Crystal structure of di-chlorido-bis-(N,N'-di-methyl-thio-urea-κS)mercury(II).

The mol-ecular structure of the title compound, [HgCl2(C3H8N2S)2], has point group symmetry 2, with the twofold rotation axis passing through the Hg(II) atom. The latter is coordinated by two Cl atoms and two N,N'-di-methyl-thio-urea (Dmtu) ligands through their S atoms, defining a distorted tetra-hedral coordination sphere with bond angles in the range 102.47 (4)-118.32 (4)°. Intra- and inter-molecular hydrogen bonds of the type N-H⋯Cl with S(6) and R 2 (2)(12) ring motifs are present. The inter-molecular contacts make up polymeric chains extending parallel to [101].

Chemical context

X-ray structural studies of mercury(II) complexes with thio­urea ligands (L) or derivatives thereof have shown that in combination with a halide or pseudohalide X, some of the complexes exist as mononuclear species [HgX 2 L 2] (Popović et al., 2000 ▸), while the others exist in a dimeric or polymeric form as [HgX 2 L] (Bell et al., 2001 ▸) in the solid state. In both types of complexes, monomeric (1:2) or polymeric (1:1), the coordination environment around HgII is distorted tetra­hedral or pseudo-tetra­hedral. We have recently reported the crystal structures of HgCl2 and Hg(CN)2 complexes with methyl­thio­urea as an auxiliary ligand (Isab et al., 2011 ▸), N,N′-di­methyl­thio­urea (Malik et al., 2010a ▸), N,N′-di­ethyl­thio­urea (Mufakkar et al., 2010 ▸), N,N′-di­butyl­thio­urea (Ahmad et al., 2009 ▸) and tetra­methyl­thio­urea (Nawaz et al., 2010 ▸).

In this article, we report on synthesis and crystal structure of HgCl2 with di­methyl­thio­urea (Dmtu) as an additional ligand, [HgCl2(C3H8N2S)2], (I).

Structural comments

The mercury atom in complex (I) lies on a twofold rotation axis (Fig. 1 ▸). It exhibits a distorted tetra­hedral coordination environment defined by two S atoms of symmetry-related Dmtu ligands and two Cl atoms. The S—Hg—S bond angle is 118.32 (4)°. At 102.47 (4)°, the Cl—Hg—Cl bond angle is significantly smaller, which can be attributed to the bulkier Dmtu ligands. The Hg—S, Hg—Cl and other bond lengths (Table 1 ▸) have similar values compared with other [HgCl2 L 2] complexes (Ahmad et al., 2009 ▸; Isab et al., 2011 ▸; Malik et al., 2010a ▸; Mufakkar et al., 2010 ▸; Popović et al., 2000 ▸). In (I), the N—(C=S)—N skeleton of the Dmtu ligand is essentially planar with an r.m.s. deviation of 0.0135 Å.

Figure 1

The mol­ecular structure of compound (I). Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as small circles of arbitrary radius. [Symmetry code: (i) −x + 1, y, −z + .]

Table 1

Selected bond lengths ()

Hg1S1

2.4622(7)

Hg1Cl1

2.5589(7)

Supra­molecular features

From a supra­molecular point of view, adjacent mol­ecules are connected by inter­molecular N2—H2⋯Cl1 hydrogen bonds (Table 2 ▸, Fig. 2 ▸) into (12) ring motifs (Bernstein et al., 1995 ▸). The supra­molecular chains formed this way extend parallel to [101]. Additional intra­molecular hydrogen bonds N1—H1⋯Cl1 (Table 2 ▸) with S(6) loop motifs (Bernstein et al., 1995 ▸) are also present.

Table 2

Hydrogen-bond geometry (, )

DHA	DH	HA	D A	DHA
N1H1Cl1	0.86	2.37	3.223(3)	170
N2H2Cl1i	0.86	2.49	3.270(3)	151

Symmetry code: (i) .

Figure 2

Crystal packing of compound (I) viewed approximately along [010]. N—H⋯Cl hydrogen bonds are shown as dashed lines (see Table 2 ▸ for details).

