Electrochemical synthesis of nickel(II) complexes of tosylamides: Crystal structures of [(4-methylphenyl)sulfonyl]-imino-1H-pyridine], 2,2′-bipyridine bis{[(4-methylphenyl) sulfonyl]-2-pyridyl-amide}nickel(II) and 1,10-phenanthroline bis{[(4-methylphenyl) sulfonyl]-2-pyridyl-amide}nickel(II)

Article abstract of DOI:10.1016/S0277-5387(99)00049-2

The complex [NiL₂] has been synthesised by the electrochemical oxidation of nickel in an acetonitrile solution of [(4-methylphenyl)sulfonyl]-imino-1H-pyridine (HL). When the oxidation was carried out in the presence of neutral ligands L′ (pyridine, 2,2′-bipyridine or 1,10-phenanthroline) the complexes [NiL₂py₂], [NiL₂bipy] and [NiL₂phen] were obtained. The crystal structures of [(4-methylphenyl)sulfonyl]-imino-1H-pyridine, 2,2′-bipyridine bis{[(4-methylphenyl)sulfonyl]-2-pyridyl-amide}nickel(II) and 1,10-phenanthroline bis{[(4-methylphenyl) sulfonyl]-2-pyridyl-amide}nickel(II) were determined by X-ray diffraction methods. In the monomeric complexes, the nickel atom is in a distorted octahedral environment defined by the amide and pyridyl nitrogen atoms of the two ligands and the two bipyridine or phenanthroline nitrogen atoms. The vibrational and electronic spectra of the complexes are discussed and are shown to agree with the structures. Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(99)00049-2

Polyhedron 18 (1999) 1669–1674
Electrochemical synthesis of nickel(II) complexes of tosylamides: crystal
structures of [(4-methylphenyl)sulfonyl]-imino-1H-pyridine], 2,29-bipyridine
bish[(4-methylphenyl) sulfonyl]-2-pyridyl-amidejnickel(II) and 1,10-
phenanthroline bish[(4-methylphenyl) sulfonyl]-2-pyridyl-amidejnickel(II)
a
a
a
b
´
´
´
´
´
´
Santiago Cabaleiro , Jesus Castro , Ezequiel Vazquez-Lopez , Jose A. Garcıa-Vazquez ,
Jaime Romerob, Antonio Sousab ,
*
a
´
´
Departamento de Quımica Inorganica, Universidade de Vigo, E-36200 Vigo, Galicia, Spain
Departamento de Quımica Inorganica, Universidade de Santiago, E-15706 Santiago de Compostela, Galicia, Spain
b
´
´
Received 3 December 1998; accepted 12 February 1999
Abstract
The complex [NiL2] has been synthesised by the electrochemical oxidation of nickel in an acetonitrile solution of [(4-
methylphenyl)sulfonyl]-imino-1H-pyridine (HL). When the oxidation was carried out in the presence of neutral ligands L9 (pyridine,
2,29-bipyridine or 1,10-phenanthroline) the complexes [NiL2py2], [NiL2bipy] and [NiL2phen] were obtained. The crystal structures of
[(4-methylphenyl)sulfonyl]-imino-1H-pyridine, 2,29-bipyridine bish[(4-methylphenyl)sulfonyl]-2-pyridyl-amidejnickel(II) and 1,10-phen-
anthroline bish[(4-methylphenyl) sulfonyl]-2-pyridyl-amidejnickel(II) were determined by X-ray diffraction methods. In the monomeric
complexes, the nickel atom is in a distorted octahedral environment defined by the amide and pyridyl nitrogen atoms of the two ligands
and the two bipyridine or phenanthroline nitrogen atoms. The vibrational and electronic spectra of the complexes are discussed and are
shown to agree with the structures.
