Synthesis and Characterisation of 1,4-Dithiolates of Tin

The chemistry, properties and applications of dithiolatotin complexes are reviewed. A literature search revealed that studies on compounds of this class were mainly confined to 1,2- and 1,3-dithiolate derivatives and it was therefore decided that 1,4-dithiolate systems would be investigated.
A series of tin and organotin derivatives of butane-1,4-dithiol, 4,5 dimethyl ∝,∝’o-xylylene dithiol and biphenyl-2,2’-dithiol has been prepared. Molecular weight determinations and mass spectrometric investigations indicate that these compounds are monomeric in solution and in the vapour state, though the physical properties of the butane-1,4-dithiolates would suggest that they are polymeric. The compounds were characterised by their proton Magnetic resonance, infra-red and mass spectra and fragmentation patterns in the latter are discussed.
The bis(monoalkyltin) tris(dithiolates) have two possible isomeric forms and definite structures for these compounds could not be assigned. It is tentatively suggested from spectroscopic evidence that these isomers are inter-convertible.
The Lewis acidity of these dithiolates towards a variety of oxygen and nitrogen donors was investigated though adducts could only be isolated for the bis(dithiolato)tin complexes.The structures of these adducts were assigned from their infra-red spectra.
Some reactions of the tin dithiolates were also investigated. The bis(dithiolato) tin complexes readily undergo ligand exchange with toluene-3,4-dithiol to give bis(toluene-3,4—dithiolato)tin. Reactions with a variety of inorganic and organic halides have also been demonstrated.
The dialkyltin dithiolates were examined as PVC stabilizers and the biocidal properties of the trialkyltin derivatives were also studied.