The bis(substituted cyclopentadienyl)lanthanide(III) halides [{LnCp R 2 (µ-Cl)} 2 ] (Ln ) Pr, Nd, Sm, Dy, Tb, Y), [{LnCp tt 2 (µ-X)} 2 ] (X ) Cl, Ln ) La, Nd; X ) I, Ln ) Tm), and [Nd-) have been synthesized from the appropriate LnCl 3 , TmI 3 , or LnI 2 with the selected sodium or potassium cyclopentadienide. The complexes were characterized by 1 H, 13 C, 29 Si, and 171 Yb (for Yb(II) complexes) NMR spectroscopy, elemental analysis, and mass spectrometry. The molecular structures of [{NdCp R 2 (µ-Cl)} 2 ], [{TmCp tt 2 (µ-I)} 2 ], and [Yb(Cp R′ 2 -SiMe 2 )(THF) 2 ] have been determined by single-crystal X-ray diffraction studies. Attempts to reduce the complexes [{NdCp R 2 (µ-Cl)} 2 ], [{NdCp tt 2 (µ-Cl)} 2 ], and [{TmCp tt 2 (µ-I)} 2 ] are described.Supporting Information Available: Tables of X-ray crystallographic data for 2, 9, and 23. This material is available free of charge via the Internet at http://pubs.acs.org. Crystallographic data for the structural analyses have also been deposited with the Cambridge Crystallographic Data Center. Copies of the information can be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K.
