Cadmium(II) complexes with [(4-methylphenyl)sulfonyl]-2-pyridyl-amine: Crystal structures of bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cadmium(II); Aquo-bis(pyridine) bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cadmium(II) and 1,10-phenanthroline bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cadmium(II)

Article abstract of DOI:10.1016/s0020-1693(99)00265-0

Electrochemical oxidation of cadmium in a solution of [(4-methylphenyl)sulfonyl]-2-pyridyl-amine (HL) in acetonitrile/dichloromethane afforded the compound [CdL₂]. When pyridine (py), 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) was added to the electrolytic phase, [CdL₂py₂(H₂O)], [CdL₂bipy] and [CdL₂phen] were obtained. The crystal structures of [CdL₂] (1), [CdL₂py₂(H₂O)] (2) and [CdL₂phen] (3) have been determined by X-ray diffraction techniques. The complex [CdL₂] is best described in terms of a linear polymer with the metal atom in a [CdN₄O₂] distorted octahedral environment. The [CdL₂py₂(H₂O)] and [CdL₂phen] complexes are monomeric, with the cadmium atoms in [CdN₆O] distorted pentagonal bipyramid and [CdN₆] trigonal prismatic environments, respectively.

Full text of DOI:10.1016/s0020-1693(99)00265-0

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 294 (1999) 87–94
Note
Cadmium(II) complexes with
[(4-methylphenyl)sulfonyl]-2-pyridyl-amine: crystal structures of
bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cadmium(II); aquo-
bis(pyridine) bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}-
cadmium(II) and 1,10-phenanthroline bis{[(4-methylphenyl)-
sulfonyl]-2-pyridyl-amide}cadmium(II)
Santiago Cabaleiro a, Ezequiel Va´zquez-Lo´pez a, Jesu´s Castro a,
Jose´ A. Garc´ıa-Va´zquez b, Jaime Romero b, Antonio Sousa b,*
a Departamento de Qu´ımica Inorga´nica, Uni6ersidade de Vigo, E-36200 Vigo, Galicia, Spain
b Departamento de Qu´ımica Inorga´nica, Uni6ersidade de Santiago de Compostela, E-15706 Santiago de Compostela, Galicia, Spain
Received 7 May 1999; accepted 29 June 1999
Abstract
Electrochemical oxidation of cadmium in a solution of [(4-methylphenyl)sulfonyl]-2-pyridyl-amine (HL) in acetonitrile/
dichloromethane afforded the compound [CdL2]. When pyridine (py), 2,2%-bipyridine (bipy) or 1,10-phenanthroline (phen) was
added to the electrolytic phase, [CdL2py2(H2O)], [CdL2bipy] and [CdL2phen] were obtained. The crystal structures of [CdL2] (1),
[CdL2py2(H2O)] (2) and [CdL2phen] (3) have been determined by X-ray diffraction techniques. The complex [CdL2] is best
described in terms of a linear polymer with the metal atom in a [CdN4O2] distorted octahedral environment. The [CdL2py2(H2O)]
and [CdL2phen] complexes are monomeric, with the cadmium atoms in [CdN6O] distorted pentagonal bipyramid and [CdN6]
trigonal prismatic environments, respectively. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Crystal structures; Electrochemistry; Cadmium complexes; Amide complexes
[6,7], oxygen and sulfur [8] or selenium [9] atoms as
additional donor atoms.
1. Introduction
Electrochemical procedures have been widely used
for the synthesis of metallic complexes, especially of
those of weakly acid organic ligands [1–5]. Of particu-
lar relevance to the present work are metal complexes
with heterocyclic ligands such as pyridine derivatives,
(I), containing, apart from the nitrogen atom, sulfur
We have now extended our previous work to the
electrochemical synthesis of cadmium(II) complexes
with a ligand of type (I) bearing a secondary amide
(X=NRꢀ) group. Although it is well known that metal
complex formation by metal substitution of the amide
proton is not an easy process [10], the presence of an
* Corresponding author. Tel.: +34-981-563 100; fax: +34-981-
597 525.
