Abstract Two new lanthanocenophanes [{O (Me 2 SiC 5 H 4) 2} Pr III Cl· THF] x (2; x= 1 or 2) and [{O (Me 2 SiC 5 H 4) 2} Yb III Cl] 2 3, were made from LnCl 3 (Ln= Pr or Yb) and K 2 [O (Me 2 SiC 5 H 4) 2] in THF. The 1 H NMR spectra of THF-d 8 solutions of paramagnetic 2 (at+ 35 to− 25 C) and 3 (at< 10 C) reflect an asymmetrical disposition of the siloxy linkage, while solutions of 2 in CD 2 Cl 2 (at 20 C) and 3 in THF-d 8 (at> 10 C), respectively, ...
