Synthesis, molecular and electronic structure of the first homoleptic complex of platinum with a secondary phosphine

The reaction of CpPt(eta(3)-C3H5) with (PBu2H)-H-t in acetone gives the Pt(0) mononuclear derivative Pt((PBu2H)-H-t)(3) (1). As demonstrated by variable temperature P-31{H-1} NMR spectra, complex 1 dissociates one of the phosphines in toluene solution affording the 14e(-)Pt((PBu2H)-H-t)(2). The crystal and molecular structure of 1 was solved by X-ray diffraction which reveals a trigonal planar disposition of the phosphine molecules (C24H57P3Pt: hexagonal, space group P6(3)/m, a=b=10.4150(11), c=16.263(3) Angstrom, Z=2). The P-H hydrogen atoms were located in the Fourier map and were found to lie in the coordination plane, with the t-butyl substituents in an eclipsed configuration. Ab initio and molecular dynamics calculations essentially confirm the structure obtained by X-ray diffraction. Ar. agostic Pt-H-P interaction was excluded and the geometry was explained in terms of steric interactions