E-mail addresses: fojo@uvigo.es (J. Castro), qiansoal@usc.es (A.
Sousa)
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00265-0

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S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
additional donor atom on the molecule, which allows
the formation of a stable five- or six-member chelate
ring with the metal ion [11], may facilitate this process.
In addition, the presence in the amide group of a tosyl
group, which increases the acidity of the amide hydro-
gen, makes the substitution of the proton easier [12].
as the cathode and a cadmium plate as the sacrificial
anode. For the synthesis of mixed complexes, either py,
bipy or phen was added to the electrolytic phase. In all
cases, hydrogen was evolved at the cathode.
2.2.1. Preparation of [CdL2] (1)
Electrolysis of an acetonitrile/dichloromethane (25+
25 ml) solution containing HL (202.2 mg, 0.81 mmol)
and a small amount of tetraethylammonium perchlo-
rate (ca. 20 mg) at 10 mA and 6 V for 2 h dissolved
40.1 mg of cadmium (Ef=0.48). At the end of the
experiment the white crystalline solid was filtered,
washed with hot acetonitrile and ether and dried in
vacuo. The compound was characterised as [CdL2].
Anal. Calc. for C24H22N4O4S2Cd: H, 3.7; C, 47.5; N,
9.2; S, 10.6. Found: H, 4.0; C, 47.3; N, 9.2; S, 11.1%.
IR (KBr, cm−1): 3038(w), 2920(w), 2862(w), 1593(s),
1462(s), 1317(s), 1138(s), 1091(s). 1H NMR (Cl3CD,
ppm): 2.27 (ꢀCH3); 7.0, 7.6 (benzene ring); 6.7, 7.2, 7.5,
8.0 (pyridine ring).
As a result of our continuing interest in the use of
electrochemical methods for the synthesis of amide
complexes, we now describe the electrochemical synthe-
sis of the cadmium(II) complex [CdL2] and its adducts
[CdLLn%] (where L% is pyridine, py, 2,2%-bipyridine, bipy,
and 1,10-phenanthroline, phen) with [(4-methylphenyl)-
sulfonyl]-2-pyridyl-amine, HL.
2.2.2. Preparation of [CdL2py2(H2O)] (2)
2. Experimental
Electrolysis of an acetonitrile/dichloromethane (25+
25 ml) solution containing HL (197.8 mg, 0.80 mmol),
pyridine (5 ml) and a small amount of tetraethylammo-
nium perchlorate (ca. 20 mg) at 10 mA and 13 V for 2
h dissolved 43.6 mg of cadmium (Ef=0.52). At the end
of the experiment the yellow crystalline solid was
filtered, washed with hot acetonitrile and ether and
dried in vacuo. The compound was characterised as
[CdL2py2(H2O)]. Anal. Calc. for C34H34N6O5S2Cd: H,
4.4; C, 52.1; N, 10.7; S, 8.2. Found: H, 4.4; C, 51.9; N,
10.7; S, 8.0%. IR (KBr, cm−1): 3063(w), 2923(vw),
1597(s), 1557(m), 1468(s), 1436(s), 1316(s), 1239(m),
1125(s), 1087(s), 661(m), 420(w). 1H NMR (Cl3CD,
ppm): 2.3 (ꢀCH3); 7.1, 7.4 (benzene ring); 6.7, 7.0, 7.2,
7.7, 7.9, 8.7 (pyridine rings).
Acetonitrile, dichloromethane, 2-aminopyridine, to-
syl chloride, pyridine, 2,2%-bipyridine, 1,10-phenanthro-
line and all other reagents were commercial products
and were used as supplied. Cadmium (Aldrich) was
used as 2×2 cm plates.
