Synthesis and Structure of Group IV Distanna[2]metallocenophanes

1,2-Dichloro-1,1,2,2-tetra-tert-butyldistannane reacts with 2 equiv of sodium cyclopentadienide to give a bis(cyclopentadienyl)distannane. Subsequent dilithiation with lithium diisopropylamide and reactions with suitable metal halides yield [(C(5)H(4)SntBu(2))(2)MCl2] (M = Ti, Zr, Hf). The group 4 ansa-metallocenes have all been fully characterized by means of multinuclear NMR spectroscopy, elemental analysis, and X-ray diffraction.