Pseudo-Polymeric Mercury(II) Morpholinedithiocarbamate [Hg{S2CN(CH2)4O}2] n: Supramolecular Structure (a Role of Secondary Hg···S Bonds), 13C and 15N CP-MAS NMR Spectra, and Thermal Behavior

Article abstract of DOI:10.1134/S1070328419010068

Abstract: A new representative of mercury(II) dithiocarbamate complexes, crystalline bis(morpholinedithiocarbamato-S,S')mercury(II) with the pseudo-1D-polymeric structure, is preparatively synthesized. The structure is characterized by ¹³С and ¹⁵N MAS NMR spectroscopy and X-ray diffraction analysis (CIF file CCDC no. 1821609). Pairs of symmetric secondary Hg???S bonds (3.400 ?) combine mononuclear [Hg{S₂CN(CH₂)₄O}₂] molecules, including planar polygons [HgS₄], into a linear pseudo-polymeric chain. The study of the thermal behavior shows that the two-stage mass loss detected by thermogravimetry is due to the thermal destruction of the complex with the formation of HgS and its subsequent sublimation.

Full text of DOI:10.1134/S1070328419010068

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2019, Vol. 45, No. 1, pp. 22–29. © Pleiades Publishing, Ltd., 2019.
Russian Text © O.V. Loseva, T.A. Rodina, A.V. Ivanov, 2019, published in Koordinatsionnaya Khimiya, 2019, Vol. 45, No. 1, pp. 24–31.
Pseudo-Polymeric Mercury(II) Morpholinedithiocarbamate
[Hg{S2CN(CH2)4O}2]n: Supramolecular Structure
(a Role of Secondary Hg···S Bonds), 13C and 15N CP-MAS NMR
Spectra, and Thermal Behavior
O. V. Losevaa, T. A. Rodinab, and A. V. Ivanova, *
aInstitute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences,
Blagoveshchensk, 675000 Russia
bAmur State University, Blagoveshchensk, Russia
*e-mail: alexander.v.ivanov@chemist.com
Received February 28, 2018; revised April 19, 2018; accepted July 15, 2018
Abstract—A new representative of mercury(II) dithiocarbamate complexes, crystalline bis(morpholinedith-
iocarbamato-S,S')mercury(II) with the pseudo-1D-polymeric structure, is preparatively synthesized. The
structure is characterized by 13С and 15N MAS NMR spectroscopy and X-ray diffraction analysis (CIF file
CCDC no. 1821609). Pairs of symmetric secondary Hg⋅⋅⋅S bonds (3.400 Å) combine mononuclear
[Hg{S2CN(CH2)4O}2] molecules, including planar polygons [HgS4], into a linear pseudo-polymeric chain.
The study of the thermal behavior shows that the two-stage mass loss detected by thermogravimetry is due to
the thermal destruction of the complex with the formation of HgS and its subsequent sublimation.
Keywords: mercury(II) alkylenedithiocarbamates, structural organization, secondary bonds Hg⋅⋅⋅S, X-ray
diffraction analysis, multinuclear (13C, 15N) MAS NMR spectroscopy, simultaneous thermal analysis
DOI: 10.1134/S1070328419010068
INTRODUCTION
planar (R = CH3 [9], C2H5 [10, 11], CH2CH2OH [12])
or distorted tetrahedral (R = iso-C3H7 [13, 14], iso-
C4H9 [15], C9H10 [2], cyclo-C6H11 [16]; R2 = iso-C3H7,
cyclo-C6H11 [15], C2H5, C6H5 [17], CH2–C4H3N–
CH3, CH2–C6H5 [4], CH2–C4H3N–CH3, CH2–
C5H4N [5]) geometry of the [HgS4] chromophore.
The binuclear complexes contain two bidentate-che-
lating and two tridentate-bridging ligands (R = C2H5
[10], iso-С3Н7 [7, 14], C4H9 [15], R2 = (CH2)4 [18],
(CH2)6 [19], CH3, C6H5 [20], С2Н5, cyclo-C6H11 [15],
iso-C3H7, CH2CH2OH [21]). The formally binuclear
molecules could be considered as mononuclear frag-
ments coupled due to two additional Hg–S bonds.