2.1. Preparation of [(4-methylphenyl)sulfonyl]-2-pyridyl-
amine
[(4-methylphenyl)sulfonyl]-2-pyridyl-amine was pre-
pared by reaction of the 2-aminopyridine and tosyl
chloride in a 2:1 ratio in dichloromethane. The solution
was taken to pH 11 and the white precipitate filtered
and dried in vacuo. Anal. Calc. for C12H12N2SO2: C,
58.1, H, 4.9, N, 11.3, S, 12.9. Found: C, 58.2, H, 5.0, N,
11.3, S, 13.0%. IR (KBr, cm−1): 3230(m), 3127(m),
3056(w), 1915(m), 1866(w), 1793(w), 1654(sh), 1635(s),
1534(m), 1463(w), 1393(m), 1375(m), 1357(m), 1282(m),
1163(m), 1146(m), 1086(m), 1035(w), 1020(w), 999(m),
959(m), 807(m), 785(m), 732(w), 704(w), 668(m),
633(w), 613(w), 572(m), 552(m), 515(w). 1H NMR
(Cl3CD, ppm): 2.4 (ꢀCH3); 13.5 NꢀH, 7.8, 7.3 (benzene
ring); 6.8, 7.4, 7.6, 8.3 (pyridine ring).
2.2.3. Preparation of [CdL2bipy] (3)
Electrolysis of an acetonitrile/dichloromethane (25+
25 ml) solution containing HL (203.5 mg, 0.95 mmol),
2,2%-bipyridine (55.7 mg, 0.36 mmol) and a small
amount of tetraethylammonium perchlorate (ca. 20 mg)
at 10 mA and 4 V for 2 h dissolved 42.1 mg of
cadmium (Ef=0.50). At the end of the experiment the
white crystalline solid was filtered, washed with hot
acetonitrile and ether and dried in vacuo. The com-
pound was characterised as [CdL2bipy]. Anal. Calc. for
C34H30N6O4S2Cd: H, 4.0; C, 53.5; N, 11.0; S, 8.0.
Found: H, 4.0; C, 53.0; N, 10.7; S, 7.8%. IR (KBr,
cm−1): 3112(w), 3065(m), 2920(w), 1593(w), 1559(w),
1495(s), 1462(m), 1436(m), 1315(s), 1137(s), 1086(s),
1007(w), 770(m), 737(m), 667(w). 1H NMR (Cl3CD,
ppm): 2.2 (ꢀCH3); 6.7, 7.3 (benzene ring); 6.6, 7.1, 7.4,
7.9, 8.2, 9.7 (pyridine rings).
2.2. Preparation of the complexes. General procedure
The complexes were obtained following an electro-
chemical method [5]. A solution of the ligand in a
mixture of acetonitrile/dichloromethane containing
about 20 mg of tetraethylammonium perchlorate as a
current carrier was electrolysed using a platinum wire

S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
89
2.2.4. Preparation of [CdL2phen] (4)
2.4. Crystal structure determination
Electrolysis of an acetonitrile/dichloromethane (25+
25 ml) solution containing HL (200 mg, 0.80 mmol),
1,10-phenanthroline (77.1 mg, 0.43 mmol) and a small
amount of tetraethylammonium perchlorate (ca. 20 mg)
at 10 mA and 8 V for 2 h dissolved 41.1 mg of
cadmium (Ef=0.49). At the end of the experiment the
white crystalline solid was filtered, washed with hot
acetonitrile and ether and dried in vacuo. The com-
pound was characterised as [CdL2phen]. Anal. Calc. for
C36H30N6O4S2Cd: H, 3.8; C, 54.9; N, 10.7; S, 8.1.
Found: H, 3.8; C, 54.9; N, 10.8; S, 7.7%. IR (KBr,
cm−1): 3058(w), 2920(w), 1588(s), 1517(s), 1495(s),
The data collection was carried out on a Siemens
Smart CCD area-detector diffractometer with graphite-
,
monochromated Mo Ka radiation, u=0.71073 A. Ab-
sorption correction were carried out using SADABS [13].
