276
Transition Metal Chemistry 26: 276±281, 2001.
Ó 2001 Kluwer Academic Publishers. Printed in the Netherlands.
Reactions of 2,2¢-bipyridine (bpy) and 1,10-phenanthroline (phen) with yttrium(III)
nitrate: preparation, X-ray crystal structures and spectroscopic characterization
of the bis-bpy and bis-phen complexes
Athanassios K. Boudalis, Vassilios Nastopoulos and Spyros P. Perlepes*
Department of Chemistry, University of Patras, 265 00 Patras, Greece
Catherine P. Raptopoulou and Aris Terzis
Institute of Materials Science, NCSR `Demokritos', 153 10 Aghia Paraskevi Attikis, Greece
Received 15 May 2000; accepted 19 June 2000
Abstract
Y(NO3)3 á 5H2O reacts with 2,2¢-bipyridine (bpy) and 1,10-phenanthroline (phen) to yield similar complexes of 1:2
yttrium:ligand stoichiometry. The crystal structures of the two complexes, namely, [Y(NO3)3(bpy)2] (1) and
[Y(NO3)3(phen)2] (2), are reported. The three nitrate groups are O,O¢-bidentate and the organic ligands are also
bidentate. In both structures the metal ion lies on a crystallographic two-fold axis. The stereochemistry about YIII
can be viewed as a sphenocorona. The new complexes were characterized by elemental analyses and spectroscopic
(i.r., 1H-n.m.r. and 13C-n.m.r.) techniques. The data are discussed in terms of the nature of bonding and known
solid state structures.
Introduction
The term rare earth elements is sometimes applied to the
elements La±Lu plus yttrium. The convenience of including La, which, strictly speaking, is not a lanthanide,
is obvious. The reason for including Y is that this
element has radii (atomic, metallic, ionic) that fall close
to those of Er and Ho, and all of its chemistry is in the
trivalent state [1].
In the early literature in particular, it is not
uncommon to ®nd, explicitly or implicitly, the belief
that an Y complex of a given set of ligands would be
isostructural with the corresponding late lanthanide(III)
compounds. The testing of this belief has been carried
out for only a few species and is somewhat widely
regarded as a needless waste of time and energy.
We have decided to test the above viewpoint
thoroughly, at a more detailed level, by preparing
and characterizing yttrium(III) complexes of ligands
containing O- and N-donors. The reason for this is the
increasingly high frequency of warnings concerning the
pitfalls of glibly extrapolating structurally and/or
stoichiometrically from one rare earth to the next, or
of regarding one example as typical of all, or two: one
`light' and one `heavy', as more `sophisticated'
representatives of `early' and `late' [2, 3]. Our main
objectives are to provide illuminative comparisons with
the analogous 4f complexes and to discover, if
possible, new structural types in yttrium(III) and late
* Author for correspondence
lanthanide chemistry. We herein describe some of our
®rst results along these lines, which include the
investigation of the reactions between Y(NO3)3 á 5H2O
and the chelating N,N¢-ligands 2,2¢-bipyridine (bpy)
and 1,10-phenanthroline (phen). Hitherto almost nothing has been reported about the nitrato yttrium(III)
complexes with bpy or phen; a compound with the
stoichiometry Y(NO3)3 á 2bpy appeared in the early
literature, but no spectroscopic or structural information was provided [4]. The 4f metal/NOÿ
3 /bpy [5±11] or
phen [10,12±14] chemistry has already been well
developed.
Experimental
General and physical measurements
All manipulations were performed under aerobic
conditions using solvents as received. Y(NO3)3 á 5H2O,
bpy and phen á H2O were purchased from Aldrich Co.
Elemental analyses (C, H, N) were conducted by
the University of Ioannina (Greece) Microanalytical
Laboratory using an EA 1108 Carlo Erba analyser. I.r.
spectra (4000±500 cm)1) were recorded on a PerkinElmer 16 PC FT-IR spectrometer with samples prepared
as KBr pellets and as Nujol or hexachlorobutadiene
mulls between CsI discs. 1H- and 13C-n.m.r. spectra in
CD3OD were recorded at 25 °C on an Avance DPX
spectrometer (Bruker) using 400.13 and 100.61 MHz
resonance frequencies, respectively. Chemical shifts are
quoted on the d scale and referenced w.r. to external
277
TMS or the protio impurity/methanol carbon of the
solvent used.
