Dichlorido[2-(phenyliminomethyl)quinoline-N,N′]palladium(II)

In the title complex, [PdCl2(C16H12N2)], the PdII ion is coordinated by two N atoms [Pd—N 2.039 (2), 2.073 (2) Å] from a bidentate ligand and two chloride anions [Pd—Cl 2.2655 (7), 2.2991 (7) Å] in a distorted square-planar geometry. In the crystal, π–π interactions between the six-membered rings of the quinoline fragments [centroid–centroid distances = 3.815 (5), 3.824 (5) Å] link two molecules into centrosymmetric dimers.

Financial support from the NRF (Thuthuka) and University of the Western Cape Senate Research is greatly acknowledged. We also thank Professor Roger A. Lalancette for resolving the symmetry-related geometries. The transition metal-diimine ligands are well known and have been used extensively as catalyst stabilisers in many reported catalytic processes Massa et al., 2009;Tiangpengfei et al., 2011;Ardizzoia et al., 2009). Several of these complexes, besides being heavily utilized in the catalytic field, equally double up as therapeutic agents (Keter et al., 2008;Singh et al., 2007).
The asymmetric unit of the title compound is shown in Fig. 1. In the title compound, the Pd II ion is bidentately coordinated to two N atoms of the 2-quinolylbenzylimine ligand and two chloride anions. The complex forms a distorted square planar geometry around the central metal. It is notable that the bond length of the Pd-Cl bond trans to the quinolyl-N atom are similar indicating lack of trans influence. There are two π-π interations between the quinoline ring systems as indicated by the interplanar centroid-centroid distances of 3.815 (5) and 3.824 (5) linking two molecules into a centrosymmetric dimers.

Experimental
To a suspension of PdCl 2 (cod) (0.0925 g, 0.324 mmol) in CH 2 Cl 2 (5 ml) was added a solution of (2-quinolylbenzyl)imine (0.0748 g, 0.322 mmol) in CH 2 Cl 2 (10 ml). The yellow solution was stirred under reflux for 4 h, resulting in the formation of yellow precipitate. The precipitate was filtered to obtain a pure yellow solid. Recrystallization from a mixture of a minimum of CH 2 Cl 2 and an excess of C 6 H 14 solution gave single crystals suitable for X-ray diffraction studies. The product yield was 82%.

Refinement
All hydrogen atoms were placed in idealized positions, and refined as riding, with U iso = 1.2 U eq of the parent atoms.

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication:  Special details Experimental. 'crystal mounted on a cryoloop′ 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.