All the structures were resolved by direct methods
and refined by a full-matrix least-squares based on F2
[14]. Non hydrogen atoms were refined with anisotropic
displacement parameters. Hydrogen atoms were in-
cluded in idealised positions and refined with isotropic
displacement parameters, except those from water in
[CdL2py2(H2O)] that were located. Atomic scattering
factors and anomalous dispersion corrections for all
atoms were taken from the International Tables for
X-ray Crystallography [15]. The crystal parameters and
other experimental details of data collection and refine-
ment are summarised in Table 1.
1
1436(s), 1315(m), 1133(m), 1006(s), 848(m), 727(m). H
NMR (Cl3CD, ppm): 2.2 (ꢀCH3); 6.7, 7.3 (benzene
ring); 6.6, 7.2, 7.4, 7.9, 8.2, 8.5, 10.1 (pyridine rings).
2.3. Physical measurements
The C, N, H and S analyses of the compounds were
determined on a Carlo-Erba EA 1108 microanalyser.
IR spectra were recorded as KBr mulls on a Bruker
Vector-22 spectrometer. The proton NMR spectra were
recorded on a Bruker ARX-400 MHz spectrometer
using Cl3CD as solvent.
3. Results and discussion
The cadmium complex with [(4-methylphenyl)-
sulfonyl]-2-pyridyl-amine (HL), [CdL2], and their
adducts with pyridine (py), 2,2%-bipyridine (bipy)
Table 1
Summary of crystal data and structure refinement
Compound
[CdL2]n
C24H22CdN4O4S2
606.98
[CdL2py2(H2O)]
C34H34CdN6O5S2
783.19
[CdL2phen]
C36H30CdN6O4S2
787.18
Empirical formula
Formula weight
Temperature (K)
293(2)
293(2)
293(2)
,
Wavelength (A)
Crystal system/space group
0.71073
triclinic/P1
0.71073
monoclinic/P21/c
0.71073
triclinic/P1
(
(
Unit cell dimensions
,
a (A)
9.1844(6)
10.8938(7)
14.0191(9)
73.8706(10)
73.5019(12)
68.7047(11)
1228.89(14)
2
9.3553(4)
19.0704(3)
19.1136(2)
9.9070(6)
11.5938(8)
,
b (A)
,
c (A)
16.0371(10)
82.3419(13)
75.9508(14)
73.8571(10)
1712.2(2)
h (°)
i (°)
k (°)
90.3394(4)
3
,
Volume (A )
Z
3410.0(2)
4
1.526
0.814
2
Dcalc (mg m−3
)
1.640
1.097
612
1.527
0.809
800
Absorption coefficient (mm−1
F(000)
)
1600
Crystal size (mm)/colour
q Range for data collection
Index ranges
0.40×0.30×0.10/white
2.65–25.00
−105h510, −125k512,
−165l515
7029
0.5×0.4×0.2/pale yellow
2.65–25.00
−115h510, −195k522,
−195l522
0.45×0.35×0.20/white
2.62–23.00
−85h510, −125k512,
−175l517
8015
Reflections collected
14 522
Independent reflections
Reflections observed
4251 [Rint=0.0932]
2893
5968 [Rint=0.0731]
5059
4687 [Rint=0.1621]
2478
Criterion for observation
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
I\2|(I)
I\2|(I)
I\2|(I)
full-matrix least-squares on F2
4251/0/316
full-matrix least-squares on F2
5968/2/441
full-matrix least-squares on F2
4687/0/442
1.010
1.091
0.978
R1=0.0569, wR2=0.1283
0.970 and −1.095
R1=0.0354, wR2=0.0813
0.387 and −0.0985
R1=0.0965, wR2=0.2242
1.972 and −1.874
Largest difference peak and hole
−3
,
(e A
)

90
S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
Fig. 1. The molecular structure of [CdL2].
