Samarium cyclopentadienide

By controlling the stoichiometry of the reaction between lanthanide trichlorides and sodium cyclopentadienide it is possible to replace the chloride ions stepwise. Equihbria are rapidly established, so the addition of Ln(C5H5)3 to one or two equivalents of LnCls will produce M(C5H5)2C1 and M(C5H5)Cl2, respectively. The dichlorides are known only for the lanthanides from samarium to lutetium and are obtained from THF solutions as tris-THF adducts. 

The tetrahydrofuran complex of dicyclopentadienyl samarium is made by reduction of tricyclopentadienyl samarium with KCjgHg in naphthalene in the presence of tetrahydrofuran and was isolated as a purple pyrophoric product (Watt and Gillow, 1969). Ytterbium also reacts with thallous cyclopentadienide in dimethoxyethane in the presence of a little metallic mercury with formation of Cp2Yb DME (Deacon et al., 1982a). 

In addition to the cyclopentadienides of the trivalent lanthanides, complexes of the divalent ions of samarium, europium, and ytterbium have been prepared (Fischer and Fischer, 1%5). The europium and ytterbium dicyclopentadienides... 

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