“…Most of the complexes obtained with these starting materials are homoleptic derivatives, with varying coordination numbers depending on the presence of coordinated solvents, ligand denticity, and steric properties. Salt elimination reactions have been employed for several decades in the preparation of cyclopentadienyl derivatives, such as the archetypal [Ln(Cp*) 2 (THF) 2 ] ( 93-Ln ; Ln = Sm, Yb; Slv = Et 2 O, THF). , Metallocene-type Ln(Cp) 2 complexes can be obtained by reacting group 1 cyclopentadienyl salts with SmI 2 , EuI 2 , and YbI 2 ( 93-Yb can also be obtained from YbCl 2 ) and are isolated either as solvent-free or solvated adducts of formula [Ln(Cp R ) 2 (Slv) x ] ( x = 0–2; 1 , Cp R = Cp; 73-Ln , Cp R = Cp iPr5 ; 93-Ln Cp R = Cp*; 102 R -Ln , Cp′, Cp″, Cp‴, Cp Naph , Cp SiPh3 , Cp SiPh2Me , Cp tt , Cp ttt , Cp iPr4 , Cp Bn5 ,) − (Cp′ = {C 5 H 3 SiMe 3 } − , Cp″ = {C 5 H 3 (SiMe 3 ) 2 -1,3} − , Cp‴ = {C 5 H 3 (SiMe 3 ) 3 -1,2,4} − , Cp tt = {C 5 H 3 t Bu 2 -1,3} − , Cp ttt = {C 5 H 3 t Bu 3 -1,3} − , Cp Bn5 = {C 5 (CH 2 Ph) 5 } − ) (Scheme ). These methodologies are more problematic with the highly reducing salts NdI 2 , DyI 2 , and TmI 2 .…”