and 1,10-phenanthroline (phen), [CdL2py2(H2O)],
[CdL2bipy] or [CdL2phen], are easily prepared in good
yield by the simple one-step electrochemical method. In
all cases, the product formed was easily separated by
filtration from the bottom of the cell as crystalline
products. The compounds are air stable and moderately
soluble in organic solvents such as chloroform or
ethanol.
and the oxygen atom of the other, the amide nitrogen
atom of the other and the oxygen atom of the sulfon-
amide group of a fourth ligand. Therefore, two ligands
have a distinct coordination behaviour. Thus, although
both ligands function as tridentate ligands (Namide
-
NpyO), one of them (type a) acts as a (N,N) chelating
ligand to one cadmium atom and uses an oxygen atom
to bridge another cadmium atom, the second ligand
(type b) acts as a (Npy,O) chelating ligand and uses a
Namide atom as a bridge. The coordination around the
cadmium metal is distorted octahedral, [Cd(Namide)2-
(Npy)2(O)2], with the Npy atoms in trans positions
(168.8(2)°).
The geometry distortion is in part due to the small
bite of the NꢀN bidentate ligand, with a chelate ring of
four members and an angle NꢀCdꢀN of 58.0(2)° bigger
than the angles found in similar chelate rings such as
bis(1,5-bis(p-ethoxyphenyl)-1,4-penta-azadienido)-bis-
(pyridyl)cadmium(II) [16], average 52.3°, or in the
cationic tetrakis(1,8-naphthyridine-N,N%)cadmium(II)
diperchlorate [17], average 53.8°.
The values of the electrochemical efficiency, defined
as the amount of metal dissolved per units of charge (in
F), were close to 0.5 mol F−1 irrespective of the
presence or absence of additional ligands. This fact,
and the evolution of hydrogen at the cathode are
compatible with the following mechanism:
Cathode: 2HL+2e−“2L−+H2
Anode: Cd+2L−“[CdL2]+2e−
or Cd+2L−+L%“[CdL2L% ]+2e−
n
n=1, L%=bipy or phen
n=2, L%=py
3.1. Structure of the complexes
The CdꢀNamide bond distances, 2.308(6) and 2.342(6)
,
A, are longer than those found in the five-coordinated
3.1.1. Molecular structure of [CdL2] (1)
amide cadmium(II) complex, [{Cd(bipy)2(bsglyNO)}4]
The molecular structure of [CdL2] is shown in Fig. 1,
together with the atomic numbering scheme adopted.
Selected bond distances and angles are listed in Table 2.
The structure consists of polymeric linear chains
parallel to the b axis. Each cadmium atom is coordi-
nated to four different ligands through the amide and
pyridine nitrogen atoms of one, the pyridine nitrogen
(bsglyNO=N-benzenesulfonyl)glycinate
dianion),
,
2.172(9) and 2.191(8) A [18], and are even greater than
those observed in hexacoordinate K[Cd(ClC6H4SO2-
NCONH-n-Pr)3] [19] and in [Cd(bipy)2(bsglyNO)2]
[18], mean CdꢀNamide distance 2.212(20) and
,
2.215 A, respectively. The two CdꢀNpy bond

S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
91
The phenyl and pyridine rings are practically flat
and bond distances and angles within the ligands are
normal and in the range previously observed in similar
compounds. The interplanar angle between adjacent
phenyl rings is 17.7(3)°, whereas the pyridine rings are
almost perpendicular to the phenyl ring of the same
ligand (dihedral angle of 88.5(4)° for the ligand type a,
and 84.2(3)° for the ligand type b). The interplanar
angle between the pyridine rings is 10.2(3)°.
