Stannoxane is a functional group in organotin chemistry with the connectivity (IV indicates the oxidation state of tin). Aside from the oxide group, usually 3 or 4 other substituents are attached to tin. In aqueous or aquatic environments, most organotin compounds contain this group.[1]
Stannoxanes form upon hydrolysis of organotin halides. For example, hydrolysis of dibutyltin dichloride gives the tetratin compound . The hydrolysis appears to proceed via organotin hydroxides. For example, the commercially important cyhexatin converts at 200 °C into the hexacyclohexyldistannoxane:
The condensation process is proposed to occur via an associative mechanism, involving the dimer. Support for this associative mechanism is the finding that Me3SnOH exists in solution as the dimer .
Indicative of the lability of the Sn-O bond, distannoxanes exchange with other distannoxanes:
The Sn-O-Sn bonds in simple organic derivatives are reactive toward carboxylic acid esters to give unsymmetrical distannoxanes: