Synthesis and molecular structures of methyl and phenylmercury(II) complexes with benzaldehyde-4,4-dimethylthiosemicarbazone

Article abstract of DOI:10.1016/j.jorganchem.2012.11.032

The reactions of benzaldehyde-4,4-dimethylthiosemicarbazone (LH) with methyl and phenylmercury (II) chlorides in different conditions were investigated. From the methyl derivative, two complexes [HgMeClLH] (1) and [HgMeL] (2), were obtained working in ethanol in the absence or the presence of basic medium respectively. However, in the same conditions only the complex [HgPhL] (3) was isolated. The corresponding complex containing the neutral ligand [HgPhClLH] (4) was prepared in refluxing dicloromethane. Furthermore, in the presence of hydrochloric acid, HgPhCl undergoes a symmetrization reaction to afford HgPh₂ and [Hg(LH)₂(μ-Cl)₂HgCl ₂], reported previously from the reaction with HgCl₂. Spectroscopic studies and X-ray structural analysis showed that the thiosemicarbazone is always SN coordinated, giving a distorted tetrahedral arrangement in complexes 1 and 4 and a distorted T-shaped stereochemistry around the mercury centre in complexes 2 and 3.

Full text of DOI:10.1016/j.jorganchem.2012.11.032

Journal of Organometallic Chemistry 725 (2013) 28e33
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and molecular structures of methyl and phenylmercury(II)
complexes with benzaldehyde-4,4-dimethylthiosemicarbazone
*
Elena López-Torres , M. Antonia Mendiola
Departamento de Química Inorgánica, c/Francisco Tomás y Valiente, 7, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
The reactions of benzaldehyde-4,4-dimethylthiosemicarbazone (LH) with methyl and phenylmercury (II)
chlorides in different conditions were investigated. From the methyl derivative, two complexes
[HgMeClLH] (1) and [HgMeL] (2), were obtained working in ethanol in the absence or the presence of
basic medium respectively. However, in the same conditions only the complex [HgPhL] (3) was isolated.
The corresponding complex containing the neutral ligand [HgPhClLH] (4) was prepared in refluxing
dicloromethane. Furthermore, in the presence of hydrochloric acid, HgPhCl undergoes a symmetrization
Received 10 October 2012
Received in revised form
19 November 2012
Accepted 22 November 2012
Keywords:
reaction to afford HgPh2 and [Hg(LH)2(m-Cl)2HgCl2], reported previously from the reaction with HgCl2.
Methylmercury complexes
Phenylmercury complexes
Thiosemicarbazones
Crystal structures
Spectroscopic studies and X-ray structural analysis showed that the thiosemicarbazone is always SN
coordinated, giving a distorted tetrahedral arrangement in complexes 1 and 4 and a distorted T-shaped
stereochemistry around the mercury centre in complexes 2 and 3.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
Thiosemicarbazones have been extensively studied due to their
pharmacological properties and their coordinative behaviour
Organomercury compounds of the type HgRX (R ¼ alkyl or aryl;
X ¼ halide or acetate) have received considerable attention over the
last three decades mainly related to the search for biologically
active compounds and versatile reagents in controlled trans-
metallation reactions [1,2]. However, the high affinity of organo-
mercurials for thiols and their lipophilic nature make them highly
toxic to living organism, causing irreversible damage to the central
nervous system [3,4]. The methylmercury ion, is probably the most
ubiquitous compound and one of the most dangerous pollutant
agents for animals and humans [5,6]. Recent studies have indicated
that the coordination of organomercury(II) ions by the donors so as
the increase of the metal coordination from the usual linear
dicoordination to higher coordination numbers is quite important
in the activation of the HgeC bond, both in the enzymatic degra-
dation processes and laboratory chemical reactions [7,8]. Symme-
trization is a general reaction of the organomercurials which allows
the simultaneous formation of symmetric diorganomercurials
HgR2 and Hg(II) complexes [9]. Such reactions, involving the
cleavage of an HgeC bond, are promoted by strong complexing
agents such as sulphur donors.
towards transition metal ions [10e12]. However, very few mercury
and organomercury complexes with thiosemicarbazone are known
[9,13,14]. Moreover, they are promising ligands to detoxify orga-
nomercury(II) by activation of HgeC bond using coordination, fol-
lowed by treatment with acid, to generate parent hydrocarbon (RH)
and inorganic mercury(II) salts [9,14].
