Synthesis and characterization of the adducts of bis(O-amyldithiocarbonato) nickel(II) with nitrogen donors and X-ray structure of bis(O- amyldithiocarbonato)bis (3,5-dimethylpyridine)nickel(II)

Article abstract of DOI:10.1007/s10870-012-0373-y

A series of complexes with general formula M(Xan)₂L₂ (M = Ni(II), Xan = O-amyldithiocarbonato, L = 3-methylpyridine, 2,4-; 3,4-; 3,5-dimethylpyridines and 2,4,6-trimethylpyridine) have been synthesized and characterized by elemental analysis and various physico-chemical techniques such as magnetic susceptibility measurements, conductivity measurements, UV-Visible, Infrared spectral data. On the basis of electronic spectra and magnetic susceptibility measurements, an octahedral geometry has been proposed for all the complexes. IRspectral data shows that the substituted pyridines in all these complexes coordinate to the metal ion through nitrogen atoms occupying fifth and sixth axial positions where as O-alkyldithiocarbonate act as monoanion bidentate ligand and occupy the planar positions of octahedral structures. The X-ray diffraction analysis of one of the adducts bis(O-amyldithiocarbonato) bis(3,5-dimethylpyridine) nickel(II) is also investigated. The complex crystallizes in the monoclinic space group P2₁/c with unit cell parameters a = 9.167(2) A, b = 18.255(4) A, c = 9.299(2) A and β = 103.47(2)°. The dihedral angle between dithio-groups and the pyridine ring is 88.9(1)°. The crystal structure of the molecule is stabilized by π-π interactions. Springer Science+Business Media New York 2012.

Full text of DOI:10.1007/s10870-012-0373-y

J Chem Crystallogr (2012) 42:1176–1181
DOI 10.1007/s10870-012-0373-y
ORIGINAL PAPER
Synthesis and Characterization of the Adducts
of Bis(O-amyldithiocarbonato)nickel(II) with Nitrogen Donors
and X-ray Structure of Bis(O-amyldithiocarbonato)bis
(3,5-dimethylpyridine)nickel(II)
•
Kuldeep Singh Neerupama Inderjeet Kour
•
•
•
Renu Sachar Vivek K. Gupta Verma Rajnikant
•
Received: 12 April 2012 / Accepted: 20 September 2012 / Published online: 5 October 2012
Ó Springer Science+Business Media New York 2012
Abstract A series of complexes with general formula
M(Xan)2L2 (M = Ni(II), Xan = O-amyldithiocarbonato,
L = 3-methylpyridine, 2,4-; 3,4-; 3,5-dimethylpyridines and
2,4,6-trimethylpyridine) have been synthesized and charac-
terized by elemental analysis and various physico-chemical
techniques such as magnetic susceptibility measurements,
conductivity measurements, UV–Visible, Infrared spectral
data. On the basis of electronic spectra and magnetic sus-
ceptibility measurements, an octahedral geometry has been
proposed for all the complexes. IR spectral data shows that the
substituted pyridines in all these complexes coordinate to the
metal ion through nitrogen atoms occupying fifth and sixth
axial positions where as O-alkyldithiocarbonate act as
monoanion bidentate ligand and occupy the planar positions
of octahedral structures. The X-ray diffraction analysis of one
of the adducts bis(O-amyldithiocarbonato)bis(3,5-dimethyl-
pyridine)nickel(II) is also investigated. The complex crystal-
lizes in the monoclinic space group P21/c with unit
Introduction
-
Dithioacid ligands, X–CS2 (X = OR), have a rich coordi-
nation and organometallic chemistry [1, 2]. These ligands are
obtained easily by the addition of the nucleophiles RO- to
carbon disulfide [3–5]. Dithioacid ligands and their metal
complexes have received considerable attention due to their
interesting structural and chemical properties as well as their
wide range of application in biological systems [6, 7]. They
have been generally prepared by metatheses reactions of
transition metal halides with the free ligands. In most cases the
ligand is bonded to the metal in a chelate fashion through the
two S-atoms. However, several complexes in which the mode
of coordination of the dithioacid ligands is monodentate have
been obtained and characterized [8, 9]. These O-alkyldithio-
carbonates (dithioacid ligands) are used on a large scale as
collectors in flotation processes in metal recovery, have been
investigated as adsorbents on coinage metals [10, 11] and are
known to form very strong bonds with metals. Recently some
cyclic dithiocarbonates as a new class of in situ gelling bio-
materials isreported. Cyclic dithiocarbonates with degradable
ester linkages have been synthesized and characterized [12].
