong hydrogen bond is detected between N1 and O1 with
the specific positions of both hydrogens bonded on N1 and
O1 clearly depicted on Fig. 1b (dashed line).
The initial task of the present work dealt with the
synthesis and characterization of benzoic hydrazide ligand
derivatives – 2-salicyloylhydrazono-1,3-dithiane (L2) –
which are related to the original ligand we used (2-
salicyloylhydrazono-1,3-dithiolane), yet are slightly mod-
ified (the five membered cycle – dithiolane, ligand L1 – is
replaced by a six member cycle – dithiane, ligand L2). Both
ligands (L1 and L2) were prepared according to literature
procedures [8–10]. During the present work, the crystal
structure of L2 has been determined from single crystal X-
ray diffraction. This result is briefly described hereafter.
2.2. Synthesis and structural characterization of CoII
complexes
We then decided to explore the chemistry of CoII
complexes with the supported ligands L1 and L2. Such
complexes are paramagnetic compounds and thus poten-
tially molecular magnets considering the polynuclear
species. Moreover, comparison could be made with the
previous MnII and FeII complexes previously obtained
during our systematic work [7,8]. The synthesis and crystal
structure of these complexes is described here.
2.1. Solid-state structures of the bidentate ligand L2
Considering the new complexes synthesized in this
present work, commercial crystalline CoCl2 was selected as
main metal source. Direct reactions were successively
carried out with L1 and L2 in different solvents (THF, DMF
and Methanol).
The general way to obtain the CoII complexes is
described in Scheme 1. Three new compounds were
obtained and characterized (see experimental section
Crystal data and refinement details are gathered in
Table 1 while selected bond lengths and angles are
included in the figure caption (Fig. 1). The ligand L2
crystallizes (colorless single crystals) in the monoclinic
P21/c space group. In the solid state, the L2 molecules are
not planar (the angle between the phenol cycle and the
average plan crossing the dithiane cycle is about 308 as
clearly shown on the Fig. 1a), which contrasts with our
previous observations in related ligands [6] (the ligand L1
for instance). This rotation starts from the C6–C7 single
bond (Fig. 1b), preventing the possible covering of both
and Table 1) following this procedure: complex
1
[CoII(L1)2(THF)2], complex 2 [CoII(L1)2(DMF)2] and com-
plex 3 [CoII(L2)2Cl2]. Their crystal structures were estab-
lished from single crystal X-ray diffraction.
delocalized
p
electrons system (phenol group and
Remark: the charge (0 or ꢀ1) of the ligands has been
clearly identified by single crystal X-ray diffraction, i.e.,
presence (charge 0) or absence (charge ꢀ1) of the
hydrogen atom on N1 (Fig. 1b) as well as significant
hydrazine group) occurring in such molecule. This
phenomenon could be a crucial parameter for metal
complex stability as well as their physical properties
(magnetic or photophysical for example). One classical
˚
˚
variation of dC—O(»1.245 A for charge 0 and »1.280 A for
Table 1
Crystal data and refinement details for L2 and complexes 1, 2 and 3ꢁCH2Cl2.
Compound
Ligand L2
Complex 1
Complex 2
Complex 3ꢁCH2Cl2
Formula
C11H12N2O2S2
268.35
C28H34CoN4O6S4
709.76
C26H32CoN6O6S4
711.75
C23H26Cl4CoN4O4S4
751.45
Formula weight
Crystal system
Crystal color
Crystal size
Space group
Monoclinic
Colorless
0.14 ꢂ 0.12 ꢂ 0.10
P 21/c
Triclinic
Orange
Monoclinic
Orange
Monoclinic
Yellow
0.14 ꢂ 0.12 ꢂ 0.10
P-1
0.14 ꢂ 0.12 ꢂ 0.10
C 2/c
0.14 ꢂ 0.12 ꢂ 0.10
P 21/c
˚
a (A)
12.4480(5)
8.3280(4)
12.0840(6)
90.00
9.4170(2)
9.7000(4)
18.1100(7)
99.3100(16)
92.216(2)
105.494(2)
1567.30(9)
2
17.0940(6)
8.6200(2)