In our group we explored the coordination behaviour of several
potentially tetradentate bis(thiosemicarbazones) with mercury(II)
salts and methylmercury(II) chloride. In the mercury(II) complexes,
the ligands behave as tetradentate chelate [15] even in the case of
hybrid thiosemicarbazone-hydrazone molecules [16,17], but in the
complexes obtained by the reaction of benzil bis(thiosemicarba-
zide) with methylmercury the ligand was only bonded through the
sulphur atom acting as a bidentate bridged donor [18]. In the
triazine 3-thione derivatives the cyclic molecules were bonded to
the mercury(II) and methylmercury(II) only by the sulphur atom
giving a linear coordination to the metal centre [19]. We also
studied the reactivity of the title molecule with mercury(II) salts
(bromide, chloride, iodide and nitrate) and the results showed that
the structures of the complexes depend on the counterion used.
The ligand was a NS quelate except in a dinuclear iodine derivative
containing bridged iodide in which the ligand was monodentate
through the sulphur atom [20].
In this paper we report new complexes of benzaldehyde-4,4-
dimethylthiosemicarbazone, LH, formed by reaction with HgRCl
* Corresponding author. Tel.: þ34 914972376; fax: þ34 914974833.
E-mail address: elena.lopez@uam.es (E. López-Torres).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.11.032

E. López-Torres, M.A. Mendiola / Journal of Organometallic Chemistry 725 (2013) 28e33
29
(R ¼ Me or Ph). We obtained complexes with 1:1 Hg:LH ratio and
with the ligand being neutral or deprotonated. The complexes were
characterized using multinuclear NMR, IR and mass spectrometry.
Three of the complexes were also characterized by single crystal X-
ray diffraction.
The crystal structure of complex 1 is made up of [HgMeCl(LH)]
units (Fig. 2). The ligand is neutral and coordinates in a bidentate
mode through the imine nitrogen and the sulphur atom, leading to
the formation of a five-member chelate ring. The mercury atom is
in a tetra-coordinate environment provided by the ligand, the
methyl group and the chloride. The s4 parameter is 0.54 and
therefore the metal is in an environment intermediated between
tetrahedral and square planar (s4 ¼ 1 for Td and s4 ¼ 0 for SP) [21].
In the complex the ligand is significantly more buckled and the
electronic delocalization is smaller than in the free ligand. There are
hydrogen bonds between the NH and the Cl leading to the forma-
2. Results and discussion
2.1. Synthesis of the complexes
Reaction of the ligand LH with HgMeCl in ethanol led to the
obtaining of two complexes, [HgMeCl(LH)] (1) in neutral medium
and [HgMeL] (2) when lithium hydroxide was used. By contrast,
reaction of HgPhCl in ethanol without base induced the sponta-
neous deprotonation of the ligand to yield complex [HgPhL] (4),
which was also obtained in the presence of lithium hydroxide. If
some drops of hydrochloric acid were added to the reaction
mixture to prevent ligand deprotonation, a symmetrization reac-
ꢀ
tion of dimers that are held together by S/S interactions (3.349 A,
ꢀ
SeS Van der Waals radium 3.6 A), giving rise to chains running
along the b axis. This complex represents the first example of an
organomercury(II) compound crystallographically characterized
with a thiosemicarbazone ligand in which the chloride atom is
retained.
The X-ray analysis of complex 2 reveals the presence of [HgMeL]
units, in which the metal is surrounded by a deprotonated ligand
acting as bidentate chelate and the methyl group in a distorted T-
shape environment (Fig. 3). In this complex the ligand is more
planar due to deprotonation, which induces a larger charge
delocalization.
