Organolanthanoids. XVII. The Synthesis of Bis(diphenylphosphinocyclopentadienyl)ytterbium(II) and Derived Heterobimetallic Complexes [Yb(thf)_n(C₅H₄PPh₂)₂Z] [Z=Ni(CO)₂, Mo(CO)₄ or PtMe₂; n = 1 or 2; thf = Tetrahydrofuran]. The X-Ray Crystal-Structure of [Yb(thf)₂(C₅H₄PPh₂)₂Ni(CO)₂]

Abstract

Reaction of diphenylphosphinocyclopentadiene with Yb (C₆F₅)₂ or with ytterbium metal and Hg(C₆F₅)₂ in tetrahydrofuran ( thf ) gives, after workup with toluene, the phosphinoytter-bocene , [Yb (C₅H₄PPh₂)₂( thf )]. Treatment with thf or with N,N,N′,N′- tetramethylethane-1,2-diamine ( tmen ) yields [ Yb (C₅H₄PPh₂)₂L₂] (L = thf or L₂ = tmen ). Redox trans- metallation between ytterbium metal and Tl (C₅H₄PPh₂) in l,2-dimethoxyethane ( dme ) gives thallium metal and [ Yb (C₅H₄PPh₂)₂(dme )]. The ytterbium-transition metal hetero-bimetallics [ Yb ( thf ) (C₂H₄PPh₂)₂Z]. nPhMe [Z = Ni(CO)₂, Mo(CO)₄ or PtMe₂, n = 2/3 or 1] have been prepared by reaction of [ Yb ( thf )(C₅H₄PPh₂)₂] with Ni(CO)₂(PPh₃)₂, Mo(CO)₄( nbd ) ( nbd = norbornadiene ) or PtMe₂(cod) (cod = cycloocta-1,5-diene) in toluene. Treatment of the heterobimetallics with tetrahydrofuran [Z = PtMe₂ or Mo(CO)₄] or a preparation in thf /toluene [Z = Ni(CO)₂] yields [ Yb ( thf )₂(C₅H₄PPh₂)₂PtMe₂]. thf, [ Yb ( thf )₂(C₂H₄PPh₂)₂Mo(CO)₄]. thf and [ Yb ( thf )₂ (C₅H₄PPh₂)₂Ni(CO)₂]. The X-ray crystal structure of the last compound (triclinic, space group Pi, a 14.514(5), b 13.565(1), c 10.866(5) 93.11(2), β 104.65(3), γ 97.25(2)º, U 2045 Å ³ , Z 2, 5141 data refined to R 0.031) reveals eight-coordinate ytterbium with a pseudo-tetrahedral arrangement of two thf ligands and the cyclopentadienyl ring centroids of two ή⁵ -diphenylphosphinocyclopentadienide ligands . The latter are also bonded through phosphorus to the Ni(CO)² group, resulting in tetrahedral stereochemistry for nickel. Infrared spectroscopy suggests the presence of ytterbium- isocarbonyl bonding in solid [ Yb ( thf )(C₂H₄PPh₂)₂Z] [Z = Ni(CO)₂ or Mo(CO)₄].