In this paper we report the synthesis and characterization of
the adducts of bis(O-amyldithiocarbonato)nickel(II) with
substituted pyridines. The X-ray structure of bis(O-amyldi-
thiocarbonato)bis(3,5-dimethylpyridine)nickel(II) is also being
reported.
˚
cell parameters a = 9.167(2) A, b = 18.255(4) A, c =
˚
˚
9.299(2) A and b = 103.47(2)°. The dihedral angle between
dithio-groups and the pyridine ring is 88.9(1)°. The crystal
structure of the molecule is stabilized by p–p interactions.
Keywords X-ray structure Á Metal–organic Á p–p
interaction Á Packing interactions Á Single crystal
K. Singh Á V. K. Gupta Á V. Rajnikant (&)
Experimental
X-ray Crystallography Laboratory, Post Graduate Department of
Physics, University of Jammu, Jammu Tawi 180 006, India
e-mail: rkant.ju@gmail.com; rkvk.paper11@gmail.com
Preparation of Potassium Amyldithiocarbonate
Neerupama Á I. Kour Á R. Sachar
Into a 500 ml round bottomed flask, fitted with a reflux
condenser, 4.2 g (0.075 mol) of potassium hydroxide
Department of Chemistry, University of Jammu, Jammu Tawi
180 006, India
123

J Chem Crystallogr (2012) 42:1176–1181
1177
pellets were placed and 19.271 g (23.472 ml, 0.26 mol) of
n-amyl alcohol was added. The reaction mixture was
heated under reflux for 1 h. The contents were then cooled
and liquid from reaction mixture was decanted off into
another dry 500 ml flask. To this flask, was added 5.7 g
(4.5 ml, 0.075 mol) of carbon disulphide slowly with
constant stirring. The contents of the flask were filtered
(after cooling in ice) on a sintered glass funnel at the pump
and washed with three 2.5 ml portions of ether. The
resulting product potassium O-amyldithiocarbonate was
dried in a vacuum desiccator over anhydrous calcium
chloride.
which is equipped with graphite monochromated MoKa
˚
radiation (k = 0.71073 A). A total number 32,738 of
reflections were collected of which 2,278 reflections were
treated as observed [I [ 2r(I)]. Data were corrected for
Lorentz and polarization and absorption factors. The
structure was solved by direct methods using SHELXS97
and refined by SHELXL97 [13]. All the hydrogen atoms
were located from a difference electron density map and
their positional and isotropic thermal parameters were
included in the refinement. The final refinement cycle
yielded an R-factor of 0.0420 and wR (F2) = 0.1049 for
the observed data. The residual electron density ranges
from -0.466 \ Dq \ 0.676 eA-3. The CIF for this struc-
˚
Preparation of Bis(O-amyldithiocarbonato)nickel(II)
ture has been deposited at Cambridge Crystal Data Centre
(CCDC 875502).
The saturated aqueous solutions of NiCl2Á6H2O (2.37 g,
0.01 mol) and potassium O-amyldithiocarbonate (4.04 g,
0.02 mol) were prepared separately and then mixed with
constant stirring. Dark green precipitates were formed
which were filtered immediately and dried in a vacuum
desiccator over anhydrous calcium chloride. The compo-
sition of the complex was established to be [Ni(S2-
COC5H11)2] by the elemental analysis. Found (Calc.)
C = 36.11 (37.43), H = 5.01 (5.71), S = 32.98 (33.27),
Ni = 14.50 (15.25).