Complex 4 consists of [HgPhL] units (Fig. 4). The metal is in
a coordination environment similar to those of complex 2 formed
by a bidentate deprotonated ligand and the phenyl group. Due to
deprotonation the ligand is much more planar than in complex 1 or
when it is uncoordinated [20].
In all the complexes the CeS distance (Table 2) is much longer
than in LH, due the strength of the HgeS bond. The HgeN distances
(Table 3) are in the range found in other mercury complexes with
thiosemicarbazones [20,22e24].
tion took place and the complex [Hg(LH)2(m-Cl)2HgCl2], which was
previously synthesized by reaction of LH with HgCl2 [20], was ob-
tained. Nevertheless, ligand deprotonation could be avoided in
refluxing dichloromethane in which complex [HgPh(LH)Cl] (3)
could be synthesized.
Mass spectra of the complexes confirmed the 1:1 ligand to metal
stoichiometry. In the spectra of complexes 1 and 3 there was a peak
corresponding to the fragment [MeCl]þ while in complexes 2 and 4
it corresponded to [M þ H]þ. The calculated and experimental
isotopic splitting patterns are identical (Fig. 1). In addition, in the
spectra of complexes 1 and 2 a peak corresponding to the ligand,
due to demetallation, is observed.
In complexes 1 and 2 the H bound to iminic carbon atom C1 is
placed in Z configuration to the hydrazinic nitrogen N2, and hence
the phenyl ring is directed to the mercury centre. By contrast, in
complex 4 the disposition is E, causing the phenyl ring is pushed
2.2. X-ray structures
Crystallographic data of complexes 1, 2 and 4 are summarized in
Table 1.
Fig. 1. FABþ mass spectrum of complex [HgMeCl(LH)] 1 including theoretical and experimental isotopic splitting pattern.

30
E. López-Torres, M.A. Mendiola / Journal of Organometallic Chemistry 725 (2013) 28e33
Table 1
complexes 2 and 4 in which the ligand has lost the acidic hydrogen
atom.
Crystal data and structure refinement for 1, 2 and 4.
1
2
4
Formula
M
HgC11H16ClN3S
458.37
Triclinic
P-1
7.6427(7)
9.3666(9)
10.7236(9)
87.980(4)
70.785(4)
74.115(5)
695.94(11)
2
HgC11H15N3S
421.91
Orthorhombic
Pbca
10.947(3)
7.2112(16)
31.959(11)
90
HgC16H17N3S
483.98
2.4. NMR spectra
Crystal system
Space group
Monoclinic
P2(1)/n
16.961(4)
5.4638(13)
17.498(4)
90
105.173(14)
90
4602.8(9)
4
The new compounds were also characterized by NMR spec-
troscopy. In the 1H NMR spectrum of complexes 1 and 3 the signal
corresponding to the NeH group is clearly observed and therefore
the ligand is neutral. By contrast, in the spectra of complexes 2 and
4 the signal has disappeared, confirming the ligand deprotonation.
In complexes 1 and 2 can be observed a singlet at high field cor-
responding to the methyl group bound to mercury, while in
complexes 3 and 4 a multiplet in the aromatic region due to the
phenylmercury moiety can be observed.
ꢀ
a/A
ꢀ
b/A
ꢀ
c/A
ꢁ
ꢁ
a
/
b
/
90
90
ꢁ
g
/
3
ꢀ
U/A
1788.1(11)
8
2.222
Z
Dc/M g mꢀ3
Absorption
coefficient mmꢀ1
F(000)
2.187
11.382
2.054
9.964
12.344
All the 13C NMR spectra were run in CDCl3 solution except the
one of complex 1, which is not soluble enough, so 13C CP/MAS NMR
spectrum was recorded. In the spectra, the signals corresponding to
the imine carbons and the thiocarbonyl groups are clearly shifted
on complexation. The methyl groups bound to mercury in
complexes 1 and 2 appear at 6.0 and 8.0 ppm respectively and the
phenyl groups bound to mercury in compounds 3 and 4 are
observed in the aromatic region.