Database survey

A systematic search in the Cambridge Structural Database (Groom & Allen, 2014 ▸) revealed a total of 25 hits for mercury chloride complexes with thio­urea ligands. The title compound is isotypic with the Zn and Cd analogues [ZnCl2(Dmtu)2] (Burrows et al., 2004 ▸) and [CdCl2(Dmtu)2] (Malik et al., 2010b ▸) and with [CdBr2(Dmtu)2] (Ahmad et al., 2011 ▸). The HgII atom in the structure of (I) shows an equivalent degree of distortion from the tetra­hedral configuration as the metals in [Zn(Dmtu)2Cl2] and [Hg(tetra­methyl­thio­urea)2Cl2] (Nawaz et al., 2010 ▸) in which the bond angles at the metal atom vary from 104.35 (2) to 113.30 (2)° and from 104.08 (4) to 120.75 (4)°, respectively. However, in [CdCl2(Dmtu)2] and [CdBr2(Dmtu)2], the coordination spheres around Cd deviate only slightly from ideal tetra­hedral values. On the other hand in [Hg(Dmtu)2(CN)2], the HgII atom exhibits a severely distorted tetra­hedral coordination sphere with bond angles in the range 94.31 (2) to 148.83 (13)° (Malik et al., 2010a ▸).

Synthesis and crystallization

For the preparation of title complex, 0.27 g (1 mmol) HgCl2 dissolved in 4 ml di­methyl­sulfoxide were mixed with two equivalents of N,N′-di­methyl­thio­urea in 10 ml aceto­nitrile. After stirring for 15 minutes, the resulting solution was filtered and the filtrate kept at room temperature. After one day colourless crystals were obtained. Yield ca. 60%.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3 ▸. All H atoms were positioned geometrically (C—H = 0.96 Å, N—H= 0.86 Å) and refined as riding with U iso(H) = 1.5U eq(C) and U iso(H) = 1.2U eq(N).

Table 3

Experimental details

Crystal data
Chemical formula	[HgCl2(C3H8NS)2]
M r	479.84
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c ()	13.1434(12), 8.9971(3), 12.6596(9)
()	107.955(4)
V (3)	1424.12(17)
Z	4
Radiation type	Mo K
(mm1)	11.45
Crystal size (mm)	0.36 0.18 0.16
Data collection
Diffractometer	Bruker Kappa APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2007 ▸)
T min, T max	0.106, 0.265
No. of measured, independent and observed [I > 2(I)] reflections	12262, 1721, 1556
R int	0.031
(sin /)max (1)	0.661
Refinement
R[F 2 > 2(F 2)], wR(F 2), S	0.018, 0.038, 1.06
No. of reflections	1721
No. of parameters	71
H-atom treatment	H-atom parameters constrained
max, min (e 3)	0.42, 0.32

Computer programs: APEX2 and SAINT (Bruker, 2007 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2014/6 (Sheldrick, 2015 ▸), ORTEP-3 for Windows and WinGX (Farrugia, 2012 ▸) and PLATON (Spek, 2009 ▸).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015015406/wm5202sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015015406/wm5202Isup2.hkl

CCDC reference: 1419298

Additional supporting information: crystallographic information; 3D view; checkCIF report

[HgCl2(C3H8NS)2]	F(000) = 904
Mr = 479.84	Dx = 2.238 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.1434 (12) Å	Cell parameters from 1556 reflections
b = 8.9971 (3) Å	θ = 3.0–28.0°
c = 12.6596 (9) Å	µ = 11.45 mm−1
β = 107.955 (4)°	T = 296 K
V = 1424.12 (17) Å3	Lath, colourless
Z = 4	0.36 × 0.18 × 0.16 mm

Bruker Kappa APEXII CCD diffractometer	1721 independent reflections
Radiation source: fine-focus sealed tube	1556 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 7.50 pixels mm-1	θmax = 28.0°, θmin = 3.0°
ω scans	h = −16→17
Absorption correction: multi-scan (SADABS; Bruker, 2007)	k = −11→11
Tmin = 0.106, Tmax = 0.265	l = −16→16
12262 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.018	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.038	H-atom parameters constrained
S = 1.06	w = 1/[σ2(Fo2) + (0.0168P)2 + 0.595P] where P = (Fo2 + 2Fc2)/3
1721 reflections	(Δ/σ)max = 0.001
71 parameters	Δρmax = 0.42 e Å−3
0 restraints	Δρmin = −0.31 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
Hg1	0.5000	0.37748 (2)	0.7500	0.04175 (6)
Cl1	0.60610 (6)	0.19941 (10)	0.66623 (6)	0.05387 (19)
S1	0.36846 (7)	0.51777 (8)	0.60297 (6)	0.04873 (19)
N1	0.40138 (19)	0.3089 (3)	0.4670 (2)	0.0464 (6)
H1	0.4588	0.2910	0.5206	0.056*
N2	0.24749 (19)	0.4417 (3)	0.4042 (2)	0.0433 (5)
H2	0.2332	0.3894	0.3446	0.052*
C1	0.3374 (2)	0.4131 (3)	0.4824 (2)	0.0362 (6)
C2	0.3824 (3)	0.2226 (4)	0.3672 (3)	0.0553 (8)
H2A	0.4381	0.1500	0.3772	0.083*
H2B	0.3819	0.2870	0.3066	0.083*
H2C	0.3146	0.1732	0.3513	0.083*
C3	0.1704 (3)	0.5533 (4)	0.4096 (3)	0.0580 (9)
H3A	0.1572	0.5471	0.4800	0.087*
H3B	0.1048	0.5371	0.3509	0.087*
H3C	0.1978	0.6501	0.4015	0.087*