Methods
Carbon, hydrogen, nitrogen and sulphur contents of the
addition complexes were determined on Elemental ana-
lyzer, CHNS-932, LECO corporation, USA. Molar con-
ductance of the adducts was determined on the millimolar
solution in Dimethylformamide by using Digital conduc-
tivity meter ‘‘Century CC 601’’. Infrared spectra of the
complexes over the region 4,000–200 cm-1 were recorded
using KBr pellets on the Infrared spectrophotometer
(Perkin Elmer FT-IR spectrometer).The electronic spectra
of the adducts were recorded in DMF on Systronics 119
UV–Visible spectrophotometer. Magnetic moments were
determined at the room temperature by VSM method
(Princeton Applied Research-Model No. 155). The ana-
lytical data, molar conductance and magnetic moments of
the adducts isolated are presented in Table 1. Important IR
bands and electronic spectral data are cited in Table 2.
Preparation of Adducts of Bis
(O-amyldithiocarbonato)nickel(II) with Substituted
Pyridines
The 1:2 adducts of bis(O-amyldithiocarbonato)nickel(II)
with substituted pyridines were prepared by stirring
[Ni(S2COC5H11)2] (1 g, 0.0026 mol) in about 70 ml of
acetone for about 20 min followed by the addition of substi-
tuted pyridine [3-methylpyridine = 0.480 g, 2,4-dimeth-
ylpyridine = 0.567 g, 3,4-dimethylpyridine = 0.567 g, 3,
5-dimethylpyridine = 0.567 g and 2,4,6-trimethylpyri-
dine = 0.63 g (0.0052 mol)] and mixture was again stirred
for 20 min. The contents of the reaction mixture were then
filtered and allowed to stand for 20–24 h, depositing
shining green crystalline solids which were then washed
with the solvent used in their preparation and dried over
calcium chloride at room temperature.
Results and Discussion
The adducts of bis(O-amyldithiocarbonato)nickel(II) with
substituted pyridines are all microcrystalline green solids
and are soluble in common organic solvents like acetone,
chloroform, dimethylformamide and dimethylsulphoxide
but insoluble in benzene, carbontetrachloride, nitrobenzene
and water. The analytical results of the adducts isolated
suggest that they have the stoichiometry 1:2 and may be
assigned the formula Ni(S2COCH2CH2CH2CH2CH3)2L2
(where L = 3-methylpyridine, 2,4-; 3,4-; 3,5-dimethyl-
pyridines and 2,4,6-trimethylpyridine). The molar con-
ductance measurements of the millimolar solutions of the
adducts under study were carried out in dimethylformam-
ide. The molar conductivity values are in the range
of 22.51–68.33 X-1 mol-1 cm2 suggesting that these
X-ray Structure Determination
Detailed structural information on the conformation of the
molecule in the crystalline state was obtained by employ-
ing X-ray crystallographic techniques. A dark green
blocked-shaped single crystal of the title compound mea-
suring 0.30 9 0.20 9 0.20 mm was picked up for X-ray
intensity data collection on a CCD area-detector diffrac-
tometer (X’calibur system—Oxford diffraction make, UK)
123

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J Chem Crystallogr (2012) 42:1176–1181
Table 1 Physical and analytical data of the adducts of bis(O-amyldithiocarbonato)nickel(II) with substituted pyridines
Adduct
Formula
% Found
C
% Calculated
Molar
leff
(BM)
conductance
(X-1 cm2 mol-1
H
N
S
Ni
C
H
N
S
Ni
)
Bis(O-amyldithiocarbonato)bis
(3-methylpyridine)nickel(II)
C23H36O2S4Ni
