Dichloridobis(N,N,N′,N′-tetra­methyl­thio­urea-κS)mercury(II)

In the title compound, [HgCl₂(C₅H₁₂N₂S)₂], the Hg^II atom is located on a twofold rotation axis and is bonded in a distorted tetra­hedral coordination mode to two chloride ions and to two tetra­methyl­thio­urea (tmtu) mol­ecules through their S atoms. The crystal structure is stabilized by C—H...N and C—H...S hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](N-C) = 0.006 Å
• R factor = 0.020
• wR factor = 0.040
• Data-to-parameter ratio = 24.8

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Hg1    --  S1      ..      12.48 su

Alert level C
CRYSC01_ALERT_1_C The word below has not been recognised as a standard
            identifier.
            plate
CRYSC01_ALERT_1_C No recognised colour has been given for crystal colour.
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Hg1    --  Cl1     ..       9.48 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N2

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The coordination chemistry of mercury(II) complexes with thiourea type ligands has been the subject of several recent studies because of the importance of such systems as structural models in biology (Popovic et al., 2000; 2002). Mercury(II) is known form a wide variety of 1:1 and 1:2 complexes of the types LHgX₂ (Popovic et al., 2002) and L₂HgX₂ (Ahmad et al., 2009; Chieh, 1977: Lobana et al., 2008), where X is a halide or pseudohalide, having structural arrangements entirely based on tetrahedral or pseudo-tetrahedral environments. We have recently reported the crystal structure of a Hg(CN)₂ complex of N,N'-dibutylthiourea (dbtu) (Ahmad et al., 2009). Herein we report on the crystal structure of a mercury(II) chloride complex of tetramethylthiourea (tmtu), [Hg(C₅H₁₂N₂S₂)₂Cl₂], (I) .

The crystal structure of (I) consists of discrete molecular species in which the mercury atom is located on a twofold rotation axis (Fig. 1) and is bonded in a distorted tetrahedral coordination mode to two chloride ions and to two tetramethylthiourea (tmtu) molecules. The Hg—S and Hg—Cl bond lengths are 2.5329 (7) and 2.5028 (8) Å, respectively. The bond angles around Hg are in the range expected for a tetrahedral coordination, with the S—Hg—S angle (120.75 (4)°) having the largest deviation from the ideal value. The main cause of this deviation is the steric interaction between the —CH₃ groups. The SCN₂— moiety of Tmtu is essentially planar with the C—N and C—S bond lengths corresponding to the values intermediate between single and double bonds.

The structure of the title compound is isotypic with [Cd(tmtu)₂Br₂] (Nawaz et al., 2010a) and [Cd(tmtu)₂I₂] (Nawaz et al., 2010b).

For a more detailed description of the structure, see: Nawaz et al. (2010a).

Related literature

For background to Hg(II) complexes with thiourea ligands, see: Ahmad et al. (2009); Chieh (1977); Lobana et al. (2008); Popovic et al. (2000, 2002). The structure of the title compound is isotypic with [Cd(tmtu)₂Br₂] (Nawaz et al., 2010a) and [Cd(tmtu)₂I₂] (Nawaz et al., 2010b).

S2. Experimental

To 0.27 g (1.0 mmol) mercury(II) chloride in 10 ml methanol was added two equivalents of tetramethylthiourea in 15 ml methanol. A clear solution was obtained that was stirred for 30 minutes. The colorless solution was filtered and the filtrate was kept at room temperature for crystallization. As a result, a white crystalline product was obtained, that was finally washed with methanol and dried.

S3. Refinement

H atoms were placed in calculated positions with a C—H distance of 0.96 Å and U_iso(H) = 1.5 U_eq(C).

Computing details

Data collection: SMART (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. The molecular structure of title compound with atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H-atoms were omitted for clarity.

Dichloridobis(N,N,N',N'-tetramethylthiourea- κS)mercury(II)

Crystal data

[HgCl2(C5H12N2S)2]	F(000) = 1032
Mr = 535.94	Dx = 1.936 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 12167 reflections
a = 18.7418 (12) Å	θ = 2.6–28.3°
b = 9.5920 (6) Å	µ = 8.88 mm^−1
c = 13.5177 (9) Å	T = 293 K
β = 130.834 (1)°	Colourless, plate
V = 1838.6 (2) Å^3	0.29 × 0.24 × 0.11 mm
Z = 4

Data collection

Bruker SMART APEX area detector diffractometer	2281 independent reflections
Radiation source: normal-focus sealed tube	2103 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
ω scans	θmax = 28.3°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −24→24
Tmin = 0.183, Tmax = 0.442	k = −12→12
12167 measured reflections	l = −18→18

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.020	H-atom parameters constrained
wR(F^2) = 0.040	w = 1/[σ^2(Fo^2) + (0.0109P)^2 + 2.5249P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.002
2281 reflections	Δρmax = 0.72 e Å^−3
92 parameters	Δρmin = −0.79 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00244 (8)

