Mercury(II) cyanide complexes of thioureas and the crystal structure of [(N-methylthiourea)2 Hg(CN)2]

Article abstract of DOI:10.1134/S1070328411030055

Mercury(II) cyanide complexes of thioureas (Tu), N-methylthiourea (MeTu), and N,N′-dimethylthiourea (DmTu)) have been prepared and characterized by IR and NMR (¹H and ¹³C) spectroscopy, and the crystal structure of one of them was determined by X-ray crystallography. An upfield shift in ¹³C NMR and downfield shifts in ¹H NMR are consistent with the sulfur coordination to mercury(II). The appearance of a band around 2200 cm^-1 in IR and a resonance around 145 ppm in ¹³C NMR indicates the binding of cyanide to mercury(II). The NMR data show that the [(Thione)₂Hg(CN)₂] complexes are stable in solution and undergo no redistribution reactions. In the crystal structure of the title complex, mercury atom is coordinated to two thione sulfur atoms of MeTu and to two cyanide carbon atoms in a distorted tetrahedral mode with the bond angles in the range of 90.2(2)°-169.3(3)°.

Full text of DOI:10.1134/S1070328411030055

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2011, Vol. 37, No. 3, pp. 180–185. © Pleiades Publishing, Ltd., 2011.
Mercury(II) Cyanide Complexes of Thioureas and the Crystal
1
Structure of [(NꢀMethylthiourea) Hg(CN) ]
2
2
a
a
b
b
c
d,
A. A. Isab , M. Fettouhi , M. R. Malik , S. Ali , A. Fazal , and S. Ahmad *
a
Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
b
Department of Chemistry, QuaidꢀiꢀAzam University, Islamabad, Pakistan
c
Center of Research Excellence in Petroleum Refining and Petrochemicals, Research Institute,
King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
Department of Chemistry, University of Engineering and Technology, Lahore 54890, Pakistan
d
*
Eꢀmail: saeed_a786@hotmail. com
Received June 14, 2010
Abstract—Mercury(II) cyanide complexes of thioureas (Tu), Nꢀmethylthiourea (MeTu), and N,N'ꢀdimethꢀ
1
13
ylthiourea (DmTu)) have been prepared and characterized by IR and NMR ( H and C) spectroscopy, and
13
the crystal structure of one of them was determined by Xꢀray crystallography. An upfield shift in C NMR
1
and downfield shifts in H NMR are consistent with the sulfur coordination to mercury(II). The appearance
of a band around 2200 cm–1 in IR and a resonance around 145 ppm in C NMR indicates the binding of
13
cyanide to mercury(II). The NMR data show that the [(Thione) Hg(CN) ] complexes are stable in solution
2
2
and undergo no redistribution reactions. In the crystal structure of the title complex, mercury atom is coorꢀ
dinated to two thione sulfur atoms of MeTu and to two cyanide carbon atoms in a distorted tetrahedral mode
with the bond angles in the range of 90.2(2)°–169.3(3)°.
DOI: 10.1134/S1070328411030055
1
INTRODUCTION
of one of them, namely, [Hg(NꢀMethylthiourea) (CN) ]
2 2
–
(I). The purpose of the study is to see if the CN ligand
The coordination chemistry of mercury(II) with Nꢀ
can be dissociated from the complexes to form
[Hg(CN) ] as it was seen in our previous studies on
and Sꢀdonor ligands is of special interest because of the
importance of such complexes as structural models in biꢀ
ological systems [1–5]. Being a typical soft Lewis acid
2–
4
gold(I) [27, 28]. The structures of thiones used in this
study are below:
[
6, 7] mercury(II) shows a specific affinity to sulfur doꢀ
nors, such as thiolates [8–13], thiones [14–24] and
dithiocarbamates [25, 26]. With thiones ( ), mercury(II)
is known to form a wide variety of 1 : 1 and 1 : 2 complexes
of the types LHgX [16, 17] and L HgX [18–24], respecꢀ
L
CH3
NH
CH3 CH3
HN NH
H N
NH2
H N
2
2
2
2
2
tively (where X is halide or pseudohalide), having strucꢀ
tural arrangements entirely based on tetrahedral or pseuꢀ
doꢀtetrahedral fourꢀcoordinate mercury(II). These studꢀ
ies demonstrate that the complexes may be discrete
monomeric [17–21, 23], dimeric [16], or polymeric [24].
