Bis(μ-diisopropylphosphanido-κ2 P:P)bis[hydrido(triisopropylphosphane-κP)platinum(II)]

In the centrosymmetric molecular structure of the title compound [Pt2(C6H14P)2H2(C9H21P)2], each PtII atom is bound on one side to a phosphane ligand (PiPr3) and a hydrido ligand. On the other side, it is bound to two phosphanide ligands (μ-PiPr2), which engage a bridging position between the two PtII atoms, forming a distorted square-planar structure motif. The Pt⋯Pt distance is 3.6755 (2) Å. A comparable molecular structure was observed for bis(μ-di-tert-butylphosphanido)bis[hydrido(triethylphosphane)platinum(II)] [Itazaki et al. (2004 ▶). Organometallics, 23, 1610–1621].

The bond angles P(13)-Pt(1)-P(13 i ) [77.47 (3)°] and Pt(1)-P(13)-Pt(1 i ) [102.53 (3)°] are slightly out of range of the structural parameters of the complexes without Pt-Pt bonding from Itazaki et al. (2004) [P-Pt-P 74.6-77.2° and Pt-P-Pt 102.8-105.4°]. This could be due to the less sterical hindrance of the iso-propyl groups by contrast with the tert-butyl groups in the reference substance [Pt 2 H 2 (µ-P t Bu 2 ) 2 (PEt 3 ) 2 ]. Chiang et al. (1984) reported the bond length of a terminal Pt-H bond determined by neutron diffraction method. They found for the Pt-H bond on a five coordinate platinum centre a bond length of 1.610 (2) Å in the compound The group of Knobler et al. (1983) also determined the Pt-H bond length by X-Ray diffraction in [Pt 2 H 3 (Ph 2 PCH 2 CH 2 PPh 2 ) 2 ] + [BPh 4 ]to be 1.527 Å, however without further refinement.
The bonding dictances Pt-P in trans-position to the hydrido ligand are with 2.3773 (7) Å longer than the bonding distances in trans-position to the phosphine ligand 2.3343 (7) Å.

Experimental
Bis(tri-iso-propylphosphine)platinum (50.0 mg, 0.09 mmol) dissolved in 1 ml benzene was added to a solution of dichloro(2,3,5,6-tetramethylphenyl)borane (29.5 mg, 0.09 mmol) in 1 ml benzene. The solvent was removed under reduced pressure and the obtained dark brown residue was disolved in hexanes. The title compound was obtained as a off-white solid. Colourless crystals suitable for X-ray analysis were grown from a hexanes solution at 238 K.

Refinement
The H atoms were placed at idealized positions and treatet as riding atoms: C-H = 0.98 Å (CH 3 ), 1.00 Å (aliphatic Hatoms). U iso (H) values were fixed at 1.5 times (for primary H atoms) and 1.2 times (tertiary H atoms) U eq of the attached C atoms.

Figure 1
The molecular structure of the title compound showing the atom numbering scheme and displacement ellipsoides for the non-H atoms at the 50% probability level. Hydrogen atoms are omitted for clarity.

Bis(µ-diisopropylphosphanido-κ 2 P:P)bis[hydrido(triisopropylphosphane-κP)platinum(II)]
Crystal data [Pt 2 (C 6 H 14 P) 2 H 2 (C 9 H 21 P) 2 ] M r = 946.94 Monoclinic, P2 1 /n Hall symbol: -P 2yn a = 8.8301 (3)  Special details Experimental. The crystal was immersed in a film of perfluoropolyether oil, mounted on a polyimide microloop (MicroMounts of MiTeGen) and transferred to stream of cold nitrogen (Oxford Cryostream 700). 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.