1999 Elsevier Science Ltd. All rights reserved.
Keywords: Electrochemical synthesis; Nickel (II) complexes; Amide complexes; X-ray
1. Introduction
For these reasons, and as a result of our interest in the
metallic complexes of amide ligands, we now report the
electrochemical synthesis of a nickel(II) complex with
It is well known that metal complex formation by the
substitution of a metal ion for an amide proton is a very
difficult process [1]. However, this process is facilitated by
the presence of an additional donor atom on the molecule,
permitting the formation of a stable five or six membered
chelate ring with the metal ion [2,3], or by the presence in
the amide group of groups, such as tosyl, which have a
strong inductive electronic effect and thereby increase the
acidity of the amide hydrogen.
[(4-methylphenyl)sulfonyl]-imino-1H-pyridine (HL),
a
molecule containing a weakly acidic N–H group and a
pyridine ring which can lead to chelation involving the
pyridine nitrogen and the deprotonated nitrogen of the
amide. We have also prepared mixed complexes containing
this anionic ligand and pyridine (py), 2,29-bipyridine
(bipy) or 1,10-phenanthroline (phen) by the same method.
2. Experimental
Acetonitrile, dichloromethane, 2-aminopyridine, tosyl
chloride, pyridine, 2,29-bipyridine, 1,10-phenanthroline
and all other reagents were commercial products and were
used as supplied. Nickel (Aldrich Chemie) was used as
232 cm plates.
*Corresponding author. Tel.: 134-981-563-100; fax: 134-981-597-
525.
The parent molecule, HL (1) was prepared by reaction
of the amine and the tosyl chloride in a 2:1 ratio in
E-mail addresses: fojo@uvigo.es (J. Castro), qiansoal@usc.es (A.
Sousa)
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00049-2
1999 Elsevier Science Ltd. All rights reserved.

1670
S. Cabaleiro et al. / Polyhedron 18 (1999) 1669–1674
dichloromethane. A diluted aqueous solution of K2CO3
was added to the mixture until pH 10 and the resultant
white product collected by filtration of the organic phase,
and dried in vacuo. Anal: C: 58.19%, H: 5.06%, N:
11.33%, S: 12.98%; Calc for C12H12N2SO2: C: 58.05%,
H: 4.88%, N:11.29%, S: 12.91%. 1H NMR (Cl3CD, ppm)
2.4 -CH3; 13.6 N–H; 7.8, 7,3 benzene ring; 6.8, 7.4, 7.6,
8.3 pyridine ring. IR (KBr, cm21): 3230(m); 3127(m);
3056(w); 1915(w); 1866 (w); 1793(w); 1654 (sh); 1635(s);
1534 (m); 1463(w); 1393(m); 1375 (m); 1282 (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). The product was recrystallised from
CH3CN/(CH3)2CO to give crystals suitable for X-ray
diffraction crystallography.
for [C34H32N6O4S2Ni]: H, 4.53%; C, 57.40%; N 11.81%;
S, 9.01%. IR (KBr, cm21): 3061(w); 1595(s); 1559(m);
1464 (s); 1267(m); 1133(s); 1091(m); 1020(m); 988(m);
780(m); 759(m); 703(m); 662(s) 631(w); 577(m); 555(m);
531(m); 437(m).
[NiL2bipy] (4). Electrolysis of an acetonitrile–dichloro-
methane (25125 cm3) solution containing HL (200.3 mg,
0.81 mmol), 2,29-bipyridine (53.2 mg, 0.40 mmol) and
tetraethylammonium perchlorate (ca. 20 mg) at 10 mA and
14 V for 2 h dissolved 20.5 mg of nickel (Ef 50.47). At
the end of the experiment the blue-grey solid was filtered,
washed with hot acetonitrile and diethyl ether and dried in
vacuo. This solid was recrystallised from (CH3)2CO/
CH3CN to give crystals suitable for X-ray diffraction. The
compound was characterised as [NiL2bipy].(CH3)2CO.
Anal. Found: C, 57.57%; H, 4.66%; N, 11.38%; S, 7.89%.
