[1,2-Bis(diphenylphosphanyl)ethane-κ2 P,P′]{2-[(4-nitrobenzoylmethyl)diphenylphosphanyl]phenyl-κ2 C,C′}palladium(II) trifluoromethanesulfonate–dichloromethane–n-hexane (1/1/0.5)

In the cation of the title compound, [Pd(C26H19NO3P)(C26H24P2)]CF3O3S·CH2Cl2·0.5C6H14, the PdII atom has a slightly tetrahedrally distorted square-planar coordination geometry. The PdC3P and PdC2P2 five-membered metallacycles adopt envelope and twist conformations, respectively. In the crystal, intermolecular C—H⋯O hydrogen bonds link cations and anions into a three-dimensional network. The dichloromethane solvent molecule is disordered over three orientations with a site-occupancy ratio of 0.5/0.3/0.2. The n-hexane solvent molecule has a crystallographically imposed centre of symmetry.

Financial support from the Universitá degli Studi di Parma is gratefully acknowledged.

Comment
The synthesis and characterization of cyclopalladated metal complexes (Rietling et al., 2002) has attracted considerable attention due to their potential applications in organic synthesis and homogenous catalysis (Aguilar et al., 2008;Dupont et al., 2001;Chen et al., 2009). As a continuation of our ongoing project devoted to the development of new catalysts based on ortho-palladated α-ketophosphorus ylides complexes (Karami et al., 2010;Karami, Rizzoli & Salah, 2011;Karami, Rizzoli & Borzooie, 2011), we report herein the synthesis and crystal structure of the title compound.

Experimental
The title compound was obtained according to the procedure recently reported elsewhere (Karami, Rizzoli & Borzooie, 2011). Crystals suitable for X-ray analysis were obtained by slow evaporation of a dichloromethane/n-hexane (1:1 v/v) solution at room temperature.

Refinement
All H atoms were placed in calculated positions and refined using a riding model, with C-H = 0.93-0.98 Å, and with U iso (H) = 1.2 U eq (C) or 1.5 U eq (C) for methyl H atoms. The dichloromethane solvent molecule was found to be disordered over three orientations (called A, B, and C) with site-occupancy factors of 1/2, 0.3 and 1/5, respectively. During the refinement, supplementary materials sup-2 the C-Cl and Cl···Cl distances were constrained to 1.75 (1) and 2.75 (2) Å, respectively, and only the major component of disorder was refined anisotropically. The n-hexane molecule, which has crystallographically imposed centre of symmetry, showed rather high displacement ellipsoids, suggesting the presence of disorder. Attempts to model the molecule in terms of disordered contributors were unsuccessful, however. The molecule was therefore anisotropically refined by constraining the C-C bond lengths to 1.54 (1) Å, and the 1-3 C···C separations to 2.52 (2) Å. Fig. 1. The asymmetric unit of the title compound, with displacement ellipsoids drawn at the 30% probability level. Only the major component of the disordered dichloromethane molecule is shown. Symmetry code: (i) -x, 1 -y, -z.

Figures
Crystal data [Pd(C 26 H 19

Special details
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.