Synthesis and characterization of the adducts of bis (o- butyldithiocarbonato)nickel(ii) with substituted heterocyclic amines and x-ray structure of bis(o-butyldithiocarbonato)bis (4-cyanopyridine)nickel(ii)

Article abstract of DOI:10.1007/s10870-011-0228-y

We report the synthesis and study of a new series of the adducts of Bis(O-butyldithiocarbonato)nickel(II) with substituted heterocyclic amines such as amino and cyanopyridines. Analytical results show that the adducts have 1:2 stoichiometry with general formulaM(Xan)2L2 (M = Ni(II), Xan = O-butyldithiocarbonate, L = 2-, 3- and 4-aminopyridines, 3- and 4-cyanopyridines). The complexes have been characterized by analytical, magnetic susceptibility measurements, molar conductivity measurements, IR, electronic spectral data and X-ray diffraction analysis. One of the adducts, bis(O-butyldithiocarbonato)bis(4-cyanopyridine)- nickel(II), crystallizes in the monoclinic space group P21/c with unit cell parameters : a = 12.546(4), b = 11.495(3), c = 9.351(3) A , β = 102.73(3)8, Z = 2. Crystal structure was solved by direct methods and refined by full matrix least squares procedures to a final R-value of 0.0299 for 2,788 observed reflections. The packing of layers of molecules is stabilized by weak C-H...N and C-H...p hydrogen bonds. Springer Science+Business Media, LLC 2011.

Full text of DOI:10.1007/s10870-011-0228-y

J Chem Crystallogr (2012) 42:222–226
DOI 10.1007/s10870-011-0228-y
ORIGINAL PAPER
Synthesis and Characterization of the Adducts of Bis
(O-butyldithiocarbonato)nickel(II) with Substituted Heterocyclic
Amines and X-ray Structure of Bis(O-butyldithiocarbonato)bis
(4-cyanopyridine)nickel(II)
•
Sanjay Kapoor Renu Sachar Kuldeep Singh
•
•
•
Vivek K. Gupta Verma Rajnikant
Received: 24 June 2011 / Accepted: 17 November 2011 / Published online: 4 December 2011
Ó Springer Science+Business Media, LLC 2011
Abstract We report the synthesis and study of a new series
of the adducts of Bis(O-butyldithiocarbonato)nickel(II) with
substituted heterocyclic amines such as amino and cyano-
pyridines. Analytical results show that the adducts have 1:2
stoichiometry with general formula M(Xan)2L2 (M = Ni(II),
Xan = O-butyldithiocarbonate, L = 2-, 3- and 4-amino-
pyridines, 3- and 4-cyanopyridines). The complexes have
been characterized by analytical, magnetic susceptibility
measurements, molar conductivity measurements, IR, elec-
tronic spectral data and X-ray diffraction analysis. One of the
adducts, bis(O-butyldithiocarbonato)bis(4-cyanopyridine)-
nickel(II), crystallizes in the monoclinic space group P21/c
with unit cell parameters : a = 12.546(4), b = 11.495(3),
Introduction
O-alkyldithiocarbonates, popularly known as xanthates, are
generally obtained by the reaction of an alcohol with CS2 in
the presence of KOH or NaOH. Xanthates are used in curing
and vulcanization of rubber, as collectors of sulphide ores or
minerals in froth-floatation process, as fungicides in agri-
culture and in the manufacture of synthetic textiles [1–5].
Metal xanthate complexes and their reaction products with a
variety of Lewis bases have been extensively studied [6–8].
The soluble alkali metal xanthates are widely used in
extraction and separation of Hg, Ag, Cd etc., [9–11]. Sodium
and potassium ethyl xanthate have antidotal effects in acute
mercury poisoning. Transition metal xanthate complexes
have been investigated for non linear optical applications
[12]. To the best of our knowledge, the reaction products of
Ni(II) xanthate with substituted heterocyclic amines (Lewis
bases) have been much less extensively studied than other
similar compounds. In this article, we report the synthesis
and investigation of the 1:2 adducts of bis(O-butyldithio-
carbonato)nickel(II) with substituted heterocyclic amines
such as 2-, 3- and 4-aminopyridines and 3- and 4-cyano-
pyridines. The X-ray crystal structure of [Ni(C6H4N2)2
(S2CO-n-C4H9)2] i.e. Bis(O-butyldithiocarbonato)bis(4-
cyanopyridine)nickel(II) is also reported in this paper.
