O,O′-dialkyldithiophosphato and O-alkyldithiophosphato nickel(II) complexes with bidentate P-donor ligands

Article abstract of DOI:10.1016/S0277-5387(03)00101-3

The following complexes, having the general formula [Ni(S₂P{O}OR)(P-P)]{R = Et (1), i-Pr (2), P-P = dppe; R = Et (3), P-P = 1,4-bis(diphenylphosphino)butane (dppb)}, [Ni(S₂P{OR}₂)(P-P)]X {R = i-Pr (4), Et (5), P-P = 1,2-bis(diphenylphosphino)ethane (dppe); R = Et, P-P = 1,1-bis(diphenylphosphino)methane (dppm) (6); X = ClO₄^-} and [Ni(S₂P{OR}2)(dppe)X] {R = i-Pr, X = NCS^- (7); R = Et, X = Br^- (8)}, have been synthesized. All the compounds have been characterized by elemental analyses, IR, UV-Vis, and ³¹P{¹H} NMR spectral studies, magnetic and conductivity measurements. Single crystal X-ray analysis revealed the molecular structures of [Ni(S₂P{O}OEt)(dppe)] (1), [Ni(S₂P{O}OEt)(dppb)]·EtOH (3) and [Ni(S₂P{OEt}₂)(dppe)]ClO₄ (5), and confirmed a square-planar geometry around the nickel atoms. We have reason to believe that the coordination geometry in [Ni(S₂P{OEt}₂)(dppe)Br]·H₂O (8) is probably tetrahedral with monodentate coordinated (S₂P{OEt}₂) monoanion.

Full text of DOI:10.1016/S0277-5387(03)00101-3

Polyhedron 22 (2003) 1341ꢂ1348
/
www.elsevier.com/locate/poly
O,O?-Dialkyldithiophosphato and O-alkyldithiophosphato nickel(II)
complexes with bidentate P-donor ligands
Lucie Szucˇova´ a, Zdeneˇk Tra´vn´ıcˇek a,*, Jarom´ır Marek b
˝
a Department of Inorganic and Physical Chemistry, Palacky´ University, Krˇ´ızˇkovske´ho 10, CZ-771 47 Olomouc, Czech Republic
b Laboratory of Functional Genomics and Proteomics, Masaryk University, Kotla´rˇska´ 2, CZ-611 37 Brno, Czech Republic
Received 26 November 2002; accepted 10 February 2003
Abstract
The following complexes, having the general formula [Ni(S2P{O}OR)(Pꢀ
Pꢀ1,4-bis(diphenylphosphino)butane (dppb)}, [Ni(S2P{OR}2)(PꢀP)]X {Rꢀ
no)ethane (dppe); RꢀEt, PꢀPꢀ1,1-bis(diphenylphosphino)methane (dppm) (6); Xꢀ
i-Pr, Xꢀ Et, Xꢀ
NCSꢁ (7); Rꢀ Brꢁ (8)}, have been synthesized. All the compounds have been characterized by elemental
analyses, IR, UVꢂ
Vis, and 31P{1H} NMR spectral studies, magnetic and conductivity measurements. Single crystal X-ray analysis
revealed the molecular structures of [Ni(S2P{O}OEt)(dppe)] (1), [Ni(S2P{O}OEt)(dppb)]×EtOH (3) and [Ni(S2P{OEt}2)(dppe)]ClO4
(5), and confirmed a square-planar geometry around the nickel atoms. We have reason to believe that the coordination geometry in
H2O (8) is probably tetrahedral with monodentate coordinated (S2P{OEt}2) monoanion.
/
P)] {Rꢀ
i-Pr (4), Et (5), Pꢀ
ClO4ꢁ} and [Ni(S2P{OR}2)(dppe)X] {Rꢀ
/
Et (1), i-Pr (2), Pꢀ
/
Pꢀ
/
dppe; Rꢀ
/
Et (3), Pꢀ
/
/
/
/
/
Pꢀ
/1,2-bis(diphenylphosphi-
/
/
/
/
/
/
/
/
/
/
[Ni(S2P{OEt}2)(dppe)Br]×
/
# 2003 Elsevier Science Ltd. All rights reserved.
Keywords: Nickel(II); Dithiophosphates; Syntheses; X-ray structures
1. Introduction
decades [7]. These complexes, with the ligands acting
as a chelate and forming four-membered rings with
nickel, can readily react with both monodentate and
polydentate nitrogen- or phosphorus-donor ligands,
thereby increasing the coordination number of nickel.
To date, considerable attention has been devoted to
adducts of [Ni(S2P{OR}2)2] with nitrogen-donor ligands
O,O?-Dialkyl(aryl)esters of dithiophosphoric acid
(RO)2P(S)SH have been well documented [1], with
previous applications as insecticides and as inhibitors
of hydrolysis of the enzyme acetylcholinesterase to its
substrate acetylcholine, thus causing muscular paralysis
[2]. The insecticidal, rodenticidal and fungicidal activ-
ities of esters with the general formula (RO)2P(S)SX
[3,8ꢂ10]. Only a few studies have focused on the
/
preparation and characterization of nickel-dithiopho-
sphato complexes in combination with monodentate P-
(Xꢀacetylphenyl or alkylurea), as well as the use of
/
these compounds in the process of rubber vulcanization
have also been described [3,4]. O,O?-Dialkyldithiophos-
phates can also be used in analytical chemistry as
extraction agents [5], such as the proposed use of
bis(O,O?-dipropyldithiophosphato)nickel(II) for spec-
troscopic determination of the alcohol contents in
alcoholic drinks [6]. In relation to these findings,
square-planar complexes with the formula [Ni(S2-
P{OR}2)2] have been also investigated for several
donor ligands [11ꢂ
bidentate nature [15]. However, the reaction between
[Ni(S2P{OMe}2)2] and dppe (dppeꢀPh2PꢀCH2CH2ꢀ
/
14], especially with those that are of a
/
/
/
PPh2) led to formation of [Ni(S2P{O}OMe)(dppe)].
