Crystal structure of bis­(thio­cyanato-κS)bis­(thio­urea-κS)mercury(II)

A Baskaran; K Rajarajan; M NizamMohideen; P Sagayaraj

doi:10.1107/S2056989015000584

. 2015 Jan 17;71(Pt 2):m28–m29. doi: 10.1107/S2056989015000584

Crystal structure of bis(thiocyanato-κS)bis(thiourea-κS)mercury(II)

A Baskaran ^a, K Rajarajan ^a,^*, M NizamMohideen ^b,^*, P Sagayaraj ^c

PMCID: PMC4384628 PMID: 25878839

Abstract

In the title complex, [Hg(NCS)₂(CH₄N₂S)₂], the Hg^II atom is four-coordinated having an irregular four-coordinate geometry composed of four thione S atoms of two thiocyanate groups and two thiourea groups. The S—Hg—S angles are 172.02 (9)° for the trans-thiocyanate S atoms and 90.14 (5)° for the cis-thiourea S atoms. The molecular structure is stabilized by an intramolecular N—H⋯S hydrogen bond, which forms an S(6) ring motif. In the crystal, molecules are linked by a number of N—H⋯N and N—H⋯S hydrogen bonds, forming a three-dimensional framework. The first report of the crystal structure of this compound appeared in 1966 [Korczynski (1966 ▸). Rocz. Chem. 40, 547–569] with an extremely high R factor of 17.2%, and no mention of how the data were collected.

Keywords: crystal structure, thiourea, thiocyanate, mercury(II), molecular complex, hydrogen bonding

Related literature

For literature on thiourea- and thiocyanate-based metal–organic crystalline materials and their derivatives, see: Ramesh et al. (2012 ▸); Shihabuddeen Syed et al. (2013 ▸). For the concept of hard and soft acids and bases, see: Ozutsumi et al. (1989 ▸); Bell et al. (2001 ▸). For the crystal structures of similar compounds, see: Nawaz et al. (2010 ▸); Safari et al. (2009 ▸); Shihabuddeen Syed et al. (2013 ▸). For the first report of the crystal structure of the title compound, see: Korczynski (1966 ▸). graphic file with name e-71-00m28-scheme1.jpg

Experimental

Crystal data

[Hg(NCS)₂(CH₄N₂S)₂]
M _r = 468.99
Orthorhombic,
a = 8.5359 (5) Å
b = 9.0337 (5) Å
c = 15.7575 (10) Å
V = 1215.07 (12) Å³
Z = 4
Mo Kα radiation
μ = 13.33 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.15 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▸) T _min = 0.176, T _max = 0.240
19798 measured reflections
2397 independent reflections
2158 reflections with I > 2σ(I)
R _int = 0.058

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.075
S = 1.15
2397 reflections
137 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.44 e Å⁻³
Δρ_min = −1.03 e Å⁻³
Absolute structure: Flack (1983 ▸), 1149 Freidel pairs.
Absolute structure parameter: 0.034 (12)

Data collection: APEX2 (Bruker, 2004 ▸); cell refinement: APEX2 and SAINT (Bruker, 2004 ▸); data reduction: SAINT and XPREP (Bruker, 2004 ▸); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸) and PLATON (Spek, 2009 ▸); software used to prepare material for publication: WinGX (Farrugia, 2012 ▸) and PLATON.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015000584/su5058sup1.cif

e-71-00m28-sup1.cif^{(19KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015000584/su5058Isup2.hkl

e-71-00m28-Isup2.hkl^{(115.4KB, hkl)}

Click here for additional data file.^{(1.2MB, tif)}

. DOI: 10.1107/S2056989015000584/su5058fig1.tif

A view of the molecular structure of the title complex, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular N—H⋯S hydrogen bond is shown as a double dashed line (see Table 1 for details).

Click here for additional data file.^{(2.1MB, tif)}

a . DOI: 10.1107/S2056989015000584/su5058fig2.tif

The crystal packing of the title complex, viewed along the a axis. Hydrogen bonds are shown as dashed lines (see Table 1 for details).

