Direct electrochemical synthesis of cobalt(II) complexes of tosylamides: Crystal structures of [CoL2py2], [CoL2DMF2], [CoL2bipy] and [CoL2phen], L = [(4-methylphenyl)sulfonyl]-2-pyridylamide

Article abstract of DOI:10.1016/S0277-5387(00)00437-X

Several complexes with tosylamides were synthesised by the electrochemical oxidation of cobalt in an acetonitrile solution of [(4-methylphenyl)sulfonyl]-imino-1H-pyridine (HL) and the appropriate neutral coligand: L' (pyridine, 2,2'-bipyridine, 1,10-phenanthroline or N,N-dimethylformamide). The structures of bis-(N,N-dimethylformamide)bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}c obalt(II), bis-(pyridine)bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cobalt(II), 2,2'-bipyridine bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cobalt(II) and 1,10-phenanthroline bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cobalt(II) were determined by X-ray diffraction methods. In these monomeric complexes, the cobalt atom is in a distorted octahedral environment. The vibrational and electronic spectra of the complexes are discussed and are shown to agree with the structures. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(00)00437-X

www.elsevier.nl/locate/poly
Polyhedron 19 (2000) 1607–1614
Direct electrochemical synthesis of cobalt(II) complexes of
tosylamides: crystal structures of [CoL2py2], [CoL2DMF2],
[CoL2bipy] and [CoL2phen],
L=[(4-methylphenyl)sulfonyl]-2-pyridylamide
Santiago Cabaleiro a, Jesu´s Castro* a,1, Jose´ A. Garc´ıa-Va´zquez b, Jaime Romero b,
A. Sousa* b,2
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, E-15706 Santiago de Compostela, Galicia, Spain
Received 7 February 2000; accepted 17 May 2000
Abstract
Several complexes with tosylamides were synthesised by the electrochemical oxidation of cobalt in an acetonitrile solution of
[(4-methylphenyl)sulfonyl]-imino-1H-pyridine (HL) and the appropriate neutral coligand: L% (pyridine, 2,2%-bipyridine, 1,10-
phenanthroline or N,N-dimethylformamide). The structures of bis-(N,N-dimethylformamide)bis{[(4-methylphenyl)sulfonyl]-2-
pyridyl-amide}cobalt(II), bis-(pyridine)bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cobalt(II), 2,2%-bipyridine bis{[(4-methyl-
phenyl)sulfonyl]-2-pyridyl-amide}cobalt(II) and 1,10-phenanthroline bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}cobalt(II)
were determined by X-ray diffraction methods. In these monomeric complexes, the cobalt atom is in a distorted octahedral
environment. The vibrational and electronic spectra of the complexes are discussed and are shown to agree with the structures.
© 2000 Elsevier Science Ltd. All rights reserved.
Keywords: Electrochemical synthesis; Cobalt(II) complexes; Crystal structures; Tosylamide complexes
1. Introduction
The coordination chemistry of amides is scarce due
to the difficulty of the substitution of a metal ion for an
amide proton. However, if a sulfonamide group substi-
tutes the amide group, the electron withdrawal of the
sulfonyl group causes important changes and the for-
mation of the complexes is facilitated [1].
This is one of the reasons why the coordination
chemistry of sulfonamide ligands has been investigated
in recent years [2,3]. Electron withdrawal of the sulfo-
nyl group causes important changes in both the neutral
ligand and in the complexes. Free molecules, such as
tosylsulfonylimino-1H-pyridine, are expected to exist in
the form I. However, crystallographic and spectro-
scopic data show that the most stable is II [3]. This
electron withdrawal of the sulfonyl group increases the
acidity of the hydrogen on the pyridine group and
complexes are easily obtained by the deprotonation of
1 *Corresponding author. Fax: +34-986-813-798; e-mail:
fojo@uvigo.es
2 *Corresponding author. Tel.: +34-981-594-488/14255; fax: +34-
981-597-525; e-mail: qiansoal@usc.es
0277-5387/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(00)00437-X

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S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
the ligand. This deprotonation may be carried out with
an electrochemical procedure.
430(m). Crystals suitable for X-ray diffraction studies
were obtained by crystallisation from (CH3)2CO–
CH3CN.
Electrochemical methods have been widely used for
the synthesis of metallic complexes, especially those of
weakly acid organic ligands [4–8]. Of particular rele-
vance to the present work are metal complexes with
heterocyclic ligands, such as pyridine derivatives con-
taining, apart from the nitrogen atom, sulfur [9,10],
oxygen and sulfur [11] or selenium [12] atoms as addi-
tional donor atoms.
In this paper, we now report the electrochemical
synthesis and characterisation of several cobalt(II) com-
plexes with the mentioned ligand, where an N-tosyl-
amido group substitutes a pyridine ring, and the addi-
tional atom is another nitrogen atom.