Numerous adducts of mercury halides with thiourea
ligands have been structurally characterized [14–19, 24],
S
S
S
Thiourea
NꢀMethylthiourea N,N'ꢀDimethylthiourea
EXPERIMENTAL
Materials and IR and NMR measurements. Merꢀ
cury(II) chloride and thiourea were obtained from
whereas the number of complexes defined with Hg(CN)2
is much more limited [20–23]. In our previous work on Merck Chemical Company (Germany). NꢀMethylthꢀ
cyanidogold(I) complexes, we observed that the [Thioneꢀ iourea and N,N'ꢀdimethylthiourea were purchased
AuCN] complexes underwent dissociation in solution from Acros Organics (Belgium).
–
due to the very large formation constant of [Au(CN)2]
The solidꢀstate IR spectra of the ligands and their
[
27, 28], while the [ThioneꢀAgCN] complexes remained mercury(II) cyanide complexes were recorded on a
undissociated when dissolved in solution [29, 30]. This reꢀ PerkinElmer FTꢀIR 180 spectrophotometer using
10
–1
1
port extends our study of thione complexes of
d
metals KBr pellets over the range 4000–400 cm . The H
were
with the spectroscopic characterization of the NMR spectra of the complexes in DMSOꢀ 6
d
[
Hg(Thione) (CN) ] complexes and the crystal structures obtained on a Jeol JNMꢀLA 500 NMR spectrometer
2
2
operating at a frequency of 500.00 MHz at 297 K using
1
13
The article is published in the original.
a 0.10 M solution. The C NMR spectra were
180

MERCURY(II) CYANIDE COMPLEXES OF THIOUREAS
Table 1. Elemental analysis and melting points of mercury(II) cyanide complexes
181
Сontents (found/calcd), %
Complex
Yield, %
M.p.,
178
°
C
C
N
H
S
[
[
[
Hg(Tu) (CN) ]
2
11.40/
1.86/
1.99
21.32/
20.76
18.92/
19.41
18.63/
18.23
14.90/
15.84
14.03/
14.81
13.32/
13.91
50
45
60
2
1
1.87
16.30/
6.65
20.10/
0.84
Hg(MeTu) (CN) ]
2
2.48/
2.79
141–142
158–160
2
1
Hg(DmTu) (CN) ]
2
3.35/
3.50
2
2
1
obtained at a frequency of 125.65 MHz with H broadꢀ with the data observed for other thione complexes
band decoupling at 298 K. The spectral conditions [22–24, 27, 29, 34, 35]. Another important vibrational
were as follows 32 K data points, 0.967 s acquisition
band observed in the IR spectra of the thiones is
13
time, 1.00 s pulse delay, and 45
°
pulse angle. The C
–1
ν(NH), which appears around 3200 cm . Upon coorꢀ
chemical shifts were measured relative to TMS.
Synthesis of complexes. Mercury(II) cyanide was
prepared by mixing solutions of HgCl2 in methanol
and KCN in water in a molar ratio of 1 : 2. The resultꢀ
ing colorless solution was concentrated by evaporaꢀ
tion, and the white crystalline product was separated
by filtration.
dination to Hg(CN)2 this band shifts to higher wave
–1
numbers. The presence of a band around 3200 cm in
Table 2. Crystal data and details of the structure refinement for
compound
I
Parameter
Value
The complexes were prepared by adding two equivꢀ
alents of thiones in 15 ml of methanol to a solution of
Hg(CN)2 (0.25 g, 1.0 mmol) in 10 ml of methanol, and
the solutions were stirred for 0.5 h. White crystalline
Formula
C H N S Hg
6 12 6 2
Formula weight
432.93
products were obtained from the resulting colorless Crystal system
Monoclinic
solutions, which were washed with methanol. The eleꢀ
mental analysis of the complexes and their melting
points are given in Table 1.
Space group
, Å
, Å
, Å
, deg
Å3
P
2 /
1
c
a
10.805(4)
b
4.2618(15)
28.299(9)
96.533(7)
1294.7(8)
4
Xꢀray structure determination. Singleꢀcrystal data
c
collection for complex
Axs Smart Apex system equipped with a graphite
monochromatized Mo radiation ( = 0.71073 Å).