Special details

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Hg1	1.0000	0.703186 (17)	0.2500	0.04539 (7)
Cl1	1.14323 (5)	0.55933 (9)	0.34397 (8)	0.0591 (2)
S1	1.02994 (5)	0.83371 (9)	0.43697 (7)	0.04983 (18)
N1	0.91286 (18)	0.7622 (3)	0.4747 (3)	0.0482 (6)
N2	0.84430 (16)	0.8798 (3)	0.2830 (2)	0.0488 (6)
C1	0.92029 (18)	0.8240 (3)	0.3933 (3)	0.0367 (5)
C2	0.8466 (3)	0.8103 (4)	0.4900 (4)	0.0704 (10)
H2A	0.8192	0.8971	0.4446	0.106*
H2B	0.8793	0.8232	0.5812	0.106*
H2C	0.7977	0.7421	0.4542	0.106*
C3	0.9842 (3)	0.6647 (4)	0.5756 (4)	0.0769 (11)
H3A	1.0131	0.6182	0.5468	0.115*
H3B	0.9549	0.5970	0.5914	0.115*
H3C	1.0313	0.7149	0.6548	0.115*
C4	0.7491 (2)	0.8240 (5)	0.2114 (4)	0.0802 (12)
H4A	0.7531	0.7329	0.2441	0.120*
H4B	0.7174	0.8179	0.1200	0.120*
H4C	0.7144	0.8847	0.2231	0.120*
C5	0.8518 (3)	0.9798 (4)	0.2094 (4)	0.0774 (11)
H5A	0.9121	1.0250	0.2669	0.116*
H5B	0.8027	1.0483	0.1711	0.116*
H5C	0.8454	0.9323	0.1414	0.116*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.05014 (10)	0.04849 (10)	0.05259 (11)	0.000	0.04018 (9)	0.000
Cl1	0.0519 (4)	0.0599 (5)	0.0652 (5)	0.0126 (3)	0.0381 (4)	0.0065 (4)
S1	0.0386 (3)	0.0716 (5)	0.0453 (4)	−0.0091 (3)	0.0300 (3)	−0.0142 (3)
N1	0.0611 (15)	0.0488 (13)	0.0566 (14)	0.0005 (11)	0.0480 (13)	0.0002 (11)
N2	0.0439 (13)	0.0560 (15)	0.0465 (13)	0.0051 (11)	0.0295 (11)	0.0020 (11)
C1	0.0415 (13)	0.0364 (13)	0.0415 (13)	−0.0023 (10)	0.0312 (12)	−0.0061 (10)
C2	0.085 (2)	0.081 (3)	0.092 (3)	−0.011 (2)	0.078 (2)	−0.014 (2)
C3	0.098 (3)	0.070 (2)	0.076 (2)	0.015 (2)	0.063 (2)	0.024 (2)
C4	0.0387 (17)	0.116 (3)	0.070 (2)	−0.0013 (18)	0.0292 (17)	−0.015 (2)
C5	0.088 (3)	0.081 (3)	0.069 (2)	0.027 (2)	0.054 (2)	0.029 (2)

Geometric parameters (Å, º)

Hg1—Cl1^i	2.5028 (8)	C2—H2B	0.9600
Hg1—Cl1	2.5028 (8)	C2—H2C	0.9600
Hg1—S1	2.5329 (7)	C3—H3A	0.9600
Hg1—S1^i	2.5329 (7)	C3—H3B	0.9600
S1—C1	1.730 (3)	C3—H3C	0.9600
N1—C1	1.336 (3)	C4—H4A	0.9600
N1—C2	1.460 (4)	C4—H4B	0.9600
N1—C3	1.461 (4)	C4—H4C	0.9600
N2—C1	1.327 (3)	C5—H5A	0.9600
N2—C5	1.453 (4)	C5—H5B	0.9600
N2—C4	1.466 (4)	C5—H5C	0.9600
C2—H2A	0.9600
Cl1^i—Hg1—Cl1	113.08 (4)	H2A—C2—H2C	109.5
Cl1^i—Hg1—S1	104.08 (3)	H2B—C2—H2C	109.5
Cl1—Hg1—S1	107.56 (3)	N1—C3—H3A	109.5
Cl1^i—Hg1—S1^i	107.56 (3)	N1—C3—H3B	109.5
Cl1—Hg1—S1^i	104.08 (3)	H3A—C3—H3B	109.5
S1—Hg1—S1^i	120.75 (4)	N1—C3—H3C	109.5
C1—S1—Hg1	101.20 (9)	H3A—C3—H3C	109.5
C1—N1—C2	122.2 (3)	H3B—C3—H3C	109.5
C1—N1—C3	121.9 (3)	N2—C4—H4A	109.5
C2—N1—C3	114.4 (3)	N2—C4—H4B	109.5
C1—N2—C5	121.5 (3)	H4A—C4—H4B	109.5
C1—N2—C4	122.9 (3)	N2—C4—H4C	109.5
C5—N2—C4	114.2 (3)	H4A—C4—H4C	109.5
N2—C1—N1	119.5 (2)	H4B—C4—H4C	109.5
N2—C1—S1	121.6 (2)	N2—C5—H5A	109.5
N1—C1—S1	118.9 (2)	N2—C5—H5B	109.5
N1—C2—H2A	109.5	H5A—C5—H5B	109.5
N1—C2—H2B	109.5	N2—C5—H5C	109.5
H2A—C2—H2B	109.5	H5A—C5—H5C	109.5
N1—C2—H2C	109.5	H5B—C5—H5C	109.5

Symmetry code: (i) −x+2, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···N2	0.96	2.52	2.849 (6)	100
C3—H3A···S1	0.96	2.68	2.996 (6)	100
C5—H5A···S1	0.96	2.62	3.024 (5)	105