Calc. for [C37H36N6NiO5S2]: C, 57.90%; H, 4.73%; N,
10.95%; S, 8.36%. IR (KBr, cm21): 3094(vw); 3060(vw);
1706(m); 1592(s); 1559(w); 1461(s); 1438(s); 1319(s);
1140(s); 1112(w) 1089(m); 1043(w); 1010(m); 984(m);
813(w); 773(m); 735(m); 709(w); 668(m); 657(m); 577(s);
553(m).
[NiL2phen] (5). Electrolysis of an acetonitrile–dichloro-
methane (25125 cm3) solution containing HL (220.4 mg,
0.89 mmol), 1,10-phenanthroline (80.0 mg, 0.44 mmol)
and tetraethylammonium perchlorate (ca. 20 mg) at 10 mA
and 10 V for 2 h dissolved 20.2 mg of nickel (Ef 50.46).
At the end of the experiment the blue-grey solid was
filtered, washed with hot acetonitrile and diethyl ether and
dried in vacuo. This solid was recrystallised from
(CH3)2CO/CH3CN and crystals suitable for X-ray diffrac-
tion were obtained. The compound was characterised as
[NiL2phen]: Anal. Found: C, 58.61%; H, 4.05%; N,
11.51%; S, 8.90%. Calc. for [C36H30N6O4S2Ni]: C,
58.95%; H, 4.12%; N, 11.46%; S, 8.74%. IR (KBr, cm21):
3056(vw); 3025(vw); 1652(m); 1589(s); 1557(m); 1520(m);
1495(w); 1457(m); 1134(m); 1010(m); 844(m); 776(m);
728(m); 707(m); 675(m); 655(m); 577(m); 552(m).
2.1. Electrochemical synthesis
The electrochemical procedure was similar to that
described by Odlhan and Tuck [4]. The cell was a 100 cm3
beaker fitted with a rubber bung through which the
electrochemical leads entered the cell. The nickel anode
was suspended from a platinum wire, and another platinum
wire formed the cathode. The tosyl parent (HL) and the
additional ligand (py, bipy or phen) were dissolved in
acetonitrile–dichloromethane and a small amount of tetra-
ethylammonium perchlorate (ca. 20 mg) was added as
current carrier. Direct current was obtained from a pur-
pose-built d.c. power supply. In all cases, hydrogen was
evolved at the cathode. The cells can be summarised as:
Pt(2) /CH3CN1HL1(py, bipy or phen)/Ni(1)
.
[NiL2] (2). Electrolysis of an acetonitrile–dichlorome-
thane (25125 cm3) solution containing HL (200 mg, 0.81
mmol) and tetraethylammonium perchlorate (ca. 20 mg) at
10 mA and 12 V for 2 h dissolved 21.2 mg of nickel
(Ef 50.48). At the end of the experiment the green/blue
crystalline solid was filtered, washed with acetonitrile and
diethyl ether, dried in vacuo, and crystallised from
CH3CN. The compound was characterised as [NiL2].H2O:
Anal. Found: H, 3.91%; C, 50.21%; N 10.48%; S, 10.83%.
Calc. for [C24H24N4O5S2Ni]: H, 4.23%; C, 50.46%; N
9.81%; S, 11.22%. IR(KBr, cm21) 2360(vw); 1733(w);
1384(w); 1590(s); 1563(w); 1506(m); 1457(m); 1318(m);
1267(m); 1137(m); 1091(m); 1041(w); 1012(m); 991(m);
818(w); 793(m); 769(s); 748(w); 709(m); 668(m); 651(m);
577(m) 553(m); 418(w).
[NiL2py2] (3). Electrolysis of an acetonitrile–dichloro-
methane (25125 cm3) solution containing HL (190.0 mg,
0.77 mmol), pyridine (127 mg, 1.60 mmol) and tetra-
ethylammonium perchlorate (ca. 20 mg) at 10 mA and 7 V
for 2 h dissolved 18.3 mg of nickel (Ef 50.42). At the end
of the experiment the solid product was filtered, washed
with hot acetonitrile and diethyl ether and dried in vacuo.
