Structure of bis(dipropyldithiocarbamate) cadmium(II), [Cd2(n-Pr2dtc)4] (dtc = dithiocarbamate)

Article abstract of DOI:10.1023/A:1009586530825

The cadmium complex of bis(dipropyldithiocarbamate), [Cd₂(n-Pr₂dtc)₄] (dtc = dithiocarbamate) was crystallized from ethylether. It crystallizes in the monoclinic system, space group P₂₁/c, with lattice parameters, a = 8.2532(1), b = 19.4519(1), c = 13.4163(2) A, β = 99.243(1)°, and Z = 4. The X-ray single-crystal structure of [Cd₂(n-Pr₂dtc)₄] reveals that the complex is binuclear in the solid state and the Cd atom has a distorted square-pyramidal coordination environment and four equatorial donors are the two bidentate chelate sulfur atoms from two dtc ligands, of which the sulfur atom from the bridging dtc ligand occupies the apical position of the symmetry-related Cd atom in the dimer structure.

Full text of DOI:10.1023/A:1009586530825

Journal of Chemical Crystallography, Vol. 29, No. 2, 1999
Structure of bis(dipropyldithiocarbamate) cadmium(II),
[Cd2(n-Pr2dtc)4] (dtc ؍ dithiocarbamate)
Fangfang Jian,(1) Zuoxiang Wang,(1) Zhiping Bai, Xiaozeng You,(1) Hoong-Kun Fun,(2) and
Kandasamy Chinnakali(2)
Received September 28, 1998
The cadmium complex of bis(dipropyldithiocarbamate), [Cd2(n-Pr2dtc)4] (dtc ϭ dithiocarba-
mate) was crystallized from ethylether. It crystallizes in the monoclinic system, space group
˚
P2I/c, with lattice parameters, a ϭ 8.2532(1), b ϭ 19.4519(1), c ϭ 13.4163(2) A, ͱ ϭ 99.243(1)Њ,
and Z ϭ 4. The X-ray single-crystal structure of [Cd2(n-Pr2dtc)4] reveals that the complex
is binuclear in the solid state and the Cd atom has a distorted square-pyramidal coordination
environment and four equatorial donors are the two bidentate chelate sulfur atoms from
two dtc ligands, of which the sulfur atom from the bridging dtc ligand occupies the apical
position of the symmetry-related Cd atom in the dimer structure.
KEY WORDS: X-ray structure; dtc; cadmium complex.
Introduction
for cadmium intoxication; uncharged vicinal dithiols5
and dithiocarbamates.6,7 Oddly enough, relatively
The development of effective antidotes for cad-
little is known about the behavior of cadmium
complexes with either of these types of chelating
agents. Herewith, we report the crystal structure
of bis(dipropyldithiocarbamate) cadmium.
mium intoxication has proven to be a task of
considerable difficulty. On the one hand, cadmium
is much more toxic than lead, and the normal
physiological processes by which it is immobilized
involve its bonding to an intracellular protein in
the liver and the kidney rather than the semi-
permanent deposition of lead in the bone;1 on the
other hand, this metal-intracellular protein complex,
cadmium metallothionein (CdMT) does have a rea-
sonably slow rate of transfer from one organ to
another, which is more toxic to it than cadmium
bound to high molecular weight serum protein.2
Since this passage to intracellular sites occurs quite
rapidly,3 these compounds are effective antagonists
only while the cadmium is still in the extracellular
space.4 In recent years it has become apparent that
two types of chelating agents can effect antidotes
Experimental
All chemicals were obtained from a commercial
source and used without further purification. Re-
agent n-Pr2dtcNa was synthesized by the reaction
of n-Pr2NH, NaOH, and CS2 in water. To a heated
aqueous solution of Na(n-Pr2dtc) [0.01 mol] was
added an EtOH solution of cadmium perchlorate
[Cd(ClO4)2, 0.054 mol] with stirring. The white
precipitate was collected by filtration, washed with
water, and dried over P4O10. These were collected
and submitted for elemental analysis. Anal. Calcd.
For [Cd2(n-Pr2dtc)4]: C, 36.16% H, 6.07%; N, 6.02%.
Found: C, 36.50%; H, 6.29%; N, 6.24%. The solid
of [Cd(n-Pr2dtc)2] was dissolved in ethylether and
allowed to evaporate slowly. This resulted in the
formation of needle-like crystals which were then
used in the crystallographic study. The IR spectra
(1) Coordination Chemistry Institute and the State Key Laboratory
of Coordination Chemistry, Nanjing University, Nanjing 210093,
P. R. China
(2) X-ray Crystallography Unit, School of Physics, Universiti Sains
Malaysia, 11800 USM, Penang, Malaysia
227
1074-1542/99/0200-0227$16.00/0 1999 Plenum Publishing Corporation

