Stannoxane is a
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the res ...
in
organotin chemistry
Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered by ...
with the connectivity Sn
IV-O-Sn
IV (IV indicates the
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. ...
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.
[Davies, Alwyn George. (2004) Organotin Chemistry, 2nd Edition Weinheim: Wiley-VCH. ]
:
Synthesis and formation
Stannoxanes form upon
hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolysis i ...
of organotin halides. For example, hydrolysis of dibutyltin dichloride gives the tetratin compound {
u2ClSnsub>2O}
2. The hydrolysis appears to proceed via organotin hydroxides. For example, the commercially important (C
6H
11)
3SnOH converts at 200 °C into the distannoxane:
:2 (C
6H
11)
3SnOH →
C6H11)3Snsub>2O + H
2O
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 (Me
3Sn)
2(
μ-OH)
2.
Reactivity
Indicative of the lability of the Sn-O bond, distannoxanes exchange with other distannoxanes:
:(R
3Sn)
2O + (R'
3Sn)
2O → 2 R
3SnOSnR'
3
The Sn-O-Sn bonds in simple organic derivatives are reactive toward carboxylic acid esters to give unsymmetrical distannoxanes:
2 R
2SnO + R'CO
2R" → R"OSnR
2-O-SnR
2O2CR'
References
Tin(IV) compounds