Thus, the reaction is accompanied by the removal of
one (S2P{OMe}2)ꢁ ligand and the elimination of a
methyl group from the other (S2P{OMe}2)ꢁ to afford
(S2P{O}OMe)2ꢁ. In the case of [Ni(S2P{O}OR)(dpae)]×
0.5C6H6, where (dpaeꢀPh2PꢀCH2CH2ꢀAsPh2), single
/
/
/
/
crystal X-ray analysis confirmed the existence of the
derived product [15]. A similar elimination has been also
observed in [Pd(PPh3)2(S2P{O}O-i-Pr)] for which the X-
ray structure has been determined [16].
* Corresponding author. Tel.: ꢃ
522-5737.
E-mail address: trav@aix.upol.cz (Z. Tra´vn´ıcˇek).
/
420-68-563-4361; fax: ꢃ420-68-
/
0277-5387/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0277-5387(03)00101-3

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L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ1348
/
Here, we describe the preparation and characteriza-
slowly evaporating the solvent at 4 8C, were suitable for
X-ray diffraction study.
tion of the new nickel(II) mixed ligand complexes
containing bidentate phosphorus donor ligands (dppm,
dppe, dppb) and (S2P{OR}2)ꢁ [O,O?-dialkyldithiopho-
sphates] or (S2P{O}OR)2ꢁ [O-alkydithiophosphates] in
the coordination sphere of nickel but also the first
examples of their X-ray structural characterizations.
2.2.4. [Ni(S2P{OEt}2)(dppm)]ClO4×
[Ni(S2P{O-i-Pr}2)(dppe)(NCS)] (7) and
[Ni(S2P{OEt}2)(dppe)Br]×H2O (8)
The complex [Ni(S2P{OEt}2)(dppm)]ClO4×
/
H2O (6),
/
/
H2O (6)
was obtained as a light orange crystalline product using
the similar procedure as described for compound 5,
while the complexes [Ni(S2P{O-i-Pr}2)(dppe)(NCS)] (7)
2. Experimental
and [Ni(S2P{OEt}2)(dppe)Br]×
/
H2O (8) were prepared by
2.1. Materials
the same method as for 4. Unfortunately, the crystals of
these products were unsuitable for single crystal X-ray
analysis.
P4S10, dppm, dppe and dppb were obtained commer-
cially from Fluka or Aldrich. Ni(ClO4)2×
/
6H2O and
Ni(SCN)2×2H2O were purchased from Lachema and
/
2.3. Methods
used without further purification. [Ni(S2P{OEt}2)2] and
[Ni(S2P{O-i-Pr}2)2] were prepared by the methods
reported in Ref. [3].
Partial elemental analyses (C, H, N) were performed
on an EA1108 CHN analyser (Fisons Instruments). The
chlorine and bromine contents were determined by the
Scho˝niger’s method, while the nickel content was
estimated by chelatometric titration. Electronic absorp-
tion spectra (diffuse-reflectance) were obtained with a
SPECORD M40 (Carl Zeiss, Jena) spectrometer within
2.2. Syntheses of nickel(II) complexes
2.2.1. [Ni(S2P{O}OEt)(dppe)] (1), [Ni(S2P{O}O-
i-Pr)(dppe)] (2) and [Ni(S2P{O}OEt)(dppb)]×
/
EtOH
(3)
the 11 000ꢂ
carried out on a FT-IR NEXUS 670 spectrometer
(ThermoNicolet) in the region of 150ꢂ
600 cmꢁ1. Mid-
IR spectra were obtained with a Specord M80 instru-
ment (Carl Zeiss, Jena) in the 400ꢂ
4000 cmꢁ1 region.
/
35 000 cmꢁ1 range. Far-IR spectra were
Dppe (1 mmol) was added to an EtOH solution (40
cm3) of [Ni(S2P{OEt}2)2] (1 mmol). The mixture was
stirred under reflux for 4 h. The solution was then
/
filtered and kept at low temperature (:
/
4 8C) for 10
/
days. The orange crystalline solid, formed, was sepa-
rated, washed with petroleum ether and finally dried in a
vacuum desiccator. The crystals obtained were suitable
for X-ray diffraction study. Compounds 2 and 3 were
prepared by the same method, the appropriate ligands
were used only.
Molar conductivities were performed using a Cond340i/
SET Conductivity Meter (WTW, Germany) in DMFA
and acetone at 25 8C. The concentration of the com-
plexes in solutions was 10ꢁ3 mol dmꢁ3
.
Magnetic susceptibilities of all the complexes were
measured by the Faraday method at 298 K.
Hg[Co(NCS)4] was used as a calibrant. In the case of
complex 8, data were corrected for diamagnetic con-
tributions using Pascal’s constants [17]. 31P{1H} NMR
spectra were measured on a Bruker Avance DRX 300
spectrometer operating at frequencies of 121.44 MHz
(31P). The measurements were performed at 300 K. The
samples were prepared by dissolving the compounds in
CDCl3, and 85% H3PO4 was used as an external
reference.
2.2.2. [Ni(S2P{O-i-Pr}2)(dppe)]ClO4 (4)
Finely powdered [Ni(S2P{O-i-Pr}2)2] (1 mmol) was
added to a suspension of Ni(ClO4)2×
/
6H2O (1 mmol) in
CHCl3 (40 cm3), then stirred at room temperature. To
the resulting mixture, dppe (1 mmol) was added. The
solution immediately turned to an orangeꢂbrown col-
/
our. The solution was heated under reflux and stirred
for 4 h, then filtered. Approximately 4/5 of the original
volume was allowed to evaporate at room temperature.
An excess of Et2O was then added into the mixture.
Yellow microcrystals were obtained by this procedure,
which were filtered, washed with Et2O and dried in a
vacuum desiccator.
