Phenylmercury(II) complexes with pyrimidine-2-thionato ligands: Synthesis and characterization

Article abstract of DOI:10.1016/j.jorganchem.2010.02.022

The treatment of phenylmercury(II) acetate with several pyrimidine-2-thiones (RpymSH) results in the formation of the corresponding pyrimidine-2-thionato complexes [PhHg(RpymS)]. The crystal structure of [PhHg(4,6-Me₂pymS)] shows a nearly lineal coordination environment for the mercury atom, with the ligand using the exocyclic sulfur atom to bind the metal; a weak interaction between mercury and one of the heterocyclic nitrogens is also observed. Vibrational and ¹H, ¹³C and ¹⁹⁹Hg NMR spectroscopic data of the complexes are discussed and related to the structure.

Full text of DOI:10.1016/j.jorganchem.2010.02.022

Journal of Organometallic Chemistry 695 (2010) 1271–1275
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Phenylmercury(II) complexes with pyrimidine-2-thionato ligands: Synthesis
and characterization
b
b
b
b
Antonio Rodríguez a, , Antonio Sousa-Pedrares , José A. García-Vázquez , Jaime Romero , Antonio Sousa
*
a Departamento de Química Fundamental, Universidade da Coruña, 15071-A Coruña, Spain
b Departamento de Química Inorgánica, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
The treatment of phenylmercury(II) acetate with several pyrimidine-2-thiones (RpymSH) results in the
formation of the corresponding pyrimidine-2-thionato complexes [PhHg(RpymS)]. The crystal structure
of [PhHg(4,6-Me2pymS)] shows a nearly lineal coordination environment for the mercury atom, with
the ligand using the exocyclic sulfur atom to bind the metal; a weak interaction between mercury and
one of the heterocyclic nitrogens is also observed. Vibrational and 1H, 13C and 199Hg NMR spectroscopic
data of the complexes are discussed and related to the structure.
Received 23 December 2009
Received in revised form 12 February 2010
Accepted 18 February 2010
Available online 24 February 2010
Keywords:
Ó 2010 Elsevier B.V. All rights reserved.
Organomercurials
Heterocycles
S ligands
1. Introduction
2. Experimental
The coordination chemistry of S, N donor ligands has known an
increasing interest because of their potential application as models
for metalloproteins [1,2]. More particularly, heterocyclic thione/
thionato complexes have been considered as models for interac-
tions of a number of biological molecules with metals [3–5]. Many
metal complexes containing sulfur donor atoms have demon-
strated their capability in the treatment of rheumatoid arthritis,
anticancer activity or a variety of biochemical applications [6–9].
Moreover, heterocyclic thiones have been also proposed as models
of adsorbent materials for the retention of heavy metals from the
environment [10].
On the other hand, the coordination chemistry of organomercu-
ric(II) cations (RHg+; R = Ph, Me, etc.) is also very important since
they show very high toxicity because of their capability to bind
cysteine thiolato groups and so, detoxificating agents are required
[11]. Despite this, only a few studies on the interaction between
heterocyclic thiones and organomercuric(II) compounds have been
reported [12–15].
2.1. Materials
Pyrimidine-2-thione, 4,6-dimethylpyrimidine-2-thione, 4-tri-
fluoromethyl pyrimidine-2-thione, thiourea, 1,1,1-trifluoro-2,4-
pentanedione and phenylmercury(II) acetate are commercial
products and were used without further purification.
2.2. Instrumentation
Elemental analysis were performed with a Carlo–Erba EA
microanalyser. IR spectra were recorded as KBr mulls on a Bruker
IFS-66V spectrophotometer. 1H, 13C and 19F NMR spectra were re-
corded on a Bruker AMX 300 MHZ instrument with CDCl3 as sol-
vent. Chemical shifts are given relative to TMS as the internal
standard. 199Hg NMR spectra were recorded on a Bruker AMX500
spectrophotometer with CDCl3 as solvent. The mass spectra (FAB)
were recorded on a Micromass Autospec spectrometer, with 3-
nitrobenzyl alcohol as the matrix material. X-ray data were col-
lected on a Bruker Smart CCD 1000 diffractometer with graphite-
In this paper we report the synthesis of several phenylmer-
cury(II) complexes with different pyrimidine-2-thionato ligands
(see Scheme 1) and their characterization by analytical and spec-
troscopic methods. The crystal structure of [PhHg(4,6-Me2pymS)]
is also presented.