Table 1. Crystallographic data for complexes (1) and (2)
Compound preparation
Formula
Colour and habit
Crystal size (mm)
Crystal system
Space group
Unit cell dimensions
a (AÊ)
b (AÊ)
c (AÊ)
b (°)
V (AÊ3)
Z
Dcalcd. (g cm)3)
Radiation, k (AÊ)
Temperature (K)
Scan mode/speed (°min)1)
Scan range (°)
[Y(NO3)3(bpy)2] (1)
To a solution of Y(NO3)3 á 5H2O (0.15 g, 0.41 mmol) in
EtOH (15 cm3) was added a solution of bpy (0.14 g,
0.90 mmol) in the same solvent (20 cm3). The solution
obtained was stirred for 5 min and allowed to stand
overnight for 24 h. Well-formed, X-ray quality colourless crystals of (1) slowly appeared. These prismatic
crystals were collected by ®ltration, washed with EtOH
(5 cm3) and Et2O (2 ´ 5 cm3), and dried in air. The yield
was ca. 60% based on yttrium. (Found: C, 40.7; H, 2.8;
N, 16.4. C20 H16 YN7 O9 calcd.: C, 40.9; H, 2.7; N,
16.7%.)
[Y(NO3)3(phen)2] (2)
To a stirred solution of Y(NO3)3 á 5H2O (0.15 g,
0.41 mmol) in MeOH (40 cm3) was added a solution
of phen á H2O (0.18 g, 0.91 mmol) in MeOH (25 cm3).
The colourless solution, then obtained, rapidly precipitated a white microcrystalline powder. The reaction ¯ask was left undisturbed at room temperature
for 2 days, during which time all the powder was
transformed into colourless prismatic crystals (some of
which were suitable for di€ractometry). The crystals
were collected by ®ltration, washed with MeOH
(2 ´ 5 cm3) and Et2O (3 ´ 5 cm3), and dried in air.
Typical yields were in the 65±70% range. (Found: C,
45.7; H, 2.6; N, 15.3. C24 H16 YN7 O9 calcd.: C, 45.4;
H, 2.5; N, 15.4%.)
X-ray crystallographic studies**
Crystals of (1) and (2) were mounted in air.
Di€raction measurements were made on a Crystal
Logic Dual Goniometer di€ractometer using graphitemonochromated Mo radiation. Complete crystal data
and parameters for data collection are given in
Table 1. Unit cell dimensions were determined and
re®ned using the angular settings of 25 automatically
centred re¯ections in the range 11° < 2h < 23°.
Three standard re¯ections, monitored every 97
re¯ections, showed less than 3% intensity ¯uctuation
and no decay. Lorentz, polarization and w-scan
absorption corrections were applied using Crystal
Logic software.
The structures were solved by direct methods using
SHELXS-86 [15] and re®ned by full-matrix least-squares
techniques on F2 with SHELXL-93 [16]. For both
structures, all hydrogen atoms were located by di€erence maps and their positions re®ned isotropically. All
non-hydrogen atoms were re®ned using anisotropic
thermal parameters.
** CCDC codes : 140613 (1) and 140612 (2).
h range (°)
Re¯ections collected
Unique re¯ections (Rint)
Observed re¯ections
(I > 2r(I))
Parameters re®ned
[D/r]max
(DP)max, (DP)min (e AÊ)3)
wa
Goodness-of-®t (on F 2 )
R1b
wR2c
(1)
(2)
C20H16YN7O9
Colourless prism
0.10 ´ 0.20 ´ 0.40
Orthorhombic
Pnca
C24H16YN7O9
Colourless prism
0.10 ´ 0.30 ´ 0.40
monoclinic
C2/c
15.05(1)
16.66(1)
9.144(7)
±
2292(3)
4
1.702
MoKa (0.71073)
298
h±2h/2.5
2.3 + a1a2
separation
2.45±24.99
2015
2015 (0.0000)
1521
11.133(6)
17.850(9)
12.985(6)
100.50(2)
2537(2)
4
1.663
MoKa (0.71073)
298
h±2h/3.5
2.4 + a1a2
separation
2.18±25.00
4436
2246 (0.0448)
1905
201
0.001
+0.48, )0.35
a = 0.0000,
b = 2.5874
1.225
0.0434
0.0938
219
0.001
+0.22, )0.46
a = 0.0337,
b = 0.8891
1.078
0.0354
0.0796
a
w = 1/[r2(F2o ) + (aP)2 + bP] and P = (max(F2o , 0) + 2F2c )/3; b R1 =
S(| Fo | ) | Fc |)/S(| Fo |); c wR2 = {S[w(F2o ) F2c )2]/ S[w(F2o )2]}1/2.