2.4. X-ray structure determinations
Diffraction experiments for the complexes [Ni(S2-
P{O}OEt)(dppe)] (1), [Ni(S2P{O}OEt)(dppb)]×
/EtOH
(3) and [Ni(S2P{OEt}2)(dppe)]ClO4 (5) were carried
out on a four circle k-axis KUMA KM-4 diffractometer
2.2.3. [Ni(S2P{OEt}2)2(dppe)]ClO4 (5)
The complex was prepared by the similar procedure
as described above for [Ni(S2P{O-i-Pr}2)(dppe)]ClO4
(4), except [Ni(S2P{OEt}2)2] (1 mmol) was used instead
of [Ni(S2P{O-i-Pr}2)2] and an abs. EtOH was used as
the solvent. Yellow needles, which were obtained by
using graphite-monochromated Mo Ka radiation (lꢀ
/
˚
0.71073 A) at 120(2) K. Data collections for the
complexes 1, 3 and 5 were performed using a CCD
detector (KUMA Diffraction, Wroclaw). KUMA
KM4RED software was used for data reduction. All the

L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ
/
1348
1343
structures were solved by using the SIR-97 program [18]
incorporated in the WinGX system [19]. All non-
hydrogen atoms of 1, 3 and 5 were refined anisotropi-
cally by the full-matrix least-squares procedure
for [Ni(S2P{O}OR)(Pꢀ
/
P)] was already observed and
suggested by Gastaldi et al. [15]. The IR, electronic and
31P{1H} NMR spectral data of the prepared complexes
are summarized in Table 3.
(
SHELXL-97) [20] with weights: wꢀ
(0.0386P)2ꢃ 1/[s2(Fo2)ꢃ
0.7829P] for 1, wꢀ
for 3 and wꢀ 3.8187P] for 5,
1/[s2(Fo2)ꢃ(0.0334P)2ꢃ
where Pꢀ
(Fo2ꢃ2Fc2)/3. All H-atom positions in 1 and 5
/
1/[s2(Fo2)ꢃ
(0.0375P)2]
/
/
/
/
3.2. Conductivity and magnetic data
/
/
/
/
/
From molar conductivity values presented in Table 2
were located from Fourier difference maps and all their
parameters were refined, except for H-atoms in 3
bonded to C(1), C(2) and C(4) which were positioned
theoretically to idealized positions and treated using a
combination of riding, rigid and/or rotating model
(AFIX 23, AFIX 137). The remaining H-atoms in 3
were found in the Fourier difference maps. Their
parameters were refined isotropically. Hydrogen atom
associated with EtOH in 3 was not found in the
difference maps and so is not included in the model.
The C(31) atom as well as the hydrogens bonded to it of
EtOH are disordered over two positions. The remaining
H-atoms belonging to C(32) in EtOH were refined using
a combination of the rigid and rotating models (AFIX
137).
is clearly apparent that complexes 4ꢂ6 behave as 1:1
/
electrolytes in DMFA and acetone solutions [22]. The
results show that perchlorate anions in these complexes
are situated outside of the inner coordination sphere of
the central atom. The molar conductivities found for all
the remaining complexes [1ꢂ3, 7 and 8] illustrate the
/
non-ionic features of these compounds in the solvents
used. Somewhat higher lM values in DMFA established
for 7 and 8 can be connected with possible partial
dissociation of the compounds in this solvent. The
complexes 1ꢂ 7 are diamagnetic (see Table 2), while
/
complex 8 is paramagnetic with a room temperature
magnetic moment of 3.22 meff/mB, indicating that the
central nickel(II) atom is in the high-spin state contain-
ing two unpaired electrons [23]. Based on conductivity
and magnetic data and taking into account results from
31P{1H} NMR and IR spectral data (see below), we
assume a tetrahedral geometry in [Ni(S2P{OEt}2)-
The largest peak and hole on the final difference map
˚
for 1, 3 and 5 were 0.415 [1.00 A from P(1)] and ꢁ0.300
/
ꢁ3
˚
˚
˚
[0.80 A from P(1)] e A , 0.460 [1.00 A from C(29)] and
ꢁ3
ꢁ
/
(dppe)Br]×
/
H2O (8) with [S2P{OEt}2]ꢁ acting probably
˚
0.334 [0.77 A from P(1)] e A , and 1.031 [1.07 A
˚
˚
ꢁ3
˚
˚
0.403 [0.44 A from C(4)] e A
from C(1)] and ꢁ
/
,
as a monodentate ligand. Although, owing to the lack of
an X-ray structure, it is not possible to make a final
decision about coordination geometry around nickel in
the latter complex at this point. We suggest a square-
planar geometry around nickel in all the remaining
complexes 1-7.
respectively. Additional crystallographic details are
given in Table 1.
