{2,6-Bis[(pyridin-2-yl)sulfanylmethyl]pyridine-κ2 N,N′}(η3-prop-2-enyl)palladium(II) hexafluorophosphate

The title compound, [Pd(C3H5)(C17H15N3S2)]PF6, is built up by a [(η3-allyl)Pd]2+ fragment coordinated by a 2,6-bis[(pyridin-2-yl)sulfanylmethyl]pyridine ligand coordinated through the N atoms. One of the S atoms is at a close distance to the metal centeratom [3.2930 (8) Å]. The PdII atom is tetracoordinated in a strongly distorted square-planar environment mainly determined by the η3-allyl anion in which the central C atom is disordered over two equally occupied positions. The crystal packing is very compact and is characterized by a three-dimensional network of C—H⋯F interactions between the F atoms of each anion and several H atoms of the surrounding cationic complexes.

The title compound, [Pd(C 3 H 5 )(C 17 H 15 N 3 S 2 )]PF 6 , is built up by a [( 3 -allyl)Pd] 2+ fragment coordinated by a 2,6-bis-[(pyridin-2-yl)sulfanylmethyl]pyridine ligand coordinated through the N atoms. One of the S atoms is at a close distance to the metal centeratom [3.2930 (8) Å ]. The Pd II atom is tetracoordinated in a strongly distorted square-planar environment mainly determined by the 3 -allyl anion in which the central C atom is disordered over two equally occupied positions. The crystal packing is very compact and is characterized by a three-dimensional network of C-HÁ Á ÁF interactions between the F atoms of each anion and several H atoms of the surrounding cationic complexes.

Comment
The chemistry of palladium-allyl complexes has been reported extensively. This interest has stemmed from the relevance to palladium-catalyzed allylic substitution reactions. Attack of the nucleophile on a cationic palladium η 3 -allyl complex is conventionally accepted as the crucial step in the catalytic cycle (De Vries 2012). Multidentate nitrogen ligands or multidentate sulfur nitrogen ligands have been used for the structure analysis of (η 3 -allyl)palladium complexes and the study of their influence upon the dynamic behaviour (Betz et al., 2008). One process encountered in (η 3 -allyl)palladium complexes is a syn anti isomerism which has been subject of research for many years. The η 3 -η 1 -η 3 mechanism is well established for many [Pd(η 3 -allyl)L1L2] + cations (Solin et al., 2001). Other process usually observed is apparent allyl rotation or syn-syn anti-anti isomerism (Takao et al., 2003). Mechanisms proposed for this process include: i) an associative mechanism, involving a non-rigid five-coordinated intermediate (Barloy et al., 2000), ii) a dissociative mechanism with stabilization of tricoordinate intermediate, mostly, in some complexes with N-donor ligands (Gogoll et al., 1997). We have lately been interested in the use of potentially tridentate N, S, N ligands in coordination chemistry towards congested ruthenium(II)substrates. The contemporary presence of the congested substrate and sterically demanding ligand favoured the N,S-chelation of the thioether with formation of the four membered chelate ring (Scopelliti et al., 2001;Tresoldi et al., 2002) and the five membered chelate ring, (Baradello et al., 2004). However the exchange between these isomers was hampered by the very low abundance of the four membered species and the large value of the activation energy of the process (Tresoldi et al., 2008). The potentially polidentate N 3 S 2 or N 5 S 2 dithioethers, containing a 2,6-substitute linker with two thioether-heterocycle arms, were prepared and their reactions with some congested ruthenium substrates explored. Only the four membered species was obtained and the sulfur inversion In this paper the reaction of 2,6-bis(2-pyridylsulfanylmethyl)pyridine(psmp) with [Pd(C 3 H 5 )(acetone)] + , generate in situ from [Pd(C 3 H 5 )Cl] 2 and AgPF 6 , led to the title compound,[Pd(C 3 H 5 )(psmp)]PF 6 (I).
After 30 m silver chloride was filtered. The solution of the solvento species was added to 15 ml of acetone containing supplementary materials sup-2 Acta Cryst. (2014). E70, m134-m135 162.7 mg (0.5 mmol) of psmp and stirred for 2 h. The resulting solution was filterd on diethyl ether (120 ml) and a white precipitate was obtained, which was filtered, washed with diethyl ether (30 ml) and dried overnight. Yield 247 mg (80%).

Refinement
H atoms were included in the refinement using a riding model method with the X-H bond geometry and the H isotropic displacement parameter depending on the parent atom X. One C atom of the allyl moiety is disordered over two equally occupied positions.

Figure 1
Perspective view of the title molecule with numbering of the atoms. Non H-atoms represented as displacement ellipsoids are plotted at the 30% probability level, while H atoms are shown as small spheres of arbitrary radius. The PF 6anion and one of the disordered C atoms have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.002 Δρ max = 0.57 e Å −3 Δρ min = −0.69 e Å −3 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. 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 > 2σ(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.