Synthesis, spectral, cyclic voltammetric studies, and single crystal X-ray structure determination of the planar NiS2P2, NiS 2PN, and NiS2PC chromophores

Article abstract of DOI:10.1002/zaac.200400245

Synthesis, spectral and cyclic voltammetric characterization of [Ni(dedtc)(4-MP)₂](ClO₄) (1), [Ni(dedtc)(4-MP)(NCS)](2), [Ni(dedtc)(PPh₃)(NCS)] (3) and [Ni(dedtc)(PPh₃)(CN)] (4) (dedtc = diethyldithiocarbamate,

Full text of DOI:10.1002/zaac.200400245

Synthesis, Spectral, Cyclic Voltammetric Studies, and Single Crystal X-Ray
Structure Determination of the Planar NiS2P2, NiS2PN, and NiS2PC
Chromophores
R. Thiruneelakandan‡,a, K. Ramalingam*,a, G. Bocellib, and L. Righib
a Annamalainagar/India, Department of Chemistry, Annamalai University
b Parma/Italy, IMEM-CNR, Parco Area Delle Scienze
Received July 9th, 2004.
Abstract. Synthesis, spectral and cyclic voltammetric characteriz-
ation of [Ni(dedtc)(4-MP)2](ClO4) (1), [Ni(dedtc)(4-MP)(NCS)](2),
[Ni(dedtc)(PPh3)(NCS)] (3) and [Ni(dedtc)(PPh3)(CN)] (4)
(dedtc ϭ diethyldithiocarbamate, 4-MP ϭ tri(4-methylphenyl)-
phosphine, PPh3 ϭ triphenylphophine) are reported. IR spectra of
complexes 1- 4 show the characteristic thioureide (C-N) bands at
higher wave numbers compared to that of the parent dithiocarba-
mate complex [Ni(dedtc)2]. The d-d transitions are observed in the
region 452Ϫ482 nm.
The CV studies clearly show the presence of reduced electron den-
sity on the nickel ions in mixed ligand complexes 1-4 compared to
the parent dithiocarbamate. Single crystal X-ray structure studies
show all the complexes to containplanar NiS2P2, NiS2PN, and
NiS2PC chromophores in keeping with the observed diamagnetism.
In all the complexes the Ni-S distances are asymmetric. The thio-
ureide C-N distance of the complexes 1-4 are less thanthe C-N
distance observed in the parent [Ni(dedtc)2].
Keywords: Nickel; Dithiocarbamates; Cyanide; Crystal structures
Synthese, Spektroskopie, Cyclovoltammetrie und Einkristall-Strukturanalysen von
planaren NiS2P2-, NiS2PN- und NiS2PC-Chromophoren
Inhaltsübersicht. Es wird über die Synthese, die spektroskopische
und cyclovoltammetrische Charakterisierung von [Ni(dedtc)-
(4-MP)2](ClO4) (1), [Ni(dedtc)(4-MP)(NCS)] (2), [Ni(dedtc)(PPh3)-
(NCS)] (3) und [Ni(dedtc)(PPh3)(CN)] (4) (dedtc ϭ diethyldithio-
carbamat, 4-MP ϭ Tri(4-methylphenyl)phosphin, PPh3 ϭ Tri-
phenylphosphin) berichtet. Die IR-Spektren der Komplexe 1-4 zei-
gen die charakteristische Thioharnstoff-(CN)-Bande bei größeren
Wellenzahlen verglichen mit dem homoleptischen Dithiocarbamat-
Komplex [Ni(dedtc)2]. Die d-d-Übergänge werden im Bereich von
452-482 nm beobachtet. Die CV-Untersuchungen zeigen eine deut-
lich reduzierte Elektronendichte der Nickelionen in den Gemischt-
ligand-Komplexen 1-4 im Vergleich zu [Ni(dedtc)2]. Nach den Ein-
kristallstrukturanalysen enthalten alle Komplexe planare NiS2P2-,
NiS2PN- und NiS2PC-Chromophore, entsprechend ihrem Diamag-
netismus. In allen Komplexen sind die NiϪS-Bindungen asymme-
trisch. Die ThioharnstoffϪCN-Abstände sind in 1-4 kürzer als im
Ausgangskomplex [Ni(dedtc)2].