monochromated Mo K
collected at T = 293 K. The
a
radiation (k = 0.71073 Å). The data were
-scan technique was employed to
x
measure intensities. Decomposition of the crystal did not occur
during the data collection. The intensities of all of the data were
corrected for Lorentz and polarisation effects. Absorption correc-
tions were carried out using SADABS [16]. The structure was solved
by direct methods and refined [17] by full-matrix least squares
based on F2. Hydrogen atoms were also included in idealised posi-
tions and refined with isotropic displacement parameters. Atomic
* Corresponding author.
E-mail address: antonio.rodriguezl@udc.es (A. Rodríguez).
0022-328X/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.02.022

1272
A. Rodríguez et al. / Journal of Organometallic Chemistry 695 (2010) 1271–1275
(w), 890 (w), 871 (w), 848 (w), 840 (w), 760 (w), 723 (m), 692
R1
(m), 590 (w), 562 (w), 546 (m), 447 (m). 1H NMR (CDCl3,
300 MHz, ppm): d = 7.30–7.43 (multiplet, phenyl protons); 6.72
(s, 1H, H5); 1.58 (s, broad; 6H, methyl protons). 13C NMR-{1H}
(300 MHz, CDCl3, ppm): 166.62 (s, C2); 149.56 (s, C4/C6); 136.52–
121.13 (phenyl carbons); 116.00 (s, C5); 24.01 (s, methyl groups).
199Hg-RMN (500 MHz, CDCl3, ppm): d = ꢀ1228 ppm. MS (FAB):
m/z = 756 [PhHg(4,6-Me2pyms)2Hg]; 416 (M+) 27.9%; 215 (4,6-
Me2pymSPh) 8.9%; 139 (4,6-Me2pymS) 17.8%. Crystals suitable
for X-ray diffraction studies were obtained by crystallization from
acetone.
pymSH: R1 = R2 = H
4
4,6-Me2 pymSH: R1 = R2 = Me
4,6-CF3 MepymSH: R1 = CF3; R2 = Me
4-CF3pymSH: R1 = CF3; R 2= H
5
6
N
2
N
H
R2
S
Scheme 1. General structure for the thiones.
2.3.3. [PhHg(4,6-CF3MepymS)](3)
0.1 g (0.51 mmol) of 4,6-CF3MepymSH were dissolved in ace-
tone and this solution was added dropwise to a suspension of
phenylmercury(II) acetate (173 mg, 0.51 mmol) in the same sol-
vent. The initial suspension became a pale yellow solution instan-
taneously and the mixture was stirred at room temperature for 2 h.
The solvent was then removed under vacuum and a white solid,
which was washed with hexane and dried. Yield: 206 mg (85.8%).
Anal. Calc. for C12H9N2F3SHg: C, 30.61; N, 5.95; H, 1.93; S, 6.81.
Found: C, 29.95; N, 5.81; H, 1.75; S, 6.81%. IR (KBr, cmꢀ1): 3040
(w), 1581 (m), 1544 (m), 1385 (s), 1366 (s), 1308 (w), 1266 (s),
1227(m), 1199 (m), 1173 (m), 1141(s), 1112 (s), 1012 (m), 979
(w), 921 (w), 866 (w), 847 (m), 835 (m), 781 (m), 730 (w), 709
(s), 616 (w), 575 (w), 550 (m), 516 (w), 466 (m), 416 (w), 365
(m), 343 (w). 1H NMR (CDCl3, 300 MHz, ppm): d = 7.60 (s, 1H,
H5); 6.90–7.40 (multiplet, phenyl protons); 2.22 (s, 3H, methyl pro-
tons). 13C NMR-{1H} (300 MHz, CDCl3, ppm): 176.12 (s, C2); 168.08
(s, C6); 138.47–126.86 (phenyl carbons); 99.99 (s, C5); 13.99 (s,
CH3). 199Hg-RMN (500 MHz, CDCl3, ppm): d = ꢀ1232 ppm. 19F
NMR (CDCl3, 300 MHz, ppm): d = ꢀ100.28 (s). MS (FAB):
m/z = 546 [PhHg(4,6-CF3MepymS)Hg] 1.9%; 470 (M+) 13.7%: 393
[(4,6-CF3MepymS)Hg] 1.81%.
scattering factors and anomalous dispersion for all of the atoms
were taken from the International Tables for X-ray Crystallography
[18]. The crystal data and summary of data collection are given in
Table 2. An ORTEP 3 drawing [19] along with the numbering
scheme used is provided in the text.