Results and discussion
Synthesis and properties
The nature of the solvent and the ligand-to-YIII molar
ratio do not a€ect the identity of the products.
Complexes (1) and (2) are the only products from
the 1:1, 2:1 and 3:1 reaction mixtures in EtOH,
MeOH and MeCN. Thus, there appears to be no
synthetic evidence as yet for the isolation of any solid
Y(NO3)3/bpy or phen compounds of 1:1 and 1:3
stoichiometries. It is also of interest that the two
products have been crystallized from good donor
solvents, such as MeOH or EtOH, without the solvent
coordinating (indeed, alcohols have been employed as
a useful means of occupying some metal coordination
sites, so that any tendency toward the formation of
1:1 adducts is enhanced).
Description of structures
Selected bond distances and angles for complexes (1)
and (2) are shown in Table 2. Plots of the molecular
structures of the complexes are shown in Figures 1
and 2.
278
Table 2. Selected bond distances (AÊ) and angles (°) relevant to the
yttrium coordination sphere for [Y(NO3)3(bpy)2] (1) and [Y(NO3)3(phen)2] (2)
(1)
Bond distances
YAO(1)
YAO(2)
YAO(4)
YAN(1)
YAN(2)
Bond angles
N(1)AYAN(2)
O(1)AYAO(2)
O(4)AYAO(4)a
O(4)AYAN(1)
O(4)AYAN(2)a
O(1)AYAN(2)
O(2)AYAN(2)
O(1)AYAO(1)a
O(2)AYAO(2)a
O(1)AYAN(1)
O(1)AYAO(4)
O(2)AYAN(1)a
O(2)AYAN(2)a
2.552(4)
2.456(3)
2.444(4)
2.521(3)
2.508(4)
64.7(1)
50.8(1)
52.3(2)
82.3(1)
134.4(1)
68.3(1)
74.4(1)
169.7(1)
138.9(2)
111.2(1)
103.8(1)
122.4(1)
146.5(1)
(2)
2.514(2)
2.444(2)
2.448(2)
2.488(2)
2.547(2)
65.3(1)
51.4(1)
52.0(1)
84.3(1)
136.5(1)
69.2(1)
75.5(1)
171.9(1)
143.0(1)
113.7(1)
104.8(1)
120.4(1)
141.2(1)
Fig. 2. ORTEP view of (2) with the atom labeling scheme. Identical
numbers are used for symmetry-related atoms.
a
symmetry transformations used to generate equivalent atoms:
)x + 0.5, )y + 1, z for (1) and )x, y, )z + 0.5 for (2).
The structures of (1) and (2) are strikingly similar
and consist of isolated Y(NO3)3(L±L)2 molecules
(L±L = bpy, phen). One half of the molecule comprises the asymmetric unit of the structure in each
case, the complex molecule being disposed on a twofold crystallographic axis. The coordination sphere of
the complexes comprises ®ve bidentate ligands: two
N,N¢ chelates and three O,O¢ nitrates, the two-fold axis
passing through one of the NAO bonds of one nitrate
Fig. 1. ORTEP view of (1) with the atom labeling scheme. Identical
numbers are used for symmetry-related atoms.
group. The nitrates are classi®ed as `bidentate', not as
`anisobidentate', using the criteria of Reedijk et al. [17].