22.4670(8)
90
9.0089(2)
11.2411(4)
15.5647(6)
90.00
˚
b (A)
˚
c (A)
a
b
g
(8)
(8)
(8)
105.880(3)
90.00
108.272(12)
90
105.083(2)
90.00
V (A3)
1204.90(10)
4
3143.6(3)
4
1521.93(9)
2
Z
Density (g.cmꢀ3
)
1.479
1.504
1.504
1.640
mu (Mo K
a
) (mmꢀ1
)
0.432
0.862
0.861
1.227
F(000)
560
738
1476
766
Temperature (K)
Theta (min – max)
Dataset [h, k, l]
173(2)
173(2)
173(2)
173(2)
2.98–30.03
1.14–30.02
1.91–34.97
2.26–27.47
ꢀ17/17, ꢀ11/10, ꢀ16/14
8755, 3500, 0.0712
3022
ꢀ13/13, ꢀ13/13, ꢀ25/25
17410, 9070, 0.0521
6319
ꢀ27/13, ꢀ13/11, ꢀ36/36
13326, 6763, 0.0505
5322
ꢀ10/11, ꢀ14/13, ꢀ19/20
13746, 3495, 0.0393
2739
Tot., Uniq. Data, R(int)
Observed data (> 2 (I))
s
Nreflections, Nparameters
R2, R1, wR2, wR1, Goof
3500, 154
9070, 399
6763, 200
3495, 196
0.0715, 0.0606, 0.1492,
0.1441, 1.112
0.001, 0.000
0.0814, 0.0472, 0.1344,
0.1169, 1.039
0.002, 0.000
0.0633, 0.0449, 0.1559,
0.1386, 1.068
0.001, 0.000
0.0639, 0.0451, 0.1407,
0.1241, 1.086
0.000, 0.000
Max. and Av. Shift/Error
ꢀ3
˚
Min, Max. Res. (e.A
)
ꢀ0.623, 0.755
ꢀ1.193, 0.473
ꢀ1.512, 1.524
ꢀ0.616, 0.853

C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
345
Fig. 1. a and b: Two perpendicular ORTEP views of the ligand L2 with full labeling scheme. The ellipsoids enclose 50% of the electronic density. Selected
˚
distances (A): C8-N2: 1.295(3); N2-N1: 1.393(3); N1-C7: 1.359(3); C7-O2: 1.221(3).
charge ꢀ1) and significant variation of dC—N(»1.345 A for
The orange complex 2
[CoII(L1)2(DMF)2] (Fig. 3)
˚
˚
charge 0 and »1.325 A for charge ꢀ1). These phenomenons
have been confirmed for more than 12 other complexes
synthesized and structurally characterized in our lab.
These results will be published shortly. These observations
indicate that the charge ꢀ1 for deprotonated ligands is
delocalized between O2 and N2 – Fig. 1b.
crystallizes in the monoclinic centrosymmetric space
group C 2/c. Here again, the crystal structure shows that
the CoII ion is surrounded by two L1 (with the charge (1)
ligands in trans configuration). In this case, the
octahedral sphere is completed by two DMF molecules.
Selected distances are given in the caption of Fig. 3.
Similar complexes have been already obtained with FeII
ion11, and also with MnII but in this last case8 a cis-
configuration is observed for both ligands and the DMF
molecules.
Several syntheses have been made, testing the reactiv-
ity of the ligand L2 with CoII salt, with various solvents.
Only one new complex was stabilized and characterized
with this ligand. The corresponding yellow complex
[complex 3ꢁCH2Cl2, CoII(L2)2(Cl)2ꢁCH2Cl2] (Fig. 4) crystal-
lizes in the monoclinic centrosymmetric space group P 21/
c. As often observed with such ligands, the crystal structure
shows that the CoII ion is surrounded by two neutral L2
ligands in trans situation. The CoII surrounding is (a
deformed octahedral with typical distances and angles –
selected distances are given in Fig. 4 caption) completed by
two Clꢀ in accordance with the charge + 2 for the metal
centre.
The orange complex 1 [CoII(L1)2(THF)2] (Fig. 2) crystal-
lizes in the triclinic centrosymmetric space group P-1. The
asymmetric unit is constituted by two almost identical
molecules of 1. Only one of them is described here (see also
the corresponding cif file for further information). The
crystal structure clearly shows that the CoII ion is
surrounded by two L1 (with the charge ꢀ1) ligands in
trans situation. The Fourier map differences (crystal
structure refinement with Shelxl97) clearly shows the
absence of hydrogen atoms on N1 (or N1a, Fig. 2),
confirming the charge (1 for the ligand). The octahedral
sphere is completed by two THF molecules, indicating the
relative lability of the chloride atoms in such CoII system.