2.3. Synthesis
4-Trifluoromethyl, 6-methylpyrimidine-2-thione is not a com-
mercial product and was obtained as previously reported [20]
The syntheses of all of the complexes were carried out at room
temperature following all of the safety measures related to the tox-
icity of organomercuric(II) complexes. At the end of every synthe-
sis an acetic acid odour was observed.
2.3.1. [PhHg(pymS)] (1)
0.1 g of thione (0.89 mmol) dissolved in acetone were added to
a
suspension of [PhHg(AcO)] in the same solvent (300 mg,
0.89 mmol). A colourless solution was obtained immediately and
the mixture was stirred at room temperature for 2 h. A little
amount of solid in suspension appeared, so the mixture was fil-
tered off and the solid was rejected. The solvent was removed by
distillation under vacuum and a white powder was obtained. It
was washed with diethyl ether and dried. Yield: 289 mg (83.4%).
Anal. Calc. for C10H8N2SHg: C, 30.92; N, 7.21; H, 2.06; S, 8.24.
Found: C, 30.50; N, 7.28; H, 2.03; S, 8.23%. IR (KBr, cmꢀ1): 3021
(m), 1564 (s), 1542 (s), 1477 (m), 1457 (w), 1424(m), 1204 (m),
1175 (s), 1087 (w), 1072 (w), 1057 (w), 1025 (m), 997 (w), 982
(w), 962 (w), 939(w), 921 (w), 906 (w), 794 (m), 767 (m), 748
(s), 728 (s), 694 (m), 668 (w), 634 (m), 476 (w), 456 (m), 444
(w). 1H NMR (CDCl3, 300 MHz, ppm): d = 8.25 (d, 1H, H6); 7.27 (d,
1H, H4); 7.11–7.15 (multiplet, phenyl protons); 6.85 (dd, 1H, H5;
3J(H5H6) = 4.92 Hz; 3J(H5H4) = 3.06 Hz. 13C NMR-{1H} (300 MHz,
CDCl3, ppm): d = 157.88 (s, C4/C6); 129.10–136.53 (phenyl car-
bons); 116.74 (s, C5). 199Hg-RMN (500 MHz, CDCl3, ppm):
d = ꢀ1186 ppm. MS (FAB): m/z = 389 (M+) 25.7%; 309 (SHgPh) 2.
8%.
2.3.4. [PhHg(4-CF3pymS)](4)
0.186 g (5.55 mmol) of phenylmercury(II) acetate were sus-
pended in acetone. A solution containing 0.1 g (0.55 mmol) of thi-
one was added dropwise to the former mixture affording a
colourless solution. It was stirred for 2 h at room temperature
and the solvent was removed at low pressure. The white solid ob-
tained was washed with ether and dried. Yield: 237 mg (93.5%).
Anal. Calc. for C11H7N2F3SHg (%): C, 28.82; N, 6.11; H,1.54; S,
6.98. Found: C, 28.44; N, 5.98; H, 1.44; S, 7.01%. IR (KBr, cmꢀ1):
3041 (m), 1561 (s), 1503 (w), 1478 (m), 1426 (s), 1333 (s),
1208(s), 1172 (m), 1148(s), 1115(s), 1083 (w), 1062 (w), 1022
(m), 997 (w), 878 (w), 918 (w), 865 (w), 835 (s), 781 (w), 732 (s),
697 (m), 678 (w), 668 (s), 473 (w), 451 (m), 436 (w), 422 (w). 1H
NMR (CDCl3, 300 MHz, ppm): d = 8.67 (d, 1H, H5; 3J(H5H6) =
4.75 Hz); 7.37–7.46 (multiplet, phenyl protons); 7.32 (d, 1H, H6).
13C NMR-{1H} (300 MHz, CDCl3, ppm): d = 175.81 (s, C2); 159.21
(s, C6); 129.32–136.34 (Phenyl carbons); 112.30 (s, C5). 19F NMR
(CDCl3, 300 MHz, ppm): d = ꢀ70.57 (s). MS (FAB): m/z = 1113
[Hg(HgPh)2(4-CF3ppymS)2] 15.8%; 935 [(PhHg)2(4-CF3ppymS)Hg]
7.9%; 735 [(PhHg)2(4-CF3ppymS)] 54.8; 456 (M+) 57.5%; 255 [4-
CF3pymS-Ph] 100%.