CCDC reference: 1043131

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

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N3H3BS1	0.86	2.55	3.404(7)	174
N3H3AN2ⁱ	0.86	2.37	3.103(10)	143
N4H4AN2ⁱ	0.86	2.17	2.952(10)	151
N4H4BN1ⁱⁱ	0.86	2.56	3.085(11)	121
N5H5AN1ⁱⁱⁱ	0.86	2.26	3.025(10)	149
N5H5AS4^iv	0.86	2.80	3.384(7)	126
N5H5BN2^v	0.86	2.21	3.025(10)	158
N6H6AN1ⁱⁱⁱ	0.86	2.25	3.019(10)	149
N6H6BS2^vi	0.86	2.56	3.419(8)	172

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

The authors are grateful to the SAIF, IIT, Madras, India, for the data collection. KR thanks the University Grants Commission, Government of India, for financial support granted under a Major Research Project [F. No. 41–1008/2012 (SR)].

supplementary crystallographic information

S1. Synthesis and crystallization

A mixture of thiourea, ammonium thiocyanate and mercury (II) chloride were dissolved in aqueous solution in the molar ratio 2:2:1 and thoroughly mixed for 1 h to obtain a homogeneous mixture. The solution was allowed to evaporate slowly at ambient temperature. Colourless block-like crystals were obtained in a week.

S2. Refinement

All the H atoms were positioned geometrically with N—H = 0.86 Å and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(N).

S3. Comment

This work is part of a research project concerning the investigation of thiourea (N₂H₄CS) and thiocyanate (SCN) based metal organic crystalline materials and their derivatives (Ramesh et al., 2012; Shihabuddeen Syed et al., 2013). Transition metal thiourea and thiocyanate coordination complexes are candidate materials for device applications including their nonlinear optical properties. As ligands, both thiourea and thiocyanate are interesting due to their potential formation of metal coordination complexes as they exhibit multifunctional coordination modes due to the presence of 'S' and 'N' donor atoms. With reference to the hard and soft acids and bases) concept (Ozutsumi et al., 1989; Bell et al., 2001), the soft cations show a pronounced affinity for coordination with the softer ligands, while hard cations prefer coordination with harder ligands. Several crystallographic reports about mercury(II) complexes usually consist of discrete monomeric molecules with tetrahedral (somewhat distorted) coordination environments around mercury(II) (Nawaz et al., 2010). Herein, we report on the synthesis and crystal structure of the title complex.

The title monomeric complex is composed of two thiocyanate and two thiourea ligands coordinated to the Hg atom via the softer thione S atom (Fig. 1). The four-coordinate mercury atom adopts a severely distorted tetrahedral geometry. The S—Hg—S angles are S3-Hg1-S4 = 172.02 (9) ° for the trans thiocyanate S atoms and S1-Hg1-S2 = 90.14 (5) ° for the trans thiourea S atoms. The bond distances Hg1-S3 and Hg1-S4 are 2.390 (3) and 2.381 (3) Å, respectively, while bond distances Hg1—S1 and Hg1—S2 are 3.064818) and 3.0836 (18) Å, respectively. Bond distances and angles are in agreement with those reported for related compounds (Shihabuddeen Syed et al., 2013; Safari et al., 2009; Nawaz et al., 2010). The SCN moiety is planar [to within 0.007 (1) Å with the C-N and C-S bond lengths corresponding to the values intermediate between single and double bonds. The S2-C2-N2 and S1-C1-N1 units are nearly linear with bond angles of 178.5 (7) and 179.4 (8)°, respectively. The compound is closely related with (thiocyanato-kS)tris(thiourea-kS)mercury(II) chloride (Shihabuddeen Syed et al., 2013). The molecular structure is stabilized by intramolecular an N-H···S hydrogen bond, which forms an S(6) ring motif (Fig. 1 and Table 1).

In the crystal, molecules are connected via N-H···N hydrogen bonds, involving the thiourea NH₂ H atoms and the thiocyanate N atom (Fig. 2 and Table 1). This gives rise to the formation of a three-dimensional framework which is reinforced by N-H···S hydrogen bonds (Fig. 2 and Table 1).

The first report of the crystal structure of the title compound appeared in 1966 (Korczynski, 1966) with an extremely high R factor of 17.2 %, and no mention of how the data were collected.