ANSA-METALLOCENE DERIVATIVES OF SAMARIUM AND YTTERBIUM WITH SOFT DONOR LIGANDS

The derivative chemistry of the organolanthanide(II) complexes [Me4C2(C5H4)2]SM (1) and [Me4C2(C5H4)2]Yb (2) has been investigated. Oxidation of 2 with (t)BuCl affords the chloro-bridged binuclear ytterbium(III) complex (mu-Cl)2{[Me4C2(C5H4)2]Yb}2 (4). In contrast, treatment of 1 with (t)BuCl yields the mononuclear derivative [Me4C2(C5H4)2]SMCl(THF) (3). An organosamarium(III) selenolate, (Me4C2(C5H4)2]Sm(SeMes) (5) is prepared from 1 and dimesityldiselenide via reductive cleavage of the Se-Se bond. Similarly, the dithiocarbamates and dithiophosphates [Me4C2(C5H4)2]Ln(S2CNMe2) (Ln = Sm (6), Yb (7)) and [Me4C2(C5H4)2]Ln{S2P(OMe)2} (Ln = Sm (8), Yb (9)) are obtained by treatment of 1 or 2 with the corresponding disulphides. 2-t-Butyl-6,6-dimethylfulvene reacts with samarium metal to give the ansa-samarocene(II) complex [Me4C2(C5H3tBu)2]SM (10).