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 [(C5H4SntBu2)2MCl2] (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.