The compound was characterised as [NiL2py2]: Anal.
Found: H, 4.36%; C, 57.16%; N 11.52%; S, 8.43%. Calc.
2.2. Physical measurements
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 Vector-22
1
spectrophotometer. The H NMR spectra were recorded on
a Bruker ARX-400 MHz spectrometer using Cl3CD as
solvent. Solid state electronic spectra were recorded on a
Shimadzu UV 3101 PC. Magnetic measurements were
made using a DMS VSM 1160 instrument.
2.3. Crystal structure determination
The data collection was on a SIEMENS Smart CCD
area-detector diffractometer with graphite-monochromated
˚
Mo Ka radiation, l50.71073 A at room temperature.
All the structures were solved by direct methods [5] and

S. Cabaleiro et al. / Polyhedron 18 (1999) 1669–1674
1671
Table 1
Summary of crystal data and structure refinement
Compound
HL (1)
[NiL2bipy]?(CH3)2CO. (4)
[NiL2phen] (5)
Empirical formula
Formula weight
C24H24N4O4S2
496.59
C37H36N6O5S2Ni
767.55
C36H30N6NiO4S2
733.49
Crystal system/space group
Unit cell dimensions
Monoclinic/P21 /c (No. 14)
Orthorhombic/P212121 (No. 19)
Orthorhombic/P212121 (No. 19)
˚
˚
˚
a510.8142(5) A
a510.247(2) A
a510.46150(10) A
˚
˚
˚
b515.1088(7) A
b514.298(5) A
b514.0533(2) A
˚
˚
˚
c514.7701(7) A
c525.199(7) A
c525.7907(4) A
b5104.1583(13)8
2340.0(2) A
3
3
3692(2) A3
3791.71(9) A
˚
˚
Volume
Z
4
4
4
Density (calculated)
Absorption coefficient
F(000)
1.410 Mg/m3
1.381 Mg/m3
1.285 Mg/m3
0.267 mm21
1040
0.689 mm21
1600
0.666 mm21
1520
Crystal size/colour
Theta range for data collection
Index ranges
0.6030.2530.15 mm/White
1.94 to 28.308.
210#h#14, 220#k#20, 219#l#19
0.3530.1530.10 mm/grey-blue
1.62 to 28.298
213#h#13, 219#k#10, 233#l#33
0.3030.2530.15 mm/grey-blue
1.58 to 28.398
212#h#13, 218#k#16, 226#l#34
Reflections collected
Independent reflections
Reflections observed
Criterion for observation
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I.2s(I)]
Absolute structure parameter
Largest diff. peak and hole
12281
5713 [R(int)50.1015]
2256
.2s(I)
5713/0/403
0.915
19790
9077 [R(int)50.1900]
3177
.2s(I)
9077/0/460
1.018
R1 50.0903, wR2 50.1415
20.03(3)
0.532 and 20.615 e A
21155
9373 [R(int)50.1102]
4448
.2s(I)
9373/0/442
0.957
R1 50.0672, wR2 50.1298
R1 50.0834, wR2 50.1793
0.03(3)
23
23
0.650 and 20.713 e A23
˚
˚
0.300 and 20.558 e A
refined by a full-matrix least-squares based on F2 [6]. Non
hydrogen atoms were refined with anisotropic displace-
ment parameters. Hydrogen atoms were included in ideal-
ised positions and refined with isotropic displacement
parameters, except those from the free ligand which were
located. The SQUEEZE program [7] was used to correct
the reflection data for the diffuse scattering due to dis-
ordered solvent found in the [NiL2phen] complex. Correct
absolute structures of both complexes were determined by
using the Flack parameter. Atomic scattering factors and
anomalous dispersion corrections for all atoms were taken
from International Tables for X-ray Crystallography [8].
