trans-Bis[1,2-bis(diphenylphosphanyl)ethane]chlorido(ethynyl)ruthenium(II)

The molecular structure of the title compound, trans-[Cu(C2H)Cl(C26H24P2)2], consists of an RuII cation, located on an inversion centre, in an octahedral environment defined by two chelating phosphines, one acetylide and one chloride ligand. The –C CH and the chlorine ligands are disordered over two equivalent positions (0.5 occupancy each). The coordination geometry is distorted octahedral, with the –C CH fragment and the Cl ligand in trans positions. The four P atoms occupy the equatorial plane of the octahedron and the chloride and acetylide ligands the axial positions.


Related literature
For details of electronic communication, see: Hu et al. (2005) and for molecular electronics, see: Gauthier et al. (2008). For the chemistry of the trans-RuCl(C CH)(dppe) 2 , [dppe = 1,2bis(diphenylphosphanyl)ethane] complex, see: Fox et al. these mononuclear organometallic acetylide complexes exhibit usually a very electron-rich chemistry and constitute a remarkable potential use in the molecular electronics field, since the oxidation state of the metal can be easily modulated (Gauthier et al., 2008). In addition, these types of fragments have been shown to be interesting when they are attached to various unsaturated bridges. Depending on the nature of the bridge and the type of design obtained, they can exhibit different magnetic, optical or electronic properties (Faulkner et al., 1994;Zhu et al., 1999). Despite its important and widely use in the organometallic chemistry for the syntheses of vinylidene ruthenium complexes, for his rich electronic properties, the molecular structure of complex (1) has not been previously reported.
The main compound (1) crystallizes in the monoclinic space group P2 1 /n. The structure lies over a special position located in an inversion centre. the -C≡CH and the chlorine ligands are disordered over two equivalent positions (0.5 occupancy each one). The coordination geometry is a distorted octahedron with the -C≡CH fragment and the Cl ligand in trans position.
The structure of (1) shows four phosphorus atoms occupying the equatorial plane of the octahedron and the chloride and acetylide ligands occupying the axial position in trans configuration. The Cl-Ru, Ru-C(1), and C(1)-C(2) data for this complex fall within the range of those previously reported for related octahedral trans-bis(bidentate phosphine) ruthenium alkynyl complexes (Younus et al., 1999).
Finally, both inter-and intramolecular hydrogen bonds or any other kind interaction are not observed in the crystalline packing of title compound.

Experimental
A Schlenk tube under argon was loaded with [Ru(dppe) 2 Cl] + (0.400 g, 0.369 mmol), ethynyltrimethylsilane (100 ml, 0.71 mmol), and 20 ml CH 2 Cl 2 was added. The resulting mixture was stirred over night. After evaporation of the solvent, the residue was extracted with CH 2 Cl 2 and chromatographied through a 2x4 cm Al 2 O 3 column using CH 2 Cl 2 as eluant. The solution was evaporated and the remaining solid was washed with n-pentane and dried in vacuo, to afford (1) as an yellow powder (0.262 g, 68,5%). Crystals were obtained by vapor diffusion of dichloromethane and hexane solution of (1).

Refinement
The hydrogen atoms positions were calculated after each cycle of refinement with SHELXL (Sheldrick, 2008) using a riding model for each structure, with C-H distances in the range 0.95 to 0.98 Å. U iso (H) values were set equal to 1.2U eq . The ruthenium atom lies over an inversion center; in consequence, the dppe ligand occupy the equatorial position while chlorine and acetylide ligands are found on both axial positions. Both ligands were refined with 0.5 occupancies each one. On the other hand, phenyl ring (C3-C8) from dppe ligand is disordered in two positions with refined occupancies of 0.725 (17) and 0.275 (17). The anisotropic displacement parameters were constrained using the EADP instruction.

Computing details
Data  The molecular structure of title compound with full atom numbering scheme for indepent atoms. Displacement ellipsoids are presented at 50% probability level. Hydrogen atoms and disordered phenyl ring have been omitted in sake of clarity.  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.