3. Results and discussion
3.1. General features
3.3. P{1H} NMR spectra
Chemical compositions, colours, magnetic suscept-
ibilities and molar conductivity values of the NiII
complexes are included in Table 2. All of the prepared
complexes are stable on air, soluble in DMFA, acetone
and EtOH, and insoluble in n-hexane and Et2O. The
A comparison to observed resonances found for free
and coordinated S2P{OR}2 and S2P{O}OR anions, and
Pꢀ
/
P ligands in transition metal coordination com-
pounds can be used for the interpretation of 31P{1H}
NMR spectra of our nickel(II) complexes. Resonances
due to free dppm, dppe and dppb ligands are observed
reaction between [Ni(S2P{OR}2)2] (Rꢀ
bidentate PꢀP ligand (dppe or dppb) in EtOH (molar
ratio 1:1) gave complexes of the composition
[Ni(S2P{O}OR)(PꢀP)] (1ꢂ3). By the reaction of the
bidentate phosphorus ligand (PꢀP) with [Ni(S2-
P{OR}2)2] and NiX2×nH2O (Xꢀ
ClO4ꢁ, Brꢁ, NCSꢁ),
two following types of complexes were obtained:
[Ni(S2P{OR}2)(PꢀP)]X (Xꢀ (4ꢂ6) and
ClO4ꢁ)
[Ni(S2P{OR}2)(PꢀP)X] {Xꢀ
NCSꢁ (7), Brꢁ (8)}. To
/Et, i-Pr) and
/
in CDCl3 at d ꢁ
/
22.34, ꢁ
/
12.45, and ꢁ15.98 ppm,
/
respectively. A signal at approximately d 133 ppm in
CD2Cl2 is produced by free [S2P{OR}2]ꢁ [24]. The
/
/
/
31P{1H} NMR spectra of 1ꢂ
/
3 measured in CDCl3
/
/
solutions gave peaks at d 56.70ꢂ61.84 ppm indicating
/
probably the bidentate nature of the S2P{O}OR dianion
in the nickel complexes. The resonances observed at d
57.41 ppm for 1, 56.66 ppm for 2 and 28.49 ppm for 3
can be connected with bidentate coordination of the
/
/
/
/
/
our knowledge, these last two types of nickel(II)
complexes with these specific combination of ligands
have not yet been prepared. To date, neither has any
reference to these types of nickel(II) complexes been
found in the Cambridge Crystallographic Data Centre
[21]. A mechanism for elimination of the methyl group
corresponding Pꢀ/P ligand. This assertion can be fur-
ther supported by observing the resonances which
are belonging to these ligands appear at 62.80 ppm
and 30.0 ppm for [Ni(dppe)(pipdtc)](ClO4), and
[Ni(dppb)(pipdtc)](ClO4) {pipdtcꢀpiperidinedithiocar-
/

1344
L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ
/
1348
Table 1
Crystal data and structure refinement for [Ni(S2P{O}OEt)(dppe)] (1), [Ni(S2P{O}OEt)(dppb)]×/EtOH (3) and [Ni(S2P{OEt}2)(dppe)]ClO4 (5)
Compound
1
3
5
Empirical formula
Formula weight
Temperature (K)
C28H29NiO2P3S2
613.25
120(2)
C32H38NiO3P3S2
686.36
120(2)
C30H34ClNiO6P3S2
741.76
120(2)
˚
Wavelength (A)
0.71073
monoclinic
P21/n
0.71073
monoclinic
P21/c
0.71073
monoclinic
P21/n
Crystal system
Space group
Unit cell dimensions
˚
a (A)
˚
9.6064(6)
17.2244(13)
16.6954(10)
90
10.4475(4)
18.1261(8)
17.0028(8)
90
9.3052(4)
17.6954(7)
21.0597(9)
90
b (A)
˚
c (A)
a (8)
b (8)
g (8)
Volume (A )
Z
DCalc (g cmꢁ3
90.291(6)
90
93.982(4)
90
101.591(4)
90
3
˚
2762.5(3)
4
1.475
3212.1(2)
4
1.419
3397.0(2)
4
1.450
)
Absorption coefficient (mmꢁ1
F(0 0 0)
)
1.053
1272
0.916
1436
0.954
1536
Crystal size (mm)
u Range for data collection (8)
Index ranges (h, k, l)
0.50ꢄ
3.40 to 28.52
120h 012
220k 021
200l 022
17 550
6490 [Rint
/
0.50ꢄ
/
0.30
0.50ꢄ
3.20 to 25.00
80h 012
210k 021
200l 020
16 453
5614 [Rint
/
0.50ꢄ
/
0.40
0.60ꢄ
3.46 to 25.00
110h 011
190k 021
210l 025
18 024
5946 [Rint
/
0.30ꢄ
/
0.20
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ/
/
/
ꢁ/
/
/
ꢁ/
/
/
Reflections collected
Independent reflections
Refinement method
ꢀ/
0.0440]
ꢀ/0.0364]
ꢀ/0.0341]
Full-matrix least-squares on F2
Data/restraints/parameters
Goodness-of-fit on F2
6490/0/441
0.987
5614/0/530
1.012
5946/0/494
1.011
Final R indices [I ꢀ
/
2s(I)]
R1ꢀ/0.0360, wR2ꢀ/0.0743
R1ꢀ/0.0302, wR2ꢀ/0.0679
R1ꢀ
/
0.0314, wR2ꢀ/0.0741
R indices (all data)
R1ꢀ/0.0550, wR2ꢀ/0.0812
R1ꢀ/0.0438, wR2ꢀ/0.0729
R1ꢀ
/
0.0369, wR2ꢀ/0.0767
Table 2
Colours, chemical compositions, magnetic data and molar conductivities of the complexes 1ꢂ8
/
Compound
Colour
Found (Calc.) (%)
meff/mB lM
Ni
C
H
X
(S cm2 molꢁ1
)
[Ni(S2P{O}OEt)(dppe)] (1)
[Ni(S2P{O}O-i-Pr)(dppe)] (2)
orange
9.6 (9.6)
54.9 (54.8)
4.9 (4.8)
5.2 (5.0)
5.6 (5.7)
5.0 (5.0)
4.7 (4.6)
4.4 (4.6)
5.0 (5.3)
4.5 (4.9)
ꢁ
/
Dia
Dia
Dia
Dia
Dia
Dia
Dia
3.22
1.2a
3.2b
orange
9.7 (9.4)
8.6 (8.5)
7.2 (7.6)
7.9 (7.9)
7.9 (7.9)
8.4 (8.1)
7.6 (7.9)
55.9 (55.5)
56.0 (55.9)
49.3 (49.9)
48.5 (48.6)
46.9 (46.7)
54.9 (54.4)
48.8 (48.7)
ꢁ/
0.8a
1.5b
[Ni(S2P{O}OEt)(dppb)]×
/
EtOH (3)
light red
yellow
ꢁ/
1.1a
1.2b
[Ni(S2P{O-i-Pr}2)(dppe)]ClO4 (4)
[Ni(S2P{OEt}2)(dppe)]ClO4 (5)
4.6 (4.6)
4.7 (4.8)
4.7 (4.8)
1.8 (1.9)
70.0a
105.8b
69.4a
120.2b
95.0a
140.2b
44.6a
11.5b
34.5a
11.7b
yellow
[Ni(S2P{OEt}2)(dppm)]ClO4×
[Ni(S2P{O-i-Pr}2)(dppe)(NCS)] (7)
[Ni(S2P{OEt}2)(dppe)Br]×H2O (8)
/
H2O (6)
light orange
yellow
/
light brown
10.8 (10.8)
Xꢀ
/
Cl, Br or N; Diaꢀdiamagnetic.