I was performed on a Brukerꢀ
β
K
λ
α
V,
The data were collected using SMART [31]. The data
integration was performed using SAINT [31]. An
empirical absorption correction was carried out using
SADABS [32]. The structure was solved with the
Z
ρ
calcd
, g cm–3
2.221
μ(MoK
α
), mm–1
12.191
808
direct methods and refined by fullꢀmatrix leastꢀ
F(000)
2
squares methods based on
F
, using the structure
Crystal size, mm
Temperature, K
0.35
×
0.10
293(2)
1.45–28.40
14; –5
37 37
16413/3242
× 0.08
determination and the graphic packages SHELXSꢀ97
and SHELXLꢀ97 [33]. Hydrogen atoms were located
on a difference Fourier map and refined isotropically.
Crystal data and details of the data collection are sumꢀ
marized in Table 2. Supplementary material has been
deposited with the Cambridge Crystallographic Data
Centre (no. 772367; deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk).
θ
range, deg
Limiting indices
–14
≤
h
–
≤
≤
k ≤ 5;
≤ ≤
l
Reflections
Collected/unique
Rint = 0.0706
2079
Observed data (
Tmin Tmax
Npar
I
> 2σ(I))
,
0.1000, 0.4422
138
RESULTS AND DISCUSSION
Selected IR spectroscopic vibration bands for the
free ligands and their mercury(II) complexes are given
R1
,
wR2
,
S
(I >
2σ
(I))
0.0473, 0.1021, 1.034
1.795 and –1.637
(C=S) vibration, which occurs Largest diff. peak and hole, e
Å–3
around 700–600 cm for the free ligands, is shifted to
lower frequency upon complexation in accordance
in Table 3. The
ν
–
1
2
o
2
2
2
)2 + 1.6454
]–1, where
w
= [
σ
(F ) + (0.0242
P
P P = (F + 2F )/3.
o c
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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2011

182
ISAB et al.
–1
Table 3. Melting points and selected IR frequencies (cm ) of the free ligands and their Hg(CN) complexes
2
Compound
Hg(CN)2
Tu
M.p., °C
ν
(C=S)
ν
(C–N)
ν
(NH , NH)
2
δ
(NH)
ν
(C≡N)
2185
2185
2169
2172
730
714
634
606
641
639
1473
1506
1488
1496
1521
1527
3156, 3365
3186, 3376
3163, 3245
3257
1604
1620
1624
1625
1552
1601
[
Hg(Tu) (CN) ]
2
178
2
MeTu
[Hg(MeTu) (CN)
2
141
⎯
⎯
142
160
2
DmTu
3203
[Hg(DmTu) (CN) ]
2
158
3256
2
Table 4. 1H and C NMR chemical shifts (in ppm) of various species in DMSOꢀd6
13
(1H)
δ
( C)
13
δ
Compound
N–H
CH3
>C=S
183.81
N–CH3
CN
Tu
6.98, 7.25
7.29, 7.52
[
Hg(Tu) (CN) ]
2
182.10
145.66
144.76
2
MeTu
6.95, 7.45, 7.65
7.09, 7.67, 8.08
7.38
2.65, 2.86
2.74, 2.88
2.79
181.10, 184.10
177.85, 183.13
182.70
29.90, 31.10
30.11, 31.20
30.75
[Hg(MeTu) (CN)2
2
DmTu
[
Hg(DmTu) (CN) ]
2
8.11, 8.43
2.80, 3.03
179.70
30.86
144.41
145.25
2
Hg(CN)2
free ligands, as well as in the complexes, indicates the ducing a partial double bond character in the C–N
existence of the thione form of the ligands in the solid bond as observed in other metal complexes of thiourea
state. A sharp band around 2200 cm–1 for the CN [22–24, 27, 29, 30, 34]. The shift difference for the
stretch was observed for all the complexes indicating C(2) resonance of thiones upon complexation is
the presence of cyanide.