This lability is not observed in the case of FeII species [7,11].
All distances and angles (Fig. 2 caption) are coherent with
such CoII complex. Quite similar species were observed
previously with MnII ion (complex 4b in [8]).
Scheme 1. General procedure for the synthesis of the CoII complexes. Solvents are THF, DMF or CH2Cl2. (n = 1 or 2 for L1 and L2 respectively).

346
C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
Fig. 2. ORTEP view of one molecule of the asymmetric unit of complex 1 with partial labeling scheme. The ellipsoids enclose 50% of the electronic density.
˚
Selected distances (A): Co1-O2: 1.992(1); Co1-N2: 2.133(1); Co1-O3: 2.179(1); N2-N1: 1.412(2); O2-C7: 1.277(2). Symmetry codes for equivalent
positions: a: ꢀx + 1, ꢀy + 1, ꢀz + 1.
2.3. Synthesis and structural characterization of CoIII
complexes
was driven in the presence of air, with a basic solution.
With this approach, three new complexes (two mono-
nuclear and one dinuclear) were obtained and structurally
characterized. Direct reaction of the ligands with Co(OH)3
freshly prepared (see below) is another way to synthesize
these mononuclear complexes as well as the dinuclear
compounds (with two equivalents of the ligand), as
Considering the possibility of stabilizing CoIII com-
plexes with these supporting ligands, several tests were
done. The target point was to obtain dinuclear CoIII
compounds. Firstly, the oxidation process of CoII into CoIII
˚
Fig. 3. ORTEP view of complex 2 with partial labeling scheme. The ellipsoids enclose 50% of the electronic density. Selected distances (A): Co-O2: 2.015(1);
Co-N2: 2.134(1); Co-O3: 2.174(1); N2-N1: 1.404(2); O2-C7: 1.281(2). Symmetry codes for equivalent positions: a: ꢀx + 3/2, ꢀy + 1/2, ꢀz + 1.

C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
347
Fig. 4. ORTEP view of complex 3ꢁCH2Cl2, with partial labeling scheme. The solvent molecule was removed for clarity. The ellipsoids enclose 50% of the
˚
electronic density. Selected distances (A): Co1-O1: 2.057(2); Co1-N1: 1.186(2); Co1-Cl1: 2.446(1); N2-N1: 1.384(3); O1-C7: 1.245(3). Symmetry codes for
equivalent positions: a: ꢀx + 1, ꢀy + 1, ꢀz.
described in the experimental section. The Co(OH)3
reagent was prepared following this procedure:
* The red brown complex 5ꢁCH2Cl2 [CoIII(L2)3ꢁCH2Cl2]
(Fig. 6) crystallizes in the triclinic centrosymmetric space
group P -1. The asymmetric unit contains only one isomer
of the octahedral CoIII complex supported by three L2
ligands (with ꢀ1 charge), as clearly shown in Fig. 6. All
distances are classical and very similar to those occurring
in the complex 4ꢁCH2Cl2. Selected distances are gathered in
the Fig. 6 caption. To our knowledge, it constitutes the first
example of transition metal complex supported by the 2-
salicyloylhydrazono-1,3-dithiane ligand (L2).
2CoCl2ðaqÞ þ NaOClðaqÞ þ 4NaOH þ H2O
! 2CoðOHÞ3ðsÞ þ 5NaCl
The general way to obtain the CoIII complexes is
described in Scheme 2.
Both CoIII mononuclear complexes 4ꢁCH2Cl2 and
5ꢁCH2Cl2 supported by L1 and L2 ligands respectively
were obtained as single crystals suitable for X-ray
diffraction. Their crystal structures are described hereafter.
* The red brown complex 4ꢁCH2Cl2 [CoIII(L1)3ꢁCH2Cl2]
(Fig. 5) crystallizes in the monoclinic centrosymmetric
space group P 21/a. The crystal structure clearly shows that
the CoIII ion is surrounded by three L1 (with the charge ꢀ1)
ligands inducing conformation chirality for each molecule.
As clearly demonstrated in Fig. 5 (insert), two diastereoi-
somers constitutes the asymmetric unit with a total of four
diastereoisomers in the unit cell. Selected distances are
given in the Fig. 5 caption.