228
Jian, Wang, Bai, You, Fun, and Chinnakali
were recorded in the 4000–400 cmϪ1 region using
KBr pellets on a Nicolet 170 SX FTIR spectrometer,
which showed the characteristic bands of the com-
plex; the band in the 1480–1510 cmϪ1, attributed
to the ␯(CUN) stretching vibration,8 the band in the
940–990 cmϪ1, belonging to the ␯(CUSN) stretching
vibration,8,9 which is considered indicative of dithio-
carbamate acting as a bidentate ligand.10 The Raman
spectra were recorded 3500–100 cmϪ1 using RFS
100 Fourier transform Raman spectrophotometer,
which showed bands in the region 450–300 cmϪ1,
due to the ␯(CdUS) stretching vibration. All bands
are consistent with the expected compound.
Table 1. Summary of Crystallographic Result for [Cd2(n-Pr2dtc)4]
Color/shape
CCDC deposit no.
Formula
Formula weight
Crystal size (nm)
Space group
Colorless needle
CCDC-1003/5514
C28H56Cd2N4S8
930.04
0.62 ϫ 0.38 ϫ 0.22
P21/c
Unit cell dimensions
˚
a, A
8.2532(1)
19.4519(1)
13.4163(2)
90
˚
b, A
˚
c, A
Ͱ, deg
ͱ, deg
99.243(1)
90
2125.89(4)
2
1.453
1.416
Ͳ, deg
Vol. A3
A summary of the key crystallographic informa-
tion is given in Table 1. The selected crystal of [Cd(n-
Pr2dtc)2] was mounted on a SMART CCD diffracto-
meter. Reflection data were measured at 20ЊC using
Z
D (calcd.), mg/m3
Abs coeff., mmϪ1
F(000)
952
˚
Radiation
Temp., K
␪ range, deg.
Limiting indices
Mo KͰ (␭ ϭ 0.71073 A)
293(2)
2.60–25.00
˚
graphite monochromated Mo-KͰ (␭ ϭ 0.71073 A) ra-
diation with a detector distance of 4 cm and swing
angle of Ϫ35Њ. A hemisphere of reciprocal space was
covered by combination of three sets of exposures;
each set had a different ␾ angle (0,88,180Њ) and each
exposure of 30 s covered 0.3Њ in Ͷ. The collected data
were reduced by using the program SAINT11 and
empirical absorption correction was done by using
the SADABS12 (Tmin ϭ 0.395 and Tmax ϭ 0.786) pro-
Ϫ9 Յ h Յ 9, 0 Յ k Յ 23,
0 Յ l Յ 15
3731
No. unique reflection
R
0.0215
RͶ
0.0478
1.033
0.308 and Ϫ0.410 eA
Goodness-of-fit on F2
Largest diff. peak and hole
Ϫ3
˚
Fig. 1. Molecular structure for [Cd2(n-Pr2dtc)4] with the atomic numbering scheme.