related to the strength of the metal–sulfur bond [23,
The H and C chemical shifts of the complexes in 34]. The smallest C(2) shift of 1.7 ppm was detected in
1
13
1
DMSOꢀd6
are summarized in Table 4. In the H NMR the Tu complex, while the highest one was found in the
spectra of the complexes, the N–H signal of thioureas MeTu complex showing that the Hg–S bond should be
became less intense upon coordination and shifted the strongest for [Hg(MeTu) (CN)2] among these
2
13
downfield from their positions in free ligands. The complexes. It should be noted that MeTu in C NMR
deshielding is related to an increase in
sity in the C–N bond upon coordination [27, 29, 30,
4]. The appearance of the N–H signal shows that the
π
ꢀelectron denꢀ
gives two signals for both >C=S and N–CH3 carbons
showing that the compound exists in two isomeric
forms [35]. For [Hg(DmTu) (CN)2], two signals were
3
2
ligands are coordinated to mercury(II) via the thione
group. Table 4 shows that the N–H protons of MeTu
are nonequivalent (NH2 appears as a doublet). The
N–H and CH3 protons of DmTu are equivalent but
after coordination they become nonequivalent as
observed in the DmTuꢀAgCN [29] and DmTuꢀAuCN
expected for N–CH3carbon as observed in our previꢀ
ous studies [27, 29, 34]. Only a single broad resonance
was detected, showing that methyl groups are equiliꢀ
13
brating at different positions. A typical C spectrum
for a representative complex [Hg(MeTu) (CN)2] is
2
shown in Fig. 1.
[
27] complexes.
13
In 13C NMR the C=S resonance of thioureas
In the CN region of the C NMR spectrum, a
shifted upfield upon complexation compared to their sharp singlet was observed around 145 ppm for all four
positions in the free state. The upfield shift is attribꢀ complexes. For the analogous AuCN complexes, two
uted to a lowering of the C=S bond order upon coorꢀ resonances were observed in the CN region; one for
dination and a shift of the N
→
C electron density proꢀ the CN carbon of LAuCN and another due to
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

MERCURY(II) CYANIDE COMPLEXES OF THIOUREAS
183
175
150
125
100
75
50
25
δ
, ppm
Fig. 1. 13C NMR spectrum of [Hg(MeTu) (CN) ] (showing two sets of resonances for the CH and C=S carbon atoms).
2
2
3
[
Au(CN) ]– [27, 28]. This showed that they underwent cury(II) complexes of thiones [17–21, 23, 24]. This
2
disproportionation in solution according to the equation shows relatively weaker binding of sulfur to Hg(II).
+
–
The Hg–C distance is slightly longer than that in the
structure of Hg(CN) (2.015(3) [37].
2
L
⎯
Au
⎯
CN
ꢀ
[AuL ] + [Au(CN) ] .
2
(1)
2
Å)
2
The formation of ionic species was related to the
very high stability constant of [Au(CN) ] (log
36) [27, 28, 36]. However, for the
LAgCN complexes only one CN resonance was
–
In
I
, the C(1)Hg(1)C(6) angle is 169.3(3)
much larger than the normal tetrahedral value of 109.5
This large angle is counterbalanced by the S(1)Hg(1)S(2)
°
, which is
β
of
2
°.
[
Au(CN)2]–
≈
observed [29, 30]. For the complexes under study (of bond angles of 98.52(6)°. This tetrahedral distortion inꢀ
the type L2Hg(CN)2) only one CN resonance was
detected, which suggests that they do not dissociate in
Table 5. Selected bond distances (
Å
) and bond angles (deg) for
solution and, hence, equilibrium of the type (1) does
not exist for L2Hg(CN)2
The molecular structure of
compound
I
.
I
together with the
Bond
d,
Å
Angle ω, deg
atomic labeling scheme is shown in Fig. 2. Selected
bond lengths and bond angles are presented in Table 5.
The complex is mononuclear consisting of mercury
Hg(1)–S(1) 2.9658(18) S(1)Hg(1)S(2)
98.52(6)
95.9(2)
90.2(2)
93.9(2)
93.9(2)
atoms bound to two S atoms of thiourea and to two Hg(1)–S(2) 2.992(2)
cyanide carbon atoms. The Hg atom lies on a twofold
rotation axis possessing crystallographic C2 symmetry
and exhibits a severely distorted tetrahedral geometry Hg(2)–C(2) 2.2055(8)
completed by the two S atoms of thiourea ligands and
two C atoms of the cyanide groups. The methylthioꢀ
S(1)Hg(1)C(1)
S(1)Hg(1)C(2)
S(2)Hg(1)C(1)
S(2)Hg(1)C(2)
Hg(1)–C(1) 2.2048(8)
C(1)–N(1) 1.150(10)
urea ligands behave as Sꢀdonors and bind in a terminal
mode, although the bridging mode has also been
observed in some other metalꢀthiourea systems [17]. S(1)–C(3)
C(2)–N(2) 1.141(10)
C(1)Hg(1)C(2) 169.3(3)
C(1)S(1)Hg(1) 102.8(2)
N(1)C(1)Hg(1) 175.7(7)
N(2)C(2)Hg(1) 177.2(7)
1.717(6)
1.729(7)
The Hg–S distances are comparable to that in
S(2)–C(5)
[
3
(H4pymthH) Hg(CN) ] (~2.9
,4,5,6ꢀtetrahydropyrimidineꢀ2ꢀthione) to Hg(II). N(4)–C(3) 1.302(8)
Å
)
[23] (H4pymthH is
2
2
However, this distance is somewhat longer than the
reported mean distance of ~2.6 Å in many other merꢀ
N(4)–C(4)
1.434(8)
N(4)C(3)S(1)
120.5(5)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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2011

184
ISAB et al.
