As an example the organic synthesis of tributyl-[(Z)-5-phenyl-2-penten-2-yl]stannane [2]:
A Grignard reagent is prepared from magnesium turnings and (Z)-2-bromo-5-phenyl-2-pentene in dry tetrahydrofuran and titrated with tributyltin chloride until the solution decolourises. The resulting solution is stirred at room temperature for 1 hour and the solvent is removed in a rotavapor. Diethyl ether is added and the ether extract is washed with brine and filtered and the ether evaporates in a rotavapor. The crude product is kugelrohr distilled to yield tributyl-[(Z)-5-phenyl-2-penten-2-yl]stannane as a colourless oil.
Tetraorganotins are very stable molecules with low toxicity and low biological activity. They are unusable as biocides, but they can be metabolized to toxic triorganotin compounds. They are used as starting materials for catalysts.
Triorganotins are very toxic. Tri-n-alkyltins are phytotoxic and therefore cannot be used in agriculture. Depending on the organic groups, they can be powerful bactericides and fungicides. Tributyltins are used as industrial biocides, eg. as antifungal agents in textiles and paper, wood pulp and paper mill systems, breweries, and industrial cooling systems. Tributyltins are also used in marine anti-fouling paint. Triphenyltins are used as active components of antifungal paints and agricultural fungicides. Other triorganotins are used as miticides and acaricides.
Diorganotins have no antifungal activity, low toxicity, and low antibacterial activity, except for diphenyltins. They are used in polymer manufacturing, as PVC heat stabilizers, catalysts, in the manufacturing of polyurethane and silicone curing.
Monoorganotins have no biocidal activity and their toxicity to mammals is very low. Methyltin, butyltin, octyltin and monoestertins are used as PVC heat stabilizers.
Important compounds
Tetrabutyltin starting material for the di- and tributyl compounds
Dialkyl- and monoalkyltin octylthiogylates used as heat stabilizers for polyvinyl chloride
Polystannanes are polymeric stannanes of the type (SnR2)n
Hypercoordinated stannanes
Unlike their carbon analogues, tin compounds can also be coordinated to five and even six atoms instead of the regular four. These hypercoordinated compounds usually have electronegative substituents for stabilization. Lithium pentaorganostannates were first detected and characterized in solution in 1986,[4] and in 2007 a crystal structure of room-temperature stable (in argon) all-carbon pentaorganostannane was reported [5] as the lithium salt with this structure:
^Synthetic aspects of tetraorganotins and organotin(IV) halides Sander H.L. Thoonen a, Berth-Jan Deelman b, Gerard van Koten Journal of Organometallic Chemistry 689 (2004) 2145–2157 article
^Tributyl-[(Z)-5-phenyl-2-penten-2-yl]stannane Martin J. Stoermer, John T. Pinhey Molecules 1998, 3, M67 articleopen access publication
^Lithium-Metalloid Exchange Reactions. Observation of Lithium Pentaalkyl/aryl Tin Ate Complexes, H. J. Reich and N. H. Phillips, J. Am. Chem. Soc. 1986, 108, 2102 doi:10.1021/ja00268a067.
^Synthesis and Structure of Pentaorganostannate Having Five Carbon Substituents Masaichi Saito, Sanae Imaizumi, Tomoyuki Tajima, Kazuya Ishimura, and Shigeru Nagase J. Am. Chem. Soc. 2007, 129, 10974-10975 doi:10.1021/ja072478+