/
a
Measured in DMFA.
Measured in acetone.
b

L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ
/
1348
1345
Table 3
IR, diffuse-reflectance and 31P{1H} NMR spectral data of the complexes 1ꢂ
/
8
a
Compound
IR [cmꢁ1
n(NiꢀS)
]
VISꢄ
/
103 [cmꢁ1
]
31P{1H} NMR
P b dtp c
/
n(Pꢀ/S)s
n(Pꢀ/S)as
n(Pꢀ/O)
Pꢀ
/
[Ni(S2P{O}OEt)(dppe)] (1)
[Ni(S2P{O}O-i-Pr)(dppe)] (2)
333s
359s
345s
533vs
532vs
525vs
529vs
528vs
536s
660m
660m
659m
656s
996s
1042s
996s
19.5
26.0
19.4
26.0
19.0
26.0
26.0
57.41(s)
56.66(s)
28.49(s)
66.30(s)
66.34(s)
-33.64(s)
61.13(s)
61.97(br)
61.84(s)
60.94(s)
56.70(s)
84.76(s)
89.22(s)
88.92(s)
55.56(s)
57.37(br)
1042s
998m
1046s
984s
[Ni(S2P{O}OEt)(dppb)]×
/
EtOH (3)
340m
363m
331m
363w
331s
[Ni(S2P{O-i-Pr}2)(dppe)]ClO4 (4)
[Ni(S2P{OEt}2)(dppe)]ClO4 (5)
1046w
988s
660s
26.1
26.0
26.0
355m
330s
1042s
988s
[Ni(S2P{OEt}2)(dppm)]ClO4×
[Ni(S2P{O-i-Pr}2)(dppe)(NCS)] (7)
[Ni(S2P{OEt}2)(dppe)Br]×H2O (8)
/
H2O (6)
654m
689vsd
692vsd
357m
331s
534vs
531vs
998s
1044s
998m
1044s
/
348w
360w
14.0
25.0
a
b
c
Diffuse reflectance.
PꢀPꢀdppm, dppe or dppb.
dtpꢀDithiophosphate anion; brꢀ
S).
/
/
/
/
broad signal.
d
n(Pꢁ
/
bamate anion}, respectively [25]. The 31P{1H} NMR
spectra of the complexes 4ꢂ6 containing ionic perchlo-
librium may exist between diamagnetic, four-coordi-
nated (square-planar) and high-spin, four-coordinated
(tetrahedral) complexes. Moreover, an equilibrium be-
tween low-spin and high-spin five-coordinated com-
plexes is possible, even if this outcome is less probable
in connection with the anticipated monodentate coordi-
nation of [S2P{OR}2]ꢁ, as was proposed above.
/
rate anion show resonances at 84.76, 89.22 and 88.92
ppm, respectively, due to bidentate nature of S2P{OR}2
monoanion. This deduction can be made owing to the
fact that peaks observed at 92.80 and 89.47 ppm in
31P{1H} NMR spectra of [Ni(S2P{OEt}2)2], and
[Ni(S2P{O-i-Pr}2)2], respectively, correspond to biden-
tate chelated S2P{OR}2 monoanions to nickel. This is
also consistent with literature data (92.9 ppm) found for
31P NMR spectrum of [Ni(S2P{OEt}2)2] measured in
3.4. IR and electronic spectra
IR spectra of the complexes 1ꢂ
the range 150ꢂ
4000 cmꢁ1. The bands appearing in the
regions of 331ꢂ348 and 355ꢂ
363 cmꢁ1 may be assigned
to n(NiꢀS) vibrations [3,9]. For comparison, theoreti-
/8 were measured over
CDCl3 [26]. The bidentate nature of Pꢀ
can be supported by chemical shifts observed at 66.30
ppm for dppe in 4, 66.34 ppm for dppe in 5, ꢁ33.64
/
P ligands in 4ꢂ8
/
/
/
/
/
/
ppm for dppm in 6, 61.13 ppm for dppe in 7 and 61.97
ppm for dppe in 8 [25]. The assignment of the peak at
cally calculated values for n(Niꢀ
/
S) in [Ni(S2P{OEt}2)2]
are 347.0 and 358.1 cmꢁ1 [27]. The maxima observed
between 528 and 536 cmꢁ1 may be assigned to the
ꢁ33.64 ppm to bidentate coordination of dppm in 6 is
/
also consistent with the assignment for [h1-dppm)-
symmetric Pꢀ
region 654ꢂ
660 cmꢁ1 are connected with the asym-
metric PꢀS vibration. The strong bands found at 689
cmꢁ1 (for 7) and 692 cmꢁ1 (for 8) are shifted to higher
frequencies (by :
30 cmꢁ1) as compared to peaks
observed for 1ꢂ6. For this reason, these peaks are
attributable to the PꢁS vibrations. These frequencies are
/S vibration while the bands present in the
(h2-dppm)Pt(h1-S2P{OEt}2](S2P{OEt}2) where the va-
/
lue of ꢁ32.1 ppm has been found for bidentate chelated
/
/
dppm [24]. The resonances appeared in the 31P{1H}
NMR spectrum of 7 and 8 at 55.56 ppm, and 57.37 ppm,
respectively, also indicating the coordination of the
S2P{OR}2 monoanion to nickel. However, both peaks
are significantly shifted downfield with respect to the
resonances assigned to bidentate coordination of the
/
/
/
typical for O,O?-dialkylesters of dithiophosphoric acids
and their ammonium salts [9]. These findings support,
albeit indirectly, the existence of monodentate coordi-
nated [S2P{OR}2]ꢁ ligand in the latter two complexes.