2.1.2. [CoL2 (DMF)2] (2)
Electrolysis of an acetonitrile–N,N-dimethylfor-
mamide (50+10 ml) solution containing HL (327.8
mg, 1.3 mmol) and tetraethylammonium perchlorate
(ca. 20 mg) at 10 mA and 14 V for 2.2 h dissolved 22.2
mg of cobalt (Ef=0.46). At the end of the experiment
the pale pink solid product was filtered, washed with
hot acetonitrile and ether and dried in vacuo. The
compound was characterised as [CoL2DMF2]: Anal.
Found: H, 4.93; C, 51.6; N, 12.09; S, 9.52. Calc. for
[C30H36CoN6O6S2]: C, 51.50; H, 5.19; N, 12.01; S,
9.17%. IR (KBr, cm−1): 3082(w), 3064(vw), 2923(m),
2851 (w), 1650(s), 1596(m), 1466(s), 1450(m), 1392(m),
1321(s), 1265(m), 1137(m), 1090(m), 784(m), 661(m),
577(m), 554(m). Crystals were obtained by recrystallisa-
tion from (CH3)2CO–CH3CN.
2. Experimental
Acetonitrile, dichloromethane, 2-aminopyridine, to-
syl chloride, pyridine, 2,2%-bipyridine, 1,10-phenanthro-
line, N,N-dimethylformamide and all other reagents
were commercial products and were used as supplied.
Cobalt (Aldrich Chemie) was used as 2×2 cm plates.
The proligand, HL, was prepared by reaction of the
amine and the tosyl chloride following the method
previously described [3]. Before its use, the product was
recrystallized from CH3CN/(CH3)2CO.
2.1.3. [CoL2 bipy] (3)
Electrolysis of an acetonitrile–dichloromethane
(25+25 ml) solution containing HL (201.0 mg, 0.81
mmol), 2,2%-bipyridine (67.2 mg, 0.43 mmol) and te-
traethylammonium perchlorate (ca. 20 mg) at 10 mA
and 10 V for 2.16 h dissolved 22.1 mg of cobalt
(Ef=0.47). At the end of the experiment the pale pink
solid was filtered, washed with hot acetonitrile and
ether and dried in vacuo. The compound was character-
ised as [CoL2bipy]. Anal. Found: C, 57.5; H, 4.5; N,
11.8; S, 8.9. Calc. for [C34H30CoN6O4S2]: C, 57.5; H,
4.3; N, 11.8; S, 9.0%. IR (KBr, cm−1): 3107(w),
3064(vw), 2919(m), 1595(s), 1465(s), 1319(s), 1138(s),
1138(s), 1088(m), 1011(m), 976 (m), 764(m), 736(s),
667(s). Crystals were obtained by crystallisation from
(CH3)2CO–CH3CN.
2.1. Preparation of complexes. General procedure
The complexes were obtained following an electro-
chemical procedure [8]. A solution of the proligand and
the appropriated coligand (either pyridine, DMF, 2,2%-
bipyridine or 1,10-phenanthroline) in a mixture of ace-
tonitrile–dichloromethane containing about 20 mg of
tetraethylammonium perchlorate as a current carrier
was electrolysed using a platinum wire as the cathode
and a cobalt plate as the sacrificial anode. In all cases,
hydrogen was evolved at the cathode.
2.1.4. [CoL2 phen] (4)
Electrolysis of an acetonitrile–dichloromethane
(25+25 ml) solution containing HL (202.1, 0.81
mmol), 1,10-phenanthroline (83.3 mg, 0.46 mmol) and
tetraethylammonium perchlorate (ca. 20 mg) at 10 mA
and 13.5 V for 2.12 h dissolved 21.7 mg of cobalt
(Ef=0.46). At the end of the experiment the pale pink
solid was filtered, washed with hot acetonitrile and
ether and dried in vacuo. The compound was character-
ised as [CoL2phen]: Anal. Found: C, 58.74; H, 4.23; N,
11.52, S, 8.41. Calc. for [C36H30CoN6O4S2]: C, 58.93; H,
4.12; N, 11.45; S, 8.74%. IR (KBr, cm−1): 3062(w),
3023(w), 2921(sh), 1588(s), 1559(s), 1515(m), 1495(m),
1315(m), 1178(m), 1134(m), 1038 (m), 981(m), 847(m),
727(s), 702(s), 662(m). Crystals by crystallisation from
(CH3)2CO–CH3CN.