Introduction
such as NH3 and pyridine, due to symbiotically induced
softness [5, 6]. On reaction with PR3, they form complexes
with chromophore NiS2P2 which are diamagnetic in nature
[7Ϫ9]. Mixed ligand complexes of the type
[Ni(dtc)(PR3)(X)] were obtained by reacting NiX2 with
dithiocarbamate and PR3 [10]. Complexes of the type
Group X dithiolates containing planar MS4 chromophores
show interestingvariations in their reactions with Lewis
bases [1, 2]. Soft PdII and PtII dithiolates preferably interact
with soft phosphines to give rise to planar MS2P2 chrom-
ophores [3, 4]. Unlike its congeners, NiII is a border line
acceptor. NiII complexes of dithiocarbamates are typical
complexes containing planar NiS4 chromophores. The
planar dithiocarbamates prefer to react with soft Lewis
bases such as phosphines and border line bases like isothio-
cyanate and cyanide rather than hard nitrogenous bases
[Ni(dtc)(PPh3)Cl] and [Ni(dtc)(PPh3)2](ClO4) (dtc
ϭ
Ϫ
(H5C2)2NCS2Ϫ, (H10C5)NCS2 (Pri)2NCS2Ϫ, HOH4C2-
(CH3)NCS2Ϫ) have also been reported from our laboratory
[11Ϫ16]. Recently, single crystal X-ray structural study of
[Ni(dnpdtc)(PPh3)2](ClO4) (dnpdtc ϭ di-n-propyldithiocar-
bamate anion) complex has also been reported [17]. In this
paper, we report the synthesis, spectral, CV studies and sin-
gle crystal X-ray structure analysis of the complexes 1 ؊ 4.
‡ Present address: Department of Chemistry, SET, Bharathidasan
University, Tiruchirappalli Ϫ 620024/India
Results and Discussion
* Dr. K. Ramalingam
Department of Chemistry
Annamalai University
Annamalai nagar Ϫ 608 002/India
e-mail: krauchem@yahoo.com
IR and electronic spectra
IR spectra of the complexes 1 ؊ 4 show thioureide (C-N)
bands at 1538, 1532, 1537 and 1525 cmϪ1, respectively. The
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193
DOI: 10.1002/zaac.200400245
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
187

R. Thiruneelakandan, K. Ramalingam, G. Bocelli, L. Righi
shift in νC-N bands to higher frequencies compared to the
parent [Ni(dedtc)2] (1519 cmϪ1) is due to the mesomeric
drift of electron density from the dithiocarbamate moiety
towards the nickel ions. The νC-N bands appear at around
995 cmϪ1, without any splitting, supporting the isobident-
ate coordination of the dithiocarbamate moiety [18]. IR
spectra also show strong bands around 2100, and
2098 cmϪ1 in complex 2 and 3, respectively, which corre-
spond to the N-coordinated thiocyanate [19]. In complex 4,
a band of medium intensity at 2112 cmϪ1 indicate the
presence of C-coordinated cyanide ion [19]. The electronic
absorption bands at 482, 478and 480 nm in complexes 1-3,
respectively, are due to d-d transitions [20]. The yellow
orange complex 4 gives d-d band at 452 nm.
ene are obtained at 1.2 and 3.5 ppm, respectively. For the
neutral complexes 2, 3 and 4, the ethyl groups are non-
equivalent and hence methyl and methylene protons are
split into a doublet of triplet and a doublet of quartet,
respectively, indicating a substantial barrier to CϪN bond
rotation. The methylene protons adjacent to nitrogen atom
undergo strong deshielding to give signal at 3.5 ppm. A
multiplet in the region of 7.20 Ϫ 7.60 ppm is due to aro-
matic protons. Methyl protons attached to phenyl rings
appear at 2.3 ppm.
13C NMR
From the 13C NMR spectra of complexes, the chemical
shifts of the thioureide carbon atom are correlated to the
Cyclic voltammetry
Ϫ
All the complexes show metal centered one-electron re-
duction processes [20]. Parent [Ni(dedtc)2] showes a large
irreversible reduction potential relatively in keeping with its
reluctance to add electron density to already electron rich
metalcenter. Complex 1 with two phosphine groups shows
a relatively higher potential than thecomplexes 2, 3, and 4.
Following is the increasing order of reduction poten-
tials(mV): Ϫ1506 (2) < Ϫ1510 (4) < Ϫ1515 (3) < Ϫ1522 (1)
< Ϫ1584 [Ni(dedtc)2].
π-bonding in the NCS2 fragment [20]. Generally higher
νC-N values correlate with lower NCS2Ϫ ppm values for d-
Ϫ
block element [20]. The thioureide carbon atom (N13CS2
)
chemical shifts are observed at 203.0, 202.9 and 203.6 ppm
for neutral complexes 2-4, respectively. For ionic complex
Ϫ
1, the N13CS2 signal appeared significantly upfield at
198.2 ppm. The alleviation of excess electron density on
nickel by phosphine, cyanide and isothiocyanate results in
a drift of electron density towards the metal atom through
thioureide bond from nitrogen atom and hence a significant
shift is observed. Among phosphines, cyanide, and isothio-
cyanate, phosphines have a maximum back bonding ability.