The presence of a direct bond of NCSꢁ to nickel via the
nitrogen atom in 7 can be supported by the existence of
intensive peaks at 2090, 819 and 483 cmꢁ1, which may
ligand (d :90 ppm) and thus indicate monodentate
/
ligation with a high possibility. The broadening of the
signal observed at 57.37 and 61.97 ppm for 8 can be
ascribed both to an existence of paramagnetic species in
the CDCl3 solution [26], i.e. the presence of nickel in the
high-spin state, and also the possibility that an equi-
be assigned to n(Cꢀ
/
N), n(Cꢀ
/
S), and d(NCS) vibrations,

1346
L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ1348
/
respectively [28]. On the other hand, it is not as easy to
prove the coordination of a Brꢁ anion to nickel, as
predicted in 8, even if the stretching vibration belonging
to the terminal Niꢀ
/
Br bond is expected in the region of
300 cmꢁ1 [28]. Moreover, it is known that, the
200ꢂ
/
peak position strongly depends on the coordination
geometry around nickel, thereby making it difficult to
assign specific peaks. However, we assume that the
maximum observed at 295 cmꢁ1 in the spectrum of 8
may be correctly assigned to this type of vibration. The
bands present in the IR spectra of all the complexes in
the regions of 984ꢂ
be attributed to n[(P)ꢀ
tively [9]. The ionic nature of the perchlorate anion in
/
998 cmꢁ1 and 1042ꢂ
/
1046 cmꢁ1 can
(C)], respec-
/
OꢀC] and n[PꢀOꢀ
/
/
/
complexes 4ꢂ6 can be characterized by maxima at
/
approximately 1104 cmꢁ1 [n3(ClO4)] and 948 cmꢁ1
[n4(ClO4)] [28].
The assumption of square-planar geometry around
the NiII atoms in 1ꢂ
/
7 can also be supported by their
electronic spectra. The maxima exhibited at approxi-
Fig. 1. Molecular structure of [Ni(S2P{O}OEt)(dppe)] (1). Hydrogen
atoms are omitted for the sake of clarity.
mately 19 400 cmꢁ1 are assigndable to the A1g0
transition, while maxima appearing at approximately
26 000 cmꢁ1 can probably be connected with the
/
1A2g
1
1A1g0
/
1B1g transition. These observed bands are char-
acteristic for square-planar NiII complexes with chelated
dithiophosphate ligands, as reported in literature data
[3,29]. Based on an assumption of tetrahedral geometry,
the peaks found in the diffuse-reflectance spectra of the
complex 8 at 14 000 and 25 000 cmꢁ1, may be assigned
3
to the dꢂ
den T10
/
d transition T10
/
3T1(P) and the spin-forbid-
3
/
1T2 transition, respectively.
3.5. X-ray structures of [Ni(S2P{O}OEt)(dppe)] (1),
EtOH (3) and
[Ni(S2P{OEt}2)(dppe)]ClO4 (5)
[Ni(S2P{O}OEt)(dppb)]×
/
The molecular structures of 1, 3 and 5 along with the
atom numbering scheme are depicted in Figs. 1ꢂ
/3, with
selected bond distances and angles given in Tables 4ꢂ
/6.
The geometry at the Ni centre in each of the complexes
is square-planar with the NiP2S2 chromophore. The
nickel(II) atoms are bound by two phosphorus atoms
Fig. 2. Molecular structure of [Ni(S2P{O}OEt)(dppb)]×EtOH (3).
/
Hydrogen atoms and EtOH are omitted for the sake of clarity.
from one Pꢀ
/
P ligand and two sulfur atoms from one O-
This enlarged value relates to the longer alkyl string in
dppb as compared with dppe. This fact also provides for
ethyl phosphorodithioato [in 1 and 3] or O,O?-diethyl
phosphorodithioato ligand [in 5]. The coordination
geometries around nickel are distorted from an ideal
arrangement, as can be seen mainly from differences in
selected bond angles in the vicinity of the central atom,
a substantial decrease in the S(2)ꢀ
an increase in the P(1)ꢀS(1)ꢀNi(1) and P(1)ꢀ
angles for 3 compared to those values found for 1 and 5
(see Tables 4ꢂ6). Owing to the fact that X-ray structures
/
Ni(1)ꢀ
/
S(1) angle and
/
/
/
S(2)ꢀNi(1)
/
/
P(3)ꢀ
178.14(3)8 for 5; P(2)ꢀ
171.21(3) for 3, 177.74(3) for 5; S(2)ꢀ
88.70(2)8 for 1, 86.80(2)8 for 3, 89.32(2)8 for 5; P(3)ꢀ
Ni(1)ꢀP(2), 87.72(2)8 for 1, 95.26(2)8 for 3, 86.22(2)8 for
5. It was presumed that the P(3)ꢀNi(1)ꢀP(2) angles
/
Ni(1)ꢀ
/
S(1), 173.69(2)8 for 1, 175.10(2)8 for 3,
Ni(1)ꢀS(2), 173.56(2)8 for 1,
Ni(1)ꢀS(1),
of the nickel complexes with a combination of these
specific ligands have not been published, it is impossible,
at this point, to perform a comparison of interatomic
parameters of the structures presented in this paper with
literature data. The molecular structure of similar
/
/
/
/
/
/
/
/
complex [Ni(dpae)(S2P{O}(OMe)] {dpaeꢀ/1-(diphenyl-
would be similar in 1 and 5, however they appear to
arsino)-2-(diphenyphosphino)ethane} was elucidated up
differ significantly from each other, and increase in 3.