432
1.127
32,957
3565 [R(int)
¼ 0.0429]
0.0192, 0.0507
1584
1.372
14,923
2576 [R(int)
¼ 0.0759]
0.0901, 0.2210
920
1.098
11,382
2974 [R(int)
¼ 0.0524]
0.0311, 0.0730
Goodness of fit on F2
Reflections collected
Independent
reflections
Final R1and wR2
[I > 2s(I)]
Residual electron
ꢀ0.895, 1.155
ꢀ7.249, 2.298
ꢀ1.197, 1.480
The 199Hg NMR is a useful tool to determine the metal envi-
ronment, since the chemical shift is very sensitive to its coordina-
density (min, max)
ꢀꢀ3
(e A
)
tion sphere. According to the literature,
a decrease in the
coordination number tends to give greater deshielding [14,25e28].
Electronegative substituents linked to mercury or to the atom next
to mercury tend to increase 199Hg nuclear shielding, whereas
electropositive substituents cause deshielding [29]. Tetra-
coordinated complexes 1 and 3 exhibit resonances at ꢀ830.5 and
ꢀ640.8 ppm respectively, while in three-coordinated complex 2
appears at ꢀ443.2 ppm. In the spectrum of complex 4, also with
coordination number of three, three signals can be observed, one at
ꢀ317.3 ppm corresponding to the complex, one at ꢀ748.1 ppm
corresponding to HgPh2 [29] and the last one at ꢀ1403.0 ppm
corresponding to HgCl2 [28], indicating the partial symmetrization
of the complex.
away from the phenyl ring bound to mercury, probably due to steric
hindrance.
To date there were only eight three-coordinated phenylmercury
complexes with a thiosemicarbazone ligand, and complex 2 is the
first example of an analogous methylmercury derivative structur-
ally characterized.
2.3. Infrared spectra
The band corresponding to n(NeH) is observed in complexes 1
and 3 indicating that the ligand behaves as a neutral molecule, but
it is absent in complexes 2 and 4, confirming the ligand deproto-
nation. The coordination by sulphur induces a strong decrease in
3. Experimental
the
show a band assigned to the
lower wavenumbers than in LH, although the shift is much larger in
n
(CS), as could be expected from the X-ray data. All the spectra
n
(CeH), which is clearly shifted two
IR spectra in the 4000e400 cmꢀ1 range were recorded as KBr
pellets on
a Jasco FT/IR-410 spectrophotometer. Fast atom
Fig. 2. Molecular structure of complex [HgMeCl(LH)] 1. Thermal ellipsoids at 50% probability.

E. López-Torres, M.A. Mendiola / Journal of Organometallic Chemistry 725 (2013) 28e33
31
Fig. 3. Molecular structure of complex [HgMeL] 2. Thermal ellipsoids at 50% probability.
bombardment (FAB) mass spectra were recorded on a VG Auto Spec
3.1. Synthesis of the ligands and the complexes
instrument using Cs as the fast atom and m-nitrobenzylalcohol
(mNBA) as the matrix. 1H, 13C and 199Hg NMR spectra were recorded
on a spectrometer Bruker AMX-300 using CDCl3 or DMSO-d6 as
All the reagents and solvents were commercially obtained and
used without further purifications.
solvents and TMS (1H and 13C) or HgMe2 199Hg) as internal refer-
(
ence. 13C CP/MAS NMR spectra were recorded at 298 K in a Bruker
AV400WB spectrometer equipped with a 4 mm MAS NMR probe
(magic-angle spinning) and obtained using cross-polarization pulse
sequence. The external magnetic field was 9.4 T, the sample was
spun at 10e14 kHz and the spectrometer frequency was
100.61 MHz. For the recorded spectra a contact time of 4 ms and
recycle delays of 4 s were used. Chemical shifts are reported relative
toTMS, using the CH group of adamantane as a secondary reference
(29.5 ppm).
3.1.1. Benzaldehyde-4,4-dimethylthiosemicarbazone (LH)
The ligand LH was prepared by condensation of benzaldehyde
and 4,4-dimethylthiosemicarbazide, following the procedure
previously reported [20]. Anal. Calcd. for C10H13N3S: C, 57.97; H,
6.28; N, 20.28; S, 15.46. Found: C, 57.94; H, 6.21; N, 20.25; S, 15.44.