2.3.2. [PhHg(4,6-Me2pymS)](2)
A
solution of 4,6-dimethylpyrimidine-2-thione (0.1 g,
0.71 mmol) in acetone was added dropwise to a suspension of
phenylmercury(II) acetate (240 mg, 0.71 mmol) in the same sol-
vent. The suspension became a colourless solution and was stirred
for 2 h at room temperature. The solvent was removed by distilla-
tion under vacuum and a white solid was obtained. This solid was
washed with Et2O and dried. Yield: 240 mg (81.1%). Anal. Calc. for
C12H12N2SHg: C, 34.61; N, 6.73; H, 2.88; S, 7.69. Found: C, 34.61; N,
6.85; H, 2.89; S, 7.69%. IR (KBr, cmꢀ1): 3043 (m), 2920 (w), 1578 (s),
1524 (s), 1499 (m), 1477 (m), 1428 (m), 1384 (m), 1364 (m), 1353
(w), 1357 (m), 1305 (w), 1251 (s), 1187 (w), 1175 (w), 1155 (w),
1093 (w), 1061 (w), 1031 (w), 1021 (w), 1008 (w), 996 (w), 975
3. Results and discussion
3.1. General
Neutral complexes of formula [PhHg(RpymS)] have been ob-
tained in reasonable yields (81–94%) by reaction of phenylmer-
cury(II) acetate with several pyrimidine-2-thiones.; the thiones

A. Rodríguez et al. / Journal of Organometallic Chemistry 695 (2010) 1271–1275
1273
Fig. 1. Crystal structure of [PhHg(4,6-Me2pymS)] (2).
displaced the acetate ligand from the mercury coordination sphere
and became anionic thionato species.
amidato ligands [14,15,23,28], neutral thioamides [14] or even
simple mercury(II) complexes with thionato ligands [21,24,29].
They are also shorter than that observed for a phenylpyridine
cyclometallated mercury(II) complex containing a thiosemicarba-
zone ligand [22]. All of the mentioned complexes are proposed as
examples for HgꢁꢁꢁꢁN weak interactions.
3.2. Crystal structure of [PhHg(4,6-Me2pymS)] (2)
Fig. 1 shows the crystal structure of complex 2 together with
the labelling scheme used. Main bond lengths and angles are given
in Table 1.
The observed C–S bond lengths are (1.747(8) and 1.755(9) Å)
are intermediate between those observed for the free ligands 4,6-
dimethylpyrimidine-2-thione [30] and 4,6-dimethyl-1-phenylpyr-
imidine-2-thione [31] (1.392(2) and 1.686(4) Å respectively) which
exist in the thione form in the solid state, and the values of
The crystal structure of this complex consists of mononuclear
discrete molecules (two per asymmetric unit) with the ligand
showing basically a monodentate behaviour; the thionato ligand
binds the metal centre through the exocyclic sulfur atom. How-
ever, a very weak interaction between the mercury atom and one
of the heterocyclic nitrogen atoms is also observed (see below).
The mercury atom presents a pseudo SHgC linear coordination
environment with SHgC bond angles showing very small devia-
tions from the ideal value (178.6(3)° and 178.5(3)°). This angle is
a little bigger than that found for the phenylmercury(II) complex
containing the corresponding neutral thione (4,6-Me2pymSH)
[14] and the dimeric complex of phenylmercury(II) with pyri-
dine-2-thionato [15]. A dimeric dithiouracilato pheylmercury(II)
complex [14] shows quite similar values: 178.3(4) and 175.2(4)°.