Considering the results obtained with mononuclear
complexes, we tried to synthesize the
m-methoxo dinuc-
lear compounds by the way of direct synthesis of Co(OH)3
with ligands L1 and L2, respectively. Unfortunately, the
numerous tests made with methanol as reagent as well as
solvent did not give any result, probably due to the lack of
solubility of Co(OH)3 in methanol. On the other hand,
syntheses carried out in ethanol as solvent (Scheme 3)
allowed us to isolate a dinuclear complex with hydroxo
bridges, but only with the ligand L1. Curiously, with the
same synthetic procedure no reaction was observed with
the ligand L2.
Many examples of such a coordination sphere around
the CoIII metal ion were reported [12] but only one example
with hydrazine derivative ligand was already described;
however, it involves a MnIII ion [5].
The dinuclear complex 6 were obtained as single
crystals ready for X-ray diffraction by slow diffusion of
Scheme 2. The two different ways for the synthesis of the CoIII complexes.

348
C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
Fig. 5. ORTEP view of one molecule of the asymmetric unit of complex 4ꢁCH2Cl2 with partial labeling scheme. The ellipsoids enclose 50% of the electronic
˚
density. Selected distances (A): Co1-O2: 1.877(4); Co1-O4: 1.872(4); Co1-O6: 1.898(1); Co1-N2: 1.929(5); Co1-N4: 1.918(5); Co1-N6: 1.940(5). Insert: the
two diastereoisomers of the asymmetric unit.
Fig. 6. ORTEP view of complex 5ꢁCH2Cl2 with full labeling scheme. The ellipsoids enclose 50% of the electronic density. Hydrogen atoms are not represented
˚
for clarity. Selected distances (A): Co1-O2: 1.879(3); Co1-O4: 1.884(3); Co1-O6: 1.876(3); Co1-N2: 1.948(4); Co1-N4: 1.955(4); Co1-N6: 1.961(4).

C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
349
Scheme 3. Synthesis of the CoIII m-hydroxo dinuclear complex (6) supported by the ligand L1.
pentane in CH2Cl2. The corresponding crystal structure is
described hereafter.
* The black complex 6ꢁ5/2CH2Cl2 [CoIII2(L1)4(OH)2ꢁ5/
2CH2Cl2] (Fig. 7) crystallizes in the triclinic centrosym-
metric space group P -1. As clearly shown on Fig. 7, the
for both metal ions, MnIII or FeIII, supported by specific non
classical CH- interactions between the dithiolane group
and the phenol ring (see, for instance, Fig. 1 in [5]).
Moreover, each one of the octahedral sites is strongly
deformed in the asymmetric complexes, as clearly shown
in the insert of Fig. 7. In the present CoIII dinuclear complex,
p
molecular structure can be described as a ‘symmetric’
m-
hydroxo bridged dinuclear complex in which both CoIII
ions are in a slightly deformed octahedron (each one of
them constituted by four oxygen atoms and two nitrogen
atoms). The hydrogen atoms connected to the O9 and O10
oxygen atoms were found by Fourier transform, confirm-
ing that O9 and O10 are effectively hydroxy type bridges in
this dinuclear compound. All distances and angles are
classical with such a CoIII complex. The main particularity
of this new complex is the ‘symmetric’ conformation
observed: it is the first example with ligand L1. In fact,
previous works involving dinuclear complexes with this
ligand [5,7,13] always reveal a asymmetric configuration
no specific intramolecular CH-p interaction has been
detected. Only classical H-bonds occur between the OH
group of the phenol rings and the hydrazine groups
indicating the charge (1 for the four supported ligands.
2.4. Concluding remarks
In this article, we have presented the results of CoII and
CoIII chemistry with the ligands 2-salicyloylhydrazono-
1,3-dithiolane ligand (L1) and 2-salicyloylhydrazono-1,3-
dithiane (L2). Thus, six new complexes were synthesized
and structurally characterized. Both ligands considered in
Fig. 7. Left: ORTEP view of complex 6ꢁ5/2CH2Cl2 with partial labeling scheme. The ellipsoids enclose 50% of the electronic density. Arrows indicate the
˚
intramolecular hydrogen bonds. Selected distances (A) and angles (8): Co1-O4: 1.878(4); Co1-O9 1.887(4); Co1-O2 1.893(4); Co1-O10 1.920(5); Co1-N4
1.926(6); Co1-N2 1.935(5); Co1-Co2 2.8695(12); Co2-O9 1.879(4); Co2 O8 1.885(5); Co2 O6 1.889(5); Co2 N8 1.916(5); Co2 O10 1.934(4); Co2 N6 1.939(6);
Co1-O10-Co2: 96.2(2); Co2-O9-Co1: 99.3(2). Insert: cores of the dinuclear iron complex (i)13(asymmetric) and of the dinuclear cobalt complex (symmetric,
present work).