Details of crystal data and structural refinement are given
in Table 1.
The overall reactions can be described as
Ni 1 2HL → [NiL2] 1 H2
9
Ni 1 2HL 1 nL9 → [NiL2Ln] 1 H2.
3.1. Description of the structure of HL, (1).
Fig. 1 shows a view of 1 together with the atomic
3. Results and discussion
Anodic oxidation of nickel metal in the presence of
(4-methylphenyl)sulfonyl]-imino-1H-pyridine, alone or
dissolved with the coligands pyridine (py), 2,29-bipyridine
(bipy) or 1,10-phenanthroline (phen) yields crystalline
products with formula [NiL2], [NiL2py2], [NiL2bipy] and
[NiL2phen], respectively. The values of the electrochemi-
cal efficiency, defined as the amount of metal dissolved per
number of Faradays, were close to 0.5 mol F21 in all
cases. This value is compatible with the mechanism,
Cathode: HL 1 2e2 → 2L2 1 H2
Fig. 1. ORTEP draw of the compound HL (1) showing the atom label
scheme and the hydrogen bonds.
Anode: Ni → Ni21 1 2e2

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S. Cabaleiro et al. / Polyhedron 18 (1999) 1669–1674
Table 2
Table 3
˚
Selected bond lengths [A] and angles [8] for HL (1)
Hydrogen bonds in the asymmetric unit of the ligand
S(1)–O(11)
S(1)–N(12)
N(11)–C(11)
N(12)–C(15)
S(2)–O(22)
S(2)–N(22)
N(21)–C(21)
N(22)–C(25)
1.433(3)
1.611(3)
1.339(5)
1.346(4)
1.439(3)
1.600(3)
1.358(5)
1.354(5)
S(1)–O(12)
S(1)–C(16)
N(11)–C(15)
C(14)–C(15)
S(2)–O(21)
S(2)–C(26)
N(21)–C(25)
C(24)–C(25)
1.435(3)
1.767(4)
1.362(5)
1.406(5)
1.451(3)
1.762(4)
1.364(5)
1.411(6)
Atoms: A???HD
d(D–H)
d(H..A)
d(D..A)
,DHA
N(12)???H(2)–N(21)
N(22)???H(1)–N(11)
O(12)???H(2)–N(21)
O(22)???H(1)–N(11)
0.90(4)
0.83(4)
0.90(4)
0.83(4)
2.01(4)
2.13(4)
2.78(4)
2.86(4)
2.909(5)
2.959(5)
3.266(5)
3.330(4)
169.98
172.48
115.38
117.78
O(11)–S(1)–O(12)
O(12)–S(1)–N(12)
O(12)–S(1)–C(16)
C(11)–N(11)–C(15)
N(11)–C(11)–C(12)
N(12)–C(15)–C(14)
O(22)–S(2)–O(21)
O(21)–S(2)–N(22)
N(22)–S(2)–C(26)
C(21)–N(21)–C(25)
C(22)–C(21)–N(21)
N(22)–C(25)–C(24)
117.7(2)
104.9(2)
106.6(2)
124.2(4)
121.3(4)
130.7(4)
117.3(2)
113.9(2)
105.6(2)
123.8(4)
119.7(5)
130.7(4)
O(11)–S(1)–N(12)
O(11)–S(1)–C(16)
N(12)–S(1)–C(16)
C(15)–N(12)–S(1)
N(12)–C(15)–N(11)
N(11)–C(15)–C(14)
O(22)–S(2)–C(26)
O(21)–S(2)–C(26)
O(22)–S(2)–N(22)
C(25)–N(22)–S(2)
N(22)–C(25)–N(21)
N(21)–C(25)–C(24)
114.0(2)
107.5(2)
105.2(2)
123.1(3)
114.0(3)
115.2(4)
107.4(2)
107.0(2)
105.0(2)
122.1(3)
113.4(4)
115.8(4)
other, so each H(N) atom is participating in a bifurcated
hydrogen bond with the Namide and one oxygen atom of the
other molecule in the asymmetric unit. These bond lengths
and angles are given in Table 3.
