Redetermination of (2,2′-bipyridine-κ2 N,N′)dichloridopalladium(II) dichloromethane solvate

In the title compound, [PdCl2(C10H8N2)]·CH2Cl2, the Pd2+ ion is four-coordinated in a slightly distorted square-planar environment by two N atoms of the 2,2′-bipyridine (bipy) ligand and two chloride ions. The compound displays intramolecular C—H⋯Cl hydrogen bonds and pairs of complex molecules are connected by intermolecular C—H⋯Cl hydrogen bonds. Intermolecular π–π interactions are present between the pyridine rings of the ligand, the shortest centroid–centroid distance being 4.096 (3) Å. As a result of the electronic nature of the chelate ring, it is possible to create π–π interactions to its symmetry-related counterpart [3.720 (2) Å] and also with a pyridine ring [3.570 (3) Å] of the bipy unit. The present structure is a redetermination of a previous structure [Vicente et al. (1997 ▶). Private communication (refcode PYCXMN02). CCDC, Cambridge, England]. In the new structure refinement all H atoms were located in a difference Fourier synthesis. Their coordinates were refined freely, together with isotropic displacement parameters.

In the title compound, [PdCl 2 (C 10 H 8 N 2 )]ÁCH 2 Cl 2 , the Pd 2+ ion is four-coordinated in a slightly distorted square-planar environment by two N atoms of the 2,2 0 -bipyridine (bipy) ligand and two chloride ions. The compound displays intramolecular C-HÁ Á ÁCl hydrogen bonds and pairs of complex molecules are connected by intermolecular C-HÁ Á ÁCl hydrogen bonds. Intermolecularinteractions are present between the pyridine rings of the ligand, the shortest centroidcentroid distance being 4.096 (3) Å . As a result of the electronic nature of the chelate ring, it is possible to create interactions to its symmetry-related counterpart [3.720 (2) Å ] and also with a pyridine ring [3.570 (3) Å ] of the bipy unit. The present structure is a redetermination of a previous structure [Vicente et al. (1997). Private communication (refcode PYCXMN02). CCDC, Cambridge, England]. In the new structure refinement all H atoms were located in a difference Fourier synthesis. Their coordinates were refined freely, together with isotropic displacement parameters.

Comment
The asymmetric unit of the title compound, [PdCl 2 (C 10 H 8 N 2 )].CH 2 Cl 2 , contains a neutral Pd II complex and a solvent molecule (Fig. 1). The compound crystallized in the triclinic space group P1, whereas the previously reported complex [PdCl 2 (C 10 H 8 N 2 )] crystallized in the orthorhombic space group C222 1 (Maekawa et al., 1991). The X-ray structure analysis of the title compound was previously carried out (Vicente et al., 1997) and the structure is stored in CCDC code: RAGVUQ.
The stored and our crystal structures are in agreement, however, the new structure determination provides data on hydrogen bonding based on H atoms positions located from a difference Fourier synthesis and refined isotropically.

Experimental
To a solution of Na 2 PdCl 4 (0.300 g, 1.020 mmol) in EtOH (30 ml) was added 2,2'-bipyridine (0.159 g, 1.018 mmol) and stirred for 5 h at room temperature. The precipitate obtained was separated by filtration and washed with EtOH and water and dried under vacuum, to give a yellow powder (0.302 g). Crystals suitable for X-ray analysis were obtained by slow evaporation from a CH 2 Cl 2 solution.

Refinement
All H atoms were located from Fourier difference maps and refined isotropically.
supplementary materials sup-2 Figures   Fig. 1. The structure of the title compound, with displacement ellipsoids drawn at the 40% probability level for non-H atoms. (2,2'-Bipyridine-κ 2 N,N')dichloridopalladium(II) dichloromethane solvate Crystal data [PdCl 2 (C 10  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 Rfactors(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 Pd1 0.32112 (