Hence, ionic complex (1) containing two phosphine groups
shows signal at 198.2 ppm in the upfield. The isothio-
cyanate carbon atom shifts in complexes 2 and 3 appear
at 143.4 and 143.8 ppm, respectively. Complex 4 gives the
cyanide carbon atom shift at 130.5 ppm. Cyanide carbon
atom signal merged with the phenyl ring signals in the re-
gion of 128-135 ppm. The 4-methyl carbon atom attached
to phenyl rings appears at 21 ppm.
Nuclear magnetic resonance spectra
1
The H, 13C and 31P NMR chemical shift values are given
in Table 1 with splitting patterns.
1H NMR
For the ionic complex 1, ethyl groups are equivalent and
hence only one triplet for methyl and a quartet for methyl-
Table 1 Chemical shift values / ppm
Ϫ
Complex
NMR
CH3
CH2
PPh3/4-MP
Phenyl-CH3
NCS2
NCSϪ/CNϪ
Ni(dedtc)2
1H
1.23
12.2
3.65
43.6
13C
206.4
198.2
1
2
3
4
1H
1.15
12.5
3.56
44.3
7.05Ϫ7.37
134.9Ϫ124.8
30.91
2.35
21.4
13C
31P
1H
1.12, 1.22
12.5, 12.3
3.37, 3.43
43.9, 43.7
7.26Ϫ7.76
134.2Ϫ128.8
21.72
2.34
21.6
13C
31P
202.9
203.0
203.6
143.8
143.4
130.5
1H
1.11, 1.23
12.6, 12.4
3.43, 3.59
43.8, 43.6
7.21Ϫ7.62
134.2Ϫ125.1
20.03
13C
31P
1H
1.13, 1.23
12.6, 12.3
3.55, 3.40
44.0, 43.7
7.26Ϫ7.66
134.2Ϫ128.6
20.97
13C
31P
1H and 31P nmr chemical shifts are listed to 0.01 ppm accuracy and the 13C nmr chemical shifts to 0.1 ppm accuracy
188
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193

NiS2P2, NiS2PN and NiS2PC Chromophores
Fig. 1 ORTEP diagram of [Ni(dedtc)(4-MP)2](ClO4)
31P NMR
Fig. 2 ORTEP diagram of [Ni(dedtc)(4-MP)(NCS)]
31P NMR show signals at 30.9, 20.3, 21.7 and 21.0 ppm for
complexes 1؊4, respectively. The free PPh3 phosphorus
resonates at the more upfield region of Ϫ5.8 ppm [21]. A
very high deshielding observed in the case of complex 1
indicates the most effective coordination of phosphine to
nickel atom. The minimum value observed for NiS2PN
chromophore with 4-methylphenylphosphine indicates a
steric influence on the stability of the compound.
˚
range: 1.375Ϫ1.413 A. The OϪClϪO angles vary from
103.2(4)° to 112.2(4)°, indicating distortion from the tetra-
hedral geometry as observed in many complexes of similar
nature reported from our laboratory [11Ϫ15].
ORTEP diagram of complex 2 is shown in Figure 2. The
complex is monomeric and discrete. It does not show sig-
nificant intermolecular contacts. Four formula units are
present in the unit cell. The complex contains planar
NiS2PN chromophore in keeping the observed diamagne-
tism of the compound. The NiϪS bond distances,
X-ray crystal structure analyses
ORTEP diagram of complex 1 is shown in Figure 1. The
cation is mononuclear with no significant interionic con-
tacts. Four formula units are present in the unit cell. The
nickel atom is coordinated approximately planar in keeping
with the observed diamagnetism. It is not of perfect square
geometry because of small bite angle (78.24(4)°) associated
˚
˚
2.170(1) A and 2.225(1) A are quite different, in contrast
˚
to the parent dithiocarbamate, [Ni(dedtc)2] (2.195(2) A and
˚
2.207(2) A). This is ascribed to the different trans influences
exerted by phosphine and NCSϪ ligand. The bond para-
˚
with the dithiocarbamate. The NiϪS bonds, 2.200(1) A and
˚
2.228(1) A show clear asymmetry, as reported earlier for
meters of the dithiocarbamate moiety are found to be nor-
˚
similar compounds [11Ϫ15]. The bulkiness of phosphine
groups is responsible for the asymmetry in the NiϪP dis-
mal. The thioureide CϪN distance, 1.311(4) A observed in
the present compound is shorter than that observed in the
˚
˚
˚
tances (2.214(1) A and 2.236(1) A) and also an increase in
the PϪNiϪP angle (98.64(4)°). The asymmetry in the NiϪP
bonds reflects on the NiϪS bonds. The thioureide CϪN
corresponding parent dithiocarbamate viz., 1.33(1) A, indi-
cating mesomeric drift of electron density from the dithi-
ocarbamate towards the metal centre. The NiϪP distance
˚
˚
distance is observed to be 1.300(5) A, which is significantly
observed in the complex 2.207(1) A is the shortest distance
different from the distancein the parent dithiocarbamate
[Ni(dedtc)2], 1.33(1) A, indicating a mesomeric drift of elec-
reported for divalent Ni-phosphorus complexes [23]. The
shorter NiϪP distance may be the result of strong back
donation from nickel atom. The NiϪN distance is
˚
tron density fromthe dithiocarbamate moiety towards the
nickel atom. The short CϪN bond distance observed in the
mixed ligand complex agrees very well with IR spectral ob-
˚
1.865(3) A, which is also significantly short. The PϪNiϪN
angle (92.47 (9)° is slightly different from the right angle
and NiϪNϪC(ϪS) angle (174.1(3)° shows a small devi-
ation from linearity. The CϪN and CϪS distances viz.,
˚
servations. The CϪN bond distances (mean 1.473 A) of N-
ethyl groups are in the range of clear single bond distances.