MS (FABþ): m/z (%): 208.1 (100) [M þ H]þ. 1H NMR (300 MHz, CDCl3,
25 ꢁC):
d
¼ 9.00 (s, 1H, NH), 7.71 (s, 1H, CH), 7.59 (m, 2H, Ph), 7.37
(m, 3H, Ph), 3.44 (s, 6H, CH3) ppm. 1H NMR (300 MHz, [D6]DMSO,
25 ꢁC):
¼ 10.89 (s, 1H, NH), 8.17 (s, 1H, CH), 7.62 (m, 2H, Ph), 7.41
d
Fig. 4. Molecular structure of complex [HgPhL] 4. Thermal ellipsoids at 50% probability.

32
E. López-Torres, M.A. Mendiola / Journal of Organometallic Chemistry 725 (2013) 28e33
Table 2
solution was refluxed for 6 h. The scarce amount of solid was
filtered off and discarded. The yellow solution was evaporated to
afford a yellow solid. (0.22 g, 88%). MS (FABþ): m/z (%): 485.0 (100)
ꢀ
Selected bond distances (A) of the ligand backbone in LH [20] and complexes
1, 2 and 4.
[MeCl]þ. 1H NMR (300 MHz, CDCl3, 25 ꢁC):
d
¼ 12.03 (br s, 1H, NH),
8.8 (s, 1H, CH), 8.2 (d, 2H, Ph), 7.6 (d, 3H, Ph), 7.5e7.1 (m, 5H, Ph), 3.4
(s, 6H, CH3) ppm. 13C NMR (300 MHz, CDCl3, 25 ꢁC):
¼ 150.4 (CS),
137.6 (CN), 136.5, 132.8, 130.9, 130.3, 129.0, 128.9, 128.7, 128.3 (Ph),
42.9 (CH3). 199Hg NMR (300 MHz, CDCl3 25 ꢁC):
¼ ꢀ640.8 ppm. IR
(KBr, cmꢀ1):
(NH) 3163, (CH)Ph 3091, 3033, (CH)Me 2977, 2930,
(CN) 1599, (CS) 923.
LH
1
2
4
C(1)eN(1)
N(1)eN(2)
N(2)eC(2)
C(2)eN(3)
C(2)eS(1)
1.276(3)
1.371(3)
1.356(3)
1.341(3)
1.678(3)
1.272(4)
1.388(3)
1.342(4)
1.326(4)
1.724(3)
1.28(3)
1.37(2)
1.29(2)
1.36(3)
1.74(2)
1.310(7)
1.364(7)
1.328(8)
1.352(8)
1.757(6)
d
d
n
n
n
n
n
(m, 3H, Ph), 3.27 (s, 6H, CH3) ppm. 13C NMR (300 MHz, CDCl3,
25 ꢁC):
¼ 181.8 (CS), 142.9 (CN), 134.1, 130.5, 129.2, 127.5 (Ph), 44.5
(CH3) ppm. IR (KBr, cmꢀ1):
(NH) 3229, (CH) 3165, (CH)Ph 3009,
(CH)Me 2925, 2894, (CN) 1600, (HNCS) 1551, (CS) 1020.