Table 2
Selected bond distances (A) and angles (°) for [CdL2]n (1) a
,
CdꢀN(12)
2.240(6) CdꢀN(21)
2.308(6)
2.342(6)
2.738(6)
1.788(9)
1.771(9)
1.349(9)
1.383(9)
1.343(9)
CdꢀN(22)
CdꢀO(12)
2.320(6) CdꢀN(11)c1
2.355(5) CdꢀO(21)c2
1.563(6) S(1)ꢀC(16)
1.589(6) S(2)ꢀC(26)
1.428(9) N(12)ꢀC(15)
1.361(9) N(21)ꢀC(25)
1.341(9) N(22)ꢀC(25)
S(1)ꢀN(11)
S(2)ꢀN(21)
N(11)ꢀC(15)
N(12)ꢀC(11)
N(22)ꢀC(21)
N(12)ꢀCdꢀN(21)
N(21)ꢀCdꢀN(22)
116.9(2) N(12)ꢀCdꢀN(22)
58.0(2) N(12)ꢀCdꢀN(11)c1
168.8(2)
95.6(2)
95.6(2)
146.8(2)
90.5(2)
78.1(2)
3.1.2. Molecular structure of [CdL2py2(H2O)] (2)
The [CdL2py2(H2O)] ORTEP drawing is shown in Fig.
2, and selected bond distances and angles are given in
Table 3.
The crystal structure of 2 consists of monomeric
units with the metal in a [CdN6O] pentagonal bipyra-
mid environment. The axial positions are occupied by
the nitrogen atoms of the pyridine molecules and the
equatorial positions are occupied by the pyridine and
amide nitrogen atoms of two bidentate chelating ligand
(L−), and the oxygen atom of the water molecule. The
N(21)ꢀCdꢀN(11)c1 111.9(2) N(22)ꢀCdꢀN(11)c1
N(12)ꢀCdꢀO(12)
N(22)ꢀCdꢀO(12)
83.02(19) N(21)ꢀCdꢀO(12)
97.12(19) N(11)c1ꢀCdꢀO(12)
N(12)ꢀCdꢀO(21)c2 78.90(19) N(21)ꢀCdꢀO(21)c2
N(22)ꢀCdꢀO(21)c2 90.01(19) N(11)c1ꢀCdꢀO(21)c2 169.99(18)
O(12)ꢀCdꢀO(21)c2 80.54(18) O(11)ꢀS(1)ꢀO(12)
114.2(3)
106.8(4)
118.1(6)
120.4(6)
N(11)ꢀS(1)ꢀC(16)
C(15)ꢀN(11)ꢀS(1)
C(25)ꢀN(21)ꢀS(2)
109.0(3) N(21)ꢀS(2)ꢀC(26)
122.0(5) C(15)ꢀN(12)ꢀC(11)
124.2(5) C(21)ꢀN(22)ꢀC(25)
a Symmetry transformations used to generate equivalent atoms:
c1 −x+1, −y, −z+1; c2 −x+1, −y+1, −z+1.
,
cadmium atom is displaced by 0.060(2) A from the
,
least-squares plane of the five atoms N(22)O(1)-
N(11)N(12)N(21). The equatorial atoms N(21) and
O(1) are both below the best square plane 0.133(2) and
distances are different, 2.240(6) and 2.320(6) A, with
the first value significantly shorter than the CdꢀNpy
distances found in other hexacoordinated cadmium
complexes, 2.310–2.346 A [20,21], whose values do not
significantly differ from the longer CdꢀNpy distance
observed in 1.
The CdꢀO bond distances are very different between
them. The shorter CdꢀO distance, 2.355(5) A, is similar
to those observed in complexes with a hexacoordi-
nated environment, like as in {Cd(H2O)4[(CH3-
SO2)2N]2} and {Cd(py)4[(CH3SO2)2N]2}, 2.3032(14)
and 2.3436(14) A, respectively [21]. The longer CdꢀO
distance, 2.738(6) A, is shorter than the sum of the van
,
0.137(2) A while N(11), N(12) and N(22) are above it
,
,
(0.076(2), 0.003(2) and 0.201(2) A). The bond angles
within the equatorial plane vary markedly from those
of
N(12)=54.96(8)°, N(21)ꢀCdꢀN(22)=51.95(9)°, N(12)ꢀ
CdꢀN(21)=93.92(8)°, N(22)ꢀCdꢀO(1)=84.77(11)°,
a
regular pentagonal bipyramid, N(11)ꢀCdꢀ
,
N(11)ꢀCdꢀO(1)=75.46(9)°. The axial positions form
an angle N(3)ꢀCdꢀN(4) of 175.91(9)° and the angle
between this axis and the pentagonal plane is
85.2(1)°.