However, one of the Hg–S bonds in the bridging
ligands is substantially weakened, whereas the strength
of the bond formed with the mercury atom in the adja-
cent mononuclear fragment is comparable with that
for the terminal ligands. The central eight-membered
ring [Hg2S4C2] in the binuclear molecules is stabilized
The dithiocarbamate complexes of mercury(II) are
convenient precursors for the preparation of film and
nanocrystalline mercury sulfides in various thermo-
chemical processes [1–3]. Mercury sulfides are char-
acterized by a small forbidden band gap and, hence,
are among promising materials for semiconductor
industry in producing ultrasonic sensors, photoelec-
tric converters, infrared detectors, catalysts, and oth-
ers. In addition, mercury(II) dithiocarbamates are
capable of luminescing in both the crystalline state
and solution [4, 5] and of efficient chemisorption
binding of gold(III) from solutions [6, 7]. Since mer-
cury has a high chemical affinity to sulfur, a number of
dithio reagents was proposed for the efficient binding
of toxic elemental mercury, which includes oxidation
and the formation of stable Hg(II) complexes as indi-
vidual forms of mercury fixation [8].
Mercury(II) with dialkyl(aryl)dithiocarbamate
(symmetrically and nonsymmetrically substituted) in a chair conformation with the single known excep-
and alkylenedithiocarbamate ligands mainly forms tion: [Hg2{S2CN(C4H9)2}4] (boat conformation) [15].
molecular complexes of two types: mononuclear
[Hg(S2CNR2)2] and binuclear [Hg2(S2CNR2)4]. Each
Polymorphism in the discussed mercury complexes
(for example, three modifications are described for the
mononuclear complex contains two S,S′-bidentate- di-iso-propyldithiocarbamate complex: α [13], β [14],
chelating ligands and is characterized by the square- and γ [7]) is caused by the participation of mononu-
22

PSEUDO-POLYMERIC MERCURY(II) MORPHOLINEDITHIOCARBAMATE
23
clear or/and binuclear molecules in the formation of formation of fine needle-like yellowish crystals of
the crystal lattice.
complex I.
Among the binuclear molecular forms of mer-
cury(II) dithiocarbamates, the [Hg2(S2CNR2)4] com-
plex (R2 = CH2–C10H7, CH2–C5H4N) is distin-
guished by a special dimerization mode: owing to two
symmetric Hg–N bonds involving the heterocyclic
nitrogen atoms in the peripheral moiety of the ligands
[5]. In addition to the mononuclear and binuclear
forms, the single trinuclear complex is known for mer-
cury(II): [Hg3{S2CN(C9H10)}6] · N(C5H5) including
the 1,2,3,4-tetrahydroquinolinedithiocarbamate ligand
and outer-sphere pyridine molecule [2], as well as the
polynuclear cationic complexes, for example,
[Hg3{S2CN(C2H5)2}4]2+ and [Hg5{S2CN(C2H5)2}8]2+
[22].
Secondary interactions of the nonvalent type
(Hg⋅⋅⋅S, C–H⋅⋅⋅S, O–H⋅⋅⋅O, C–H⋅⋅⋅π) in the crystal-
line mercury(II) dithiocarbamates result in the forma-
tion of diverse supramolecular structures, the system-
atization of which was discussed in detail [12, 21].
In this work, we synthesized and characterized in
detail crystalline bis(morpholinedithiocarbamato-
S,S′)mercury(II), [Hg{S2CN(CH2)4O}2] (I). This is a
new representative of mercury(II) dithiocarbamates
with a rare pseudo-1D-polymeric structure, the for-
mation of which provides pair secondary interactions
Hg···S between the adjacent molecules. The spectral
characteristics, structural organization, and thermal
behavior of complex I were determined by 13С and 15N
CP-MAS NMR spectroscopy, X-ray diffraction anal-
ysis, and simultaneous thermal analysis (STA).
13С,
15N
CP-MAS
NMR,
δ,
ppm:
[Hg{S2CN(CH2)4O}2]n: 200.4 (48)* (−S2CN=), 65.8,
65.3 (1 : 1, −OCH2−), 54.4, 53.1 (1 : 1, =NCH2−);
121.9 (60)** (=N–). (* Asymmetric doublet 13C–14N,
in Hz; ** spin-spin interaction constant J(15N–
3
199Hg), in Hz).