3.1.5. [HgPhL] (4)
d
Solid HgPhCl (0.152 g, 0.48 mmol) was added to a solution of LH
(0.100 g, 0.48 mmol) in ethanol (10 mL). The mixture was stirred for
2 h at room temperature. The solid formed was filtered off, washed
with Et2O and dried in vacuo. (0.17 g, 73%). MS (FABþ): m/z (%):
n
n
n
n
n
d
n
3.1.2. [HgMeCl(LH)] (1)
485.0 (50) [M þ H]þ. 1H NMR (300 MHz, CDCl3, 25 ꢁC):
¼ 8.6 (s,1H,
d
To a solution of LH (0.100 g, 0.48 mmol) in ethanol (10 mL) solid
HgMeCl (0.120 g, 0.48 mmol) was added and stirred at room
temperature. Immediately a colourless solution was formed and
after 2 h a white solid was obtained which was filtered off and dried
in vacuo. (0.19 g, 86%). MS (FABþ): m/z (%): 424.1 (100) [MeCl]þ
CH), 8.3 (d, 1H, Ph), 7.47 (M, 3H, Ph), 7.42e7.21 (m, 6H, Ph), 3.3 (s,
3H, CH3) ppm. 13C NMR (300 MHz, CDCl3, 25 ꢁC):
147.2 (CN), 137.6, 136.9, 131.5, 129.9, 129.6, 128.7, 128.2. 128.0 (Ph),
d
¼ 153.5 (CS),
¼ ꢀ317.3,
40.2 (CH3) ppm. 199Hg NMR (300 MHz, CDCl3, 25 ꢁC):
d
ꢀ748.1, ꢀ1403.0 ppm. IR (KBr, cmꢀ1):
n(CH) 3048, n(CH)Ph 3018,
208.1 (80) [LH þ H]þ. 1H NMR (300 MHz, CDCl3, 25 ꢁC):
d
¼ 10.62
n(CH)Me 2926, n(CN) 1593, n(CS) 930. Single crystals suitable for X-
(br s, 1H, NH), 8.33 (s, 1H, CH), 7.63 (m, 2H, Ph), 7.40 (m, 3H, Ph),
3.47 (s, 6H, CH3), 0.98 (s, JHgeH ¼ 198 Hz, 3H, HgCH3) ppm. 13C CP/
MAS NMR: 170.2 (CS), 152.6 (CN), 132.5, 131.7129.1, 125.8 (Ph), 45.4,
43.2 (CH3), 9.6 (CH3Hg). 199Hg NMR (300 MHz, CDCl3 þ DMF, 25 ꢁC):
ray diffraction analysis were obtained from the mother liquor.
This complex was also obtained when the reaction was carried
out in the presence of LiOH$H2O. When the reaction was carried out
in the presence of 5 drops of HCl, the complex [Hg(LH)2(m-
Cl)2HgCl2], which was previously synthesized from HgCl2 [20], was
obtained.
d
¼ ꢀ830.5 ppm. IR (KBr, cmꢀ1):
n
(NH) 3157,
n
(CH) 3099,
n(CH)Ph
3018,
n
(CH)Me 2996, 2916,
n(CN) 1601,
d(HNCS) 1577, n
(CS) 881.
Single crystals suitable for X-ray diffraction analysis were obtained
from the mother liquor.
3.2. X-ray crystallography
3.1.3. [HgMeL](2)
Data for complexes 1, 2 and 4 were acquired using a Bruker AXS
Kappa Apex-II diffractometer equipped with an Apex-II CCD area
A solution of LH (0.100 g, 0.48 mmol) and LiOH$H2O (0.02 g,
0.48 mmol) in ethanol (10 mL) was mixed with solid HgMeCl
(0.120 g, 0.48 mmol) at room temperature to yield a yellow solu-
tion. After stirring for 2 h a yellow solid was obtained which was
filtered off and dried in vacuo. (0.14 g, 68%). MS (FABþ): m/z (%):
422.9 (60) [M þ H]þ 208.0 (30) [LH þ H]þ. 1H NMR (300 MHz, CDCl3,
detector using a graphite monochromator (Mo Ka radiation,
ꢀ
l
¼ 0.71073 A). The substantial redundancy in data allows empirical
absorption corrections (SADABS) [30] to be applied using multiple
measurements of symmetry-equivalent reflections. The raw
intensity data frames were integrated with the SAINT program,
which also applied corrections for Lorentz and polarization effects
[31]. The software package SHELXTL version 6.10 was used for space
group determination, structure solution and refinement. The
structures were solved by direct methods (SHELXS-97) [32],
completed with difference Fourier syntheses, and refined with full-
25 ꢁC):
d
¼ 8.60 (s,1H, CH), 7.60 (m, 2H, Ph), 7.41 (m, 3H, Ph), 3.29 (s,
6H, CH3), 0.56 (s, JHgeH ¼ 177 Hz, 3H, CH3Hg) ppm. 13C NMR
(300 MHz, CDCl3, 25 ꢁC):
d
¼ 169.8 (CS), 152.7 (CN), 134.7, 129.4,
128.4, 128.1 (Ph), 40.2 (CH3), 8.0 (HgCH3) ppm. 199Hg NMR
(300 MHz, CDCl3, 25 ꢁC):
3029, (CH)Ph 3018, n(CH)Me 2915, 2886, n(CN) 1586, n(CS) 877.