N(2)
C(2)
C(6)
N(5)
C(5)
N(6)
S(1)
S(2)
Hg(1)
C(3)
N(4)
C(4)
C(1)
N(3)
N(1)
Fig. 2. Molecular structure of
I. Displacement ellipsoids are drawn at the 50% probability level.
0
z
x
Fig. 3. View of the crystal packing in compound I showing the N–H⋅⋅⋅NC and N–H⋅⋅⋅S hydrogen bonds.
dicates a weak binding of thiourea ligand to Hg, which is
also evident from the longer Hg–S distances. The SCN2 connected by intermolecular N–H⋅⋅⋅NC (cyanide)
⋅⋅⋅
cules. The crystal packing and hydrogen bonding patꢀ
terns of is illustrated in Fig. 3. The hydrogen bonding
In the crystal packing, the adjacent molecules are
and
N⎯H S hydrogen bonds between adjacent moleꢀ
moiety of thioureas is essentially planar with the C–N
and C–S bond lengths corresponding to the values interꢀ
mediate between single and double bonds (Table 5). This
is attributed to the delocalization of electrons in the
I
scheme is believed to stabilize the encountered disꢀ
torted tetrahedral geometry.
SCN fragment and the significant sp2 character of the
2
The present report shows that the reaction of Nꢀ
methylthiourea (MeTu) with mercury cyanide results
in complexes with a distorted tetrahedral geometry in
which thiourea ligands are coordinating through the
sulfur atom in a monodentate terminal mode. The
study also shows that the L2Hg(CN)2 complexes are
stable in solution, unlike the LAuCN complexes,
which undergo dissociation in solution.
two nitrogen atoms. The complex
the monoclinic space group 2 / (Table 2), while the
crystals of the two closely related compounds
bis(cyanido)bis(N,N'ꢀdibutylthioureaꢀ )mercury(II),
I crystallizes in
P
c
1
(
κ
S
[Hg(Dbtu) (CN) ], and bis(cyanido)bis(N,N'ꢀdimethylꢀ
thioureaꢀ
2
2
κ
S
)mercury(II), [Hg(Dmtu) (CN) ]), were
2
2
found to belong to
C2/c
space group [20, 21].
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

MERCURY(II) CYANIDE COMPLEXES OF THIOUREAS
185
ACKNOWLEDGMENTS
19. Lobana, T.S., Sharma, R., Sharma, R., et al., Z. Anorg.
Allg. Chem., 2008, vol. 634, p. 718.
Financial support from Pakistan Council for Sciꢀ
ence and Technology (Islamabad, Pakistan) and from
King Fahd University of Petroleum & Minerals
2
0. Ahmad, S., Sadaf, H., Akkurt, M., et al., Acta Crystalꢀ
logr., Sect. E: Structure Reports Online, 2009, vol. 65,
p. m1191.
(
Dhahran, Saudi Arabia) is gratefully acknowledged.
2
1. Malik, M.R., Ali, S., Ahmad, S., et al., Acta Crystalꢀ
logr., Sect. E: Structure Reports Online, 2010, vol. 66,
p. m1060.
REFERENCES
2
2
2
2
2
2
2. Wazeer, M.I.M. and Isab, A.A., Spectrochim. Acta, Part
1
. Bruckner, C., Rettig, S.J., and Dolphin, D., Inorg.
Chem., 2000, vol. 39, p. 6100.
A
, 2007, vol. 68, p. 1207.
3. Popovic, Z., Pavlovic, G., MatkovicꢀCalogovic, D.,
et al., Inorg. Chim. Acta, 2000, vol. 306, p. 142.