2.1.1. [CoL2 py2] (1)
Electrolysis of an acetonitrile–dichloromethane
(25+25 ml) solution containing the proligand HL
(201.4 mg, 0.81 mmol), pyridine (ca. 1 ml) and te-
traethylammonium perchlorate (ca. 20 mg) at 10 mA
and 14 V for 2 h dissolved 21.1 mg of cobalt (Ef=
0.48). At the end of the experiment the pale pink solid
product was filtered, washed with hot acetonitrile and
ether and dried in vacuo. The compound was character-
ised as [CoL2py2]: Anal. Found: H, 4.7; C, 57.2; N,
11.8; S, 8.7. Calc. for [C34H32CoN6O4S2]: C, 57.4; H,
4.5; N, 11.8; S, 9.0%. IR (KBr, cm−1): 3071(m),
3069(m), 2973(sh), 1593(s), 1463(s), 1315(b), 1135(b),
1038(s), 981(vb), 702(s), 662(s), 579(s), 559(b), 531(s),

S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
1609
2.2. Physical measurements
from the International Tables for X-ray Crystallogra-
phy [17]. Details of crystal data and structural refine-
ment are given in Table 1.
The C, N, H and S contents of the compounds were
determined on a Carlo–Erba EA 1108 microanalyser.
IR spectra were recorded as KBr mulls on a Bruker
1
3. Results and discussion
Vector-22 spectrophotometer. The H NMR spectrum
of the ligand was recorded on a Bruker ARX-400 MHz
spectrometer using Cl3CD as solvent. Solid-state elec-
tronic spectra were recorded on a Shimadzu UV 3101
PC. Magnetic measurements were made using a DMS
VSM 1160 instrument.
Anodic oxidation of cobalt metal in a non-aqueous
solution containing (4-methylphenyl)sulfonyl]imino-
1H-pyridine and one coligand as pyridine (py), N,N-
dimethylformamide (DMF), 2,2%-bipyridine (bipy) or
1,10-phenanthroline (phen) yields crystalline products
of formulae [CoL2py2], [CoL2DMF2], [CoL2bipy] and
[CoL2phen], respectively. The values of the electro-
chemical efficiency, defined as the amount of metal
dissolved per number of Faradays, were close to 0.5
mol F−1 in all cases. This value is compatible with the
mechanism
2.3. Crystal structure determination
The data collection, in all the cases at room tempera-
ture, was taken on a MACH3 Enraf–Nonius using Mo
Ka radiation for [CoL2py2] and for [CoL2bipy]. Data
were corrected for polarization and Lorentz effects.
c-scan absorption corrections were applied [13]. The
data collection for [CoL2DMF2] and [CoL2phen] was
taken on a Siemens Smart CCD area-detector diffrac-
tometer with graphite-monochromated Mo Ka radia-
tion. Absorption corrections were carried out using
SADABS [14].
Cathode: 2HL+2e− “2L− +H2
Anode: Co“Co2+ +2e−
The overall reactions can be described as
Co+2HL+nL%“[CoL2L% ]+H2
n
All the structures were solved by direct methods and
refined by a full-matrix least-squares based on F2 [15].
Non-hydrogen atoms were refined with anisotropic dis-
placement parameters. Hydrogen atoms were included
in idealised positions and refined with isotropic dis-
placement parameters. Correct absolute structures of
[CoL2phen] were determined by using the Flack
parameter [16]. Atomic scattering factors and anoma-
lous dispersion corrections for all atoms were taken
n=1; L%=bipy or phen.
n=2; L%=py or DMF.
3.1. Description of the structures of [CoL2 py2](1),
[CoL2 DMF2] (2), [CoL2 bipy] (3), and [CoL2 phen] (4)
The molecular structures are shown in Figs. 1–4.
Selected bond lengths and angles are given in Tables
Table 1
Summary of crystal data and structure refinement
Compound
[CoL2py2]
[CoL2DMF2]
[CoL2bipy]
[CoL2phen]
Empirical formula
Formula weight
Crystal system
C17H16Co0.5N3O2S
355.85
monoclinic
C15H18Co0.5N3O3S
349.85
monoclinic
C34H30CoN6O4S2
709.69
monoclinic
C36H30CoN6O4S2
733.71
monoclinic
P21 (no. 4)
Space group
P21/n (no 14)
P21/n (no 14)
P21/n (no. 14)
Unit cell dimensions
,
a (A)
9.5603(11)
18.934(2)
9.7615(15)
109.457(9)
1666.0(4)
4
9.5240(2)
18.5979(3)
10.21420(10)
111.4133(7)
1684.32(5)
4
10.8443(19)
21.2416(6)
14.386(4)
93.90(3)
3306.0(11)
4
9.4524(5)
19.6321(10)
9.6993(5)
109.8834(11)
1692.6(2)
2
,
b (A)
,
c (A)
i (°)
Volume (A )
3
,
Z
Absorption coefficient (mm−1
Reflections collected
Independent reflections
Reflections observed [\2|(I)]
Data/restraints/parameters
Final R indices [I\2|(I)]
)
0.688
4226
0.683
11983
0.693
7059
0.680
9376
4001 [Rint=0.0750]
1546
4001/0/266
R1=0.0495,
wR2=0.0853
4113 [Rint=0.0226]
3452
4113/0/205
R1=0.0363,
wR2=0.0955
6704 [Rint=0.1331]
2297
6703/0/424
R1=0.0642,
wR2=0.1276
7312 [Rint=0.0410]
4864
7312/1/442
R1=0.0718,
wR2=0.1294
−0.03(2)
Absolute structure parameter
Largest difference peak and hole (e A
−3
,
)
0.345 and −0.340
0.290 and −0.423
0.540 and −0.556
0.287 and −0.506

1610
S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
Fig. 1. Molecular structure of [CoL2py2] (1).