The average YAO and YAN bond distances in (1) are
2.48(1) and 2.51(1) AÊ, respectively, almost identical with
the values of 2.47(1) and 2.52(1) AÊ found for (2). The
average YAO distances are very close to the YAOnitrate
distances in [Y(NO3)3(H2O)4 ] á 2H2O [18], in which YIII
is ten-coordinate, and slightly longer than the average
YAOnitrate bond distances in nine-coordinate yttrium(III) complexes containing bidentate chelating nitrate
groups [19±21]. The average YAN bond distance in (1)
is slightly longer than the corresponding distance
[2.49(1) AÊ] in complexes containing the eight-coordinate
cation [Y(H2O)6(bpy)]3+ [22]. The average YAN distance in (2) is identical with that in the eight-coordinate
complex [YCl(H2O)3(phen)2]Cl2 á H2O [23] and shorter
than that in the eight-coordinate dinuclear species
[Y2(OH)2(H2O)4(phen)4]Cl4 á 2phen á MeOH [24]. The
NAYAN bite angles of 64.7(1) for (1) and 65.3(1)°
for (2) are typical for YIII±bpy [22] or YIII±phen [23, 24]
complexes.
Each individual pyridine ring of the bpy ligand in (1)
is planar, but rotation around the C(5)AC(6) bond gives
a small dihedral angle of 11.3°; the YIII atom is
displaced from the ring planes N(1)C(1)C(2)C(3)C(4)C(5) and N(2)C(6)C(7)C(8)C(9)C(10) by 0.84 and
0.21 AÊ, respectively. In (2) the metal ion is displaced
from the mean phen plane by 0.46 AÊ. These displacements and the non-planarity of the bpy ligand arise, at
least to some extent, from the size of the metal ion
which does not allow it to be coplanar with the organic
ligand.
Of the accessible ten-coordinate polyhedra for [M(bidentate ligand)5] systems [25, 26] (bicapped square
antiprism, sphenocorona, pentagonal antiprism, tetracapped trigonal prism), the sphenocorona (Figure 3) is
279
I.r. and n.m.r. spectra
Fig. 3. The sphenocoronal archetype; the ligand disposition with
respect to this ideal polyhedron is detailed in Table 3.
the most appropriate for (1) and (2). The ideal
sphenocorona (tetradecahedron) has 14 faces (12
triangles, 2 squares) and 4 types of vertices. Latitudes
/ and longitudes h appropriate to an n = 6 repulsion
law exponent [10, 25] are given in Table 3, together with
values derivative of the two complexes discussed in this
paper. Parts of the distortion from idealized sphenocorona arises from the decrease in the value of the
normalized bite from 1.07 to 0.87 due to the small
chelate ring of the nitrate ligands [10].
There appear to be intermolecular stacking interactions between parallel phen ligands in (2) [closest interatomic separation, C(3)áááC(12) ()x + 0.5, )y + 0.5,
)z), is 3.480 AÊ]; such interactions aid in stabilizing the
crystal structure.
Compounds (1) and (2) are isostructural with their
lanthanide(III) counterparts [Ln(NO3)3(bpy)2], where
Ln is La [6,7], Nd [11], Tb [5], Lu [10] and [Ln(NO3)3(phen)2], where Ln = La [13], Gd [12], Lu [10].
I.r. assignments of selected diagnostic bands are given in
Table 4. The cited nitrate frequencies arise from spectra
obtained as Nujol and hexachlorobutadiene mulls.
These spectra di€er from the KBr pellet spectra in the
regions of the nitrate bands, while the bpy and phen
frequencies are identical in both mull and pellet spectra.
The spectra obtained in KBr are indicative of the
simultaneous presence of ionic and coordinated nitrates
as evidenced by the appearance of a medium to strong
band at ca. 1385 cm)1 assigned [27] to the m3(E¢)
[md(NO)] mode of the D3h ionic NOÿ
3 . It is well-known
that pressing a KBr pellet a€ects the nitrate coordination and this phenomenon has fully been discussed [17].
The m(CAC) and m(CAN) bands of bpy in the 1600±
)1
1400 cm region are sensitive to chelation [28, 29]. The
1578 and 1556 cm)1 bands of free bpy shift to higher
frequencies with simultaneous splitting in (1); a higher
frequency shift is also observed for the bands at 1452
and 1414 cm)1 which appear at 1472 and 1438 cm)1 in
the spectrum of the complex. Other characteristic
vibrations of free bpy are the CAH out-of-plane
deformations which appear as a strong band at
756 cm)1 and a weak satellite at 739 cm)1; upon
chelation two strong bands at 772 and 740 cm)1 are
observed. Bands of phen in the 1630±1400 cm)1 region
attributed to ring stretching vibrations, shift to higher
frequencies upon chelation [24] in (2). Similar shifts
occur for the bands between 1250 and 1100 cm)1, while
those between 1050 and 700 cm)1 shift to lower
frequencies with splitting of the two strong bands at
ca. 850 and 740 cm)1 (out-of-plane CAH deformations).