Bis(dipropyldithiocarbamate) cadmium(II)
229
gram. Reflections with 2␪ Ͻ 50Њ were used for struc-
ture solution and refinement.
meric entities. Figure 1 shows a perspective view
of the dimeric unit with the atomic numbering
scheme, and Fig. 2, a perspective view of the crystal
packing in the unit cell. Table 2 contains atomic
positions and equivalent temperature factors for
nonhydrogen atoms. Selected bond distances and
angles are listed in Table 3. The coordination sphere
of the cadmium ions is best described as a distorted
square pyramid. The basal coordination positions
are occupied by four sulfur atoms belonging to two
dtc ligands. The fifth coordination is achieved by
linking to a sulfur atom from a third ligand occu-
pying the equatorial site in the coordination polyhe-
dron of the centrosymmetrically related cadmium
ion. Therefore, each bridging sulfur simultaneous
occupies an equatorial coordination site on one
cadmium ion and an apical site on the other Cd.
The topology of the informed dimers is then viewed
as edge-sharing distorted square-pyramids. As ex-
pected, the axial Cd(1)US(4)#1 bond distance
The structure was solved by direct methods and
refined by full-matrix least-squares method on F2obs
by using the SHELXTL13 software package. One of
the propyl chain (C9 to C11) is found to be disor-
dered; the occupancies of the disordered atoms were
initially refined and later fixed. The populations of
the major and minor components are 60 and 40%,
respectively. All non-H-atoms were anisotropically
refined. The hydrogen atoms were geometrically
fixed and allowed to ride on the parent atoms to
which they attach. The final conventional R(F) ϭ
0.215 and wR(F2) ϭ 0.0478 for 3280 reflections with
I Ͼ 2␴(I); the weighting scheme, w ϭ l/[␴2(F2o) ϩ
(0.0154P)2 ϩ 0.9927P], where P ϭ (F2c)/3. The molec-
ular graphics were created by using SHELXTL.
Atomic scattering factors and anomalous dispersion
corrections were taken from International Table for
X-Ray Crystallography.14
˚
[2.6212(6) A] is a little longer than three of the
Results and discussion
Table 2. Atomic Coordinates (ϫ104) and Equivalent Isotropic
Displacement Parameters (A2 ϫ 103)
The X-ray structure of the cadmium complex
[Cd2(n-Pr2dtc)4] is built up of centro-symmetric di-
x
y
z
U(eq)a
Cd(1)
S(1)
S(2)
S(3)
S(4)
N(1)
N(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
4575(1)
4773(1)
5026(1)
2585(1)
2707(1)
5058(2)
612(3)
4968(3)
5014(4)
6657(4)
8030(5)
5130(4)
3454(5)
3592(8)
1835(3)
Ϫ538(7)
34(9)
5786(1)
6995(1)
5670(1)
5876(1)
4610(1)
6906(1)
4802(1)
6557(1)
7662(1)
7996(2)
7781(2)
6549(1)
6411(2)
6042(3)
5071(1)
5257(4)
5195(4)
5681(7)
5095(3)
5607(4)
5908(8)
4124(1)
3550(2)
2873(2)
5521(1)
6335(1)
7470(1)
3824(1)
5085(1)
8335(1)
3378(2)
7471(2)
8358(2)
8296(2)
9123(3)
9313(2)
9576(2)
10588(3)
4013(2)
2671(5)
1696(7)
907(8)
47(1)
53(1)
50(1)
74(1)
45(1)
48(1)
71(1)
41(1)
61(1)
79(1)
96(1)
62(1)
98(1)
157(2)
49(1)
69(2)
93(2)
133(4)
44(2)
62(3)
10(4)
64(1)
76(1)
86(1)
C(9A)b
C(10A)b
C(11A)b
C(9B)c
C(10B)c
C(11B)c
C(12)
C(13)
C(14)
Ϫ1021(17)
301(9)
Ϫ1129(10)
Ϫ1657(20)
Ϫ123(3)
579(4)
2265(6)
2246(6)
1244(10)
3519(2)
2982(2)
3087(3)
Ϫ289(4)
a U(eq) is defined as one third of the trace of the orthogonalized
Uij tensor.
Fig. 2. A view of the crystal packing down the a axis for
b Occupancy ϭ 0.60.
c Occupancy ϭ 0.40.
[Cd2(n-Pr2dtc)4].