L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ
/
1348
1347
Table 5
Selected bond lengths [A] and angles [8] for [Ni(S2P{O}OEt)(dppb)]×
EtOH (3)
˚
/
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
/
P(2)
P(3)
S(1)
S(2)
2.1969(6)
2.2068(6)
2.2081(6)
2.2270(6)
2.0402(8)
2.0364(8)
1.4802(16)
1.5954(16)
1.824(2)
1.831(2)
1.845(2)
1.827(2)
1.827(2)
1.841(2)
1.455(3)
0.832(16)
1.032(11)
1.528(3)
1.516(3)
1.531(3)
P(2)ꢀ
P(3)ꢀ
P(2)ꢀ
S(1)ꢀ
P(1)ꢀ
P(1)ꢀ
O(1)ꢀ
O(1)ꢀ
O(2)ꢀ
O(1)ꢀ
O(2)ꢀ
S(2)ꢀP(1)ꢀ
C(2)ꢀC(1)ꢀ
C(3)ꢀC(2)ꢀ
C(2)ꢀC(3)ꢀ
C(3)ꢀC(4)ꢀ
C(6)ꢀC(5)ꢀ
C(18)ꢀ
C(22)ꢀ
C(24)ꢀ
C(28)ꢀ
/
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
/
P(3)
S(1)
S(2)
95.26(2)
/
/
/
175.10(2)
171.21(3)
86.80(2)
/
/
/
/
/
/S(2)
S(1)ꢀ
S(2)ꢀ
P(1)ꢀ
P(1)ꢀ
P(2)ꢀ
P(2)ꢀ
P(2)ꢀ
P(3)ꢀ
P(3)ꢀ
P(3)ꢀ
O(2)ꢀ
O(3)ꢀ
O(4)ꢀ
C(1)ꢀ
C(2)ꢀ
C(3)ꢀ
/
P(1)
/
S(1)ꢀ
S(2)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
/
Ni(1)
88.42(3)
88.00(3)
/P(1)
/
/Ni(1)
/
O(1)
O(2)
C(23)
C(17)
C(4)
/
/
O(2)
S(2)
S(2)
S(1)
S(1)
106.30(9)
116.64(8)
109.08(7)
117.71(8)
110.02(7)
96.75(3)
/
/
/
/
/
/
/
/
/
/
/
/
/
C(11)
/
/S(1)
/
C(5)
/
/
P(3)
C(1)
C(4)
P(2)
P(3)
114.01(17)
115.5(2)
114.7(2)
/
C(1)
/
/
/
C(29)
C(31)
C(31)
C(2)
/
/
/
/
/
116.21(17)
120.58(19)
120.74(18)
120.91(19)
117.93(17)
123.79(18)
/
/
/
/
/
C(17)ꢀ
C(17)ꢀ
C(23)ꢀ
C(23)ꢀ
/P(2)
/
C(3)
/
/
P(2)
P(2)
P(2)
/
C(4)
/
/
Fig. 3. Molecular structure of [Ni(S2P{OEt}2)(dppe)]ClO4 (5). Hydro-
gen atoms are omitted for the sake of clarity.
/
/
Table 4
˚
Selected bond lengths [A] and angles [8] for [Ni(S2P{O}OEt)(dppe)] (1)
Table 6
˚
Selected bond lengths [A] and angles [8] for [Ni(S2P{OEt}2)
(dppe)]ClO4 (5)
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
/
P(3)
P(2)
S(2)
S(1)
2.1414(6)
2.1608(6)
2.2124(6)
2.2224(6)
2.0348(8)
2.0432(8)
1.4757(16)
1.6053(15)
1.816(2)
1.815(2)
1.840(2)
1.813(2)
1.816(2)
1.838(2)
1.451(3)
1.505(3)
1.522(3)
P(3)ꢀ
P(2)ꢀ
P(3)ꢀ
S(2)ꢀ
O(1)ꢀ
O(1)ꢀ
O(2)ꢀ
O(1)ꢀ
O(2)ꢀ
S(1)ꢀP(1)ꢀ
C(4)ꢀP(3)ꢀ
C(1)ꢀO(2)ꢀ
O(2)ꢀC(1)ꢀ
C(4)ꢀC(3)ꢀ
C(3)ꢀC(4)ꢀ
P(1)ꢀS(1)ꢀ
P(1)ꢀS(2)ꢀ
/
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
/
P(2)
S(2)
S(1)
87.72(2)
/
/
/
173.56(2)
173.69(2)
88.70(2)
/
/
/
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
/
P(3)
P(2)
S(2)
S(1)
P(1)
2.1550(6)
2.1680(6)
2.2272(6)
2.2410(6)
2.8085(6)
1.9964(8)
1.9954(8)
1.5670(17)
1.5724(17)
1.813(2)
1.817(2)
1.845(2)
1.808(2)
1.809(2)
1.833(2)
1.488(3)
1.477(3)
1.437(5)
1.433(5)
1.530(3)
P(3)ꢀ
P(2)ꢀ
P(3)ꢀ
S(2)ꢀ
P(3)ꢀ
P(2)ꢀ
S(2)ꢀ
S(1)ꢀ
P(1)ꢀ
P(1)ꢀ
O(1)ꢀ
O(1)ꢀ
O(2)ꢀ
O(1)ꢀ
O(2)ꢀ
S(2)ꢀP(1)ꢀ
O(1)ꢀP(1)ꢀ
O(2)ꢀP(1)ꢀ
S(2)ꢀP(1)ꢀ
S(1)ꢀP(1)ꢀ
C(1)ꢀO(1)ꢀ
C(3)ꢀO(2)ꢀ
C(2)ꢀC(1)ꢀ
C(4)ꢀC(3)ꢀ
C(6)ꢀC(5)ꢀ
C(5)ꢀC(6)ꢀ
/
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
Ni(1)ꢀ
/
P(2)
S(2)
S(1)
86.22(2)
/
/
/
S(1)
/
/
/
177.74(3)
178.14(3)
89.32(2)
S(1)ꢀ
S(2)ꢀ
P(1)ꢀ
P(1)ꢀ
P(2)ꢀ
P(2)ꢀ
P(2)ꢀ
P(3)ꢀ
P(3)ꢀ
P(3)ꢀ
O(2)ꢀ
C(1)ꢀ
C(3)ꢀ
/
P(1)
/
/
O(2)
S(1)
S(1)
S(2)
S(2)
105.39(9)
117.62(8)
109.02(7)
116.46(7)
109.12(6)
98.97(3)
/
/
/
/
P(1)
/
/
/
/
/
S(1)
/
O(1)
/
/
/
/
/P(1)
136.38(2)
136.58(2)
44.87(2)
/
O(2)
/
/
S(1)ꢀ
S(2)ꢀ
P(1)ꢀ
P(1)ꢀ
P(2)ꢀ
P(2)ꢀ
P(2)ꢀ
P(3)ꢀ
P(3)ꢀ
P(3)ꢀ
O(1)ꢀ
O(2)ꢀ
C(1)ꢀ
C(3)ꢀ
C(5)ꢀ
/
P(1)
/
/P(1)
/
C(11)
C(21)
C(3)
/
/
/P(1)
/
/
P(1)
P(1)
/
/
/
S(2)
/
O(1)
/
/
44.85(2)
/
/
/
Ni(1)
108.36(7)
121.82(14)
107.4(2)
/
O(2)
/
S(1)ꢀ
S(2)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
/
Ni(1)
82.81(3)
83.19(3)
97.75(9)
/
C(41)
C(31)
C(4)
/
