Ytterbium complexes cyclopentadienyl halides

Structural studies by Baker, Brown, and Raymond (42) have shown the dimeric nature of lanthanide dicyclopentadienyl halides. They reported that the molecular structure of [Y (C H CH ) Cl] consists of two ytterbium atoms, each with two n -bound methyl-cyclopentadienyl rings, which are nearly symmetrically bridged by the two chlorine atoms. The crystal structure of Yb(C(.H Me was reported by Halton et al. (43). The complex actually nas a dimeric structure, Cp2YbMe2YbCp2, remarkably similar to Me2ALMe2 AlMe2 The overall molecular geometry is identical with that or the chloride analogue Yb(C H CH )2CI. 

Iodine cleaves one erbium-cyclopentadienyl bond in tricyclopentadienyl erbium with formation of pink dicyclopentadienyl erbium iodide (Maginn et al., 1963), and the tricyclopentadienyl complexes of neodymium and ytterbium are cleaved by hydrogen cyanide with formation of the corresponding dicyclopentadienyl lanthanide cyanide (Kanellakopulos et al., 1974). The colors and some physical data of the cyclopentadienyl rare earth halides and cyanides are given in table 4. 

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