,
,
,
The CdꢀNpy bond distance, 2.267(3) A, is similar to
,
der Waals radii (3.10 A) [22]. If this last bond is
those found in [CdL2]ꢀ, and shorter than the other
considered as a secondary interaction, the structure of
the compound can be described as the result of associ-
ating into a linear polymer dimer units containing
five-coordinated cadmium atoms through sulfo-
namide oxygen bridges. The coordination around each
cadmium atom in the dimer can be described as a
square pyramid with N(12), N(22), N(21) and O(12)
atoms forming the base, and the N(11%) atom in the
apical position. The cadmium atom lies at 0.3476(26)
,
CdꢀNpy distances, 2.344(3), 2.379(3) and 2.424(3) A,
with these last two values significantly greater than
those of [CdL2]ꢀ and of other cadmium pyridine con-
taining complexes [20,21]. The CdꢀNamide distances are
very different among them, being the shorter one,
,
2.518(3) A, much greater than the one observed in
[CdL2]ꢀ and in other hexacoordinated amide cadmium
complexes [19]. The other CdꢀNamide distance, 2.790(3)
,
A, is much longer than the above, but it is significantly
,
A out of the plane of the base. In the trans position to
shorter than the sum of the van der Waals radii (3.05
this N(11%) atom there is an empty position through
which the cadmium atom is slightly bonded to the
O(21%) atom. This association produces two different
,
A) [22]. The CdꢀOW is also longer than the one found
in tetraaqua bis(dimesylamide-O)cadmium(II), 2.266(2)
,
and 2.244(2) A [21].
,
Cd···Cd distances. The shorter one, 4.725 A, corre-
sponds to the interatomic distance in the dimer, and
the longer one, 6.334 A, to the cadmiumꢀcadmium
bond distance between adjacent atoms of different
dimers.
In the solid state, the complex presents an in-
tramolecular hydrogen bond between the water
molecule and the oxygen atom of a SO2 group and an
intermolecular bond with SO2 groups of their neigh-
,
,
bours, OꢀO bond distances of 2.728(4) and 2.846(4) A.

92
S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
Fig. 2. The molecular structure of [CdL2py2(H2O)].
Fig. 3. The molecular structure of [CdL2phen].
3.1.3. Molecular structure of [CdL2phen] (4)
contains discrete molecules of [CdL2phen] with the
metal coordinated to the nitrogen atoms of two
monoanionic bidentate ligands and to two nitrogen
atoms of the phenanthroline molecule. The coordina-
The molecular structure of [CdL2phen] is shown in
Fig. 3 with the labelling scheme used. The selected bond
distances and angles are given in Table 4. The crystal

S. Cabaleiro et al. / Inorganica Chimica Acta 294 (1999) 87–94
93
Table 3
Selected bond distances (A) and angles (°) for [CdL2py2(H2O)] (2)
due to the small bite of the anionic ligand, NꢀCdꢀN
56.5(3) and 53.6(4)°. The NꢀCdꢀN angle of the neutral
ligand of 72.6(4)° is similar to those reported for hexa-
coordinated cadmium complexes containing coordi-
nated phenanthroline.
