{1-[1-(3-Carboxypropanamido)ethyl]-1′,2-bis(diphenylphosphino)ferrocene-κ2 P,P′}dichloridoplatinum(II) dichloromethane 1.25-solvate

The dinuclear title compound, [FePtCl2(C17H14P)(C23H23NO3P)]·1.25CH2Cl2, has a slightly distorted cis-PtCl2P2 square-planar geometry around the Pt atom, and the ferrocenylphosphine ligands are staggered at an angle of 29.4 (2)° about Pt. In the crystal structure, the complex forms centrosymmetric dimers via two strong intermolecular O—H⋯O bonds resulting in R 2 2(8) rings. A weak intramolecular N—H⋯Cl bond leads to an S(8) motif. The solvent is highly disordered and has not been modelled with discrete atoms.

The dinuclear title compound, [FePtCl 2 (C 17 H 14 P)(C 23 H 23 -NO 3 P)]Á1.25CH 2 Cl 2 , has a slightly distorted cis-PtCl 2 P 2 square-planar geometry around the Pt atom, and the ferrocenylphosphine ligands are staggered at an angle of 29.4 (2) about Pt. In the crystal structure, the complex forms centrosymmetric dimers via two strong intermolecular O-HÁ Á ÁO bonds resulting in R 2 2 (8) rings. A weak intramolecular N-HÁ Á ÁCl bond leads to an S(8) motif. The solvent is highly disordered and has not been modelled with discrete atoms.   improve the biological applications of already existing drugs (Beagley et al., 2003, Top et al., 2003.

Related literature
Here we report the title compound, (I), a solvated platinum(II) complex with substituted 1,1′-bis(diphenylphosphino)ferrocene. The substituent is aimed to act as a linker arm with polar functionalities in order to increase the solubility of the compound in polar solvents. The carboxylic acid moiety is likely to facilitate further functionalization towards the synthesis of biologically active molecules.
The geometry around atom Pt1 in (I) is a slightly distorted square planar with the two phosphorous atoms cis to each other ( Table 1). The P2-Pt1-P1 angle of 97.55 (2)° is significantly larger than 90° due to the geometry of the ferrocenyl moiety. The other bond angles about the Pt atom in (I) are consistent with those seen in related structures (Allen, 2002). Around Pt1, atoms P1 and Cl2 are slightly below and atoms P2 and Cl1 are slightly above the least squares plane defined by atoms Pt1, P1, P2, Cl1, and Cl2. This distorted square planar geometry is typical of this class of compounds with a cis substitution pattern around the central platinum(II) atom.

S3. Refinement
Compound (I) co-crystallizes with approximately 1.25 solvent molecules of dichloromethane per platinum complex. A significant amount of time was invested in identifying and refining the disordered dichloromethane solvent molecules.
Bond length restraints were applied to model the molecules but the resulting isotropic displacement coefficients suggested the molecules were mobile. In addition, the refinement was computationally unstable. Option SQUEEZE of program PLATON (Spek, 2003) was used to correct the diffraction data for diffuse scattering effects and to identify the solvate molecules. PLATON calculated the upper limit of volume that can be occupied by the solvent to be 476.2 Å 3 , or 12.2% of the unit cell volume. The program calculated 216 electrons in the unit cell for the diffuse species. This approximately corresponds to 1.25 molecules of dichloromethane (52.5 electrons) per compound (I).
The highest difference peak is 0.xxÅ from Pt1. The molecular structure of (I) drawn with 30% probability ellipsoids. All hydrogen atoms attached to carbon atoms are omitted for clarity.

{1-[1-(3-Carboxypropanamido)ethyl]-1′,2-bis(diphenylphosphino)ferrocene-κ 2 P,P′}dichloridoplatinum(II
Special details 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 Rfactors based on ALL data will be even larger.