Heteroleptic poly(pyrazolyl)borate derivatives of the lanthanide ions. The synthesis of acetylacetonate complexes and the molecular structures of [Ln{HB(C3N2H3)3)2(MeC(O)CHC(O)Me}](Ln = Ce or Yb)

Abstract

The air- and moisture-stable complexes [Ln{HB(C₃N₂H₃)₃}₂{MeC(O)CHC(O)Me}](Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, or Y) have been prepared and characterised. Evidence was found that intramolecular ligand reorganisation processes were occurring on the n.m.r. time-scale down to –80 °C. The molecular structures of the compounds with Ln = Ce and Yb have been determined. Polytopal analysis of these structures reveals that a substantial distortion of the near bicapped trigonal prismatic co-ordination geometry, found for the cerium complex, towards square antiprismatic is necessary to allow the ligand set to accommodate the smaller Yb³⁺ ion.