The nitrate vibrations in the mull spectra of (1) and
(2) con®rm the presence of bidentate chelating nitrate
groups since [27] the separation of the two highest
Table 3. The sphenocoronal stereochemistry for complexes [Y(NO3)3(bpy)2] (1) and [Y(NO3)3(phen)2] (2)
Positiona
A
B
C
D
E
F
G
H
I
J
Atom in (1)
and (2)b
O(4¢)
O(4)
O(1)
O(2)
O(1¢)
O(2¢)
N(1¢)
N(1)
N(2)
N(2¢)
Normalized bite angles, b(°)c
O(4)AO(4¢)
O(1)AO(2)
N(1)AN(2)
a
Ideal sphenocorona
(1)
Polar coordinates (°)
u
h
u
h
u
h
32.7
32.7
80.3
80.3
80.3
80.3
114.6
114.6
145.3
145.3
26
26
85
69
85
69
106
106
143
143
0
180
43
93
223
273
)26
154
85
265
26
26
86
72
86
72
108
108
147
147
0
180
43
94
223
274
)23
157
84
264
1.08
1.06
1.15
0
180
57.5
122.5
237.5
302.5
0
180
90
270
1.07
0.88
0.86
1.07
(2)
0.87
0.88
0.86
1.08
0.87
see Figure 3; b primed atoms are related by the intramolecular two-fold axis; c the normalized bite angle is
de®ned in terms of the bond angle jYi subtended by the bidentate ligand as b = 2sin(jYi/2) [25].
280
Table 4. Diagnostic i.r. spectral data (cm)1) for complexes (1) and
(2)
Assignment
m(CAC), v(CAN)
m1(A1)nitrate
v5(B2)nitrate
v2(A1)nitrate
v6(B1)nitrate
c(CH)
(1)
(2)
1606sh,1598s, 1576m,
1566w, 1472s, 1438s
1518sb
1312sb
1016s
810m
772s, 740s
1628m, 1592, 1510sb,
1484sb, 1424s
1510sb
1322s
c
816m
856m, 842s, 742m,726s
a
the cited wavenumbers of the nitrate groups arise from spectra
recorded as Nujol and hexachlorobutadiene mulls (see text); b overlapping bands; c hidden by phen absorption.
b = broad; m = medium; s = strong; sh = shoulder; w = weak.
frequency bands m1(A1) and m5(B2) [under C2v symmetry]
is large (ca. 200 cm)1).
The n.m.r. assignments of complexes (1) and (2)
presented in Tables 5 and 6, respectively, are based on
the work of FreÂchette [30] for the LaIII/NOÿ
3 /bpy system
/phen
system.
and FreÂchette et al. [13] for the LaIII/NOÿ
3
The 1H- and 13C-n.m.r. spectra of (1) in CD3OD are
identical with those of free bpy in the same solvent (and
under identical experimental conditions), indicating that
the structure of the complex is not retained in solution
and the solution complex species do not contain
coordinated bpy. FreÂchette [30] investigated the reaction
between La(NO3)3 á 6H2O and bpy in CD3CN by means
of 139La-, 17O-, 13C- and 1H-n.m.r. spectroscopy.
She showed that during the complexation process ®ve
di€erent LaIII species are formed, two of which, namely
[La(NO3)3(solvent)4 ] and [La(NO3)3(solvent)3(H2O)], do
not contain bpy. The 1H- and 13C-n.m.r. spectra of (2)
in CD3OD are indicative of the presence of one solution
species containing coordinated phen. The 1H-n.m.r.
spectrum consists of four resonances [13]. Considerable down®eld coordination shifts, Dd(Hi)
[Dd(Hi) = d(Hi)complex 2 ) d(Hi)free phen], are observed
for all resonances, their values being 0.13, 0.26, 0.31
and 0.20 for the protons of the positions (1,10), (3,8),
(5,6) and (2,9), respectively (see Figure 2 for the atom
labeling scheme). The resonances for the carbons of the
(2,9), (3,8) and (5,6) positions exhibit down®eld
coordination shifts (0.2±1.3 p.p.m.), while the signal
assigned to C(4) and C(7) is shifted up®eld by
Table 5. 1H- and
13
C-n.m.r. spectral dataa of (1) in CD3OD
Positionb
d (p.p.m.)