350
C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
this work have very similar behavior with regard to the
stabilization and crystal structures of the mononuclear
compounds. On the other hand, only one dinuclear CoIII
complex could be identified and structurally characterized
with the supported ligand L1. In addition, this new
Elemental analysis: anal. Calc. for C10H10N2O2S2: C,
47.23; H, 3.96; N, 11.01; Found: C, 47.40; H, 4.10; N, 11.20.
IR
1716 cmꢀ1, (C N) 1629 cmꢀ1
n
(cmꢀ1): (OH) 3018 cmꢀ1, (N–H) 2920 cmꢀ1, (C O)
.
dinuclear
m
-oxo dinuclear CoIII complex has, in contrast
3.4. Ligand L2: 2-salicyloylhydrazono-1,3-dithiane
to the closly related compounds containing manganese
and iron ions, a ‘symmetrical’ structure considering the
configuration of the two ligands around each CoIII ion.
Despite the fact that the complex is diamagnetic, this point
is very interesting for our work within the framework of
molecular magnetism. Indeed, for the strongly ferromag-
netic compound containing manganese +III ion, we have
shown that the origin of the strong ferromagnetic
interaction is related to the perpendicularity of both dz2
orbitals of the metal ion, i.e., related to the asymmetric
situation in that complex. The challenge becomes, in that
case, the possible control of the magnetic coupling by the
Yield: 65% (10.45 g).
1H NMR (300 MHz, DMSO-d6, 300K)
d/ppm: 11.75 (br s,
1H, OH), 11.40 (br s, 1H, NH), 7.96–7.93 (d, 1H, Ar), 7.42–
7.37 (t, 1H, Ar), 7–6.94 (m, 2H, Ar), 3.26–3.21(m, 2H,
SCH2CH2CH2S), 3.18–3.13(m, 2H, SCH2CH2CH2S), 2.19–
2.10 (m, 2H, SCH2CH2CH2S).
Elemental analysis: anal. calc. for C11H12N2O2S2 + H2O:
C, 46.14; H, 4.93; N, 9.78; Found: C, 46.20; H, 4.98; N, 9.75.
IR
1714 cmꢀ1, (C N) 1629 cmꢀ1
n
(cmꢀ1): (OH) 3017 cmꢀ1, (N–H) 2922 cmꢀ1, (C O)
.
3.5. General method for CoII complexes
synthesis, either of
a symmetrical complex, awaited
antiferromagnetic, or of asymmetrical complex awaited
to be ferromagnetic. We currently work in that direction
within our group.
To a solution of ligand (2 mmol) in THF, DMF or CH2Cl2
(ꢃ 35 mL), anhydrous CoCl2 (0.13 g, 1 mmol) was added.
The mixture was stirred at room temperature overnight.
The precipitate was filtered and washed with ether.
3. Experimental
3.6. Complex CoII(L1)2(THF)2
3.1. General procedures
X-ray quality crystals have been obtained by slow
diffusion of pentane in THF.
All reactions and manipulations, excepted for ligands L1
and L2, were carried out under inert atmosphere of argon
(AirLiquide, U-grade) using standard Schlenk tube techni-
ques. Solvents were dried under nitrogen prior to use:
tetrahydrofuran over sodium-benzophenone and dimethyl-
formamide over sodium hydride. Elemental C, H, N, and S
analyses were performed by the ‘Service de Microanalyses’
of Le Bel Institute and Charles Sadron Institute (ULP,
Strasbourg, France). Infrared spectra were recorded as films
on KBr disks, on a Perkin-Elmer 1600 series FTIR spectro-
meter. The1HNMRspectrawererecordedona300 MHzona
Bruker AVANCE 300 instrument.
Yield: 75% (0.42 g).
Elemental analysis: anal. calc. for C28H34CoN4O6S4: C,
47.38; H, 4.83; N, 7.89; Found: C, 47.29; H, 4.57; N, 8.02.
Mass spectroscopy (ESMS) m/z: calc: 709.07 Found:
(M + H).708.13.
IR
n .
(cmꢀ1): (OH) 3026 cmꢀ1, (C N) 1631 cmꢀ1
3.7. Complex CoII(L1)2(DMF)2
X-ray quality crystals have been obtained by slow
diffusion of pentane in DMF.
