[{(OC)5W}{µ-Sn2(OtBu)4}]

The fluxional behaviour of the alkoxy stannylenes has been recognised after their syntheses (see M. Veith, F. Töllner J. Organomet. Chem. 1983, 246, 219-26): terminal and bridging OtBu residues do exchange.

By coordination of the stannylene, the dynamic behaviour gets a multistep process: at lower temperature, one terminal residue exchanges with the bridging groups. It is only at high temperature that the second terminal OtBu group enters the exchange.

For details see: M. Veith, M. Ehses, V. Huch New J. Chem. 2005, 29, 154-64.