Some oxygen-donor complexes of cyclopentadienyluranium(IV) halides

Abstract

The oxygen-donor complexes [U(cp)X₃L₂][cp =η-C₅H₅, X = Cl or Br, L = Me₃CCONMe₂(dmpva) or PPh₃O],[U(cp)Cl₃L₂][L = MeCONMe₂(dma)], and [{U(cp)X₃L}₂][X = Cl or Br, L = Ph₂(O) PCH₂CH₂P(O) Ph₂(dppoe)] have been prepared. Products of composition ‘U (cp)₂Cl₂·dma,’‘U(cp)₂X₂·dmpva,’ and ‘U(cp)₂X₂(PPh₃O)₂’(X = Cl or Br) obtained from [U(cp)X₃L₂] have been shown to be disproportionation mixtures which include [U(cp)₃X] and free ligand, whereas [{U(cp)₂X₂(dppoe)}₂](X = Cl or Br) do not appear to disproportionate to an appreciable extent. The lability of the cp ligand has been utilised to prepare [U(cp)Cl₃(PPh₃O)₂] from [U(cp)₃Cl] and [UCl₄(PPh₃O)₂] in the presence of PPh₃O. The complexes [U(mcp)Cl₃(thf)₂], [U(cp)(mcp)₂Cl], and [U(cp)Br₃(thf)₂] have also been prepared (mcp =η-methylcyclopentadienyl, thf = tetrahydrofuran). Infrared and u.v.-visible (solution and reflectance) spectra are reported.