Yield: 71% (0.42 g).
3.2. Synthesis
Elemental analysis: anal. calc. for C26H32CoN6O6S4: C,
43.87; H, 4.53; N, 11.81; Found: C, 43.39; H, 4.67; N, 11.85.
Mass spectroscopy (ESMS) m/z: calc: 711.06 Found:
(M + H) 710.79.
3.2.1. General method for ligands
To a well-stirred solution of salicylhydrazide (9.13 g,
60 mmol) and NaOH (4.8 g, 120 mmol) in absolute ethanol
(150 mL) at room temperature, CS2 (4.3 mL, 72 mmol) was
added and the mixture was left under stirring overnight.
Followed by the addition of 1,2 dibromoethane (5.2 mL,
60 mmol) (L1) or 1,3 dibromopropane (6.1 mL, 60 mmol)
(L2). Stirring was continued for 8 h and the mixture was
poured into ether. The resulting white precipitate was
filtered and washed with ether. Recristallization was
performed from absolute ethanol.
IR
n .
(cmꢀ1): (OH) 3025 cmꢀ1, (C N) 1625 cmꢀ1
3.8. Complex CoII(L2)2Cl2
X-ray quality crystals have been obtained by slow
diffusion of pentane in CH2Cl2.
Yield: 67% (0.40 g).
Elemental analysis: anal. calc. for C22H24CoCl2N4O4S4:
C, 39.64; H, 3.63; N, 8.41; Found: C, 40.70; H, 3.59; N, 9.27.
Mass spectroscopy (ESMS) m/z: calc: 664.94 Found:
(M + H) 663.79.
3.3. Ligand L1: 2-salicyloylhydrazono-1,3-dithiolane
IR
n .
(cmꢀ1): (OH) 3023 cmꢀ1, (C N) 1624 cmꢀ1
Yield: 76% (11.58 g).
1H NMR (300 MHz, DMSO-d6, 300K)
d/ppm: 11.81(br s,
4. General method for CoIII complexes
1H, OH), 10.99 (br s, 1H, NH), 7.95–7.93 (d, 1H, Ar), 7.44–
7.38 (t, 1H, Ar), 7.01–6.94 (m, 2H, Ar), 3.77–3.73(m, 2H,
SCH2CH2S), 3.62–3.58 (m, 2H, SCH2CH2S).
Method 1: To a solution of ligand (3 mmol) in ethanol
(30 ml), was added anhydrous CoCl2 (0.13 g, 1 mmol). The

C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
351
mixture was stirred at room temperature overnight
followed by the addition of KOH (0.17 g, 3 mmol). The
solvent was removed under vacuum and the complex was
extracted with dichloromethane.
Method 2: A solution of ligand (3 mmol) and Co(OH)3
(0.11 g, 1 mmol) in ethanol (30 ml) was heated to 373K
(100 8C) over 6 h. The solvents were removed under
vacuum and the complex was extracted with dichlor-
omethane.
Elemental analysis: anal. Calc. for C33H33CoN6O6S6: C,
46.04; H, 3.86; N, 9.76; Found: C, 45.98; H, 3.91; N, 9.69.
Mass spectroscopy (ESMS) m/z: calc: 860.012 Found:
(M + H) 860.023.
IR
4.3. Complex CoIII2(L1)4(
solution of 2-salicyloylhydrazono-1,3-dithiolane
n
(cmꢀ1): (OH) 3036 cmꢀ1, (C N) 1640 cmꢀ1
.
m
-OH)2
A
(0.51 g, 0.2 mmol) and Co(OH)3 (0.11 g, 0.1 mmol) in
absolute ethanol (60 ml) was heated to 373K (100 8C)
over 1 h and then the solution was dry under vacuum. The
complex was extracted with dichloromethane and the
resulting solution was dry under vacuum to obtain the
complex.
4.1. Complex CoIII(L1)3
X-ray quality crystals (red brown) were obtained by
slow diffusion of pentane in CH2Cl2.
Yield: 46% (0.38 g) method 1, 70% (0.57 g) method 2.
1H NMR (300 MHz, DMSO-d6, 300K)
d
/ppm: 11.14 (br s,
X-ray quality crystals (black) have been obtained by
slow diffusion of pentane in CH2Cl2.
