(Bis{2,4,6-triisopropylphenyl}stannylene)ferrocenophane and related ring-opened products

The addition of bis(2,4,6-triisopropylphenyl)tin dichloride (1) to a hexane/THF slurry of 1,1'-dilithioferrocene-tmeda produces the corresponding stannyleneferrocenophane (2) in good yield. Structural analysis of 2 reveals a dihedral angle between the two cyclopentadienyl rings of 14.7 degrees and a relatively short Fe-Sn atomic distance of 2.994(2) Angstrom. Cyclic voltammetry of 2 exhibits reversible redox behavior. Whereas treatment with MeOH and H2O failed to produce ring-opened compounds, silica gel catalyzed hydrolysis of 1 leads to ring-opened Fc(i-Pr3C6H2)(2)SnOH (3), which crystallizes as a H-bonded dimer. Thermal treatment of 2 at 180 degrees C leads to the ring-opened polymerization product 4, which after precipitation from toluene remains insoluble in organic solvents. Solid-state C-13 and Sn-119 NMR spectra of 4 confirm the structure of the material. The X-ray structural analysis of 1 is reported and compared to that of 2.