˚
c = 9.351(3) A, b = 102.73(3)8, Z = 2. Crystal structure
was solved by direct methods and refined by full matrix least
squares procedures to a final R-value of 0.0299 for 2,788
observed reflections. The packing of layers of molecules is
stabilized by weak C–HÁÁÁN and C–HÁÁÁp hydrogen bonds.
Keywords Adducts Á O-alkyldithiocarbonates
(Xanthates) and substituted heterocyclic amines Á
Direct methods Á Crystal structure Á
C–HÁÁÁN and C–HÁÁÁp hydrogen bonding
Electronic supplementary material The online version of this
article (doi:10.1007/s10870-011-0228-y) contains supplementary
material, which is available to authorized users.
Experimental
S. Kapoor Á R. Sachar
Preparation of Potassium Salt
Department of Chemistry, University of Jammu,
Jammu Tawi 180 006, India
of O-Butyldithiocarbonate
K. Singh Á V. K. Gupta Á V. Rajnikant (&)
The potassium salt of O-butyldithiocarbonate was prepared
by the standard published method [13]. 42 g (0.75 mol) of
KOH Pellets were placed in a 500 mL flask and 193 g
X-ray Crystallography Laboratory, Post Graduate Department
of Physics, University of Jammu, Jammu Tawi 180 006, India
e-mail: rkvk.paper11@gmail.com
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J Chem Crystallogr (2012) 42:222–226
223
Methods
(238 mL) of butan-1-ol was added. The resulting solution
was heated under reflux for 1 h and then allowed to cool.
From the reaction mixture liquid portion was carefully
decanted off. The residual solid was transferred into a dry
500 mL flask to which 57 g (45 mL, 0.75 mol) of CS2 was
added slowly with constant shaking. The resulting solid
yellow mass was filtered after cooling in ice on a sintered
glass funnel at the pump and it was washed with three
25 mL portions of ether. The potassium O-butylditiocar-
bonate obtained was dried in a vacuum dessicator over
silica gel.
Carbon, Hydrogen, Nitrogen and Sulfur were determined
on elemental analyzer (elemental vario EL III, carlo Erba
1108). Molar conductance was determined on the milli-
molar solution in DMF using century CC 601 Conductivity
Bridge. Infrared spectra of the complexes over the region
4,000–200 cm21 were recorded using KBr pellets on
Infrared spectrophotometer (Perkin Elmer FT-IR). The
electronic spectra of the adducts were recorded in DMF on
systronics 119 UV–visible spectrophotometer. Magnetic
moments were determined at room temperature by VSM
method (Princeton Applied Research-Model No. 155). The
analytical data, molar conductance and magnetic moments
of the adducts isolated are presented in Table 1S. Important
IR bands and electronic spectral data are cited in Table 2S.
Preparation of bis(O-butyldithiocarbonato)nickel(II)
The complex bis(O-butyldithiocarbonato)nickel(II) was
prepared by mixing and constant stirring of the aqueous
solution of nickel(II) chloride (2.36 g, 0.01 mol) and
potassium salt of O-butyldithiocarbonate (3.7 g, 0.02 mol).
Green precipitates were formed which were filtered
immediately and dried in a vacuum dessicator over anhy-
drous calcium chloride. The composition of the complex
was established to be [Ni(S2COC4H9)2] by the elemental
analysis. Found (Calc.) C = 33.25(33.64), H = 4.89(5.04),
S = 35.52 (35.88), Ni = 16.21 (16.45).
