The Lewis acidity of organolanthanides. The interaction of cyclopenta-dienyl-lanthanides with some carbonyl and nitrosyl complexes

Abstract

The i.r. and ¹H n.m.r. spectra of a number of compounds containing sites of Lewis basicity change in the presence of selected cyclopentadienyl-lanthanides, R₃Ln. These spectral changes indicate that the lanthanides can act as Lewis acids towards bases such as bridging and terminal carbonyl ligands, terminal nitrosyl ligands, appropriate transition metals and some carbon–carbon triple bonds. Several solid adducts can be isolated and characterized. The preparation of the new compounds R₂LnM(π-C₅H₅)(CO)₃[Ln = Dy, Ho, Er, or Yb; M = Mo or W] is described, and evidence for the existence of isocarbonyl linkages in these complexes is presented.