Unexpected behavior of alkoxycarbonyl ligands. Crystal and molecular structure of trans-bis (ethoxycarbonyl) bis (triphenylphosphine) platinum

The crystal and molecular structures of the title compound have been determined from three-dimensional X-ray data collected by counter methods. The crystals are triclinic, space group P1, with Z = 1; cell dimensions: a = 10.204(8), b = 11.602(8), c = 8.363(7)Å, α = 106.04(8)°, β = 88.04(7)°, γ = 108.98(7)°. The structure, determined from 3435 reflections, has been refined by full-matrix least-squares methods down to R = 0.038. It consists of discrete centrosymmetric molecules; the Pt atom lies on an inversion centre. PtP and PtC bonds lengths are 2.302(2) and 2.059(7) Å respectively. Essentially planar PtCOO moieties are present, which make an angle of 80.8° with the coordination plane.
A trans configuration for a complex containing two Pt11C bonds is unexpected; alkoxycarbonyl ligands therefore show a peculiar behaviour which deserves further investigation.