d
¼ ꢀ443.2 ppm. IR (KBr, cmꢀ1):
n(CH)
n
matrix least squares using SHELXL-97 minimizing
u
ðF02 ꢀ Fc2Þ.
Single crystals suitable for X-ray diffraction analysis were obtained
from the mother liquor.
Weighted R factors (Rw) and all goodness of fit S are based on F2;
conventional R factors (R) are based on F [33]. All non-hydrogen
atoms were refined with anisotropic displacement parameters.
The NH hydrogen atom in complex 2 was located in a difference
Fourier map and its coordinate and isotropic thermal parameters
subsequently refined. CH hydrogen atoms were positioned
geometrically after each cycle of refinement. All scattering factors
and anomalous dispersions factors are contained in the SHELXTL
6.10 program library.
3.1.4. [HgPhCl(LH)] (3)
LH (0.100 g, 0.48 mmol) dissolved in dichloromethane (10 mL)
was mixed with solid HgPhCl (0.152 g, 0.48 mmol). The yellow
Table 3
ꢁ
ꢀ
Selected bond distances (A) and angles ( ) in complexes 1, 2 and 4.
1
2
4
4. Conclusions
Hg(1)eN(1)
Hg(1)eS(1)
Hg(1)eC(5)
Hg(1)eCl(1)
C(5)eHg(1)eN(1)
C(5)eHg(1)eS(1)
S(1)eHg(1)eN(1)
C(5)eHg(1)eCl(1)
S(1)eHg(1)eCl(1)
N(1)eHg(1)eCl(1)
2.742(3)
2.3985(8)
2.078(5)
2.9152(9)
117.00(14)
166.26(13)
72.42(6)
96.80(13)
92.49(3)
2.603(17)
2.380(5)
2.09(2)
e
2.481(5)
2.3749(17)
2.084(6)
e
Four new organomercury(II) complexes with
a
thio-
semicarbazone ligand were synthesized. When the reaction of
HgMeCl is carried out without the presence of a base in the reaction
medium the ligand coordinates as a neutral molecule, while if
lithium hydroxide is added the ligand deprotonates. The reaction of
HgPhCl in ethanol and without a base induces spontaneous ligand
deprotonation. If hydrochloric acid is added to avoid ligand
deprotonation a symmetrization reaction takes place to yield
119.4(8)
165.3(7)
75.3(4)
e
117.6(2)
165.31(18)
77.04(12)
e
e
e
92.89(6)
e
e

E. López-Torres, M.A. Mendiola / Journal of Organometallic Chemistry 725 (2013) 28e33
33
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HgPhCl can be prevented in dichloromethane.
Acknowledgements
The authors thank César J. Pastor for crystal measurements. We
also thank Ministerio de Economía y Competitiviad, Instituto de
Salud Carlos III, for funding (Project PS09/00963).
[17] D.G. Calatayud, E. López-Torres, M.A. Mendiola, Eur. J. Inorg. Chem., in press,
http://dx.doi.org/10.1002/ejic.201200815.
Appendix A. Supplementary material
[18] E. López-Torres, D.G. Calatayud, M.A. Mendiola, C.J. Pastor, J.R. Procopio,
Z. Anorg. Allg. Chem. 632 (2006) 2471e2474.
CCDC 903843e903845 contain the supplementary crystallo-
graphic 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.
[19] E. López-Torres, M.A. Mendiola, C.J. Pastor, Polyhedron 25 (2006) 1464e1470.
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