Organometallic Chemistry of Ph3PC=C=O. Synthesis, Characterization, X-ray Structure Determination, and Density Functional Study of the First Stable Bis-η1-ketenyl Complex, trans-[PtCl2{η1-C(PPh3)CO}2]

Article abstract of DOI:10.1021/om990826d

Mono- and bis-η¹-ketenyl Pt(II) complexes have been synthesized by reacting Zeise's salt or the related dimeric compound, [{PtCl₂(C₂H₄)}₂], with the oxocumulenic ylide ketenyliden-etriphenylphosphorane, Ph₃PC=C=O, 1, in suitable ratios. In particular, the η¹-ketenyl derivative, trans-[PtCl₂(C₂H₄){η¹-C(PPh ₃)CO}], 2, has been isolated and characterized. The reaction of 2 with one more equivalent of 1 displaces the coordinated ethylene giving the first stable bis-η¹-ketenyl derivative, trans-[PtCl₂{η¹-C(PPh₃)CO}₂], 6. The X-ray crystal structure of 6 shows a trans centrosymmetric geometry around Pt, with the PCCO moiety and the metal lying in a plane that forms an angle of ～65° with the Pt(II) coordination plane. Density functional calculations indicate that steric effects play a leading role in determining such an arrangement. Data on the reactivity of 2 and 6 are also reported. ? Dipartimento Processi Chimici di Ingegneria, Universita? di Padova. ? Dipartimento di Chimica Inorganica, Metallorganica ed Analitica, Universita? di Padova.