Schiff-base complexes of the lanthanoids and actinoids. Part 1. Lanthanoid(III) halide complexes with the un-ionised form of NN′-ethyl-enebis(salicylideneimine) and related bases

Abstract

The Schiff base NN′-ethylenebis(salicylideneimine) and related bases, H₂L, react with hydrated lanthanoid(III) halides to give the complexes Ln(H₂L)Cl₃·nH₂O (Ln = La or Ce; n= O—2), Ln₂(H₂L)₃Cl₆·nH₂O (Ln = La, Ce, Pr, Nd, Sm, Gd, Ho, or Yb; n= O–2). Ln(H₂L)₂X₃·nH₂O (Ln = La, Ce, Pr, Nd, Sm, Gd, Ho, or Yb; X = Cl or Br; n= O–2). and Ln(H₂L)₃X₃·nH₂O (Ln = La, Ce, Pr, Nd, Sm. or Gd; X = Cl or Br; n= 0 or 1). Spectroscopic and other evidence has indicated that: (i) halide is co-ordinated to the metal ion except in the case of Ln(H₂L)₃X₃·nH₂O where the results were ambiguous; and (ii) the potentially quadridentate ligands are bidentate in these complexes with the un-ionised phenolic groups being unco-ordinated.