3.1.1. Description of the structures of [NiL2bipy] (4)
and [NiL2 phen] (5)
The molecular structures of 4 and 5 are shown in Figs. 2
and 3. Selected bond lengths and angles are given in
Tables 4 and 5, respectively. The complexes are isostruc-
tural, with the nickel atom in a highly distorted octahedral
number scheme. Selected bond lengths and angles with the
estimated deviations are listed in Table 2. The bond
distances and bond angles are similar to those found in
other N-2-pyridinyl benzenesulfonamide derivatives [9–
12].
The most relevant feature is the presence of the hydro-
gen atom on the N-pyridine ring, indicating that the free
ligand is the imido tautomer (I) rather than the amido
tautomer (II).
Fig. 2. ORTEP drawing of [NiL2bipy](CH3)2CO (4). The ellipsoids
correspond to 30% probability.
Both, the phenyl and the pyridine rings are almost
planar, with the largest deviations being 0.012(3) and
˚
0.008(3) A, respectively. The interplanar angles of
83.69(10)8 and 87.62(11)8 are similar to those found in
other sulfonamides [11]. In addition, the molecules of
[(4-methylphenyl)sulfonyl]-imino-1H-pyridine are associ-
ated by intermolecular hydrogen bonds between the atoms
in two independent molecules of the unit cell, leading to
the formation of a dimer. These hydrogen bonds are
between the pyridine nitrogen atom of one molecule and
the amide nitrogen atom of the other neighbour. In
addition, one oxygen atom of the sulfone group [O(22),
O(12)] of one molecule is involved in a hydrogen bond
with the nitrogen of the pyridine ring [N(11), N(21)] of the
Fig. 3. ORTEP drawing of [NiL2phen] (5). The ellipsoids correspond to
30% probability.

S. Cabaleiro et al. / Polyhedron 18 (1999) 1669–1674
1673
Table 4
Selected bond lengths [A] angles [8] for [NiL2bipy]?(CH3)2CO (4)
to each other. The distortion of the octahedral geometry is
mainly due to the small bite of the ligand, with an average
angle Npy –Ni–Namide of 63.0(2)8 for [NiL2bipy] and
63.8(2)8 for [NiL2phen]. These values are similar to those
found in other nickel(II) complexes containing four-
member N,N-chelate rings; e.g. N–Ni–N, 59.078 and
59.738 in bis(m2-hydroxo)-(m2-1,2-bis(phenyltriazenidyl)
benzene - N,N9,N0,N-) - bis(1,2 - bis(phenyltriazenidyl) ben-
zene)-di-nickel(II) [13] and 66.688 in chloro-(6-methoxy-
methyl-1,3,6,8,11,14-hexa-azabicyclo(12.2.1)heptadecane-
N,N9,N0,N-,N+)-nickel(II)perchlorate [14].