The oxygen atoms of the (ClO4)Ϫ ion show large thermal
vibrations, due to disorder. The ClϪO distances are in the
˚
1.148(4) and 1.613(4) A show the double bonded nature as
expected.
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193
zaac.wiley-vch.de
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
189

R. Thiruneelakandan, K. Ramalingam, G. Bocelli, L. Righi
Fig. 4 ORTEP diagram of [Ni(dedtc)(PPh3)(CN)]
Fig. 3 ORTEP diagram of [Ni(dedtc)(PPh3)(NCS)]
90.56,(6)° which supports the planar coordination of the
nickel atom. The NiϪNϪC(ϪS) angle is 176.2(2)°, which
indicates the deviation from linearity due to steric effect of
the bulky phosphine. The short NϪC and CϪS bond dis-
tances 1.153(3) A, 1615(3) A respectively show character-
istic double bondednature of NϭCϭSϪion. The NϪCϪS
angle is 179.1(2)°, which indicates the near linearity of the
isothiocyanate moiety.
ORTEP diagram of complex 3 is shown in Figure 3. The
molecule contains discrete mononuclear units, which have
no significant intermolecular contacts. Four formula units
are present in the unit cell. The complex contains planar
NiS2PN chromophore in keeping the observed diamagne-
tism of the compound. The two NiϪS bonds, 2.167(1) and
˚
˚
˚
2.224(1) A are quite different, as a contrast to the parent
˚
dithiocarbamate (2.195(2) and 2.207(2) A). Phosphine be-
ORTEP diagram of the complex 4 is shown in Figure 4.
It is monomeric with no significant intermolecular contacts.
Four molecules are present in the unit cell. Ni, S(1), S(2),
P and C of the cyanide are coplanar. The planarity of the
coordination around NiII is also supported bythe observed
diamagnetism of the compound. The deviation of this plane
from a perfect square is caused by the small bite angle
(79.08(4)° of the dithiocarbamate. The two NiϪS bonds
ing a good π-acceptor has a greater trans influence and
hence the NiϪS bond trans to P is longer than that trans
to NCSϪ. Asymmetry in the NiϪS bonds leads to an in-
crease in NiϪSϪC angle and decrease in SϪCϪS angle
when compared to the parent dithiocarbamate complex.
The NiϪSϪC angle is 86.9(1)°(85.3(4)° for [Ni(dedtc)2])
and SϪCϪS angle is 108.8(1)° (110.5(4)°for [Ni(dedtc)2]).
˚
˚
˚
The thioureide CϪN distance is 1.304(3) A, which is lower
2.193(1) A, 2.207(1) A are significantly different. The NiϪS
bond trans to P is longer than that trans to CNϪ due to
different trans influences of phosphine and cyanide. Asym-
metry in the NiϪS bonds leads to an increase in NiϪSϪC
angle and decrease in SϪCϪS angle when compared to par-
ent dithiocarbamate complex. The thioureide CϪN dis-
˚
than the distance 1.33(1) A observed in the parent
[Ni(dedtc)2] [24]. Similar trend was observed in
[Ni(dedtc)(PPh3)2]ϩ [20] and in [NiCl(dedtc)(PPh3)] [16].
Other bond parameters of the dithiocarbamate moiety are
˚
normal. The NiϪN distance, 1.863(2) A is also short. Short
˚
˚
NiϪP and NiϪN distances are as a result of strong back
bonding effects from nickel atom. The PϪNiϪN angle is
tance is 1.305(4) A, which is significantly different from the
distance 1.33(1) A observed in the parent [Ni(dedtc)2] [24].
˚
Table 2 Comparison of bond distances/A and bond angles/°
Complex
NiϪS(1)
NiϪS(2)
NiϪP(1)
NiϪP(2)
NiϪN/
NiϪC
CϪN
SϪNiϪS
PϪNiϪP/
PϪNiϪN/
PϪNiϪC
Ref.
