Chlorido(chlorodiphenylphosphine-κP)(diphenylpiperidinophosphine-κP)(η5-pentamethylcyclopentadienyl)ruthenium(II)

The title compound, [Ru(C10H15)Cl(C12H10ClP)(C17H20NP)], is a half-sandwich complex of RuII with the chlorodiphenylphosphine ligand formed from the diphenylpiperidinophosphine and chlorine of the precursor complex [Ru(η5-C5Me5)(κ1P—Ph2PNC5H10)Cl2] by an unexpected reaction with NaBH4. The complex has a three-legged piano-stool geometry, with Ru—P bond lengths of 2.2598 (5) Å for the chlorophosphine and 2.3303 (5) Å for the aminophosphine.

The title compound, [Ru(C 10 H 15 )Cl(C 12 H 10 ClP)(C 17 H 20 NP)], is a half-sandwich complex of Ru II with the chlorodiphenylphosphine ligand formed from the diphenylpiperidinophosphine and chlorine of the precursor complex  Me 5 )( 1 P-Ph 2 PNC 5 H 10 )Cl 2 ] by an unexpected reaction with NaBH 4 . The complex has a three-legged piano-stool geometry, with Ru-P bond lengths of 2.2598 (5) Å for the chlorophosphine and 2.3303 (5) Å for the aminophosphine.

Related literature
For general background to the reaction of half-sandwich ruthenium aminophosphine complexes with diynes, see: Pavlik et al. (2006). For the unexpected formation and the crystal structure of a related Ru chlorodiphenylphosphine complex, see: Torres-Lubia et al. (1999). For the unexpected formation of another Mn chlorodiphenylphosphine complex, see: Liu et al. (1995). For the preparation of [Ru(Cp*)Cl 2 ] 2 , see: Oshima et al. (1984).

Experimental
Crystal data [Ru(C 10 Table 1 Selected bond lengths (Å ). Ru Financial support by the FWF Austrian Science Fund (project No. P16600-N11) is gratefully acknowledged.
After workup of the reaction, NMR spectra indicated that another unknown Ru complex must have formed which was studied subsequently with X-ray diffraction and is reported here. The title compound, (I), turned out to contain, in addition to an intact piperidinodiphenylphosphine (Ph 2 PNC 5 H 10 ), a chlorodiphenylphosphine as the second phosphine ligand of a half-sandwich complex with a three-legged piano-stool structure (Fig. 1). It is a Ru II complex with the chemical formula [Ru(Cp*)(κ 1 P-Ph 2 PCl)(κ 1 P-Ph 2 PNC 5 H 10 )Cl] that bears similarities to [Ru(Cp*)(κ 1 P-Ph 2 PCl) 2 Cl] (Torres-Lubia et al., 1999) with respect to stereochemistry of the complex, but also with respect to its formation. In case of [Ru(Cp*)(κ 1 P-Ph 2 PCl) 2 Cl] the chlorophosphine was not directly introduced but formed from [Ru(Cp*)(κ 1 P-Ph 2 PH) 2 Cl] (Ph 2 PH = hydridodiphenylphosphine) in CDCl 3 as the solvent in the presence of the strong base DBN (1,5-diazabicyclo[4.3.0]non-5-ene) by a stepwise chlorine/hydride exchange between the solvent and the two hydridophosphines. In a related way the title compound must have formed from [Ru(Cp*)(κ 1 P-Ph 2 PNC 5 H 10 )Cl 2 ] and NaBH 4 . However, there were no chlorinated solvents present in our reaction and the chlorine of the generated chlorophosphine must originate from the starting complex. It can be speculated that the formation of the title compound involves the intermediary formation of a hydridodiphenylphosphine, which by a hydride/chloride substitution leads to the chlorodiphenylphosphine of the title compound obtained in a poor yield of only 9%. A related and also unexpected transformation of a thiol-substituted hydridodiphenylphosphine into a thiol-substituted chlorodiphenylphosphine was observed in the reaction with Mn(CO) 5 Br in chloroform (Liu et al., 1995). Bond lengths and angles in the title compound (see Table 1 and supplementary materials) are similar to those of [Ru(Cp*)(κ 1 P-Ph 2 PCl) 2 Cl] (Torres-Lubia et al., 1999), which has <Ru-C> = 2.246 (20) Å (2.245 (21) Å for (I)), Ru-P = 2.242 (2) and 2.257 (2) Å,  (2) Å, and P-Cl = 2.085 (3) Å. Both Ru complexes adopt related conformations and have in common that the Ru-bonded and the P-bonded Cl lie on opposite sides. In both complexes the phosphine ligands adopt orientations that lead to a stabilization by intramolecular π-π-stacking between the two adjacent phenyl rings ( Fig. 1) with a shortest contact distance of C(12)···C(28) = 3.183 (3) Å in the title compound (ring-ring centroid distance 3.717 (2) Å, ring-ring inclination angle 12.96°). Moreover, it is remarkable that the title compound shows eight intramolecular C-H···Cl/N interactions (seven to Cl, one to N), but only one intermolecular C-H···Cl interaction (see supplementary materials).

S2. Experimental
The synthesis of [Ru(Cp*)(κ 1 P-PPh 2 NC 5 H 10 )(κ 1 P-PPh 2 Cl)Cl], (I), was carried out as follows: A solution of [Ru(Cp*)Cl 2 ] 2 (322 mg, 0.52 mmol) (Oshima et al., 1984) in THF (10 ml) in THF (10 ml) was treated with Ph 2 PNC 5 H 10 (300 mg, 1.2 mmol) and the solution was stirred for 1 h at room temperature. After that NaBH 4 (150 mg, 4.0 mmol) was added and the mixture was stirred for 12 h. After evaporation of the solvent an oily residue was obtained from which the product was extracted with pentane (2 x 10 ml). The volume of the solution was then reduced to about 0.5 ml whereupon red crystals of the title compound were obtained. Yield: 42 mg (9%

S3. Refinement
All H atoms were placed in calculated positions, with C-H = 0.93-0.98 Å, and were thereafter treated as riding, with U iso (H) values of 1.5U eq (C) for methyl groups and 1.2U eq (C) for others.

Figure 1
Perspective view of the title compound with the atom numbering scheme. Displacement ellipsoids are at the 30% probability level.

Chlorido(chlorodiphenylphosphine-κP)(diphenylpiperidinophosphine-κP)(η 5pentamethylcyclopentadienyl)ruthenium(II)
Crystal data [Ru(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 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Ru 0.319239 (8)