13C and 15N CP-MAS CP-NMR spectra were
recorded on an Ascend Aeon spectrometer (Bruker)
with a working frequency of 100.64 and 40.56 MHz,
respectively, and a superconducting magnet (В0 =
9.4 T) with the closed condensation cycle through an
external compressor and Fourier transform. Cross-
polarization (CP) from the protons was used, and the
proton decoupling effect was applied to suppress
13C−1H and 15N−1H interactions using the radiofre-
quency field at the resonance frequency of protons
[25]. A sample (~60 mg) was placed in a 4.0-mm
ceramic rotor of ZrO2. The magic angle spinning
(MAS) of the samples at a frequency of 10000(1) Hz
was used to measure C and 15N MAS NMR spectra
13
(the acquisition number was 656 and 20360, duration
of proton π/2 pulses was 2.7 and 2.5 μs; the contact
time of H−13C and H−15N was 3.0 and 3.0 ms, and
the interval between pulses was 3.0 and 3.0 s, respec-
tively). Isotropic 13C and 15N chemical shifts (ppm) are
given relative to one of the components of an external
standard, which was crystalline adamantane (δ =
38.48 ppm relative to (CH3)4Si) or crystalline NH4Cl
(δ = 0.0 ppm, or ‒341 ppm in the absolute scale [26])
with a correction to the drift of the magnetic field
strengt the frequency equivalent of which was 0.025
and 0.09 Hz/h, respectively.
1
1
EXPERIMENTAL
Sodium morpholinedithiocarbamate was synthe-
sized by the reaction of carbon disulfide (Merck) and
morpholine (Aldrich) in an alkaline medium [23] and
characterized by the 13С and 15N MAS NMR spectral
data. 13С, 15N MAS NMR, δ, ppm: Na{S2CN-
(CH2)4O} · 2H2O: 204.8 (−S2CN=), 67.6, 67.2
(−OCH2−), 54.6, 53.9, 53.5 (=NCH2−); 130.8
(=N−) [24].
Synthesis of complex I. Ions Hg2+ were precipitated
from the aqueous phase with sodium morpholinedith-
iocarbamate taken in a stoichiometric ratio. A solution
containing Na{S2CN(CH2)4O} · 2H2O (0.0841 g,
0.380 mmol) in water (10 mL) was poured to a solution
containing Hg(NO3)2 · H2O (Fluka) (0.0651 g,
0.190 mmol) in water (10 mL). To suppress hydrolysis,
a solution of mercury(II) nitrate was acidified with
nitric acid to pH 2. A fine clotted white precipitate
with a yellowish tint was multiply washed with distilled
water and dried on a filter. The yield was 99.3%. For
X-ray diffraction analysis was carried out for nee-
dle-like crystals of complex I on a Bruker-Nonius X8
Apex CCD diffractometer (MoKα radiation, λ =
0.71073 Å, graphite monochromator) at 296(2) K.
Data were collected using a standard procedure: ϕ and
ω scan modes of narrow frames. An absorption correc-
tion was applied empirically using the SADABS pro-
gram [27]. The structure was determined by a direct
2
method and refined by least squares (for F ) in the
full-matrix anisotropic approximation of non-hydro-
gen atoms. The positions of hydrogen atoms were cal-
culated geometrically and included into the refine-
ment in the riding model. The calculations of struc-
ture determination and refinement were performed
using the SHELXTL program package [27]. The main
crystallographic data and the structure refinement
results for complex I are presented in Table 1. Selected
bond lengths and bond angles are given in Table 2.
The coordinates of atoms, bond lengths, and angles
diffraction experiment, the powdered complex was were deposited with the Cambridge Crystallographic
dissolved in N,N-dimethylformamide on heating. The Data Centre (CIF file CCDC no. 1821609; deposit@
cooling down of the solution was accompanied by the ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 1 2019

24
LOSEVA et al.