[Ni(dedtc)2]
2.195(2)
2.190(2)
2.200(1)
2.170(4)
2.207(2)
2.239(2)
2.228(1)
2.232(3)
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
1.33(1)
79.3(1)
78.2(1)
78.24(4)
78.4(1)
Ϫ
[24]
[Ni(dedtc)(PPh3)2]ϩ
[Ni(dedtc)(4-MP)2]ϩ
[Ni(dedtc)(PPh3)Cl]
2.200(2)
2.214(1)
2.204(3)
2.230(3)
2.236(1)
Ϫ
1.307(1)
1.300(5)
1.323(16)
99.7(1)
98.64(4)
[20]
This work
[16]
2.187(3)
93.7(1)
(NiϪCl)
(PiϪNiϪCl)
[Ni(dedtc)(4-MP)(NCS)]
[Ni(dedtc)(PPh3)(NCS)]
[Ni(dedtc)(PPh3)(CN)]
2.170(1)
2.167(1)
2.193(1)
2.225(1)
2.224(1)
2.207(1)
2.207(1)
2.188(1)
2.175(1)
Ϫ
Ϫ
Ϫ
1.865(3)
1.863(2)
1.863(4)
1.311(4)
1.304(3)
1.305(4)
78.87(4)
79.04(3)
79.08(4)
92.8(1)
90.6(1)
91.0(1)
This work
This work
This work
190
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193

NiS2P2, NiS2PN and NiS2PC Chromophores
CAUTION! Metal perchlorate with organic ligands are potentially
explosive and Potassium cyanide is highly poisonous. Only, small
amounts of complex should be prepared, and these should be handled
with great caution.
This clearly indicates the mesomeric drift of electron den-
sity from dithiocarbamate moiety towards the metal atom.
The other bond parameters of the dithiocarbamate moiety
are normal. NiϪP and NiϪC distances in the compound
˚
˚
are 2.175(4) A and 1.863(4) A, respectively. The observation
is as a result of a highly favourable steric environment in
addition to effective back bonding effects. The PϪNiϪC
angle is 91.03(10)°, which shows the planar coordination
of the nickel atom. The NiϪCϪN angle is 179.0(3)° which
indicates the slight deviation from linearity due to steric
effect of phosphine ligand. The short CϪN distance,
IR spectra were recorded on a Avator Nicolet FT-IR spectrophoto-
meter (range: 4000 Ϫ 400 cmϪ1) as KBr pellets. The uv-visible spec-
tra in CH2Cl2 were recorded in a Hitachi U-2001 double beam
spectrophotometer. 1H, 13C and 31P NMR spectra were recorded
on a Bruker AMXϪ400 spectrophotometer at room temperature.
CDCl3 was used as solvent and TMS was used as reference.
˚
1.144(4) A indicates the characteristic triple bonded nature.
Phenyl rings show normal bond parameters. The observed
average PϪC distance is 1.826 A. The CϪPϪC angles devi-
Preparation
˚
ate appreciably from the normal tetrahedral angle and the
resultant crowding of the phenyl rings causes the PϪCϪC
angles to be asymmetric.
Bis[tri(4-methylphenyl)phosphine)](diethyldithiocarbamato)nickel(II)
perchlorate; [Ni(dedtc)(4-MP)2](ClO4) (1)
Comparative structural parameters are given in Table 2.
All the complexes are asymmetric with respect to NiϪS dis-
tances. This is attributed to the difference in trans influences
exerted byphosphines, NCSϪ and CNϪ. The thioureide
CϪN distances in the present complexes 1, 2, 3, and 4 are
relatively short compared tothat in the parent compound.
A mixture of [Ni(dedtc)2] (0.36 g, 1 mmol), 4- MP (1.23 g, 4 mmol),
NiCl2·6H2O (0.24 g, 1 mmol) and NH4ClO4 (0.23 g, 2 mmol) in
acetonitrile-methanol (1:1, 50 cm3) was refluxed for about 3 hours
followed by concentration to ca. 25 cm3. The red solution obtained
was left undisturbed for two days. Red crystals suitable for X-ray
structure analysis were obtained directly (yield 85 %; dec. 158 °C).
(Diethyldithiocarbamato)(isothiocyanato)(tri(4-methylphenyl)-
phosphine)nickel(II); [Ni(dedtc)(4-MP)(NCS)] (2)
Experimental
All the reagents and solvents employed were commercially available
high-grade purity materials (E-Merk) used as supplied without
further purification.
