Organolanthanoids. XXI Synthesis of Bis- and Tris-(diphenylphosphinocyclopenta- dienyl)lanthanoid Compounds and the X-Ray Crystal Structures of [Ln(C5H4PPh2)3(OPPh3)]·(thf)1

Abstract

Redox transmetallation ofTl(C₅H₄PPh₂)with an excess of Sm in refluxing thf (thf = tetrahydrofuran) or Eu indme (dme = 1,2-dimethoxyethane) at room temperature gave thelanthanoid(II) compounds[Sm(C₅H₄PPh₂)₂](1) and[Eu(C₅H₄PPh₂)₂(dme)](2). Crystallization of (1) or[Yb(C₅H₄PPh₂)₂(dme)]with OPPh₃ in dme yielded[Sm(C₅H₄PPh₂)₂(OPPh₃)₂](3) and[Yb(C₅H₄PPh₂)₂(OPPh₃)₂](4). Room-temperature transmetallation ofTl(C₅H₄PPh₂)with Nd gave the lanthanoid(III) compound[Nd(C₅H₄PPh₂)₃(thf)](5), but analogous reactions with La, Pr, Er, Gd and Y in refluxing thfgenerally gave intractable oils, although in one instance impure[La(C₅H₄PPh₂)₃(thf)]_·(thf)_{0 · 5},namely(6)_·(thf)_{0 · 5}, wasisolated. This complex was also obtained at room temperature by usingLaI₃-activated La metal. Oxidation of (1) with 1 equiv.ofTl(C₅H₄PPh₂)in toluene yielded solvent-freeSm(C₅H₄PPh₂)₃(7). Addition of OPPh₃ to these systems allowed theisolation of[Ln(C₅H₄PPh₂)₃(OPPh₃)]_·(thf)_x(x = 0-1 · 5; Ln = La (8), Pr (9),Nd (10), Sm (11), Er (12), Y (13)). Single-crystal X-ray structuredetermination of(10)_·(thf)_{1 · 5},(11)_·(thf)_{1 · 5} and(12)_·(thf)_{1 · 5}revealed formally 10-coordinate complexes with an O-bondedOPPh₃, threeη⁵-C₅H₄PPh₂ligands and lattice thf. The centroids of the C₅ ringsand the oxygen atom surround the central metal in a distorted tetrahedralarray.