a
,
CdꢀN(22)
CdꢀN(3)
CdꢀO(1)
CdꢀN(21)
S(1)ꢀC(16)
S(2)ꢀN(21)
O(1)ꢀO(21)c1
O(1)ꢀH(2)
2.267(3)
2.379(3)
2.424(3)
2.790(3)
1.765(3)
1.568(3)
2.846(4)
0.86(3)
CdꢀN(12)
CdꢀN(4)
CdꢀN(11)
S(1)ꢀN(11)
O(12)ꢀO(1)
S(2)ꢀC(26)
O(1)ꢀH(1)
2.344(3)
2.424(3)
2.518(3)
1.586(3)
2.728(4)
1.787(3)
0.85(3)
In this complex, the CdꢀNamide bond distances of
,
2.234(12) and 2.280(10) A are comparable to those
found in the above complexes. The two CdꢀNphen
,
bonds 2.304(11) and 2.374(10) A are similar to those
found in other cadmium containing phenanthroline
N(22)ꢀCdꢀN(12)
N(12)ꢀCdꢀN(3)
N(12)ꢀCdꢀN(4)
N(22)ꢀCdꢀO(1)
N(3)ꢀCdꢀO(1)
N(22)ꢀCdꢀN(11)
N(3)ꢀCdꢀN(11)
O(1)ꢀCdꢀN(11)
N(12)ꢀCdꢀN(21)
N(4)ꢀCdꢀN(21)
N(11)ꢀCdꢀN(21)
144.93(10)
85.85(9)
90.28(9)
84.77(11)
92.20(11)
158.54(10)
92.28(9)
75.46(9)
93.92(8)
97.47(9)
148.87(8)
N(22)ꢀCdꢀN(3)
N(22)ꢀCdꢀN(4)
N(3)ꢀCdꢀN(4)
N(12)ꢀCdꢀO(1)
N(4)ꢀCdꢀO(1)
N(12)ꢀCdꢀN(11)
N(4)ꢀCdꢀN(11)
N(22)ꢀCdꢀN(21)
N(3)ꢀCdꢀN(21)
O(1)ꢀCdꢀN(21)
96.81(9)
87.13(10)
175.91(9)
130.19(10)
89.27(12)
54.96(8)
84.39(9)
51.95(9)
84.15(9)
135.45(9)
,
complexes [23]. The CdꢀNpy, 2.399(11) A, is similar to
,
the value of 2.424(3) A, found for [CdL2py2(H2O)], but
the other CdꢀNpy bond distance is much greater,
,
2.616(13) A.
4. Supplementary material
O(11)ꢀS(1)ꢀN(11) 114.19(15)
The atomic positions, full list of bond lengths and
angles and other crystallographic data have been de-
posited as supplementary publication nos. CCDC
118535, 118536 and 118537. Copies can be obtained
from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK.
O(12)ꢀS(1)ꢀN(11) 105.20(14)
O(12)ꢀS(1)ꢀC(16) 106.24(15)
S(1)ꢀO(12)ꢀO(1)
O(11)ꢀS(1)ꢀC(16)
N(11)ꢀS(1)ꢀC(16)
O(22)ꢀS(2)ꢀN(21) 115.52(16)
106.56(15)
107.80(14)
110.41(14)
O(21)ꢀS(2)ꢀN(21) 105.89(15)
O(21)ꢀS(2)ꢀC(26) 106.37(15)
O(22)ꢀS(2)ꢀC(26)
N(21)ꢀS(2)ꢀC(26)
105.50(16)
108.70(15)
a Symmetry transformations used to generate equivalent atoms:
c1 x+1, y, z.
Acknowledgements
Table 4
We thank the Xunta de Galicia (Xuga 20302B97) for
financial support.
,
Selected bond distances (A) and angles (°) for [CdL2phen] (4)
CdꢀN(22)
CdꢀN(32)
CdꢀN(11)
S(1)ꢀN(12)
S(2)ꢀN(22)
2.234(12)
2.304(11)
2.399(11)
1.606(10)
1.611(10)
CdꢀN(12)
CdꢀN(31)
CdꢀN(21)
S(1)ꢀC(16)
S(2)ꢀC(26)
2.280(10)
2.374(10)
2.616(13)
1.767(12)
1.784(15)
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