Bis[benzyl N′-(3-phenylprop-2-enylidene)dithiocarbazato-κ2 N′,S]mercury(II)

In the title compound, [Hg(C17H15N2S2)2], the HgII ion lies on a crystallographic twofold rotation axis giving a very distorted tetrahedral coordination geometry best described as bisphenoidal, being chelated by two deprotonated N,S Schiff base ligands through the azomethine nitrogen and the thiolate sulfur donors. The dihedral angle between the two chelating ligand moieties is 79.75 (10)°. In the crystal, weak C—H⋯S interactions give rise to chains extending along the c axis.

In the title compound, [Hg(C 17 H 15 N 2 S 2 ) 2 ], the Hg II ion lies on a crystallographic twofold rotation axis giving a very distorted tetrahedral coordination geometry best described as bisphenoidal, being chelated by two deprotonated N,S Schiff base ligands through the azomethine nitrogen and the thiolate sulfur donors. The dihedral angle between the two chelating ligand moieties is 79.75 (10) . In the crystal, weak C-HÁ Á ÁS interactions give rise to chains extending along the c axis.

Related literature
For the structures of uncoordinated Schiff bases, see  ;. For the corresponding Zn II complex, see: . For the coordination behaviour of metal ions (Co, Ni, Cu, Zn, Cd, and Hg) with the cinnamaldehyde Schiff base of S-methyldithiocarbazate, see: Liu et al. (2009);Abram et al. (2006).
Hg-S18 2.3668 (11) Hg-N20 2.489 (3) Table 2 Hydrogen-bond geometry (Å , ). In continuation of our interests in the chemistry of Schiff bases derived from S-benzyldithiocarbazate  and on their metal complexes  due to their intriguing coordination behaviour, physico-chemical properties, and potential biological activities, the title compound, [Hg(C 17 H 15 N 2 S 2 ) 2 ] ( Fig.   1), was synthesized. In the structure, the Hg II ion lies on a crystallographic twofold axis and has a very distorted tetrahedral coordination geometry best described as bisphenoidal, being chelated by two deprotonated benzyl N′-(3-  (Table 1), giving one-dimensional chain motifs extending along the c axis. The crystal is further stabilized by C-H···π interactions involving the phenyl ring of the 3-phenylprop-2-enylidene moiety.

Experimental
The Schiff base, benzyl N′-(3-phenylprop-2-enylidene)hydrazinecarbodithioate was prepared following the literature method . Mercury(II) chloride (0.068 g, 0.25 mmol) in absolute ethanol (20 ml) was added to a hot refluxing solution of the Schiff base (0.163 g, 0.5 mmol) also dissolved in hot absolute ethanol and the reflux was continued for 30 min. The yellow precipitate formed was filtered off, washed with hot ethanol and dried under vacuum over anhydrous CaCl 2 . Yield: 0.198 g (86%). 50 mg of the compound was dissolved in chloroform (15 ml) and allowed to stand at ambient temperature. Yellow microcrystals, obtained after 4 days, were redissolved in chloroform (15 ml) and mixed with toluene (5 ml) and again allowed to stand at room temperature. Yellow rectangular prism shaped single crystals (m.p. 472-473 K) suitable for X-ray analysis were formed after 7 days.

Refinement
All H atoms were located geometrically and treated as riding atoms, with C-H = 0.95 Å for C(aromatic) and 0.99 Å, for C(methylene), with U iso (H) = 1.2U eq (C). The highest residual electron density peak (1.76 eÅ -3 ) is located at 0.60 Å from C1.

Figure 1
An ORTEP drawing (ellipsoids at the 50% probability level) of the title compound with atom labelling scheme of the independent moiety. For symmetry code: (i) -x + 1, y, -z + 3/2.

Bis[benzyl N′-(3-phenylprop-2-enylidene)dithiocarbazato-κ 2 N′,S]mercury(II)
Crystal data [Hg(C 17  Special details Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).