4. Popovic, Z., MatkovicꢀCalogovic, D., Soldin, Z.,
et al., Inorg. Chim. Acta, 1999, vol. 294.
5. Ivanov, A.V., Korneeva, E.V., Bukvetskii, B.V., et al.,
Russ. J. Coord. Chem., 2008, vol. 34, p. 59.
6. Altaf, M., StoeckliꢀEvans, H., Batool, S.S., et al.,
J. Coord. Chem., 2010, vol. 63, p. 1176.
7. Ahmad, S., Isab, A.A., and Perzanowski, H.P., Can.
J. Chem., 2002, vol. 80, p. 1279.
2
. Henkel, G. and Krebs, B., Chem. Rev., 2004, vol. 104,
p. 801.
. Blowers, P.J. and Dilworth, J.R., Coord. Chem. Rev.
987, vol. 76, p. 121.
. Dance, I.G., Polyhedron, 1986, vol. 5, p. 1037.
. Satoh, A.M., Nishimura, N., Kanayama, Y., et al., J.
Pharmacol. Exp. Ther., 1997, vol. 283, p. 1529.
. Pearson, R.G., Hard and Soft Acids and Bases, New
York: Dowden, Hutchinson and Ross, 1973.
. Cotton, F.A. and Wilkinson, G., Basic Inorganic Chemꢀ
istry, New York: Wiley, 1988.
. Melnick, J.G., Yurkerwich, K., Buccella, D., et al.,
Inorg. Chem., 2008, vol. 47, p. 6421.
3
,
1
4
5
6
7
8
9
28. Ahmad, S., Coord. Chem. Rev., 2004, vol. 248, p. 231.
2
9. Ahmad, S., Isab, A.A., and Ashraf, W., Inorg. Chem.
Commun., 2002, vol. 5, p. 816.
30. Ashraf, W., Ahmad, S., and Isab, A.A., Transition Met.
Chem., 2002, vol. 29, p. 400.
. Mah, V. and Jalilehvand, F., J. Biol. Inorg. Chem., 2008,
vol. 13, p. 541.
3
1. SMART APEX, Software for SMART APEX Detector,
Version 5.05, SAINT, Software for SMART APEX Detecꢀ
tor, Version 5.0, Madison (WI, USA): Bruker Axs Inc.,
1
1
1
1
0. Jalilehvand, F., Leung, B.O., Izadifard, M., and
Damian, E., norg. Chem., 2006, vol. 45, p. 66.
1. Bharara, M.S., Bui, T.H., Parkin, S., and Atwood, D.A.,
norg. Chem., 2005, vol. 44, p. 5753.
I
2008.
I
3
2. Sheldrick, G.M., SADABS, Program for Empirical
2. Presa, A.L., Capdevila, M., and Duarte, P.G., Eur. J.
Biochem., 2004, vol. 271, p. 4872.
3. Carlton, L. and White, D., Polyhedron, 1990, vol. 9,
Absorption Correction of Area Detector Data, Göttingen
(Germany): Univ. of Göttingen, 1996.
33. Sheldrick, G.M., Acta Crystallogr., Sect. A: Found.
Crystallogr., 2008, vol. 64, p. 112.
p. 2717.
1
1
1
4. Raper, E.S., Coord. Chem. Rev., 1996, vol. 153, p. 199.
5. Akrivos, P.D., Coord. Chem. Rev., 2001, vol. 213, p. 181.
34. Ahmad, S., Isab, A.A., and Arab, M., Polyhedron
2002, vol. 21, p. 1267.
,
6. Bell, N.A., Branston, T.N., Clegg, W., et al., Inorg. 35. Ali, S., Malik, M.R., Isab, A.A., and Ahmad, S.,
Chim. Acta, 2001, vol. 319, p. 130.
J. Coord. Chem., 2009, vol. 62, p. 475.
7. Popovic, Z., Soldin, Z., Pavlovic, G., et al., Struct. 36. Sharpe, A.G., The Chemistry of Cyano Complexes of the
Chem., 2002, vol. 13, p. 425.
Transition Metals, London: Academic, 1976, p. 272.
8. Bell, N.A., Coles, S.J., Constable, C.P., et al., Inorg. 37. Seccombe, R.C. and Kennard, C.H.L., J. Organomet.
1
1
Chim. Acta, 2001, vol. 323, p. 69.
Chem., 1969, vol. 18, p. 243.
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2011