ANIONIC BIPYRIDYL COMPLEXES OF LANTHANIDES - STRUCTURE OF [YB(BIPY)(3)][LI(THF)(4)]

Reactions of Sm-II, Tb-III Tm-II, Yb-II, and Lu-III iodides with 2,2'- bipyridyllithium in THF afford [Li(THF)(4)][Ln(bipy)(n)] complexes (n = 3 or 4) containing trivalent lanthanides. X-ray structural analysis demonstrated that in the crystalline state, the Yb derivative has the ionic structure, [Li(THF)(4)](+)[Yb(bipy)(3)](-). In THF solutions, th e reversible ligand exchange between metal atoms occurs to yield neutr al compounds [Ln(bipy)(n-1)(THF)(x)] and (Li(bipy)(THF)(y)]. A decreas e in the temperature shifts the equilibrium to ionic pairs.