The Hg–S bond lengths are 2.379(2) and 2.363(2) Å, which are
quite similar to those found for the mentioned complex [14] with
the neutral thione (2.367(2) Å), the dimeric complex [15] derived
from pyridine-2-thionato (2.376(3)–2.380(3) Å) and the previously
mentioned phenyl mercury(II) complex with dithiouracilato [14].
They are also quite similar to those found in [Hg(3-CF3pyS)2] [21]
(2.3642(18)–2.3761(17) Å) and in the thiosemicarbazone deriva-
tive [Hg(C6H5C5H4N)(Hstsc)] [22] (2.357(2) Å). The Hg–S bond
lengths observed for 2 are shorter than that found for the methyl
mercury derivative [MeHg(pymS)] [23] (2.39(2) Å) which also con-
tains a pyrimidine-2-thionato ligand. However, they are longer
than those found in several Hg(II) thionato complexes as [Hg(4,6-
CF3MepymS)2]: 2.330(2) Å [24] and [Hg(5-CF3pyS)2]: 2.319(3) Å
[21]. The values observed for complex 2 fall within the range de-
fined by the distances observed for [Hg(Tab)2](PF6)2 (2.331(3) Å,
Tab = 4-trimethylamoniobenzenethiolato) [25] and [Hg2(Tab)6]3-
(PF6)Cl11 (2.787(12) Å) [25].
Table 1
Selected bond lengths (Å) and angles (°) for 2.
Hg(1)–C(7)
Hg(1)–S(1)
Hg(1–N(1)
S(1)–C(1)
2.073(8)
2.378(2)
2.785(3)
1.747(8)
Hg(2)–C(19)
Hg(2)–S(2)
Hg(2)–N(3)
S(2)–C(13)
2.065(8)
2.363(2)
2.773(5)
1.755(9)
C(7)–Hg(1)–S(1)
178.6(2)
C(19)–Hg(2)–S(2)
178.6(2)
Table 2
Crystal data and structure refinement for 2.
Empirical formula
C24H24Hg2N4S2
Formula mass
Crystal system
Space group
a (Å)
b (Å)
c (Å)
833.77
Monoclinic
P2(1)/c
14.583(3)
14.202(3)
12.436(3)
90
a
(°)
b (°)
102.546(4)
90
2414.2(9)
4
2.203
12.383
1552
c
(°)
V (Å3)
Z
Dcalc (Mg mꢀ3
)
l
(Mo K
a
) (mmꢀ1
)
F(0 0 0)
Crystal size (mm)
T (K)
0.50 ꢂ 0.18 ꢂ 0.18
293(2)
The Hg(1)–N(1) and Hg(2)–N(3) distances are 2.785(7) and
2.773(7) Å, respectively. These distances are shorter than the sum
of their van der Waals radii of N and Hg (1.73 [26] and 1.55 Å
[27] for Hg and N, respectively), which indicates that a weak inter-
action between Hg and one of the heterocyclic nitrogen atoms oc-
curs. The distances obtained for 2 are shorter than those found for
other organomercurial derivatives containing heterocyclic thio-
Number of reflections collected
28 926
5169
1.087
0.0331
0.0658
Number of independent reflections
Goodness-of-fit (GOF) on F2
Ra
Rwb
a
R = [|Fo| ꢀ |Fc|]/[|Fo|].
Rw = [(Fo ꢀ Fc2)]/(Fo2)]1/2
.
b
2

1274
A. Rodríguez et al. / Journal of Organometallic Chemistry 695 (2010) 1271–1275
Fig. 2. Crystal packing diagram for [PhHg(4,6-Me2pymS)] along the a axis. (Symmetry codes: #1: ꢀx, ꢀy + 1, ꢀz + 2; #2: ꢀx + 1, ꢀy + 1, ꢀz + 2).
1.781(2) and 1.782(3) Å found for bis(pyrimidyl)-2,20-disulfide [32]
and bis(4,6-dimethylpyrimidyl) disulfide [33], which posses a sim-
ple C–S bond. This confirms that the ligand acts as a pyrimidine-2-
thionato rather than the neutral thione.