	U11	U22	U33	U12	U13	U23
Hg1	0.04156 (10)	0.04908 (9)	0.02828 (9)	0.000	0.00146 (7)	0.000
Cl1	0.0503 (4)	0.0684 (5)	0.0368 (4)	0.0220 (4)	0.0044 (3)	−0.0017 (3)
S1	0.0591 (5)	0.0440 (4)	0.0315 (4)	0.0151 (3)	−0.0031 (3)	−0.0054 (3)
N1	0.0395 (14)	0.0570 (14)	0.0344 (13)	0.0126 (11)	−0.0007 (11)	−0.0056 (11)
N2	0.0425 (14)	0.0480 (12)	0.0308 (12)	0.0096 (11)	−0.0011 (11)	−0.0027 (11)
C1	0.0366 (16)	0.0375 (13)	0.0314 (14)	0.0001 (10)	0.0059 (12)	0.0026 (10)
C2	0.056 (2)	0.0626 (19)	0.0429 (18)	0.0096 (15)	0.0091 (16)	−0.0154 (15)
C3	0.051 (2)	0.067 (2)	0.0443 (19)	0.0258 (17)	−0.0017 (15)	−0.0002 (16)

Hg1—S1	2.4622 (7)	N2—C3	1.444 (4)
Hg1—S1i	2.4622 (7)	N2—H2	0.8600
Hg1—Cl1	2.5589 (7)	C2—H2A	0.9600
Hg1—Cl1i	2.5589 (7)	C2—H2B	0.9600
S1—C1	1.732 (3)	C2—H2C	0.9600
N1—C1	1.313 (4)	C3—H3A	0.9600
N1—C2	1.438 (4)	C3—H3B	0.9600
N1—H1	0.8600	C3—H3C	0.9600
N2—C1	1.312 (4)
S1—Hg1—S1i	118.32 (4)	N2—C1—S1	118.1 (2)
S1—Hg1—Cl1	110.67 (2)	N1—C1—S1	122.1 (2)
S1i—Hg1—Cl1	106.79 (3)	N1—C2—H2A	109.5
S1—Hg1—Cl1i	106.79 (3)	N1—C2—H2B	109.5
S1i—Hg1—Cl1i	110.67 (2)	H2A—C2—H2B	109.5
Cl1—Hg1—Cl1i	102.47 (4)	N1—C2—H2C	109.5
C1—S1—Hg1	107.88 (9)	H2A—C2—H2C	109.5
C1—N1—C2	124.8 (3)	H2B—C2—H2C	109.5
C1—N1—H1	117.6	N2—C3—H3A	109.5
C2—N1—H1	117.6	N2—C3—H3B	109.5
C1—N2—C3	125.7 (3)	H3A—C3—H3B	109.5
C1—N2—H2	117.2	N2—C3—H3C	109.5
C3—N2—H2	117.2	H3A—C3—H3C	109.5
N2—C1—N1	119.8 (3)	H3B—C3—H3C	109.5
C3—N2—C1—N1	−179.5 (3)	C2—N1—C1—S1	−177.2 (2)
C3—N2—C1—S1	−0.5 (4)	Hg1—S1—C1—N2	159.3 (2)
C2—N1—C1—N2	1.8 (5)	Hg1—S1—C1—N1	−21.6 (3)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1	0.86	2.37	3.223 (3)	170
N2—H2···Cl1ii	0.86	2.49	3.270 (3)	151