Dichloridobis[(ferrocenylmethylidene)(furan-2-ylmethyl)amine-κN]palladium(II)

The title compound, [Fe2Pd(C5H5)2(C11H10NO)2Cl2], exhibits a square-planar geometry at the PdII atom, which is determined by inversion-related chlorine and ferrocenylimine molecules across a center of symmetry. The ferrocenylimine moieties are trans to each other.

The title compound, [Fe 2 Pd(C 5 H 5 ) 2 (C 11 H 10 NO) 2 Cl 2 ], exhibits a square-planar geometry at the Pd II atom, which is determined by inversion-related chlorine and ferrocenylimine molecules across a center of symmetry. The ferrocenylimine moieties are trans to each other.

Experimental
Crystal data [Fe 2 Pd(C 5 H 5 ) 2 (C 11 H 10 NO) 2 Cl 2 ] M r = 763.58 Monoclinic, P2 1 =n a = 12.2113 (7) Å b = 7.3439 (5)  Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008b); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL. Ferrocenyl derivatives containing good donor atoms have evoked research interest because their coordination to another metal produces multicentered molecules where the two metals are in close proximity but in different environments. This property may influence the mutual cooperation of the metals in a variety of application processes (Stang et al., 1996;Rajput et al., 2004;Rajput et al., 2006;Neuse et al., 1988;Pou et al., 2007). For instance, some ferrocenyl complexes have displayed promising cytotoxicity profiles (Neuse et al., 1988;Pou et al., 2007). Preference for these complexes is derived from their convenience of preparation, facile modification and handling (Mu et al., 2007;Lu et al., 2007). In an attempt to prepare new bulky bis(ferrocenylimine) palladium II complexes which could induce apoptosis on tumor cells, the title compound was obtained.
The molecular structure contains one molecule of the Pd II complex (Fig. 1) across a center of symmetry (one-half of the molecule is the asymmetric unit). All bond lengths and angles are normal and comparable with those reported for similar structures (Rajput et al., 2004;Nelana et al., 2008;Pou et al., 2007). The Pd II ion has square planar coordination geometry around the metal center coordinated to two ferrocenylimine ligands via the imine nitrogen atoms and the chloride ions. The ferrocenylimine molecules are trans to each other across the center of symmetry. There is no trans influence observed for the chloride ligands: the Pd-Cl bond length is in agreement with known Pd-Cl bond distances for palladium complexes (Allen, 2002).

Experimental
[PdCl 2 (cod)] was prepared following literature method (Salo & Guan, 2003). To a suspension of PdCl 2 (cod) [0.0394 g, 0.138 mmol] in a mixture of CH 2 Cl 2 /Et 2 O (20 ml) was added a solution of ferrocenyl-2-furylmethyl)imine (0.0801 g, 0.2732 mmol) in CH 2 Cl 2 (5 ml). An orange precipitate was observed immediately. The reaction was stirred at room temperature for 12 hrs. The precipitate was filtered off, washed with dry hexane (2 x 5 ml) and dried under vacuum to yield an orange solid. Recrystallization of the product was done from a mixture of CH 2 Cl 2 :C 6 H 14 which gave single crystals which were used for the X-ray diffraction studies. The yield of the product was 0.0738 g which translates to 70%.

Refinement
All H atoms for (I) were found in electron density difference maps. The methylene, methine, furanyl & cyclopentadienyl Hs were placed in geometrically idealized positions and constrained to ride on their parent C atoms with C-H distances of 0.99, 1.00, 0.95, and 0.95 Å, respectively, and U iso (H) = 1.2U eq (C). The low fraction of data collected may affect the precision of the structure.

Special details
Experimental. ′Crystal mounted on a Cryoloop using Paratone-N.′ 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.