HgꢁꢁꢁN interactions in all complexes [44,45]. The spectra of the
complexes also show additional bands which are assigned to the
ring breathing vibration in the region 1190–995 cmꢀ1 and 750–
620 cmꢀ1. All of the spectra show relatively intense bands at
1250–1180 cmꢀ1, which is the typical region for C@S double or
partially double bonds [46,47]. The spectra of the complexes con-
taining methyl groups also show additional medium intensity
bands in the range 3100–2900 cmꢀ1, which correspond to the
vibrations of these groups.
The mass spectra of all complexes show peaks due to the molec-
ular ion with the expected isotopic distribution. Furthermore, sig-
nals due to the loss of phenyl fragment or the rearrangement of the
ligands to give RpymS-Ph are also observed.
The distance between two Hg atoms of two neighbouring mol-
ecules is 3.9035(8). This value is in the upper limit of the range of
the sum of the van der Waals radii (1.7–2.0 Å) [26]. It is also quite
longer than those reported for elemental mercury (3.02 Å) [34],
mercury(0) clusters (2.797(2)–3.820(2) Å) [35], dinuclear mercury
(I) complexes (Hg22+, 2.5 Å) [36] or the tris(1,3-dimethyluracil-5-
yl)mercurioxonium salt, which dimerises in two different ways
through weak HgꢁꢁꢁHg contacts [HgꢁꢁꢁHg distances in the range
3.4552(6) to 3.5974(5) Å) [37]. The observed HgꢁꢁꢁHg distance is
also much longer than that reported for methyl(2-mercapto-4-
metylpyrimidinato)mercury(II) (3.101(2) Å) [38]. It is also longer
than those found in many other mercury(II) complexes (3.848–
3578 Å) [39–43]. Thus, we conclude that if any HgꢁꢁꢁHg interaction
occurs it must be extremely weak.
The 1H NMR spectra of these complexes do not show the signal
attributable to NH group; this confirms deprotonation of the li-
gands and the presence of thionato species in the complexes. All
of them show a multiplet attributable to the phenyl protons and
the corresponding aromatic signals which are assigned to the li-
gands. The spectrum of complex 1 shows three signals for the pyri-
midinic protons. The fact that H4 and H6 show different frequencies
for their resonances, indicates that they’re not equivalent; so it
seems to confirm the presence of a Hg–N interaction also in solu-
tion. For 2 and 3 signals attributable to methyl groups are also ob-
served. In complex 2 the corresponding signal is observed as a
broad singlet, which again supports the presence of a Hg–N inter-
action. As expected the 199Hg NMR spectra of the complexes show
one signal; the frequencies for all of them are quite similar to those
found for several organomercurial complexes containing neutral
thioamides [14] or thionatos [28]; the values are also similar to
those found for several mercury(II) complexes with pyridine-2-
thionato [21] or pyrimidine-2-thionato ligands [24]. For complexes
3 and 4, 19F NMR spectra show the expected signal (ꢀ100 and
ꢀ70 ppm respectively); these frequencies are in agreement with
those reported for several metallic complexes with heterocyclic li-
gands containing –CF3 groups [48–50].
3.3. Crystal packing
The asymmetric unit of the crystal lattice contains two mercury
complexes, with the aromatic rings almost parallel to each other.
The mercury–mercury distance for this pair of complexes is
3.9035(8) Å. The aromatic rings of one complex establish very
weak p-stacking interactions with the aromatic rings of the other
complex (centroid–centroid distances: pyrimidine1ꢁ ꢁ ꢁphenyl2 =
3.799(5) Å, phenyl1ꢁ ꢁ ꢁpyrimidine2 = 3.980(5) Å). This pair of com-
plexes establishes very weak van der Waals interactions with
neighbouring pairs of complexes. Thus, the complexes are arranged
in pairs that zig–zag along the crystallographic a axis with the aro-
matic rings almost parallel to one another, as shown in Fig. 2. This
arrangement leaves the sulfur atoms pointing up and down the
crystallographic c axis. These atoms establish very weak C–HꢁꢁꢁS
interactions, connecting the zigzag rows in the c direction. These
rows of complexes (Fig. 2) are also connected to other rows in
the b direction, although in this case these interactions are weaker
van der Waals HꢁꢁꢁH contacts.
Acknowledgements
This work was supported by the Xunta de Galicia (Spain)(Grant
No. PGIDIT07PXIB203038PR) and by the Ministerio de Ciencia y
Tecnología (Spain) (Grant No. CTQ2006-05298BQU).