Results and Discussion
The complexes of bis(O-butyldithiocarbonato)nickel(II)
with amino- and cyanopyridines are crystalline solids which
are dark green or blackish-green. These adducts are soluble
in common organic solvents such as acetone, chloroform,
dimethylformamide and dimethylsulphoxide. The com-
plexes obtained in this study gave analytical results which
are concordant with the formulas assigned, as summarized
in Table 1S. On the basis of elemental analysis (Table 1S)
the adducts isolated having 1:2 stoichiometry are assigned
the formula Ni(S2COCH2CH2CH2CH3)2L2 (where L = 2-,
3- and 4-aminopyridines, 3- and 4-cyanopyridines). The
molar conductivity values calculated (in the range of
18.96–33.75 ohm21 mol21 cm2) from the conductivities
measured on millimolar solutions of the adducts Ni(S2-
COCH2CH2CH2CH3)2L2 in DMF, support the neutral and
non-ionic nature of the complexes [16, 17]. The 1:2 adducts
of bis(O-butyldithiocarbonato)nickel(II) with amino- and
cyanopyridines exhibit magnetic moment in the range of
2.98–3.21 BM which is in agreement with magnetic
moment values observed for octahedral complexes of
nickel(II) [18, 19]. A comparison of the infrared spectra of
the present complexes with those of the corresponding free
ligands reveals that most of the absorption bands of free
ligands are shifted in their respective complexes. Amino
and cyanopyridines have two possible coordinating cites. It
has been established that N–H and C–N frequencies must
show red shift if the coordination occurs through amino
group or cyano group nitrogen atom. But in the present
complexes, they show, no appreciable red shift. Thus the
possibility of coordination of 2-, 3- and 4-aminopyridines,
3- and 4-cyanopyridines through their amino or cyano
nitrogen atom with metal is ruled out. This has been further
confirmed by examining the C–H out of plane deformation
Preparation of the Adducts of bis
(O-butyldithiocarbonato)nickel(II) with Substituted
Heterocyclic Amines (substituted pyridines)
The 1:2 addition complexes of nickel(II)butylxanthate with
substituted pyridines were prepared by stirring [Ni(S2CO-
n-C4H9)2] (0.92 g, 0.0026 mol) in acetone with substituted
pyridines [2-aminopyridine = 0.488 g, 3-aminopyridine =
0.488 g, 4-aminopyridine = 0.488 g, 3-cyanopyridine =
0.541 g and 4-cyanopyridine = 0.541 g (0.0052 mol)] for
30 min. The resulting solutions were concentrated by dis-
tillation to obtain the maximum yield. The contents of the
reaction mixture were allowed to stand for 20–24 h and the
green crystalline solid obtained was washed with the sol-
vent used in their preparation and dried over calcium
chloride at room temperature.
X-Ray Structure Determination
The X-ray intensity data for one of the compounds Bis-
(O-butyldithiocarbonato)bis(4-cyanopyridine)nickel(II), were
collected by using X’Calibur OXFORD DIFFRACTION
system (now varian) with graphite monochromatic MoKa
˚
radiation (k = 0.71073 A). Data collection, reduction and
correction for title compound was achieved using the
CrysAlisPro software. The structure was solved by SHEL-
XS-97 and refined with SHELXL-97 [14, 15]. The struc-
ture converged to a final R-value of 0.0299.
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J Chem Crystallogr (2012) 42:222–226
vibrations. In amino- and cyanopyridine complexes C–H
out of the plane bands occur at lower energy positions on
complexation, indicating red shifts, which confirm that
these ligands interact with the metal ion through their
respective ring nitrogen atom. The electronic spectra of 1:2
adducts of bis(O-butyldithiocarbonato)nickel(II) have been
recorded in DMF. It shows three broad bands t1, t2 and t3
around 10,000, 18,000 and 28,000 cm21, respectively.
Table 1 Crystal and experimental data
CCDC No
818905
Crystal description
Crystal size
Hexagonal plate greenish
0.30 9 0.30 9 0.15 mm3
120 °C
Melting point
Empirical formula
Formula weight
Measurement
C22H26N4S4O2Ni
282.71
X’Calibur System (now varian)
3
3
These bands can be assigned due to, A2g(F) ? T2g(F),
˚
Radiation, Wavelength
Unit cell dimensions
MoK\a, 0.71073 A
˚
a = 12.546(4) A
3
3
3
3A2g(F) ? T1g(F) and A2g(F) ? T1g(P) transitions,
respectively. Appearance of these three broad bands along
with shoulders show that adducts are having trans octahe-
dral geometry around nickel (II) metal ion [20].
˚
b = 11.495(3) A
˚
c = 9.351(3) A
b = 102.73(3)8
Monoclinic
P21/c
Crystal system
Space group
X-ray Crystallographic Studies
3
˚
Unit cell volume
Density (calculated)
Temperature
1315.58(7) A
1.427 mg/m3
The crystallography data for bis(O-butyldithiocarbona-
to)bis(4-cyanopyridine)nickel(II) are presented in Table 1.
Selected bond distances and bond angles for non- hydrogen
atoms are listed in Table 3S. A general view of the
molecule indicating atom numbering scheme is shown in
Fig. 1. Ortep-3 for Windows [21] software was used for
making the thermal ellipsoids. The geometry of the mole-
cule was calculated using PLATON [22] and PARST [23]
software.
