Organothallium halides

Molecular weight determinations of diorganothalium(III) halides in solution indicate dimeric association, but only a relatively small number of such compounds have been subjected to X-ray crystal structure determinations. 

Bis(trimethylsilylmethyl)thal]ium(III) chloride, (Me3SiCH2)2TlCl, is dimeric, 41, with non-equivalent thallium-chlorine bridges and four-coordinate thallium [149]. 

Bis(/ -tetrafluorophenyl)thallium(III) bromide, (4-HC6F4)2TlBr, forms supramolecular arrays, 42, in the solid state, with unsymmetrical bromide bridging [ 150] it is believed that similar structures are likely for R2TlBr with R = C6F5 and 

2-HC6F4, on the basis of similar vibrational spectra, and also for (C6Fs)2TlCl, on the basis of isomorphism with the eorrespondihg bromide. In benzene solution the polymer breaks down to dimeric species. 

The same elfect is produced by donors forming diorganothallium(III) halide adducts, R2TIX-L, with L = oxygen or nitrogen donors (OPPh3, OAsPha, pyridine, etc.), which are dimeric, e.g. 43, in solution [151], 

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This is the most common and widely applicable route to R3TI. If the organothallium halide and the organolithium contain different organo groups, it is also a means of producing mixed RjTlR. ... 

Thallium(I) halides can be converted into organothallium compounds by treatment with a highly reactive reagent. Thus, MesTl is formed from Til and methyllithium in the presence of methyl iodide, and this reaction is believed to go via initial formation of MeTl followed by oxidative addition of Mel, and reaction with LiMe . 

In a similar vein, organothallium bromides can be prepared by the action of an alkylmagnesium halide reagent on either TlBrs or TlBr. ... 

Reaction of TI metal with organic halides is not favored, and only rarely is it possible to get organothalliums this way. 

Organometallic compounds such as organolithium compounds, Grignard reagents, organotin compounds and organothallium compounds react with platinum halides to afford organoplatinum compounds [11,13,19-27]. For example, reactions are shown in eqs. (21.6)-(21.13). The order of the stability of the many compounds obtained by these reaction methods are as follows ... 

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