3.4. Spectroscopic studies
The IR spectra of the complexes do not show bands due to tN–H
,
which in the free ligands appear at 3200–2050 cmꢀ1; this fact pro-
vides evidence of the deprotonation of the thiones during the for-
mation of the complexes, thereby confirming that the ligand acts
as a thionato species. This conclusion is supported by the presence
of a very strong band attributable to mC@C and mC@CN in the range
1561–1568 cmꢀ1. These bands are shifted to lower wavenumbers
with respect to their position in the spectra of the free ligands
(1650–1550 cmꢀ1). This seems to confirm the presence of weak
Appendix A. Supplementary material
CCDC 758813 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif. Supplementary data associated with this article
can be found, in the online version, at doi:10.1016/j.jorganchem.
2010.02.022.

A. Rodríguez et al. / Journal of Organometallic Chemistry 695 (2010) 1271–1275
1275
[26] A.J. Canty, G.B. Deacon, Inorg. Chim. Acta 45 (1980) L225.
[27] A. Bondi, J. Phys. Chem. 68 (1964) 441.
References
[28] M.S. García Tasende, M.I. Suárez Gimeno, A. Sánchez, J.S. Casas, J. Sordo, E.E.
[1] I.G. Dance, J. Am. Chem. Soc. 102 (1980) 3445.
Castellano, J. Organomet. Chem. 384 (1990) 19.
[29] D. Matkovic´-Calogovic´, D. Mrvoš-Sermek, Z. Popovic´, Z. Soldin, Acta
[2] G.P. Diakin, L. Fairall, A. Klug, Nature (London) 324 (1986) 698.
[3] B. Krebs, G. Henkel, Angew. Chem., Int. Ed. Engl. 30 (1991) 769.
[4] D.T. Puerta, M.O. Griffin, J.A. Lewis, D. Romero-Pérez, R. García, F.J. Villareal,
S.M. Cohen, J. Biol. Inorg. Chem. 11 (2000) 131.
[5] D.T. Puerta, J.A. Lewis, S.M. Cohen, J. Am. Chem. Soc. 126 (2004) 8388.
[6] T.S. Lobana, P.K. Bathia, J. Sci. Ind. Res. 48 (1989) 394. and references therein.
[7] E.S. Raper, Coord. Chem. Rev. 61 (1985) 115.
[8] E.S. Raper, Coord. Chem. Rev. 129 (1994) 91.
[9] E.S. Raper, Coord. Chem. Rev. 153 (1996) 1999.
[10] I. del Hierro, I. Sierra, D. Pérez-Quintanilla, F. Carrillo-Hermosilla, I. López-
Solera, M. Fajardo, Inorg. Chim. Acta 355 (2003) 347.
[11] E. Block, M. Britto, M. Gernen, D. McGoutey, H. Kang, J. Zubieta, Inorg. Chem. 29
(1990) 3172. and references therein.
[12] J.S. Casas, E.E. Castellano, A. Macías, N. Playá, A. Sánchez, J. Sordo, J.M. Varela,
E.M. Vázquez-López, Polyhedron 20 (2001) 1845.
[13] R. Carballo, J.S. Casas, M.S. García-Tasende, A. Sánchez, J. Sordo, E.M. Vázquez-
López, J. Organomet. Chem. 525 (1996) 49–55.
[14] S. Lemos, D.V. Martins, V.M. Deflon, J. Elen, J. Organomet. Chem. 694 (2009)
253.
[15] T.S. Lobana, S. Paul, A. Castiñeiras, J. Chem. Soc., Dalton Trans. (1999) 1819.
[16] G.M. Sheldrick, SADABS, An Empirical Absortion Correction Program for Area
Detector Data, University of Göttingen, Germany, 1996.
[17] G.M. Sheldrick, SHELX-97. Program for the Solution and Refinement of Crystal
Structures, University of Göttingen, Germany, 1997.
[18] International Tables for X-ray Crystallography, vol C. Kluwer, Dordrecht, 1992.
[19] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
[20] A. Rodríguez, J.A. García-Vázquez, A. Sousa-Pedrares, J. Romero, A. Sousa, Inorg.
