ORGANOMETALLIC COMPOUNDS OF THE LANTHANIDES - 127 - SYNTHESIS OF MONOMERIC BIS(CYCLOPENTADIENYL)LANTHANIDE TETRAHYDROBORATES WITH BULKY CYCLOPENTADIENYL LIGANDS - SINGLE-CRYSTAL X-RAY STRUCTURES OF [(ETA(5)-C5ME5)(2)SMBH4(THF)] AND [(ETA(5)-C5ME4ET)(2)Y(MU-H)(2)BH2(THF)]

The trichlorides of yttrium, samarium, and lutetium react with 2 equiv alents of Na[(C5H4Bu)-Bu-t] and 1 equivalent of NaBH4 to give [(eta(5) -C5H4 tBu)(2). LnBH(4)(THF)] (Ln=Y (1), Sm (2), Lu (3)) or with 2 equi valents of Na[C5Me4R)] and 1 equivalent of NaBH4 to form [eta(5)-C5Me4 R)(2) . LnBH(4)(THF)] (R = H, Ln = Y (4), Sm (5), Lu (6); R = Me, Ln = Y (7(, Sm (8), Lu (9); R = Et, Ln = Y (10), Sm (11), Lu (12); R = Pr- i, Ln = Y (13), Sm (14), Lu (15)). The new compounds have been charact erized by elemental analysis, NMR spectroscopy and mass spectrometry. The crystal structures of 8 and 10 were determined by single crystal X -ray diffraction.