A mixture of [Ni(dedtc)2] (0.36 g, 1 mmol), P(C6H4·Me-4)3 (0.61 g,
2 mmol), NiCl2·6H2O (0.24 g, 1 mmol) and NH4SCN (0.15 g,
2 mmol) in acetonitrile-methanol (2:1, 75 cm3) was refluxed for
Table 3 Crystal data, data collection and refinement parameters for 1, 2, 3 and 4
Compound
1
2
3
4
Empirical formula
FW
C47H53ClNO4P2S2Ni
916.1
0.17 ϫ 0.20 ϫ 0.38
monoclinic
P21/c
11.974(1)
23.892(1)
16.774(1)
103.02(2)
4675
C27H31N2PS3Ni
569.4
0.24 ϫ 0.31 ϫ 0.37
monoclinic
P21/n
7.611(1)
30.728(2)
12.380(1)
91.02(2)
2895
C24H25N2PS3Ni
527.3
0.11 ϫ 0.19 ϫ 0.34
monoclinic
P21/n
8.105(2)
20.097(3)
16.621(2)
100.22(3)
2664.4(8)
4
1.315
10.37
1096
Mo-Kα(0.71069)
2-28
ω-2θ
C24H25N2PS2Ni
606.3
0.24 ϫ 0.26 ϫ 0.33
monoclinic
P21/c
11.348(2)
17.026(2)
12.826(2)
101.86(2)
2425.22
4
1.356
10.5
1032
Mo-Kα(0.71069)
2-30
ω-2θ
Crystal dimensions/mm
Crystal system
Space group
˚
a/A
˚
b/A
˚
c/A
β/°
3
˚
U/A
Z
4
4
Dc/gcmϪ3
µ/cmϪ1
F(000)
1.302
6.72
1924
Mo-Kα(0.71069)
2-27
ω-2θ
Ϫ13 ՅhՅ15,
Ϫ29ՅkՅ30,
Ϫ21ՅlՅ13
10062
1.306
9.60
1192
Mo-Kα(0.71069)
2-28
ω-2θ
Ϫ10 ՅhՅ10,
Ϫ38ՅkՅ40,
Ϫ16ՅlՅ15
6822
˚
λ/A
θ range/°
Scan type
Index ranges
Ϫ10 ՅhՅ10,
Ϫ26ՅkՅ26,
Ϫ21ՅlՅ21
6168
Ϫ15 ՅhՅ15,
0ՅkՅ23,
0ՅlՅ18
7057
Reflections collected
Observed reflections
[Fo > 4σ(Fo)]
5011
2729
3235
3485
Weighting scheme
W ϭ 1 / [σ2(Fo2) ϩ (0.1252P)2 W ϭ 1 / [σ2(Fo2) ϩ (0.0301P)2 W ϭ 1 / [σ2(Fo2) ϩ (0.0293P)2 W ϭ 1 / [σ2(Fo2) ϩ (0.1627P)2
ϩ 0.0000P)
P ϭ (max (Fo ϩ 2Fc2)/3)
Number of parameters refined 735
ϩ 0.00P)
ϩ 0.0000P]
ϩ 0.0000P]
2
2
2
2
P ϭ (max (Fo ϩ 2Fc2)/3)
P ϭ max (Fo ϩ 2Fc2)/3
P ϭ max (Fo ϩ 2Fc2)/3
432
381
0.0302,0.0649
0.766
373
Final R, Rw (obs, data)
GOOF
0.0456, 0.1172
0.724
0.0407, 0.0642
0.910
0.0463, 0.1687
0.594
Crystallographic data for the structures have been deposited with the Cambridge Crystallographic Data Centre (CCDC 183244(1), CCDC 183243(2),CCDC
183256(3) and CCDC 210916(4). Copies of the data can be obtained free of charge on application to the Director, CCDC 12 Union Road, Cambridge, CB2
1EZ, UK (fax: ϩ44-1223-336033, e-mail: deposit@ccdc.ac.uk).
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193
zaac.wiley-vch.de
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
191

R. Thiruneelakandan, K. Ramalingam, G. Bocelli, L. Righi
˚
Table 4 Selected bond distances /A and angles /° for complexes 1, 2, 3, and 4.