1
H-n.m.r. datac
13
1,10
4,7
3,8
2,9
5,6
8.68d(4H)
8.33d(4H)
7.98td(4H)
7.48m(4H)
±
149.26
121.70
137.86
124.39
156.04
a
C-n.m.r. data
the spectra were run ca. 1 h after dissolution; b these positions refer to
the atomic labeling scheme of complex (1) (Figure 1); c The number of
protons in parentheses has been derived from the integration curve
considering the molecular formula of the complex. d = doublet;
m = multiplet; td = triplet of doublets.
Table 6. 1H- and
13
C-n.m.r. spectral dataa of (2) in CD3OD
Positionb
d (p.p.m.)
1
H-n.m.r. datac
13
1, 10
3, 8
5, 6
2, 9
4, 7
11, 12
9.12q(4H)
8.52q(4H)
8.00s(4H)
7.82q(4H)
±
±
149.65
137.14
126.51
123.52
144.43
128.79
C-n.m.r. data
a
the spectra were run ca. 2 h after dissolution; b these positions refer to
the atomic labeling scheme of complex (2) (Figure 2); c the number of
protons in parentheses has been derived from the integration curve
considering the molecular formula of the complex.
q = quadruplet; s = singlet.
0.93 p.p.m. with respect to that in free phen. These
shifts are characteristic of coordinated phen [13]. It is
dicult to decide from 1H- and 13C-n.m.r. experiments
alone if the complex species in solution is the same
found in the solid state.
Conclusions
Our systematic investigation of the YIII/NOÿ
3 /L±L
(L±L = bpy, phen) reaction systems has shown that
only two discrete complexes [(1), (2)] are capable
of existence. For each of the bpy and phen systems, the
yttrium(III) compound is isostructural with the lanthanide(III) complexes [Ln(NO3)3(L±L)2] [5±7, 10, 11±13].
Although there is a report [31] of the synthesis of
Ln(NO3)3(bpy)3 [Ln = Ce, Pr, Nd, Yb], and the species [La(NO3)3(bpy)(MeCN)2] and [La(NO3)3(bpy)(MeCN)(H2O)] have been identi®ed in solution by
n.m.r. spectroscopy [30], there appears to be little
evidence as yet for the isolation of any solid M(NO3)3/
L±L (M = Y, Ln; L±L = bpy, phen) compounds of 1:3
or 1:1 stoichiometries. Quite recently Bower et al. [11]
reported a poor quality X-ray structure (wR2 = 0.33,
all data) of the 1:3 Nd(NO3)3/bpy product originally
isolated by Dong et al. [31]; the structure consists of
[Nd(NO3)3(bpy)2] and non-coordinated (lattice) bpy
molecules. Nevertheless, structurally characterized examples of 1:1 Ln(NO3)3/L±L compounds exist for
Ln = La, L±L = bpy in [La(NO3)3(bpy)(H2O)2] [8]
and for Ln = Yb, L±L = phen in [Yb(NO3)3(phen)(H2O)] [14], these two species existing as 1:1 lattice
complexes with diverse crown ethers; the coordination
number of LaIII is 10 and 9 for YbIII. Interestingly,
the 1:1 adduct [La(NO3)3(bpy)(H2O)2(MeOH)] with
another crown ether (benzo-15-crown-5) has also been
structurally characterized [9], in which the coordination
sphere is augmented by a further solvate molecule
(MeOH).
A ®nal point of interest is that, according to n.m.r.
spectral evidence, the YANphen bonds persist in MeOH
solution, whereas the YANbpy bonds are not stable.
With the above considerations in mind, this work
is extended to YIII/NOÿ
3 /terpy (terpy = 2,2¢:6¢,2¢¢-
281
terpyridine) and YIII/RCOO)/bpy, phen, terpy reaction
systems. Our studies in this rich new area of yttrium(III)
coordination chemistry, already well advanced, reveal
some exciting di€erences with respect to the recently
reported analogous 4f chemistry [32±34] and they will be
reported soon.
Acknowledgements
This work was supported by the Greek General
Secretariat of Research and Technology (to S. P. P.)
and John Boutaris and Son Co. S.A. (to A. T.).
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