3H, OH), 8.14–8.02 (d, 3H, Ar), 7.35–7.26 (m, 3H, Ar), 6.97–
6.81 (m, 6H, Ar), 3.73–3.36 (m, 12H, SCH2CH2S).
Elemental analysis: anal. calc. for C30H27CoN6O6S6: C,
44.00; H, 3.32; N, 10.26; Found: C, 44.15; H, 3.35; N, 10.39.
Mass spectroscopy (ESMS) m/z: calc: 817.965 Found:
(M + H) 818.972.
Yield: 21% (0.25 g).
1H NMR (300 MHz, DMSO-d6, 300K)
d/ppm: 11.31 (br s,
4H, OH), 8.20–8.06 (m, 4H, Ar), 7.48–7.33 (m, 4H, Ar), 7.05–
6.89 (m, 8H, Ar), 3.81–3.42 (m, 16H, SCH2CH2S).
Elemental analysis: anal. calc. for C40H38Co2N8O10S8: C,
41.23; H, 3.29; N, 9.62; Found: C, 41.12; H, 3.10; N, 9.73.
Mass spectroscopy (ESMS) m/z: Calc: 1163.914; Found:
(M + Na): 1186.903.
IR
n .
(cmꢀ1): (OH) 3028 cmꢀ1, (C N) 1638 cmꢀ1
4.2. Complex CoIII(L2)3
X-ray quality crystals (red brown) were obtained by
slow diffusion of pentane in CH2Cl2.
4.4. Single crystal X-ray determination
Yield: 39% (0.34 g) method 1, 66% (0.57 g) method 2.
Single crystals of ligand L2, complexes 1, 2, 3ꢁCH2Cl2,
4ꢁCH2Cl2, 5ꢁCH2Cl2 and 6ꢁ5/2CH2Cl2 were mounted on a
1H NMR (300 MHz, DMSO-d6, 300K)
d/ppm: 11.07 (br s,
3H, OH), 8.13–8.02(d, 3H, Ar), 7.35–7.25(m, 3H, Ar), 6.96–
6.79(m, 6H, Ar), 3.21–2.02 (m, 18H, SCH2CH2CH2S).
Nonius Kappa-CCD area detector diffractometer (Mo K
˚
a
l
= 0.71073 A). The complete conditions of data collection
Table 2
Crystal data and refinement details for L2 and complexes 4ꢁCH2Cl2, 5 and 6ꢁ5/2CH2Cl2.
Compound
Complex 4ꢁCH2Cl2
Complex 5ꢁCH2Cl2
Complex 6ꢁ5/2CH2Cl2
Formula
C31H29Cl2CoN6 O6S6
903.79
C34H35Cl2CoN6O6S6
945.87
C42.5H43Cl5Co2N8O10S8
1377.44
Formula weight
Crystal system
Crystal color
Crystal size
Space group
Monoclinic
Red brown
0.20 ꢂ 0.10 ꢂ 0.10
P 21/a
Triclinic
Triclinic
Red brown
0.15 ꢂ 0.12 ꢂ 0.10
P-1
Black
0.10 ꢂ 0.10 ꢂ 0.10
P-1
˚
a (A)
17.862(5)
20.055(9)
22.136(7)
90.00
10.1690(3)
11.9820(4)
17.1820(7)
72.475(2)
88.260(2)
89.590(2)
1995.45(12)
2
14.4720(5)
14.8090(8)
15.3940(7)
61.840(2)
77.604(3)
70.858(3)
2740.7(2)
2
˚
b (A)
˚
c (A)
a
b
g
(8)
(8)
(8)
103.06
90.00
V (A3)
7725(5)
8
Z
Density (g.cmꢀ3
)
1.554
1.574
1.669
mu (Mo K
F(000)
a
) (mmꢀ1
)
0.957
0.930
1.216
3696
972
1402
Data collection
Temperature (K)
Theta (min – max)
Dataset [h, k, l]
173(2)
173(2)
173(2)
1.39–30.03
1.24–27.50
1.49–27.49
ꢀ25/24, 0/28, 0/31
69715, 22568, 0.0000
6808
ꢀ13/13, ꢀ15/15, ꢀ22/19
19381, 9140, 0.0626
6541
ꢀ18/18, ꢀ16/19, 0/19
15257, 12489, 0.0000
6491
Tot., Uniq. Data, R(int)
Observed data (> 2 (I))
s
Nreflections, Nparameters
R2, R1, wR2, wR1, Goof
22568, 937
9140, 512
12489, 675
0.2554, 0.0873, 0.2148,
0.1725, 0.841
0.001, 0.000
0.1067, 0.0746, 0.2127,
0.1869, 1.140
0.000, 0.000
0.1622, 0.0799, 0.1984,
0.1507, 0.987
0.000, 0.000
Max. and Av. Shift/Error
ꢀ3
˚
Min, Max. Res. (e.A
)
ꢀ1.046, 1.528
ꢀ0.972, 2.424
ꢀ1.306, 1.714

352
C. Toussaint et al. / C. R. Chimie 13 (2010) 343–352
(Denzo software) [14] and structure refinements are given
in Tables 1 and 2. The cell parameters were determined
from reflections taken from one set of 10 frames (1.08 steps
in phi angle), each at 20 s exposure. The structures were
solved using direct methods and refined against F2 using
the SHELXL97 software [15]. The absorption was non-
corrected.