Chem. Commun. 6 (2003) 619.
ˇ
ˇ
Crystallogr. Sect. C 60 (2004) m44.
[30] J. Abbot, D.M.L. Goodgame, Y. Jeeves, J. Chem. Soc., Dalton Trans. (1978) 880.
[31] L.R. Battaglia, R. Battistuzzi, A. Bonamartini Corradi, C. Rizzolie, P. Sgarabotto, J.
Crystallogr., Spectrosc. Res. 23 (1993) 937.
[32] S. Furberg, J. Solbakk, J. Acta Chem. Scand. 27 (1973) 2536.
[33] J.A. Castro, J. Romero, J.A. García Vázquez, A. Castiñeiras, A. Sousa, Polyhedron
14 (1995) 2841.
[34] N.N. Greenwood, E. Earnshaw, Chemistry of the Elements, 2nd ed., Pergamon
Press, Oxford, 1997, p. 1205.
[35] A.V. Tkachuk, A. Man, Inorg. Chem. 47 (2008) 1313.
[36] K. Wurst, J. Strähle, Z. Anorg. Allg. Chem. 595 (1991) 239. and references
therein.
[37] F. Zamora, M. Sabat, M. Janik, C. Siethoff, B. Lippert, Chem. Commun. (1997)
485.
[38] J. Bravo, J.S. Casas, Y.P. Mascarenhas, A. Sánchez, C.de O.P. Santos, J. Sordo, J.
Chem. Soc., Chem. Commun. (1986) 1100.
[39] R.D. Schluter, G. Krauter, W.W. Rees, J. Cluster Sci. 8 (1997) 123.
[40] J.S. Casas, A. Castiñeiras, I. Haiduc, A. Sánchez, J. Sordo, E.M. Vázquez-López,
Polyhedron 16 (1997) 781.
[41] J.S. Casas, E.M. Vázquez-López, J. Zukerman-Schpector, J. Chem. Soc., Dalton
Trans. (1996) 1973.
[42] P. Biscarini, E. Foresti, G. Pradella, J. Chem. Soc., Dalton Trans. (1984) 953.
[43] A.J. Canti, C.L. Raston, A.H. White, Aust. J. Chem. 31 (1978) 677.
[44] R.C. Paul, H.S. Makhni, P. Singh, S.L. Chadha, Z. Anorg. Allg. Chem. 377 (1970)
108.
[45] R.D. Kross, V.A. Fassel, M. Hargoshes, J. Am. Chem. Soc. 78 (1956) 1332.
[46] T.S. Lobana, S. Paul, A. Castiñeiras, Polyhedron 16 (1997) 4023.
[47] T.S. Lobana, R. Verman, R. Singh, A. Castiñeiras, Transition Met. Chem. 23
(1998) 25.
[48] D. Sanz, R.M. Claramunt, S.P. Singh, V. Kuman, R. Aggarwal, J. Elguero, I.
Alkorta, Magn. Reson. Chem. 43 (2005) 1040.
[49] N.N. Buceta, E.M. Goyanis, C.O. Della Védova, A. Haas, M. Schettino, M. Winter,
J. Phys. Org. Chem. 17 (2004) 332.
[21] A. Sousa-Pedrares, J. Romero, J.A. García-Vázquez, M.L. Durán, I. Casanova, A.
Sousa, Dalton Trans. (2003) 1379.
[22] T.S. Lobana, A. Sánchez, J.S. Casas, A. Castiñeiras, J. Sordo, M.S. García-Tasende,
Polyhedron 17 (1998) 3701.
[23] C. Chie, Can. J. Chem. 56 (1978) 560.
[24] A. Rodríguez, A. Sousa-Pedrares, J.A. García Vázquez, J. Romero, A. Sousa, Eur. J.
Inorg. Chem. (2005) 2242.
[50] D. Sanz, R.M. Claramunt, A. Saini, V. Kuman, R. Aggarwal, S.P. Singh, I. Alkorta, J.
Elguero, Mgn. Reson. Chem. 45 (2007) 513.
[25] J.-X. Chen, W.–H. Zhang, X.–Y. Tang, Z.-G. Ren, Y. Zhang, J.–P. Lang, Inorg.
Chem. 45 (2006) 2568.