230
Jian, Wang, Bai, You, Fun, and Chinnakali
a
˚
Table 3. Selected Bond Distances (A) and Bond Angles (Њ) of [Cd2(n-Pr2dtc)4]
Cd(1)US(1)
Cd(1)US(3)
Cd(1)US(4)
N(1)UC(2)
N(2)UC(8)
N(2)UC(9A)
S(2)UC(1)
S(4)UC(8)
2.5867(6)
2.5900(7)
2.7681(6)
1.472(3)
1.319(3)
1.516(8)
1.726(2)
1.749(2)
Cd(1)US(2)
Cd(1)US(4)#1
N(1)UC(1)
N(1)UC(5)
N(2)UC(12)
S(1)UC(1)
2.5911(6)
2.6212(6)
1.335(3)
1.476(3)
1.476(3)
1.732(2)
1.717(2)
2.6212(6)
S(3)UC(8)
S(4)UCd(1)#1
S(1)UCd(1)US(2)
S(2)UCd(1)US(3)
S(2)UCd(1)US(4)
S(1)UCd(1)US(4)#1
S(3)UCd(1)US(4)#1
C(1)UN(1)UC(2)
C(2)UN(1)UC(5)
C(8)UN(2)UC(9A)
C(1)US(1)UCd(1)
C(8)US(3)UCd(1)
C(8)US(4)UCd(1)#1
N(1)UC(1)US(2)
S(2)UC(1)US(1)
70.38(2)
149.43(3)
97.25(2)
113.49(2)
101.57(3)
121.9(2)
116.7(2)
120.6(3)
85.13(7)
90.10(8)
98.92(8)
120.8(2)
119.3(1)
S(1)UCd(1)US(3)
S(1)UCd(1)US(4)
S(3)UCd(1)US(4)
S(2)UCd(1)US(4)#1
S(4)UCd(1)US(4)#1
C(1)UN(1)UC(5)
C(8)UN(2)UC(12)
C(12)UN(2)UC(9A)
C(1)US(2)UCd(1)
C(8)US(4)UCd(1)
Cd(1)US(4)UCd(1)#1
N(1)UC(1)US(1)
S(3)UC(8)US(4)
107.34(2)
146.70(2)
67.49(2)
107.20(2)
99.61(2)
121.4(2)
124.0(2)
111.9(3)
85.10(7)
83.77(8)
80.39(2)
119.9(2)
118.6(1)
a Symmetry transformations used to generate equivalent atoms: #1 1-x, 1-y, 1-z.
equatorial Cd(1)US(n) ones [n ϭ 1,2,3. 2,5867(6),
Acknowledgments
˚
2.5900(7), and 2.5911(6) A] and shorter than that
˚
of Cd(1)US(4) [2.7681(6) A]. The four basal sulfur
This work was supported by the NSFC project
29501001, NSF of Jiangsu Province Project BK
95024401. The authors would like to thank The Ma-
laysian Government and Universiti Sains Malaysia
for research grant R&D No. 190/9609/2801. KC
thanks the Universiti Sains Malaysia for a Visiting
Post Doctoral Fellowship.
atoms are coplanar, but the Cd atom deviates
from that plane by 0.7176(2) A showing a slight
˚
tetrahedral distortion. The bond length of
˚
Cd(1)US(4) [2.7681(6) A] is the longest in CdUS
equatorial bond lengths due to S(4) being a bridging
atom. The bond angles S(1)UCd(1)US(2) and
S(3)UCd(1)US(4) [70.38(2) and 67.49(2)Њ] are in
agreement with the cadmium bis(dibutyldithiocarba-
mate)2 and bis(diethyldithiocarbamate)15 complexes.
The bridging network Cd(1)US(4)UCd(1)
#1US(4)#1 is strictly planar owing to the inversion
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˚
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˚
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Bis(dipropyldithiocarbamate) cadmium(II)
231
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