Fig. 2. Molecular structure of [CoL2DMF2] (2).
2–5 for each compound. In the four complexes the
cobalt atom is in a highly distorted octahedral environ-
ment but they are different to each other. In the case of
1, 3 and 4, the environment is [CoN6], and in 2 is
[CoO2N4]. Compounds 1 and 2 contain two NꢀN an-
ionic ligands and two monodentate ligands, but 3 and 4
have three bidentate NꢀN ligands, two anionic and one
neutral.
3.1.1. Molecular structure of [CoL2 py2] (1)
The cobalt atom in [CoL2py2] is in an octahedral
environment [CoN6]. The nitrogen atoms of the two
neutral pyridine molecules are in trans positions, and
the nitrogen atoms of the two anionic tosylato ligands
are in the equatorial plane. As the cobalt atom is in a
symmetry center, the equivalent nitrogen atoms of the
tosylato ligands are in trans positions.

S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
1611
The CoꢀN bond lengths of the apical positions are
anionic. Similar behaviour has been found in the pyri-
dine complex containing other anionic ligands, such as
in diaqua-dipyridyl-bis(N-(4-methyl-2-sulfamoyl-D2-1,
,
slightly longer, 2.164(3) A, than the CoꢀN bonds
lengths on the equatorial plane, 2.125(3) and 2.138(3)
A. This is probably because the apical ligands are
neutral, but the ligands in the equatorial plane are
,
3,4-thiadiazolin-5-ylidene)acetamide)cobalt(II)
[18],
,
with a Co(II)ꢀNpy distance of 2.198(2) A and other
Fig. 3. Molecular structure of [CoL2bipy] (3).
Fig. 4. Molecular structure of [CoL2phen] (4).

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S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
Table 2
3.1.2. Molecular structure of [CoL2 DMF2] (2)
,
Selected bond lengths (A) and angles (°) for [CoL2py2]
In this compound, the metal environment is
[CoN4O2]. The cobalt atom is in a centre of symmetry
coordinated by two N,N-bidentate anionic ligands and
by two molecules of DMF through the oxygen atom.
The coordination polyhedron can be described as an
octahedron with the neutral DMF ligands in the axial
positions and the anionic ligands in the equatorial
plane. As happens in [CoL2py2], the ligands in the
apical positions are slightly farther than the ligands in
the equatorial plane. All the other features are very
a
CoꢀN(11)
2.125(3)
2.138(3)
2.164(3)
1.588(3)
1.330(5)
1.383(5)
1.316(5)
CoꢀN(11
CoꢀN(12)
)
2.125(3)
2.138(3)
2.164(3)
1.772(4)
1.350(5)
1.323(5)
CoꢀN(12 a)
CoꢀN(21)
CoꢀN(21 a)
S(1)ꢀC(16)
N(11)ꢀC(15)
N(21)ꢀC(25)
S(1)ꢀN(12)
N(11)ꢀC(11)
N(12)ꢀC(15)
N(21)ꢀC(21)
N(11)ꢀCoꢀN(11 a)
N(11)ꢀCoꢀN(12)
N(11)ꢀCoꢀN(21)
N(11)ꢀCoꢀN(21 a)
N(21)ꢀCoꢀN(21 a)
C(11)ꢀN(11)ꢀC(15) 118.6(4)
N(11)ꢀC(11)ꢀC(12) 123.6(5)
C(21)ꢀN(21)ꢀC(25) 117.2(4)
N(21)ꢀC(25)ꢀC(24) 122.5(5)
180.0
N(11)ꢀCoꢀN(12 a)
117.07(11)
180.0
87.93(12)
92.07(13)
107.82(18)
123.7(3)
62.93(11) N(12 a)ꢀCoꢀN(12)
91.71(13) N(12)ꢀCoꢀN(21)
88.29(13) N(12)ꢀCoꢀN(21 a)
Table 3
180.0
N(12)ꢀS(1)ꢀC(16)
C(15)ꢀN(12)ꢀS(1)
N(11)ꢀC(15)ꢀN(12) 108.9(3)
N(21)ꢀC(21)ꢀC(22) 123.3(5)
,
Bond lengths (A) and angles (°) for [CoL2DMF2]
a
CoꢀN(1
)
2.1194(15) CoꢀN(1)
2.1415(14) CoꢀN(2)
2.1635(14) CoꢀO(21)
1.5856(14) SꢀC(6)
2.1194(15)
2.1415(13)
2.1635(14)
1.7808(18)
1.353(2)
CoꢀN(2 a)
CoꢀO(21 a)
SꢀN(2)
N(1)ꢀC(1)
N(2)ꢀC(5)
O(21)ꢀC(21)
N(21)ꢀC(23)
a Symmetry transformations used to generate equivalent atoms:
1.344(2)
1.387(2)
1.229(3)
1.434(3)
N(1)ꢀC(5)
N(21)ꢀC(22)
N(21)ꢀC(21)
−x+1, −y+1, −z+1.