˚
Ni–N(32)
Ni–N(11)
Ni–N(12)
S(1)–N(12)
N(11)–C(11)
S(2)–N(22)
N(21)–C(21)
N(22)–C(25)
N(31)–C(31)
N(32)–C(310)
2.047(5) Ni–N(31)
2.089(5) Ni–N(22)
2.104(6) Ni–N(21)
1.601(7) N(11)–C(15)
1.352(3) N(12)–C(15)
1.580(7) S(1)–C(16)
1.329(3) N(21)–C(25)
1.393(8) S(2)–C(26)
1.324(3) N(31)–C(35)
1.336(3) N(32)–C(36)
2.061(5)
2.101(7)
2.142(6)
1.349(3)
1.403(8)
1.762(6)
1.357(3)
1.771(7)
1.333(3)
1.364(3)
N(32)–Ni–N(31)
N(31)–Ni–N(11)
N(31)–Ni–N(22)
N(32)–Ni–N(12)
N(11)–Ni–N(12)
N(32)–Ni–N(21)
N(11)–Ni–N(21)
N(12)–Ni–N(21)
C(15)–N(12)–S(1)
79.8(2)
163.3(2)
102.8(3)
97.1(3)
63.1(2)
159.0(2)
93.6(2)
N(32)–Ni–N(11)
N(32)–Ni–N(22)
N(11)–Ni–N(22)
N(31)–Ni–N(12)
N(22)–Ni–N(12)
N(31)–Ni–N(21)
N(22)–Ni–N(21)
N(12)–S(1)–C(16)
98.6(2)
99.1(2)
93.9(3)
100.5(2)
153.6(3)
93.3(2)
62.9(2)
105.8(3)
˚
The Ni–Namide bond distances [2.104(6), 2.101(7) A] in
˚
4 and [2.095(6), 2.096(6) A] in 5 are very similar, but, as
expected, significantly longer than those found in tetra-
˚
hedral [1.916(3) [15], 1.839(6) [16] A] or square planar
˚
[1.904(3) A] [17] nickel(II) amide complexes, in keeping
with the lower co-ordination number in these compounds.
103.7(3)
121.4(5)
The Ni–Npy bond distances in 4 and 5 differ slightly, one
N(11)–C(15)–N(12) 105.6(5)
N(22)–S(2)–C(26) 105.1(4)
N(21)–C(25)–N(22) 107.2(5)
˚
[2.089(5) in 4 and 2.063(5) A in 5] being shorter than
C(14)–C(15)–N(12) 131.6(5)
C(25)–N(22)–S(2) 123.7(6)
C(24)–C(25)–N(22) 130.3(5)
˚
other [2.142(6) in 4 and 2.110(6) A in 5]. These values are
˚
larger than that of 1.905(4) A found in square planar
bis-m-h2-2[2-(pyridylethyl) amino]ethylthiolato] dinic-
˚
kel(II) perchlorate [18] and 1.897(3) A in bish4-methyl-N-
(2-pyridin-2-yl-ethyl) benzenesulfonamidej nickel(II) [17],
environment, [NiN6]. Two of the nitrogen atoms belong to
a bidentate bipyridine or phenanthroline ligand, and two
anionic forms L2 groups each provide an amide and a
pyridine nitrogen atom; so that each forms a four-mem-
bered chelate ring. The arrangement of the two ligands is
such that the two amide nitrogen atoms are in a cis
arrangement and the two pyridine nitrogen atoms are trans
but shorter than those in other pyridine complexes of
˚
six-coordinate nickel(II); e.g. 2.175(3) A in bishN-[2[2-(2-
pyridyl)ethyl] salicylideneiminatoj nickel(II) [19] and
˚
2.209(4) A in bish1,1,1,-trifluoromethyl)-2-pentanolatoj
nickel(II) [20], probably as a result of the anionic character
of the nitrogen donor atom.
The Ni–Nbipy bond distances of 4 are only slightly
different from those reported for Ni–Nbipy in cis-bis-
˚
(benzenethiolato)bis(2,29-bipyridine) nickel(II), 2.089 A
Table 5
˚
Selected bond lengths [A] angles [8] for [NiL2phen] (5)
[21] and for other hexacoordinated nickel(II) complexes,
such as (2,29-bipyridine)bis(pyridine-2-thiolato)nickel(II),
2.074(2) and 2.067(3) A [22]. Similarly, the Ni–Nphen
bond distances in 5 are shorter than those found in other
Ni–N(31)
Ni–N(11)
Ni–N(12)
S(1)–N(12)
N(11)–C(15)
N(12)–C(15)
S(2)–N(22)
N(21)–C(21)
N(31)–C(35)
N(32)–C(36)
2.031(6) Ni–N(32)
2.063(5) Ni–N(22)
2.096(6) Ni–N(21)
1.598(6) S(1)–C(16)
1.355(9) N(11)–C(11)
1.406(8) N(22)–C(25)
1.587(6) S(2)–C(26)
1.335(9) N(21)–C(25)
1.337(9) N(31)–C(31)
1.320(9) N(32)–C(310)
2.052(6)
2.095(6)
2.110(6)
1.717(8)
1.367(9)
1.361(8)
1.755(8)
1.391(9)
1.358(9)
1.373(8)
˚
mixed hexacoordinated nickel(II) complexes containing
˚
1,10-phenanthroline, e.g 2.121(5), 2.136(5) A in 1,10-
phenanthroline
bish[2-(2-pyrrole)-methylimino-4-methyl
phenolatojnickel(II) [23].