/
P(1)
C(2)
/
C(21)
C(11)
C(5)
/
/
Ni(1)
/
/
/
/
/
/
O(2)
S(2)
S(2)
S(1)
S(1)
/
/
/
P(2)
109.01(15)
110.25(15)
85.72(3)
/
/
/
113.69(7)
114.27(8)
112.57(7)
115.26(7)
103.77(3)
123.36(7)
138.89(7)
51.94(2)
/
C(1)
C(2)
C(4)
/
/
P(3)
/
C(31)
C(41)
C(6)
/
/
/
/
/
Ni(1)
/
/
/
/
/
/
Ni(1)
85.79(3)
/
/
/
/
C(1)
C(3)
C(2)
C(4)
C(6)
/
/
S(1)
/
/
/
Ni(1)
Ni(1)
/
/
/
to now [15]. Thus, the interatomic parameter values
around the nickel core in 1 are comparable to those
/
/
/
Ni(1)
/
/
/
Ni(1)
52.34(2)
determined for [Ni(dpae)(S2P{O}(OMe)] (Niꢀ
/
S,
P, 2.185(3) A and S(1)ꢀ
S(2), 88.4(1)8. The [Ni(dppe)(pipdtc)](ClO4) [25]
and [Ni(dppb)(plddtc)]I×H2O {plddtcꢀpyrrolidine-
/
/
P(1)
P(1)
124.09(16)
119.52(16)
114.3(3)
˚
˚
2.209(3) and 2.210(3)A; Niꢀ
/
/
/
/
/
/
O(1)
O(2)
P(2)
P(3)
Niꢀ
/
/
/
109.4(3)
/
/
/
/
109.78(16)
106.57(16)
dithiocarbamate anion} [30] complexes bearing the
same chromophore and coordination geometry have
also been structurally characterized.
/
/
trogen donor ligands are known in the literature,
examples of such structural varieties with phosphorus
donor ligands are quite uncommon. On the basis of the
above studies, including the X-ray structures of [Ni(S2-
4. Conclusions
Although numerous five and six-coordinated mono-
nuclear nickel(II) dithiophosphate complexes with ni-
P{O}OEt)(dppe)], [Ni(S2P{O}OEt)(dppb)]×
/
EtOH and
[Ni(S2P{OEt}2)(dppe)]ClO4, we conclude that tetracoor-

1348
L. Szu˝cˇova´ et al. / Polyhedron 22 (2003) 1341ꢂ1348
/
[6] Y. Sasaki, S. Tagashira, Y. Murakami, S. Kai, Anal. Sciences 9
(1993) 483.
dinated complexes with square-planar geometry around
nickel have been prepared. For [Ni(S2P{OEt}2)-
[7] B.J. Hathaway, in: G. Wilkinson, R.D. Gillard, J.A. McCleverty
(Eds.), Comprehensive Coordination Chemistry, Pergamon Press,
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(dppe)Br]×/H2O, the suggested tetrahedral geometry
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ligand coordination has also been proposed in [Ni(S2P-
{O-i-Pr}2)(dppe)(NCS)].
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5. Supplementary material
Crystallographic data of the structures presented in
this paper have been deposited with the Cambridge
Crystallographic Data Centre (The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK; e-mail:
deposit@ccdc.cam.ac.uk; www: http://www.ccdc.cam.
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ac.uk; fax: ꢃ44-1223-336033) and are available free of
/
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charge on request, quoting the deposition numbers
197 179 for 1, 197 180 for 3 and 197 181 for 5.
[19] L.J. Farrugia, J. Appl. Crystallogr. 32 (1999) 837.
[20] G.M. Sheldrick, SHELX-97, Program for Crystal Structure
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Acknowledgements
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[21] F.H. Allen, O. Kennard, Chem. Design Autom. News, 8 (1993) 1
and 31.
ˇ
The authors would like to thank Dr. Zdeneˇk Sindela´rˇ
[22] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
[23] S.G. Vulfson, Molecular Magnetochemistry, Gordon and Branch
Science Publishers, 1998, p. 354.
for magnetochemical measurements and Mr. Michal
Malonˇ for providing 31P{1H} NMR spectra. The
crystallographic part of this work was supported by
the GACR (a Grant No. 203/02/0436).
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