1.473(3)
1.321(2)
N(1 a)ꢀCoꢀN(2 a)
N(1 a)ꢀCoꢀN(2)
N(2 a)ꢀCoꢀN(2)
N(1)ꢀCoꢀO(21 a)
N(2)ꢀCoꢀO(21 a)
N(1)ꢀCoꢀO(21)
N(2)ꢀCoꢀO(21)
N(1 a)ꢀCoꢀN(1)
62.97(5) N(1)ꢀCoꢀN(2 a)
117.03(5) N(1)ꢀCoꢀN(2)
117.03(5)
62.97(5)
87.97(6)
86.41(6)
92.03(6)
93.59(6)
180.0
,
CoꢀN distance of 2.108(2) A. Nevertheless, there are
180.0
N(1 a)ꢀCoꢀO(21 a)
some examples where the CoꢀNpy bond lengths are
longer than the other CoꢀN bond lengths and all the
ligands are neutral. That is the case for (1,3,5-tris-
(pyridine-2-carboxaldimino)-cyclohexane-N1,N2,N3,N4,
N5,N6)cobalt(II) diperchlorate [19], with average bond
92.03(6) N(2 a)ꢀCoꢀO(21 a)
93.59(6) N(1 a)ꢀCoꢀO(21)
87.97(6) N(2 a)ꢀCoꢀO(21)
86.41(6) O(21 a)ꢀCoꢀO(21)
180.0
N(2)ꢀSꢀC(6)
108.91(8)
127.91(14)
C(23)ꢀN(21)ꢀC(22) 117.8(2)
O(21)ꢀC(21)ꢀN(21) 125.5(2)
C(21)ꢀN(21)ꢀC(22) 121.0(2)
C(21)ꢀO(21)ꢀCo
C(21)ꢀN(21)ꢀC(23) 121.1(2)
,
,
distances CoꢀNpy of 2.231 A and CoꢀNimino of 2.131 A,
or (1,1,1-tris(pyridine-2-aldiminomethyl)ethane)-
cobalt(II) diperchlorate [20] with average bond dis-
tances CoꢀNpy of 2.150 A and CoꢀNimino of 2.097 A.
A tetrahedral coordination around the cobalt atom
has been found for bis{[(4-methylphenyl)sulfonyl][2-
(2-pyridyl)phenyl]amine}cobalt(II) [2]. In this case, the
a Symmetry transformations used to generate equivalent atoms:
1−x+, 1−y, 1−z.
,
,
Table 4
,
Selected bond lengths (A) and angles (°) for [CoL2bipy]
CoꢀN distances are shorter, average CoꢀNamide
1.963(2) and CoꢀNpy=2.042(2) A, as expected for a
complex with a lower coordination number.
