Reactions of Acetylenes with Noble Metal Carbonyl Halides. Part 10. Synthesis and X-Ray Structural Characterization of a New Substituted Diplatina-dioxapentalene Complex PtCl(PPh3)>

Article abstract of DOI:10.1039/DT9880000017

The complex cis-, in chloroform solution at room temperature, reacts with methyl 2-butynoate in the presence of water and carbon monoxide to give Pt(CO)Cl> (1).Complex (1) is easily transformed into the related triphenylphosphine derivative PtCl(PPh3)> (2).A multinuclear (1H, 195Pt, and 31P) n.m.r. study of complex (2) is reported.The analysis of the 195Pt n.m.r. spectrum gave unambiguously the value ³J(Pt-Pt)=818 Hz.The crystal structure has been solved by Patterson and Fourier methods from counter data and refined by blocked full-matrix least squares to a final conventional R of 0.0317 for 3795 independent observed reflexions.Crystals of complex (2) are triclinic, space group P1, with unit cell dimensions a=13.921(4), b=10.386(3), c=10.006(3) Angstroem, α=107.56(7), β=103.02(6), γ=94.36(6) deg, and Z=2.The crystal contains discrete molecules of (2) with square-planar arrangements around the Pt atoms showing large angular distortions due to the two five-membered rings.The two fused metallacycles and the two co-ordination planes are essentially coplanar, giving a flat molecule.No interaction between the two metal centres is present .The bond distances between the metal atoms and the organic fragment are significantly different: the Pt-C(sp²) lengths are 1.944(7) and 1.996(9) Angstroem, with a trans chlorine atom in both cases, while the Pt-O distances are 2.118(5) and 2.017(5) Angstroem trans to the phosphine ligand and to the terminally bonded carbon monoxide, respectively.

Full text of DOI:10.1039/DT9880000017

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