293(2) K
1.081 mm-1
588
Absorption coefficient
F(000)
Scan mode
x scan
h range for entire data
collection
3.548 \ h \ 28.008
Range of indices
-16 \ h \ 7, -15 \ k \ 11
-12 \ l \ 12
6320/3148
Reflections collected/unique
Rint
In this compound the nickel (II) cation lies on an
inversion centre. The asymmetric unit comprises of half
0.0204
Rsigma
0.0323
˚
molecule. The Ni(1)–N1 bond length is 2.127(1) A while
Structure determination
Refinement
Direct methods
Full matrix least squares on F2
[I\r2(Fo2) ? (0.0467P)2 ? 0.0883P]
the Ni(1)–S1 and Ni(1)–S2 bond lengths are 2.429(4) and
˚
2.444(4) A, respectively. The two sulphur–carbon dis-
Weighing scheme
tances have almost identical values, since the nature of the
double bond inside the four atom moiety is resonating. The
six bond lengths in the pyridine ring lie in the range
where P = (Fo2 ? 2Fc2)/3
No. of parameters refined
Final R
wR(F2)
203
˚
˚
0.0299
1.334(2)–1.384(2) A; average value being 1.365(2) A.
The bond angles in the pyridine ring vary from
118.05(2) to 123.27(2)o, the average value being
119.96(7)o. The pyridine ring (N1, C2, C3, C4, C5, C6) is
0.0781
Goodness-of-fit
(D/r)max
1.003
-0.001 for yH112
-3
˚
perfectly planar with a maximum deviation of 0.010(2) A
˚
Final residual electron density -0.484 \ Dq \ 0.055 eA
(observed for atom C3). The cyano group bound to C4 is
significantly out of the plane of the phenyl ring as the
torsion angle C5–C4–C7–N2 = 26(5)o. Out-of-plane
position of the cyanide group is also evident from the least-
squares plane calculation of the pyridine ring where the
C7 and N2 atoms have been deviated below the pyridine
ring (deviations for both the atoms being -0.084(2) and
loaded with pyridine ring and butyldithiocarbonato groups
and hence give rise to stretching. The dithiocarbanato
group exhibits a non-linear character. It is evident from the
value of bond angles with respect to atom O1 [119.47(1)],
C9 [107.02(1)], C10 [113.83(2)] and C11 [112.90(2)8],
respectively. The amount of torsion present along N1–
Ni(1) bond [-52.03(1) and -53.78(1)8, respectively] is
quite substantial. It indicates that the cyanopyridine group
and dithiocarbonato groups are puckered along this bond.
The cyanide group is significantly deviated from the plane
of pyridine moiety (the deviation for C7 and N2 being
˚
-0.166(2) A, respectively).
The bond angles N1–Ni(1)–S1 and S1–Ni(1)–S2 with
respect to nickel as the nodal or pivotal atom exhibit dif-
ferent values; the values being 91.10(4) and 74.26(1)o,
respectively. The difference in these values is under-
standable as there is a significant stretch at Ni(1) as well as
at C8 position. Both these positions are asymmetrically
˚
-0.084(2) and -0.166(2) A, respectively).
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J Chem Crystallogr (2012) 42:222–226
225
form layers. Molecules within the layers are parallel to
each other. The nickel atom is located at each corner of the
unit cell. The packing of molecular layers are stabilized by
weak C–HÁÁÁN and C–HÁÁÁp hydrogen bonds. Details of
C–HÁÁÁN and C–HÁÁÁp interaction are presented in Table 4S.
Conclusions
The various investigations like analytical data, conductiv-
ity measurement, spectral and magnetic studies done on the
adducts reported in this article reveal that these adducts are
octahedral, non-electrolytic and paramagnetic in nature.
Supplementary Material
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
CCDC no. 818905 contain the supplementary crystallo-
graphic data for the compound bis(O-butyldithiocarbona-
to)bis(4-cyanopyridine)nickel(II). The data can be obtained
from free of charge via www.ccdc.cam.ac.uk/data_request/
cif by e-mailing data_request @ ccdc.cam.ac.uk.
The dihedral angle between the least-squares plane of
dithio-group (Ni(1), S1, C8, S2) and the pyridine ring is
88.53(3)o meaning thereby that both these units are held
almost perpendicular to each other. The dihedral angle
between the dithio group and carbonato group is 38.29(7)8.
Packing of the molecules in the unit cell down b-axis is
shown in Fig. 2. Molecules are arranged in a manner to
Acknowledgments We are grateful to Institute Instrumentation
Centre (IIC), Indian Institute of Technology, Roorkee for magnetic
studies. One of the Authors (Rajnikant) acknowledges the Department
of Science & Technology for single crystal X-ray diffractometer
sanctioned as a National Facility under research project No. SR/S2/
CMP-47/2003.
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