1
2
3
4
Ni1ϪS3
Ni1ϪP4
Ni1ϪP5
S2ϪC6
2.228(1)
2.214(1)
2.236(1)
1.733(2)
1.713(4)
1.300(5)
1.480(2)
1.466(5)
1.832(4)
1.836(4)
Ni1ϪS3
Ni1ϪP13
Ni1ϪN10
S2ϪC4
2.170(1)
2.207(1)
1.865(3)
1.707(4)
1.716(4)
1.311(4)
1.148(4)
1.613(4)
1.482(5)
1.495(6)
Ni1ϪS3
Ni1ϪP13
Ni1ϪN10
S2ϪC4
2.167(1)
2.188(1)
1.863(2)
1.712(3)
1.725(2)
1.304(4)
1.153(3)
1.615(3)
1.471(3)
1.474(3)
Ni1ϪS3
Ni1ϪP10
Ni1ϪC29
S2ϪC4
2.207(1)
2.175(1)
1.863(4)
1.739(3)
1.706(4)
1.305(4)
1.144(5)
1.479(6)
1.488(5)
1.829(3)
S3ϪC6
S3ϪC4
S3ϪC4
S3ϪC4
C6ϪN7
N7ϪC8
N7ϪC10
P5ϪC12
P4ϪC33
C4ϪN5
N10ϪC11
C11ϪS12
N5ϪC6
N5ϪC8
C4ϪN5
N10ϪC11
C11ϪS12
N5ϪC6
N5ϪC8
C4ϪN5
C29ϪN30
N5ϪC6
N5ϪC8
P10ϪC11
S2ϪNi1ϪS3
S2ϪNi1ϪP4
S3ϪNi1ϪP5
P4ϪNi1ϪP5
S2ϪC6ϪS3
S2ϪC6ϪN7
S3ϪC6ϪN7
C6ϪN7ϪC8
Ni1ϪS2ϪC6
Ni1ϪS3ϪC6
78.24(40
92.30(4)
90.88(4)
98.64(4)
108.4(2)
127.1(3)
124.5(3)
121.6(5)
86.9(1)
S2ϪNi1ϪS3
S2ϪNi1ϪN10
N10ϪNi1ϪP13
S3ϪNi1ϪP13
S2ϪC4ϪS3
S2ϪC4ϪN5
S3ϪC4ϪN5
C4ϪN5ϪC6
Ni1ϪN10ϪC11
N10ϪC11ϪS12
79.04(3)
95.2(1)
90.6(1)
95.27(3)
108.8(1)
126.6(2)
124.7(2)
121.4(2)
176.2(2)
179.1(2)
S2ϪNi1ϪS3
S2ϪNi1ϪN10
N10ϪNi1ϪP13
S3ϪNi1ϪP13
S2ϪC4ϪS3
S2ϪC4ϪN5
S3ϪC4ϪN5
C4ϪN5ϪC6
Ni1ϪN10ϪC11
N10ϪC11ϪS12
79.04(3)
95.2(1)
90.6(1)
95.27(3)
108.8(1)
126.6(2)
124.7(2)
121.4(2)
176.2(2)
179.1(2)
S2ϪNi1ϪS3
S3ϪNi1ϪC29
79.08(4)
93.2(1)
91.0(1)
96.70(3)
108.8(2)
124.6(3)
126.7(3)
121.1(4)
117.5(4)
179.0(3)
C29ϪNi1ϪP10
S2ϪNi1ϪP10
S2ϪC4ϪS3
S2ϪC4ϪN5
S3ϪC4ϪN5
C4ϪN5ϪC6
C4ϪN5ϪC8
Ni1ϪC29ϪN30
86.5(1)
about 3 hours followed by concentration to ca. 25 cm3. Resultant
purple red solution obtained was left for evaporation. After two
days purple red crystals suitable for X-ray structure analysis were
obtained directly (yield 85 %; dec. 159 °C).
were collected at 295 K on Bruker AXS smart single crystal
diffractometer with CCD (area detector)for complexes 1؊4 using
˚
Mo-Kα radiation (λ ϭ 0.71069 A). The absorption correction was
performed with the method inserted in SHELXTL-NT V 5.1 [25].
The structure was solved by direct method inserted in SHELXTL-
NT V5.1 in the Bruker AXS software [25]. All the ORTEP dia-
grams were drawn with ORTEP-3 [26]. All the non-hydrogen atoms
were refined anisotropically and hydrogen atoms were refined iso-
tropically. Selected bond distances are presented in Table 4.
(Diethyldithiocarbamato)(isothiocyanatio)(triphenylphosphine)nicekl(II);
[Ni(dedtc)(PPh3)(NCS)] (3)
A mixture of [Ni(dedtc)2] (0.36 g, 1 mmol), PPh3 (0.52 g, 2 mmol),
NiCl2·6H2O (0.24 g, 1 mmol) and NH4SCN (0.15 g, 2 mmol) in
acetonitrile-methanol (2:1, 75 cm3) was refluxed for about 3 hours
followed by concentration to ca. 25 cm3. Resultant purple red solu-
tion obtained was left for evaporation. After two days red solid
separated from the solution which was filtered anddried over anhy-
drous calcium chloride. Single crystals suitable for X-ray structure
analysis were obtained by recrystallization from acetonitrile (yield
80 %; dec. 161 °C).
Acknowledgement. One of the authors (RTK) is thankful to CSIR,
New Delhi, India for the financial assistance as a JRF (NET).
References
[1] A. Chakravorty, Prog. Inorg. Chem. 1996, 7, 83.
[2] J. P. Fackler, Jr., W. C. Seidel, Inorg.Chem. 1969, 8, 1631.
[3] I. J. B. Lin, H. W. Chen, J. P. Fackler, Jr., Inorg. Chem. 1978,
17. 394.