50.44
52.08
52.08
52.08
51.67
6.30
6.67
6.67
6.67
7.01
4.90
4.69
4.69
4.69
4.46
22.42
21.37
21.37
21.37
20.41
10.28
9.79
9.79
9.79
9.36
49.65
51.67
51.25
51.25
51.45
5.98
6.11
6.21
6.01
5.98
4.50
4.02
4.01
4.33
4.12
21.98
20.18
20.85
20.85
20.85
9.71
9.10
8.99
9.01
8.81
44.98
24.22
22.51
39.79
68.33
3.09
3.11
3.22
3.12
3.06
Bis(O-amyldithiocarbonato)bis
(2,4-imethylpyridine)nickel(II)
C25H40O2S4Ni
Bis(O-amyldithiocarbonato)bis
(3,4-imethylpyridine)nickel(II)
C25H40O2S4Ni
Bis(O-amyldithiocarbonato)bis
(3,5-imethylpyridine)nickel(II)
C25H40O2S4Ni
Bis(O-amyldithiocarbonato)bis
(2,4,6-trimethylpyridine)nickel(II)
C25H44O2S4Ni
Table 2 Infrared and electronic spectral data of the adducts of bis(O-amyldithiocarbonato)nickel(II) with substituted pyridines
Name of adducts
Formula
IR spectral data (cm-1
)
Electronic spectral data (cm-1
)
mas(C–
O–C)
ms(C–
O–C)
m(C–S)
m1
m2
m3
Bis(O-amyldithiocarbonato)bis
(3-methylpyridine)nickel(II)
Ni(S2COC5H11)2(C6H7N)2
Ni(S2COC5H11)2(C7H9N)2
Ni(S2COC5H11)2(C7H9N)2
Ni(S2COC5H11)2(C7H9N)2
Ni(S2COC5H11)2(C8H11N)2
1,258
1,260
1,245
1,254
1,233
1,143
1,155
1,135
1,186
1,143
1,035
1,026
1,085
1,025
1,094
15,408
15,313
15,037
14,925
14,892
22,321
20,920
21,052
21,085
21,231
27,472
29,411
27,932
27,624
26,954
Bis(O-amyldithiocarbonato)is
(2,4-dimethylpyridine)nickel(II)
Bis(O-amyldithiocarbonato)bis
(3,4-dimethylpyridine)nickel(II)
Bis(O-amyldithiocarbonato)bis
(3,5-dimethylpyridine)nickel(II)
Bis(O-amyldithiocarbonato)bis
(2,4,6-trimethylpyridine)nickel(II)
3
3
3
3
complexes are neutral and non-ionic in character [14, 15].
The magnetic moment values of 1:2 adducts of bis(O-
amyldithiocarbonato)nickel(II) with nitrogen donors come
in the range of 3.06–3.22 BM which is in agreement with
the magnetic moment values observed for the octahedral
complexes of nickel [16, 17]. A comparison of the infrared
spectra of prepared adducts with that of the free ligands
reveals that most of the bands of free ligands are shifted
from their respective positions. The C–H out of plane
deformation bands in the free methylpyridine and dimeth-
ylpyridine molecule shows red shifts while all other modes
specially the bands arising due to CÁÁÁC and CÁÁÁN ring
stretching modes, in plane and out of plane ring deforma-
tion in the free methylpyridine and dimethylpyridine show
blue shift in the adducts indicating that substituted pyri-
dines are coordinated to metal ion through nitrogen atom.
The electronic spectra of 1:2 adducts of bis(O-amyldi-
thiocarbonato)nickel(II) have been recorded in DMF and
shows three bands in the range 11,000–15,408, 19,000–
22,321 and 26,954–29,411 cm-1, which are assigned to
:3A2g ? T2g(F) (m1), A2g ? T1g(F) (m2) and A2g(F) ?
3T1g(P) (m3) transitions respectively. These bands are
characteristic of nickel(II) complexes in octahedral envi-
ronment [18].
X-ray Crystallographic Studies
The crystallography data for bis(O-amyldithiocarbona-
to)bis(3,5-dimethylpyridine)nickel(II) are presented in
Table 3. Selected bond distances and bond angles for
non-hydrogen atoms are listed in Table 4. A general view
of the molecule indicating atom numbering scheme is
shown in Fig. 1. Ortep-3 software [19] was used for
making the thermal ellipsoids. The geometry of the mole-
cule was calculated using PLATON [20] and PARST [21]
software.