All non-hydrogen atoms (excepted for CH2Cl2 in 6ꢁ5/
2CH2Cl2) were refined anisotropically and hydrogen atoms
were introduced as fixed contribution (SHELXL97) except
for all hydrogen atoms of the ligand L2 and for the
hydrogen atom of the hydroxyl group for all complexes
(found by Fourier differences).
nationale de la recherche (ANR contract n8 ANR-06-JCJC-
0008) for funding.
References
[1] O. Kahn, Molecular Magnetism, Wiley-VCH, New York, 1993.
[2] A. Cornia, A.C. Fabretti, L. Zobbi, A. Caneschi, D. Gatteschi, M. Mannini, R.
Sessoli, in: R. Winpenny (Ed.), Single-Molecule Magnets and Related
Phenomena Structure & Bonding Book Series, 122, Springer, Berlin,
Heidelberg, 2006, p. 133.
[3] R. Sessoli, Mol. Cryst. Liq. Cryst. 274 (1995) 145.
[4] C. Beghidja, G. Rogez, J. Kortus, M. Wesolek, R. Welter, J. Am. Chem. Soc.
128 (2006) 3140.
[5] M. Ferbinteanu, H. Miyasaka, W. Wernsdorfer, K. Nakata, K.I. Sugiura,
M. Yamashita, C. Coulon, R. Cle´rac, J. Am. Chem. Soc. 127 (2005) 3090.
´
[6] N. Bouslimani, thesis, 2008, Universite Louis Pasteur, France.
[7] N. Bouslimani, N. Cle´ment, G. Rogez, P. Turek, M. Bernard, S. Dagorne, D.
Martel, H.N. Cong, R. Welter, Inorg. Chem. 47 (2008) 7623.
[8] C. Beghidja, M. Wesolek, R. Welter, Inorg. Chim. Acta 358 (2005) 3881.
[9] M. Okimoto, T. Chiba, J. Org. Chem. 55 (1990) 1070–1076.
[10] D.Y. Luo, C.J. Wan, S.L. Deng, Y.L. Liu, D.S. Wu, Z.S. Li, Acta Academiae
Medicinae Sichuan 16 (2) (1985) 130–133.
Crystallographic data (excluding structure factors)
have been deposited in the Cambridge Crystallographic
Data Centre as Supplementary publication no. CCDC
742826 to CCDC 748332. Copies of these data can be
obtained free of charge on application to CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: (+44)1223-336-033;
e-mail: deposit@ccdc.cam.ac.uk).
´
[11] N. Bouslimani, N. Clement, C. Toussaint, S. Hameury, P. Turek, S. Choua,
S. Dagorne, D. Martel, R. Welter, Eur. J. Inorg. Chem. (2009) 3734.
[12] Yanhong Song, Zhanwei Xu, Qingjin Sun, Biyun Su, Quanchang Gao,
Huaqiang Liu, Jianshe Zhao, J. Coord. Chem. 61 (8) (2008) 1212–1220.
[13] N Bouslimani, N. Cle´ment, G. Rogez, P. Turek, S. Choua, S. Dagorne and
R. Welter, Inorganica Chemica Acta, (2010), 363, 213–220.
[14] Kappa CCD Operation Manual, Nonius B.V, Delft, The Netherlands,
1997.
Acknowledgements
We thank the CNRS and the ministe`re de la Recherche
[15] G.M. Sheldrick, SHELXL97, Program for the refinement of crystal
structures, University of Gottingen, Germany, 1997.
´
(Paris) for the PhD grant of Nicolas Clement and the Agence