[4] J. M. C. Alison, T. A. Stephenson, J. Chem. Soc., Dalton
Trans. 1973, 254.
[5] C. K. Jorgensen, Inorg. Chem. 1964, 3, 1201.
[6] K. Ramalingam, G. Aravamudan, V. Venkatachalam, Bull.
Chem. Soc. Jpn. 1993, 66, 1554.
[7] J. A. McCleverty, N. J. Morrison, J. Chem. Soc., Dalton Trans.
1976, 541.
(Cyano)(diethyldithiocarbamato)(triphenylphosphine)nickel(II);
[Ni(dedtc)(PPh3)(CN)](4)
A mixture of [Ni(dedtc)2] (0.36 g, 1 mmol), PPh3 (0.52 g, 2 mmol),
NiCl2·6H2O (0.24 g, 1 mmol) and KCN (0.13 g, 2 mmol) in aceto-
nitrile Ϫ methanol (1:2, 50 cm3) was refluxed for about 3 hours.
Orange yellow solution obtained was left for evaporation. After
two days orange yellow solid was obtained. The solid was filtered
and was dried over anhydrous calcium chloride. Single crystals suit-
able for X-ray analysis were obtained by recrystallization from
CH3OH Ϫ CH3CN solvent mixture (yield 60 %; dec. 153 °C).
[8] D. Lachenal, Inorg. Nucl. Chem. Lett. 1975, 11, 101.
[9] R. P. Burns, F. P. McCullough, C. A. McAuliffe, Adv. Inorg.
Chem. Radiochem. 1980, 23, 211.
[10] P. L. Maxfield, Inorg. Nucl. Chem. Lett. 1970, 6, 693.
[11] V. Venkatachalam, K. Ramalingam, T. C. W. Mak, L. Bao-
sheng, Polyhedron 1996, 15, 1295.
[12] V. Venkatachalam, K. Ramalingam, G. Bocelli, A. Cantoni,
Inorg. Chim. Acta 1997, 257, 49.
[13] R. Akilan, K. Sivakumar, V. Venkatachalam, K. Ramalingam,
K. Chinnakali, H. K. Fun, Acta Crystallogr. 1995, C51, 368.
[14] V. Venkatachalam, K. Ramalingam, R. Akilan, K. Sivakumar,
K. Chinnakali, H. K. Fun, Polyhedron 1996, 15, 1289.
[15] A. Manohar, V. Venkatachalam, K. Ramalingam, U. Casel-
lato, R. Graziani, Polyhedron 1997, 16, 1971.
[16] K. Ramalingam, K. Radha, G. Aravamudan, C. Mahadevan,
Ch. Subramaniyam, M. Seshasayee, Acta Crystallogr. 1987,
C40, 1838.
Cyclic voltammetry
ECDA-001 Basic Electrochemistry system was used for all meas-
urements. Glassy carbon was used, as working electrode and the
counter electrode was a platinum wire. The reference electrode was
Ag/AgCl. Tetrabutylammonium perchlorate (0.01M) was used as
the supporting electrolyte. The experiments were carried out under
oxygen free atmosphereby bubbling purified nitrogen gas through
the solution at room temperature.
X-ray data collection
Details of crystal data, data collection and refinement parameters
for complexes 1؊4 are summarized in Table 3. The intensity data
192
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193

NiS2P2, NiS2PN and NiS2PC Chromophores
[17] B. Arul Prakasam, K. Ramalingam, M. Saravanan, G. Bocelli,
A. Cantoni, Polyhedron 2004, 23, 77.
[18] F. Bonati, R. Ugo, J. Organomet. Chem. 1967, 110, 257.
[19] K. Nakamoto, Infrared spectra of Inorganic and Coordination
compounds, Wiley, New York, 1963.
[22] E. P. Garrou, Chem. Rev. 1981, 81, 229.
[23] H. Hope, M. M. Olmstead, P. P. Power, M. Viaggiano, Inorg.
Chem. 1984, 23, 326.
[24] M. Bonamico, G. Dessy, C. Mariani, A. Vaciago, L. Zam-
bonelli, Acta Crystallogr. 1965, C19, 619.
[25] Bruker AXS Inc. 6300 Enterprise Lane, Madison, Wi. 53719-
1173, USA.
[20] K. Ramalingam, G. Aravamudan, M. Seshasayee, Inorg. Chim.
Acta 1987, 128, 231.
[21] H. L. M. Van Gaal, J. W. Diesveld, F. W. Pijpers, J. G. M. Van
Der Lindon, Inorg. Chem. 1979, 18, 3251.
[26] L. J. Ferrugia, ORTEP-3 for Windows, University of Glasgow,
Scotland, U.K. 1999.
Z. Anorg. Allg. Chem. 2005, 631, 187Ϫ193
zaac.wiley-vch.de
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
193