The ligand bond distances and angles are normal and
do not deserve special discussion. The neutral pyridine
is almost perpendicular to the pyridine ring belonging
to the anionic ligand, with a dihedral angle of
86.93(12)°. The pyridine ring of the anionic ligand is
almost coplanar with the small chelate ring
=
CoꢀN(21)
CoꢀN(32)
CoꢀN(12)
S(1)ꢀN(12)
S(2)ꢀN(22)
N(11)ꢀC(11)
N(12)ꢀC(15)
N(21)ꢀC(25)
N(31)ꢀC(36)
N(32)ꢀC(31)
2.065(5)
2.120(5)
2.185(5)
1.606(6)
1.586(5)
1.345(8)
1.357(8)
1.361(8)
1.336(8)
1.332(8)
CoꢀN(31)
CoꢀN(11)
CoꢀN(22)
S(1)ꢀC(16)
S(2)ꢀC(26)
N(11)ꢀC(15)
N(21)ꢀC(21)
N(22)ꢀC(25)
N(31)ꢀC(310)
N(32)ꢀC(35)
2.107(6)
2.120(5)
2.259(5)
1.774(7)
1.774(7)
1.353(8)
1.332(8)
1.369(8)
1.347(8)
1.341(8)
,
CoꢀN(12)ꢀC(15)ꢀN(11), with
a dihedral angle of
N(21)ꢀCoꢀN(31)
N(31)ꢀCoꢀN(32)
N(31)ꢀCoꢀN(11)
N(21)ꢀCoꢀN(12)
N(32)ꢀCoꢀN(12)
N(21)ꢀCoꢀN(22)
N(32)ꢀCoꢀN(22)
N(12)ꢀCoꢀN(22)
N(22)ꢀS(2)ꢀC(26)
C(11)ꢀN(11)ꢀCo
C(15)ꢀN(12)ꢀS(1)
111.3(2)
76.6(2)
96.4(2)
96.0(2)
95.7(2)
N(21)ꢀCoꢀN(32)
N(21)ꢀCoꢀN(11)
N(32)ꢀCoꢀN(11)
N(31)ꢀCoꢀN(12)
N(11)ꢀCoꢀN(12)
94.3(2)
145.0(2)
113.1(2)
152.0(2)
61.4(2)
94.0(2)
97.01(19)
108.3(3)
3.92(14)°.
The most important deviation of the octahedron
from regularity is the small bite of the ligand,
62.93(11)°. This value is in the range for a four-member
chelate ring found for complexes of cobalt(II): 55.3° in
hexakis[(m2-methoxo)-(m2-s3-1,5-di-p-tolyl-1,4-penta-
azadienido)cobalt(II)] mesitylene solvate [21] and
65.8° in diaqua-bis[(N,N%-methylene-bis(L-prolinato)]-
cobalt(II) sesquihydrate [22] or 65.5° in diaqua-[N,N%-
61.36(19) N(31)ꢀCoꢀN(22)
149.1(2)
105.0(2)
107.3(3)
144.1(5)
123.4(5)
N(11)ꢀCoꢀN(22)
N(12)ꢀS(1)ꢀC(16)
C(11)ꢀN(11)ꢀC(15) 119.2(6)
C(15)ꢀN(11)ꢀCo 96.6(4)
N(11)ꢀC(15)ꢀN(12) 108.5(6)
N(12)ꢀC(15)ꢀC(14) 131.0(7)
N(11)ꢀC(15)ꢀC(14) 120.6(7)
methylene-bis(4-hydroxy-L-prolinato)]cobalt(II) [23].

S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
1613
,
Table 5
Selected bond lengths (A) and angles (°) for [CoL2phen]
shorter than the other, 2.259(6) and 2.066(6) A. Such
disposition of the ligands around the metal corresponds
approximately to non-crystallographic two-fold point
symmetry.
,
CoꢀN(31)
CoꢀN(32)
CoꢀN(11)
S(1)ꢀN(12)
S(2)ꢀN(22)
N(12)ꢀC(15)
N(11)ꢀC(11)
N(21)ꢀC(25)
N(31)ꢀC(31)
N(32)ꢀC(310)
2.113(5)
2.122(5)
2.143(5)
1.587(5)
1.586(6)
1.399(8)
1.351(8)
1.342(8)
1.339(8)
1.329(8)
CoꢀN(22)
CoꢀN(12)
CoꢀN(21)
S(1)ꢀC(16)
S(2)ꢀC(26)
N(11)ꢀC(15)
N(21)ꢀC(21)
N(22)ꢀC(25)
N(31)ꢀC(311)
N(32)ꢀC(312)
2.120(6)
2.140(5)
2.215(6)
1.782(7)
1.779(6)
1.349(8)
1.341(9)
1.390(8)
1.340(8)
1.363(7)
,
The distances CoꢀNbipy, 2.106(6) and 2.119(6) A, are
slightly shorter that those found in tris(2,2%-
bipyridine)cobalt(II) dichloride [25], average 2.130 A,
or in cis-dichloro-bis(2,2%-bipyridyl-N,N%)cobalt(II) [26],
,
,
average 2.154 A.
The distances and angles of the anionic ligands are
normal, with dihedral angles between the rings of
83.5(2) and 78.2(2)°, this last one in the case of the
anisodentate ligand. The free ligand shows dihedral
angles of 83.7(1) and 87.6(1)° [3].
