{2-[1-(2-Methoxy-6-oxidophenyl-κO 6)ethylidene]-N-methylhydrazinecarbothioamidato-κ2 N 2,S}(triphenylphosphane-κP)palladium(II) ethanol monosolvate

In the title compound, [Pd(C11H13N3O2S)(C18H15P)]·C2H5OH, the PdII atom is tetracoordinated in a slightly distorted square-planar environment by three donor atoms (NOS) from a thiosemicarbazonate ligand, forming five- and six-membered chelate rings, and a P atom from a neutral triphenylphosphane group. The five-membered ring adopts a distorted envelope conformation with PdII as the flap atom, while the six-membered ring forms a slightly twisted screw-boat conformation. A slightly distorted screw-boat form of a methoxyphenyl group is fused to the six-membered ring. Weak C—H⋯O interactions form dimers in the asymmetric unit and along [001] which help to stabilize the crystal packing.

In the title compound, [Pd(C 11 H 13 N 3 O 2 S)(C 18 H 15 P)]Á-C 2 H 5 OH, the Pd II atom is tetracoordinated in a slightly distorted square-planar environment by three donor atoms (NOS) from a thiosemicarbazonate ligand, forming five-and six-membered chelate rings, and a P atom from a neutral triphenylphosphane group. The five-membered ring adopts a distorted envelope conformation with Pd II as the flap atom, while the six-membered ring forms a slightly twisted screwboat conformation. A slightly distorted screw-boat form of a methoxyphenyl group is fused to the six-membered ring. Weak C-HÁ Á ÁO interactions form dimers in the asymmetric unit and along [001] which help to stabilize the crystal packing.

Comment
Thiosemicarbazones are a versatile class of ligands that can adopt multiple modes of binding to a metal (Lobana et al., 2009). The synthesis and structure determination of these metal complexes is an active area of research (Lobana et al., 2012). Palladium complexes with thiosemicarbazone ligands, in particular, have been shown to have a variety of biological properties including anti-fungal and anti-tumor activity (Chellan et al., 2010). A recent study compared the cytotoxic effects of a palladium thiosemicarbazone complex to be comparable to the anti-cancer drug cisplatin (Halder et al., 2008). In view of the importance of these types of complexes, we report here in the synthesis and crystal structure of the title compound, C 29 H 28 N 3 O 2 PPdS, C 2 H 6 O, (I).

Experimental
The thiosemicarbazone ligand (0.050 g, 0.20 mmol, 1 equiv) was charged to a 50 mL round bottom flask and dissolved in 8 mL of ethanol. The solution was heated under N 2 to 333° K and triethylamine (0.059 mL, 0.42 mmol, 2.1 equiv) was added via syringe. Pd(PPh 3 ) 2 Cl 2 (0.140 g, 0.20 mmol, 1 equiv) was added to the resulting solution as a solid and the mixture was stirred for seven days. Hexanes, 5 mL, were added and the solution was cooled to 273° K resulting in the formation of a golden yellow solid (Fig. 3). The solid was collected by vacuum filtration and then dissolved in minimal dichloromethane layered with hexanes and stored at 273° K for 1 week resulting in the formation of bright orange single crystals of the title compound. (m.p.: 421-423 K).

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with atom-H lengths of 0.95Å (CH), 0.99Å (CH 2 ) or 0.88° (NH). Isotropic displacement parameters for these atoms were set to 1.2 (CH, NH) or 1.5 (CH 3 , OH) times U eq of the parent atom. Idealised Me refined as rotating group: C9(H9A,H9B,H9C),

Figure 3
Synthetic scheme of (I). Special details 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.