The two pyridine portions of the bipyridine ligand are
planar, with no atom deviating from the least-squares plane
˚
N(31)–Ni–N(32)
N(32)–Ni–N(11)
N(32)–Ni–N(22)
N(31)–Ni–N(12)
N(11)–Ni–N(12)
N(31)–Ni–N(21)
N(11)–Ni–N(21)
N(12)–Ni–N(21)
C(11)–N(11)–C(15)
N(11)–C(15)–N(12)
N(12)–C(15)–C(14)
C(21)–N(21)–C(25)
N(22)–C(25)–N(21)
N(21)–C(25)–C(24)
79.6(2)
163.6(2)
102.2(2)
96.3(2)
64.0(2)
160.8(2)
92.0(2)
102.7(2)
116.1(7)
105.8(6)
130.0(7)
116.7(7)
107.2(6)
120.0(7)
N(31)–Ni–N(11)
N(31)–Ni–N(22)
N(11)–Ni–N(22)
N(32)–Ni–N(12)
N(22)–Ni–N(12)
N(32)–Ni–N(21)
N(22)–Ni–N(21)
N(12)–S(1)–C(16)
C(15)–N(12)–S(1)
N(11)–C(15)–C(14) 124.1(6)
N(22)–S(2)–C(26)
C(25)–N(22)–S(2)
N(22)–C(25)–C(24) 132.7(7)
C(35)–N(31)–C(31) 116.0(6)
98.7(2)
99.6(2)
94.2(3)
99.8(2)
154.8(2)
94.5(2)
63.6(2)
107.0(3)
121.7(5)
by more than 0.014 A. The interplanar angle between these
two pyridine rings is 9.278, similar to that found in
[Ni(bipy)3]SO4 [24] and in [Ni(bipy)3](ClO4)3 [25]. The
phenanthroline ligand is also essentially planar, with
maximum carbon and nitrogen displacements of 0.032(7)
˚
˚
A and 0.045(6) A, respectively. The bond lengths and
angles within the bipyridine and phenanthroline are similar
to those found in other bipyridine and phenanthroline
complexes. The pyridine portion of the ligand is planar,
107.1(4)
124.1(5)
˚
with the largest deviation being 0.015(6) A from the
least-squares plane. The deviation of the exocyclic nitro-
˚
gen amide atom is 0.036(5) A, so that these nitrogen atoms
C(36)–N(32)–C(310) 117.0(6)
are practically in the plane of the pyridine ring to which

1674
S. Cabaleiro et al. / Polyhedron 18 (1999) 1669–1674
they are bound. The nickel atom is also practically in the
plane of the pyridine group of one of the ligands, with
Acknowledgements
˚
deviations of only 0.055(12) A for [NiL2bipy] and
We thank the Xunta de Galicia (Xuga-20302B97) for
financial support.
˚
0.070(10) A for [NiL2phen], but lies 0.124(13) and
˚
0.269(10) A out of the plane of the pyridine portion of the
other ligand.
˚
The average N–C distance in the ligands, 1.398(8) A, is
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Supplementary data are available from the CCDC, 12
Union Road, Cambridge CB2 1EZ, UK on request, quoting
the deposition numbers 111587, 111588, and 111589.