N(31)ꢀCoꢀN(22)
N(22)ꢀCoꢀN(32)
N(22)ꢀCoꢀN(12)
N(31)ꢀCoꢀN(11)
N(32)ꢀCoꢀN(11)
N(31)ꢀCoꢀN(21)
N(32)ꢀCoꢀN(21)
N(11)ꢀCoꢀN(21)
O(12)ꢀS(1)ꢀN(12)
O(12)ꢀS(1)ꢀC(16)
N(22)ꢀS(2)ꢀC(26)
100.6(2)
104.5(2)
154.2(2)
159.4(2)
93.8(2)
96.6(2)
164.7(2)
95.3(2)
N(31)ꢀCoꢀN(32)
N(31)ꢀCoꢀN(12)
N(32)ꢀCoꢀN(12)
N(22)ꢀCoꢀN(11)
N(12)ꢀCoꢀN(11)
N(22)ꢀCoꢀN(21)
N(12)ꢀCoꢀN(21)
O(11)ꢀS(1)ꢀN(12)
O(11)ꢀS(1)ꢀC(16)
N(12)ꢀS(1)ꢀC(16)
C(15)ꢀN(12)ꢀS(1)
78.4(2)
99.0(2)
95.6(2)
99.7(2)
62.5(2)
61.8(2)
99.5(2)
106.9(3)
107.3(3)
106.1(3)
122.6(4)
3.1.4. Molecular structure of [CoL2 phen] (4)
Compound 4 contains a cobalt atom in a distorted
octahedral geometry coordinated by two nitrogen
atoms of an neutral ligand (phen), and by four nitrogen
atoms of two anionic ligands. This is similar to 3, but
there is an important difference between these com-
pounds in the disposition of the ligands around the
metal. In the case of 4, the amide nitrogen atoms of the
anionic ligands occupy the axial positions, and the
equatorial plane is formed by the pyridine nitrogen
atoms of the anionic ligands and the nitrogen atoms
of the phenanthroline molecule. This structure cor-
responds to that of the L isomer. This geometry has
also been found in the corresponding Ni(II) complexes
with this ligands and either bipyridine or phenanthro-
line [3].
112.0(3)
106.3(3)
105.8(3)
C(15)ꢀN(11)ꢀC(11) 118.5(6)
similar to those in [CoL2py2]. The CoꢀO bond length
,
(2.1635(14) A) and the angles CꢀOꢀCo (127.91(14)°) are
in the range for Co(II) complexes with DMF as the
ligand, like, for example, trans-bis(benzo(1,3)-thiazole)-
bis(N,N - dimethylformamide) - bis(isothiocyanato)co-
,
balt(II) [24], with values of 2.118 A and 126.14°, respec-
tively.
The CoꢀN distances to one of the anionic ligands are
very similar, 2.140(5) and 2.143(5) A, but the other
anionic ligand again shows an anisobidentate be-
,
3.1.3. Molecular structure of [CoL2 bipy] (3)
The cobalt atom in 3 is in a distorted octahedral
environment [CoN6], with the two anionic tosyl ligands
and the neutral bipyridine molecule as N,N-bidentate
ligands. The small bite angles of the ligands, especially
in the case of the anionic ligand, are the main reason
for the distortion. So, the angles NamideꢀCoꢀNpyridine are
61.3(2) and 61.4(2)° in each anionic ligand, with a
chelate ring of four members (see above) and 76.6(2)° in
the bipyridine, with a chelate ring of five members. The
pyridine fragments of the anionic ligands are in trans
positions, and consequently if these are considered as
the apical positions, the equatorial plane is formed by
the amide nitrogen atoms of the tosylamide ligands and
the nitrogen atoms of the bipyridine molecule. The
,
haviour, CoꢀN distances 2.120(6) and 2.215(6) A. The
dihedral angle between the pyridine ring and the phenyl
ring is 85.12(18) and 81.98(23)° in each ligand, respec-
tively. The disposition of the pyridine rings of the
ligands are almost perpendicular, with a dihedral angle
between the pyridine rings of 89.95(22)°.
,
The distances CoꢀNphen (2.113(5) and 2.122(5) A) are
quite similar to those found in 1,10-phenanthroline
bis{2-[(2-pyrrole)methylimino]phenolato}cobalt(II) [27],
2.22 and 2.16 A, and in tris(1,10-phenanthroline)-
cobalt(II) diperchlorate monohydrate [28] (average
,
,
,
,
2.128 A, max. 2.141 A, min. 2.109 A).
3.2. Spectroscopic and magnetic studies
,
cobalt atom is 0.024(3) A out of this equatorial plane.
The pyridine rings in trans positions are also almost
perpendicular between them, dihedral angle of 80.5(2)°,
and form dihedral angles with the equatorial plane of
76.5(2) and 79.3(2)°. It is worth noting that while the
CoꢀN bond distances in the case of one of the tosyl
The IR spectra of the complexes do not show the
band attributable to w(NꢀH), which in the free ligand
appears at 3230 cm−1, confirming that the hydrogen
atom of the amide group is lost during the electrolysis.
