The crystal and molecular structure of trans-[methyl- (2-oxacyclopentylidene)bis(dimethylphenylphosphine)- platinum(II)] hexafluorophosphate

Abstract

The carbene complex trans-[CH 3( CH 2 COCH 2 CH 2 )Pt{P(CH 3) 2 C 6 H 5} 2]PF 6 crystallizes in the centrosymetric orthorhombic space group Pcca ( D 8 2h) with a = 15.503(7), b = 18.81(1), c = 17.66(1) Å. The measured density of 1.81(1) g cm −3 agrees with d(calc) = 1.81 g cm −3 for M = 703.41 and Z = 8. Three dimensional X-ray diffraction data were collected on an automatic four circle diffractometer using Mo radiation. The structure was solved by a combination of Patterson, Fourier and least-squares refinement techniques. The final conventional agreement factor for the converged model is R 1 = 0.044, calculated on 1763 observations for which I > 3σ( I), with 160 variables. The anion lies on a crystallographic two-fold axis of symmetry, and is disordered. The coordination geometry is essentially square planar about the platinum atom. The cyclic carbene ligand is almost planar and is coordinated approximately perpendicular to the Pt square plane. The mean PtP distance is 2.305(5), the PtC( sp 3) bond length is 2.080(18) and the C( sp 2) atom lies 2.00(2) Å away from the platinum atom. The structure is discussed in terms of the trans-influences of the ligands, and the character of the PtC( sp 2) bond.