ASPECTS OF THE LANTHANIDE-CARBON SIGMA-BOND

Although the first sigma-bonded organolanthanides were not fully chara cterized for some 20 years after the isolation of the first pi-cyclope ntadienyls, a wide range of these compounds is unfolding. The review d iscusses synthetic routes to the compounds, both with and without ''su pporting'' polyhapto ligands and including the very recent carbenes, e xploring the principles behind their isolation. Structural information is critically reviewed, with the effects of bulky ligands and the lan thanide contraction considered. (C) 1997 Elsevier Science S.A.