Table 1. Crystallographic data and the experimental and structure refinement parameters for complex I
Parameter
Value
Empirical formula
FW
C10H16N2O2S4Hg
525.08
Crystal system
Space group
a, Å
Monoclinic
P21/n
4.2660(7)
11.616(2)
14.999(3)
90.00
b, Å
c, Å
α, deg
β, deg
γ, deg
94.067(5)
90.00
V, Å3
741.4(2)
Z
2
calcd, g/cm3
2.352
ρ
μ, mm–1
10.941
F(000)
500
Crystal size, mm
0.12 × 0.02 × 0.02
Range of data collection over θ, deg
Ranges of reflection indices
Measured reflections
2.22–27.61
–5 ≤ h ≤ 5, –15 ≤ k ≤ 15, –1 ≤ l ≤ 19
5366
Independent reflections (Rint)
Reflections with I > 2σ(I)
Refinement variables
1668 (0.0489)
1229
89
1.012
GOOF
R factors for F 2 > 2σ(F 2)
R1 = 0.0347, wR2 = 0.0666
R factors for all reflections
R1 = 0.0590, wR2 = 0.0718
Residual electron density (min/max), e/Å3
–1.065/1.320
Thermal behavior of complex I was studied by the
STA method on a STA 449C Jupiter instrument
(NETZSCH) in corundum crucibles under caps with
a hole providing a vapor pressure of 1 atm upon the
thermal decomposition of the sample. The heating
rate was 5°С/min to 600°С under argon. The sample
weight was 2.972–7.295 mg. The accuracy of the tem-
perature measurement was 0.7°С, and that of the
mass change was 1 × 10–4 mg. The correction file
and temperature and sensitivity calibrations for the
specified temperature program and heating rate were
used when recording curves of thermogravimetry
(TG) and differential scanning calorimetry (DSC).
The melting point of complex I was determined inde-
pendently on a PTP(M) instrument (OAO Khim-
laborpribor).
RESULTS AND DISCUSSION
The 13C resonance signals in the MAS NMR spec-
trum of a polycrystalline sample of complex I were
assigned to the =NC(S)S–, −OCH2−, and =NCH2−
groups (Fig. 1a). The pairs of signals of equal intensity
from each of two last groups indicate their structural
nonequivalence in the –N(CH2–CH2)2O cyclic frag-
ment of the ligand. The carbon atom in the dithiocar-
bamate group is directly bound to the nitrogen atom
by the short N–C(S)S bond characterized by a signif-
icant contribution of double bonding. Therefore, the
=NC(S)S– group is presented in the spectrum by the
asymmetric doublet with an intensity ratio of 1 : 2
(Fig. 1a) due to the dipole–dipole interaction of the
13C nucleus with the 14N quadrupole nucleus (I = 1)
[28, 29]. The single 15N resonance signal in the MAS
NMR spectrum (Fig. 1b) indicates that the MfDtc
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PSEUDO-POLYMERIC MERCURY(II) MORPHOLINEDITHIOCARBAMATE
25
Table 2. Selected bond lengths (d) and bond (ω) and torsion (ϕ) angles in the structure of complex I*
Bond
d, Å
Bond
d, Å
Hg(1)–S(1)
Hg(1)–S(2)
Hg(1)⋅⋅⋅S(1)b
S(1)–C(1)
S(2)–C(1)
N(1)–C(1)
2.4028(16)
2.9041(18)
3.400(2)
1.763(6)
1.681(7)
N(1)–C(2)
N(1)–C(5)
O(1)–C(3)
O(1)–C(4)
C(2)–C(3)
C(4)–C(5)
1.470(8)
1.462(7)
1.425(8)
1.417(8)
1.512(8)
1.521(7)
1.335(7)
Angle
ω, deg
Angle
ω, deg
S(1)Hg(1)S(2)
S(1)Hg(1)S(2)a
S(1)аHg(1)S(1)b
S(1)Hg(1)S(1)b
S(2)Hg(1)S(1)b
S(2)aHg(1)S(1)b
Hg(1)S(1)C(1)
67.45(5)
112.55(5)
86.96(5)
93.04(5)
94.77(5)
85.23(5)
93.4(2)
Hg(1)S(2)C(1)
78.9(2)
119.5(3)
116.8(5)
123.7(5)
124.0(5)
121.8(5)
113.3(5)
ϕ, deg
S(1)C(1)S(2)
S(1)C(1)N(1)
S(2)C(1)N(1)
C(1)N(1)C(2)
C(1)N(1)C(5)
C(2)N(1)C(5)
Angle
ϕ, deg
Angle
Hg(1)S(1)S(2)C(1)
S(1)Hg(1)C(1)S(2)
S(1)C(1)N(1)C(2)
170.2(4)
171.8(4)
3.3(8)
S(1)C(1)N(1)C(5)
S(2)C(1)N(1)C(2)
S(2)C(1)N(1)C(5)
171.9(4)
–176.7(5)
–8.1(8)
a
b
* Symmetry transforms: 1 – x, 1 – y, –z; x – 1, y, z.