The asymmetric unit comprises of half molecule and
nickel(II) cation lies on an inversion centre. The Ni1–N4
˚
bond length is 2.121(2) A. The bond angles in the pyridine
ring vary from 115.1(5)° to 124.3(6)°, the average value
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J Chem Crystallogr (2012) 42:1176–1181
1179
˚
Table 3 Crystal and experimental data
Table 4 Bond lengths (A) and bond angles (°) for nonhydrogen
atoms (e.s.d’s in parenthesis)
CCDC no crystal size
Crystal description
Empirical formula
Formula weight
875502
˚
Bond lengths (A)
Block shaped, green
Ni–N4
2.121(2)
2.459(8)
1.686(3)
1.459(4)
2.455(8)
1.679(3)
1.335(4)
C
26H40N2NiO2S4
Ni1–S3
599.55
S3–C12
Melting point
95 °C
X’Calibur System (now varian)
O13–C14
Measurement
Ni1–S2
˚
MoKa, 0.71073 A
Radiation, wavelength
Unit cell dimensions
S2–C12
˚
a = 9.167(2) A, b = 18.255(4) A,
˚
˚
c = 9.299(2) A
C12–O13
b = 103.47(2)°
Monoclinic
Bond angles (°)
N4–Ni1–S2
S2–Ni1–S3
C12–S3–Ni1
C5–N4–Ni1
O13–C12–S2
C12–O13–C14
S2–C12–S3
C12–S2–Ni1
C5–N4–C9
C9–N4–Ni1
O13–C12–S3
O13–C14–C15
Crystal system
Space group
90.34(7)
73.23(3)
82.62(11)
120.6(2)
116.4(2)
119.6(3)
121.21(18)
82.90(1)
117.5(3)
121.9(2)
122.4(2)
108.7(3)
P21/c
3
˚
1513.55(6) A
Unit cell volume
Density (calculated)
Temperature
1.316 g/m3
293(2) K
0.942 mm-1
636
Absorption coefficient
F (000)
Scan mode
x scan
h range for entire data
collection
3.568 \ h \ 28.998
Range of indices
-10 \ h \ 10, -21 \ k \ 21,
-11 \ l \ 11
32,738/2,627
Reflections collected/
unique
Rint
0.0414
expected, it is evident from the least-squares plane calcu-
lation of the pyridine ring that the atomic deviation of C10
and C11 atoms from the plane of pyridine ring is not sig-
nificant. As a consequence of the hybridization of the
Rsigma
0.0172
Structure determination
Refinement
Direct methods
Full Matrix Least Squares on F2
[I/r2 (Fo2) ? (0.0497P)2
? 1.5725P] where
P = (Fo2 ? 2Fc2)/3
Weighing scheme
carbon atom, the O13–C12 bond has
a distance
˚
˚
[1.326(2) A] shorter than that of O13–C14 [1.460(2) A].
The short value of bond distance for O13–C12 is consistent
with a significant contribution of the resonance form of the
xanthate anion that features a formal C=O and a negative
charge on each of S atom [26].
No. of parameters refined 163
Final R
wR (F2)
0.0420
0.1049
Goodness-of-fit
(D/r)max
1.096
The packing of the molecule within the unit cell is
shown in Fig. 2. Molecules in the unit cell are arranged in
the form of layers and within the layers the molecules are
parallel to each other. The crystal structure of the mole-
cule is stabilized by p–p interaction existing between
pyridine rings of one molecule with the pyridine ring of
symmetry related molecule (values are given in the table
below).
-0.001 for 9S1
-3
˚
Final residual electron
density
-0.466 \ Dq \ 0.676 A
being 120(2)°. The Ni–S bond lengths involving the xan-
˚
˚
thate ligands are 2.455(8) A for Ni1–S1 and 2.459(8) A for
Ni1–S2 and these values of bond angles and bond distances
are in good agreement with those reported for other anal-
ogous Ni-dithiocarbonato complexes [22–24]. The C–S
bond lengths involving the xanthate ligands are: S2–
Geometry of p–p Interaction
˚
C12 = 1.679(3) and S3–C12 = 1.686(3) A. These values
˚
˚
˚
CgI–Cg(J)
CgIÁÁÁCgJ (A) CgIÁÁÁP (A) a (°) b (°)
D (A)
show double bond character due to the delocalization over
the two C–S bonds [25]. The dihedral angle between
dithio-groups and the pyridine ring is 88.9(1)°. As
Cg(3)–Cg(3)i 3.869(2)
3.509 0.00 24.92 1.62
Symmetry code: (i) 1-x,-y,-1-z
123

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J Chem Crystallogr (2012) 42:1176–1181
Fig. 1 ORTEP view of the
molecule with displacement
ellipsoids drawn at 50 %
probability level. H atoms are
shown as small spheres of
arbitrary radii
Fig. 2 Packing diagram viewed
down the a-axis
6. Bond AM (1984) Coord Chem Rev 54:23
7. Roman E, Catheline D, Astruc D (1982) J Organomet Chem
236:229
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