Crystal structure of bis[N-phenyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamidato-κ2 N 2,S]zinc dimethyl sulfoxide monosolvate

The synthesis and crystal structure of a ZnII complex with a (3,4-dihydronaphthalen-1(2H-ylidene)-N-phenyl-carbamohydrazinothioate ligand is reported. The crystal structure shows DMSO molecules bridging the complex units, building an one-dimensional H-bonded polymer.

The reaction of the N-phenyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide ligand with zinc acetate dihydrate in a 2:1 molar ratio yielded a yellow solid, which was crystallized from DMSO to obtain the title compound, [Zn(C 17 H 16 N 3 S) 2 ]ÁC 2 H 6 OS. The Zn II ion is four-coordinated in a distorted tetrahedral environment by two deprotonated ligands. Each ligand acts as an N,S-donor, forming a five-membered metallacycle. The maximum deviation from the mean plane of the N-N-C-S chelate group is 0.0029 (14) Å for the N-donor atom of one ligand and 0.0044 (14) Å for the non-coordinating N atom of the second. The dihedral angle between the planes of the two chelate groups is 72.80 (07) . Bond lengths in the ligands are compared with those in the crystal structure of the free ligand. In the crystal, complex molecules are connected by dimethyl sulfoxide solvate molecules via N-HÁ Á ÁO hydrogenbonding interactions, building a one-dimensional hydrogen-bonded polymer along the a-axis direction. The S atom and one C atom of the dimethyl sulfoxide solvate molecules are disordered over two sets of sites with an occupancy ratio of 0.6:0.4.

Chemical context
In a continuation of our on-going research on the supramolecular chemistry of thiosemicarbazone derivatives and their complexes, we report herein the synthesis and crystal structure of a Zn II complex with the N-phenyl-2-(1,2,3,4tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamidate ligand. Thiosemicarbazone derivatives are N,S-donors with a wide range of coordination modes and a variety of applications in biological inorganic chemistry (Lobana et al. 2009;Ferraz et al. 2012). ISSN 2056-9890

Structural commentary
The molecular structure of the title compound consists of one Zn II ion, four-coordinated in a distorted tetrahedral environment by two deprotonated thiosemicarbazone ligands in a bidentate chelating mode, and one disordered DMSO solvate molecule (Fig. 1). The N,S-donor atoms together with the central zinc atom form five-membered metallacycles (Fig. 1). The maximum deviation from the mean plane of the N1-N2-C11-S1 chelate group is 0.0029 (14) Å for the N1 donor atom. For the N21-N22-C31-S21 chelate group, the maximum deviation is 0.0044 (14) Å for atom N22. The dihedral angle between the planes of the two chelate groups is 72.80 (7) , clearly showing the distorted tetrahedral geometry.
Neither of the coordinating ligands is planar. For one ligand, the dihedral angles between the aromatic rings (C5-C10 and C12-C17) is 58.25 (11) . In the second ligand, the corresponding angle is 49.99 (11) between the C25-C30 and C32-C37 rings. In addition, the aliphatic rings are also not planar. The maximum deviation from the mean plane for the C1-C5/C10 ring is 0.355 (3) Å for C3 and for the C21-C25/C30 ring the maximum deviation is 0.359 (3) Å for C23, with both of the aliphatic rings having an envelope conformation

Supramolecular features
In the crystal, the Zn II complex molecules and the DMSO solvent molecules build a monomeric entity. The DMSO molecule bridges two complex molecules via intermolecular N-HÁ Á ÁO hydrogen-bonding interactions, building a onedimensional hydrogen-bonded polymer along the a-axis direction (Fig. 2, Table 1).

Figure 1
The molecular structure of the title compound with atom labeling and displacement ellipsoids drawn at the 30% probability level. Disorder is shown with open and full bonds. Table 1 Hydrogen-bond geometry (Å , ).

Figure 2
View of the one-dimensional hydrogen-bonded polymer that elongates along the a-axis direction. Intermolecular hydrogen bonding (for details, see Table 1) is shown as dashed lines. The minor occupancy components of the disordered atoms are not shown for clarity.

Synthesis and crystallization
Starting materials were commercially available and used without further purification. The ligand synthesis was adapted from a procedure reported previously (Freund & Schander, 1902). A mixture of N-phenyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide dissolved in THF (2 mmol/40 mL) with zinc acetate dihydrate dissolved in ethanol (1 mmol/30 mL) was refluxed for 4 h under continuous stirring. An orange solid was obtained, filtered and washed with ethanol. Suitable crystals for X-ray diffraction were obtained in DMSO by slow evaporation of the solvent.
(Stoe & Cie, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013-2 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.80 e Å −3 Δρ min = −0.68 e Å −3 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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq Occ.