ligands in complex I are equivalent (and, therefore, of the mercury(II) dithiocarbamates [19], since natu-
ral mercury includes nuclide 199Hg (μ = 0.5058852 μN,
I = 1/2). Therefore, the multiplet structure of the res-
have the same structural function), which is consistent
with the 13C NMR data. The signal discussed is char-
acterized by broadening from two sides due to overlap- onance 15N signal appears due to the spin-spin inter-
action between the 15N and 199Hg nuclei with the con-
ping with two satellite lines symmetrically arranged
stant 3J(15N–199Hg) equal to 60 Hz. The natural abun-
relatively to the central 15N signal with the intensity
ratio close to 1 : 10 : 1 (Fig. 1b). This is rather typical dance of nuclide 199Hg (16.87 at %) determines the
b
125
×2
120
198
a
202
68
64
60
56
52
δ, ppm
13
15
Fig. 1. (a) С and (b) N MAS NMR spectra of complex I. The spinning frequency of the sample is 10 kHz, and the acquisition
number is (a) 656 and (b) 20360.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 1 2019

26
LOSEVA et al.
y
z
x
Fig. 2. Packing of structural units in the crystal of complex I (projection on the yz plane).
S(1)a
S(2)
C(5)
C(4)
Hg(1)
C(1)
N(1)
O(1)
C(3)
C(2)
S(1)
S(2)a
Fig. 3. Molecular structure of [Hg{S CN(CH ) O} ] (ellipsoids of 50% probability).
2
2 4
2
contribution of equidistant satellite signals to the total sum of the van der Waals radii (3.35 Å [30]), which
intensity of the 15N signal.
makes it possible to consider that the second bond is
also covalent although substantially weakened. The
diagonal arrangement of the uniform Hg–S bonds
determines the long (S(2)–S(2)a 5.808 Å) and short
(S(1)–S(1)a 4.806 Å) axes of the orthorhombic distor-
tion of the [HgS4] coordination tetragon and the devi-
ation of the angles formed by the sulfur atoms from the
right angle: S(1)S(2)S(1)a 78.34° and S(2)S(1)S(2)a
101.66°.
The structural organization of complex I was deter-
mined by X-ray diffraction analysis. The unit cell con-
tains two formula units (for the packing of structural
units, see Fig. 2). The structural unit of compound I is
the centrosymmetric molecule [Hg{S2CN(CH2)4O}2]
(Fig. 3) in which mercury(II) coordinates two S,S'-
anisobidentate MfDtc ligands to form a rectangular
chelate node [HgS4]. The S(1)⋅⋅⋅S(2) intraligand dis-
tances (2.976 Å) are much shorter than the interligand
S(1)⋅⋅⋅S(2)a distances (4.423 Å). The rigidly planar
configuration of the latter (the diagonal bond angles
The bidentate coordination mode of the MfDtc
ligands results in the formation of two metallocycles
[HgS2C] (unified by the common mercury atom),
S(1)Hg(1)S(1)a and S(2)Hg(1)S(2)a are 180°) is whose small sizes agree with the interatomic distances
caused by the outer-orbital sp2d-hybridization state of
the central mercury atom. The Hg–S bonds are sub-
stantially nonequivalent: Hg(1)–S(1) 2.4028 and
Hg(1)–S(2) 2.9041 Å (Table 2). However, the first
bond is consistent with the sum of covalent and empir-
ical covalent radii of sulfur and mercury atoms (2.37
and 2.51 Å [30]), whereas the length of the second
Hg–C (3.064 Å) and S–S (2.976 Å). The mutual
arrangement of the atoms in the cycles somewhat devi-
ates from the coplanar one, which is indicated by the
values of torsion angles Hg(1)S(1)S(2)C(1) (170.2°)
and S(1)Hg(1)C(1)S(2) (171.8°) (Table 2). The
strength of the N–C(S)S bonds is appreciably higher
than that of N–CН2 (Table 2). The bond angles at the
bond significantly exceeds these values. Nevertheless, carbon and nitrogen atoms are close to 120° due to the
this interatomic distance is considerably less than the contribution of double bonding to the formally ordi-
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PSEUDO-POLYMERIC MERCURY(II) MORPHOLINEDITHIOCARBAMATE
27
S(1)d
S(1)a
S(1)c
Hg(1)b
S(1)b
Hg(1)
Hg(1)e
S(1)e
S(1)
Fig. 4. Fragment of the pseudopolymeric chain of complex I oriented along the crystallographic axis x; secondary interactions
a
b
c
d
e
Hg···S are shown by dashed lines. Symmetry transforms: 1 – x, 1 – y, –z; x – 1, y, z; 2 – x, 1 – y, –z; –x, 1 – y, –z; 1 +
x, y, z.
