Syntheses and crystal structures of bis(tetrahydrofurfurylindenyl) lanthanocene chlorides (C4H7OCH2C9H6)2LnCl (Ln=Nd, Sm, Dy, Ho, Er, Yb)

Reaction of anhydrous lanthanide trichlorides with tetrahydrofurfuryl indenyl lithium in THF afforded bis(tetrahydrofurfurylindenyl) lanthanocene chlorides complexes (C4H7OCH2C9H6)2LnCl, Ln=Nd (1), Sm (2), Dy (3), Ho (4), Er (5), Yb (6). The X-ray crystallographic structures of all the six complexes were determined and these indicate that they are unsolvated nine-coordinate monomeric complexes with a trans arrangement of both the sidearm and indenyl rings in the solid state. They belong to the same crystal system (orthorhombic) and space group (P212121) with the same structure. Especially, they are more stable to air and moisture than the corresponding unsubstituted indenyl lanthanide complexes.