Bis[N,N-bis(diphenylphosphanyl)cyclopentanamine-κ2 P,P′]platinum(II) bis(trifluoromethanesulfonate)

The title compound, [Pt(C29H29NP2)2](CF3SO3)2, consists of a PtII atom, situated on an inversion centre, coordinated by two diphosphinoamine bidentate ligands and charge-balanced by two trifluoromethanesulfonate anions. The PtII atom has a distorted square-planar geometry defined by the four P atoms. The distortion is illustrated by the P—Pt—P bite angle of 70.31 (4)°. The geometry around the N atom deviates from a trigonal–planar geometry, evidenced by the P—N—P bite angle of 102.3 (2) °. The N atom is displaced by 0.114 (4) Å from the C/P/P plane. In order to coordinate, the orientation of the phenyl rings alters from a Cs conformation to a C 2v conformation. The cyclopentane ring is slightly twisted: the puckering parameters are q 2 = 0.420 (5) Å and ϕ = 26.5 (8) °. The trifluoromethanesulfonate anion displays a 0.511 (11):0.489 (11) positional disorder. Weak inter- and intramolecular C—H⋯O hydrogen bonds influence the crystal packing.

The title compound ( Figure 1) crystallizes with two trifluoromethanesulfonate anions with the Pt II atom situated on an inversion centre. The square-planar geometry around the metal centre is severely distorted as illustrated by the P1-Pt-P2 angle of 70.33 (4) °. The coordinated P1-N1-P2 angle indicates a severe distortion from the ideal trigonal-planar angle expected at the sp 2 -hybridized nitrogen. The P1-N1-P2 angle of the un-coordinated ligand of 121.76 (9) ° decreases to 102.3 (2) ° to accommodate coordination to the platinum. The N atom is displaced by 0.114 (4) Å from the C1, P1, P2 plane, while the Pt atom is perfectly planar with the phosphorous atoms. The orientation of the phenyl rings changes from a C s conformation when un-coordinated to a C 2v conformation in the solid state in order to coordinated to the platinum.
The trifluoromethanesulfonate anions are disordered over two positions with site occupancy factors of 0.511 (11):0.489 (11). The crystal packing is influenced by inter-and intra-molecular hydrogen bonds ( Figure 2, Table 1).
After stirring for 20 min, the solvent was removed completely under reduced pressure. Dichloromethane was added until no further dissolution of solid was evident. The resulting heterogeneous mixture was filtered through celite to remove the insoluble AgCl by-product. The colourless solid product was precipitated upon addition of methanol followed by a reduction in solvent volume under reduced pressure. The compound was isolated by filtration and washed with diethyl supplementary materials sup-2 . E68, m916-m917 ether (10 cm 3 ). Layering of a dichloromethane solution of the product with methanol gave colourless crystals, suitable for X-ray diffraction. (Yield: 60 mg, 74%)

Refinement
The methine, methylene and aromatic H atoms were placed in geometrically idealized positions at C-H = 1.00, 0.99 and 0.95 Å, respectively and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C). The highest peak is located 0.00 Å from Pt1 and the deepest hole is situated 0.06 Å from P2. The residual electron-density features are probably a consequence of an imperfect absorption correction. The only way to secure a stable refinement with regards to the disordered anion was by adopting some atoms as isotropic. A series of EADP was used for neighbouring atoms and DFIX was applied in some cases to ensure stable refinement.   Crystal packing of the title compound, viewed along the a axis showing the hydrogen bonds as dashed lines. Only applicable atoms with relevance to the hydrogen bonds are drawn at the 50% probability level.

Special details
Experimental. The intensity data were collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of 20 s/frame. A total of 1880 frames were collected with a frame width of 0.5° covering up to θ = 28.0° with 99.8% completeness accomplished. Spectroscopy data: 1 H NMR (600 MHz, CD 2 Cl 2 ): δ = 1.0 (m, 4H), 1.1 (m, 4H), 1.2 (m, 4H), 1.4 (m, 4H), 3.5 (m, 2H), 7.4 -7.8 (m, 40H). 31 P NMR (243 MHz, CD 2 Cl 2 ): δ = 39.7 (t, 1 J Pt-P = 1063.0 Hz). Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.