Organolanthanoid complexes

D. Chiral organolanthanoid complexes for olefin hydrogenation, hydroamination/cyclization, and hydrosilylation... 

This area also includes the introduction of additional catalytic sites in zeolites by organometallic precursor compounds. Both the adjustment of Brpnsted/Lewis acidity and the directed fixation of active transition metal centers inside zeolite cages and channels seem possible, but the size and structures of these precursors will be crucial. The molecular modification appears all the more important as many catalytic processes will remain heterogeneous in nature, especially when the shape-selectivity of sodalites, zeolites, pentasils, etc. is exploited. Once again, the possible versatility of organolanthanoid complexes deserves emphasis, since these metals verify to the above-mentioned acidity and catalysis effects [92]. 

Examples of organic transformations that are catalysed by organolanthanoid complexes are given below. A significant point is that only mild reaction conditions are required in many reactions. 

Within a year of Uemura s survey, however, the chemical literature witnessed at least two major reviews (Imamoto et al., 1984a Natale, 1983) as well as a cascade of research articles that described new and surprising uses for lanthanides in organic synthesis. A review article on organolanthanoid complexes by Schumann (1984) speculated on the potential of such complexes in catalysis and organic synthesis, and complemented a recent chapta in this Handbook (Schumann and Genthe, 1984). 

The existence of intramolecular short Ln...C(Me) contacts is the main structural feature of considered monomeric bis(trimethylsylyl)amide derivatives. These contacts reflect evidently the "P-agostic interaction found in the structures of organolanthanoid complexes with CH(SiMe3)2 ligands (Chapter I). 

The photophysics of the interaction between two Cp2Ln-OEt2 compounds (Ln = Eu or Yb) in toluene shows that the Yb compound quenches the emission from its Eu analog. This is the first reported example of excited-state energy transfer between two organolanthanoid complexes (Thomas and Ellis 1985). 

Diethyl ether adducts of his(pentamethylcyclopentadienyl)europium(II) and -ytterbium(II). Excited-state energy transfer with organolanthanoid complexes, A. C. Thomas, A. B. Ellis, OrganometaUics 1985, 4, 2223. 

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