nary N–C(S)S bond (owing to the admixing of the pound I is characterized by a combination of two
structural features: the planar polygon [HgS4] and
sp2- to sp3-hybridization state of the nitrogen and car-
bon atoms). Small deviations (by 3.3° and 8.1°) of the self-assembling of the pseudo-polymeric chain, which
SCNC torsion angles from 0° or 180° indicate the pre- has been found only for two complexes more:
dominantly planar geometry of the C2NC(S)S groups [Hg(S2CNR2)2]n (R = C2H5 [10, 11] and CH2CH2OH
in the MfDtc ligands (Table 2). The six-membered [12]).
heterocycles −N(CH2)4О are stabilized in the chair
The thermal behavior of complex I was studied by
conformation and are located on opposite sides rela-
the STA method with the simultaneous detection of
tive to the plane of the [HgS4] chelate node (trans ori-
TG and DSC curves. The compound is thermally sta-
entation).
ble to ~210°C. In the TG curve, two main mass loss
steps are determined by the ranges 210–315°C and
315–405°C (Fig. 5, curve a). The first, steeply
descending region is divided into two sections by the
inflection point at 291.0°C. The mass loss before the
inflection point (26.76%) suggests that the initial stage
of thermolysis of complex I is related to the elimina-
tion of the alkoxyl fragments of the (=CHCH2)2O
ligands (calcd. 26.70%) to which the formation of an
intermediate compound [Hg(S2CNH2)2] can corre-
spond. The further temperature increase is accompa-
nied by an increase in the thermolysis rate resulting in
the liberation of HgS [7, 20]. It is important that the
mass loss after the inflection point, which is equal to
47.32%, significantly exceeds the calculated value
(28.99%).
The supramolecular structure of complex I is
formed due to pair secondary interactions of the non-
valent type involving the Hg(1) atoms and diagonally
oriented S(1) atoms less strongly bound to the central
mercury atom (Fig. 4). Therefore, each [Hg{S2CN-
(CH2)4O}2] molecule forms two pairs of secondary
bonds with the nearest neighbors to form linear
pseudo-polymeric chains [Hg{S2CN-(CH2)4O}2]n
(interatomic distance Hg–Hg 4.266 Å) oriented along
the crystallographic x axis. The length of the pair sec-
ondary bonds Hg(1)⋅⋅⋅S(1)b and Hg(1)⋅⋅⋅S(1)с
(3.400 Å) is close to the sum of the van der Waals radii
of mercury and sulfur atoms: 3.35 Å [30]. The mercury
atom completes its polyhedron to a distorted octahe-
dron [HgS6] (angle S(1)bHg(1)S(1)c 180°) due to addi-
tional secondary Hg⋅⋅⋅S bonds in the axial positions.
The second, a more flat step of the TG curve (315–
Thus, among numerous mercury(II) dithiocarba- 405°C) is related to HgS sublimation [7, 20]. However,
mates known to the present time, mononuclear com- the mass loss detected in this step (21.89%) is underes-
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28
LOSEVA et al.
TG, %
DSC, mW/mg
100
а
–26.76%
5
4
3
2
80
60
40
20
–47.32%
289.7°C
392.1°C
268.7°C
278.0°C
293.7°C
1.07%
–2.95%
1
0
–21.89%
300.7°C
291.1°C
b
0
100
200
300
400
500
600
T, °C
Fig. 5. (a) TG and (b) DSC curves for complex I.
timated more than twice compared to the calculated
value for HgS (44.31%). Taking into account the over-
estimation of the mass loss in the first step of the TG
curve (after 291°С), one can conclude that a signifi-
ACKNOWLEDGMENTS
The authors are grateful to Prof. O.N. Antsutkin
and Dr. V. Gowda (Luleå University of Technology,
Sweden) for the kindly presented possibility and help
cant portion of HgS (18.33%) sublimes before the in recording 13С and 15N MAS NMR spectra.
onset of the second step and is superimposed on the
first stage of thermolysis. The earlier study of the ther-
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Translated by E. Yablonskaya
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 1 2019