The IR spectra of the mixed complexes show IR ab-
sorptions typical of coordinated pyridine (662 and 430
,
ligands are quite similar, 2.121(6) and 2.185(6) A, for
the other one, one of the distances is significantly

1614
S. Cabaleiro et al. / Polyhedron 19 (2000) 1607–1614
cm−1), N,N-dimethylformamide (2923, 2850, 1650 and
1392 cm−1), 2,2%-bipyridine (764 and 736 cm−1) and
1,10-phenanthroline (1515, 847 and 727 cm−1).
[3] S. Cabaleiro, J. Castro, E. Va´zquez-Lo´pez, J.A. Garc´ıa-Va´zquez,
J. Romero, A. Sousa, Polyhedron 18 (1999) 1669.
[4] A.D. Garnovskii, B.I. Kharisov, G. Gojo´n-Zorrilla, D.A. Gar-
novskii, Russ. Chem. Rev. 64 (1995) 201.
[5] M.C. Chakravorti, G.V.B. Subrahmanyam, Coord. Chem. Rev.
135/136 (1994) 65.
[6] A.M. Vecchio-Sadus, J. Appl. Electrochem. 23 (1993) 401.
[7] J.A. Davies, C.M. Hokensmith, V.Yu Kukushkin, Yu N.
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Practice, Word Scientific, Singapore, 1996 (Chapter. 7).
[8] D.G. Tuck, Pure Appl. Chem. 51 (1979) 2005.
[9] (a) E.S. Raper, Coord. Chem. Rev. 61 (1985) 115. (b) E.S.
Raper, Coord. Chem. Rev. 153 (1996) 199. (c) E.S. Raper,
Coord. Chem. Rev. 165 (1997) 475.
The magnetic moments of [CoL2py2], 4.49 BM
[CoL2DMF2], 4.39 BM [CoL2bipy], 4.41 BM and
[CoL2phen] 4.66 BM, are in the low limit for high-spin
Co(II) complexes (4.7–5.2 BM). The solid reflectance
spectra of [CoL2py2], [CoL2DMF2], [CoL2bipy] and
[CoL2phen] show three bands at 28 170, 21 500, 9700,
28 450, 20 325, 8740, 25 757, 20 800, 8830 and 25 850,
20 600, 8925 cm−1, respectively. They can be assigned
4
4
4
to the T1g(P)’4T1g(F), A2g’4T1g and T2g’4T1g
transitions, and are in accordance with an octahedral
geometry for the complex. These conclusions are in
keeping with the X-ray diffraction results.
[10] J.A. Garc´ıa-Va´zquez, J. Romero, A. Sousa, Coord. Chem. Rev.
193–195 (1999) 691.
[11] A. Rodr´ıguez, J. Romero, J.A. Garc´ıa-Va´zquez, A. Sousa, K.
Maresca, D.J. Rose, J. Zubieta, Inorg. Chim. Acta 281 (1998)
70.
[12] J. Romero, M.L. Dura´n, J.A. Garc´ıa-Va´zquez, A. Castin˜eiras,
A. Sousa, L. Christiaens, J. Zubieta, Inorg. Chim. Acta 255
(1997) 307 and Refs. therein.
4. Supplementary material
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[14] G.M. Sheldrick, SADABS. An empirical absorption correction
program for area detector data, University of Go¨ttingen, Ger-
many, 1996.
[15] G.M. Sheldrick, SHELX-97, Program for the solution and refine-
ment of crystal structures, University of Go¨ttingen, Germany,
1997.
[16] H.D. Flack, Acta Crystallogr., Sect. A 39 (1983) 876.
[17] International Tables for X-ray Crystallography, vol. C, Kluwer,
Dordrecht, 1992.
The atomic positions, full list of bond lengths and
angles and other crystallographic data are available on
request from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (fax: +44-1223-336-033; e-mail: de-
posit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.
ac.uk), quoting the deposition numbers CCDC
139406–139409.
[18] G. Alzuet, S. Ferrer, J. Borra´s, A. Castin˜eiras, X. Solans, M.
Font-Bard´ıa, Polyhedron 11 (1992) 2849.
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[22] S.B. Teo, C.H. Ng, S.G. Teoh, C. Wei, J. Coord. Chem. 36
(1995) 141.
Acknowledgements
This work was supported by the Xunta de Galicia
under the grant XUGA20302B97. We thank an-
gus.uvigo.es (http://angus.uvigo.es/) for X-ray solution
and refinement facilities.
[23] S.B. Teo, S.G. Teoh, C.H. Ng, H.K. Fun, J.P. Declercq, Polyhe-
dron 14 (1995) 1447.
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