Thallium, elemental reactions with

Thallium burns in fluorine with incandescence. Reactions with other halogens form halides. Thallium combines with several elements forming binary compounds. 

Salt elimination between a transition metal anion and a Group 13 halide is the most extensively exploited route into the formation of transition metal-Group 13 bonds in which the Group 13 element is in the -1-3 oxidation state. Most initial work focused on indium and thallium species and their reactions with mono-anionic carbonylmetaUates. Early examples indude [CpMo(CO)3]3Tl formed via the reaction of TljSO with 3 equiv. of Na[CpMo(CO)3] [202-204]. 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Clusters of the elements aluminum to thallium containing only one or two carbon atoms and strong direct element-element interactions, similar to boron rich car-baboranes, have not yet been synthesized, and also the corresponding silicon derivatives are relatively rare. To the best of our knowledge only one aluminum-silicon and one gallium-silicon cluster (1 and 2) has been reported in the literature. The reaction of metastable aluminum(I) chloride with decamethylsilicocene or with a mixture of SiCl4 and (AlCp )4, respectively, afforded black crystals of... 

The lack of homopolyatomic anions for elements to the left of group IV In Table I is noteworthy. Zlntl reported no success with reactions of alkali metal alloys of the copper and zinc family elements and of thallium with liquid ammonia, and the generally stabilizing effect of crypt has not been evident In our own Investigations of alloys of mercury and thallium. On the other hand. It is possible to Isolate a white crypt-potassium gold compound from ammonia solutions at low temperatures which decomposes to elemental gold (+ ) above about -10°C (30). 

Coordination compounds containing thallium(I) and heavier group 15 elements are rare. Synthesis of a tris(phosphino)borate thallium adduct has been reported. The reaction between [PhB(CH2PPh2)3]Li(TMEDA) and TlPFe affords [PhB(CH2PPh2)3]Tl (140) as a yellow powder. The P NMR spectrum shows two doublets with /xi p of 5,214Hz and 5,168 Hz, as a result of... 

However, in regard to the reactions of tungsten with metallic elements, the situation is quite different. A large number of metals exist which fail to react with tungsten, like the alkali metals, the alkaline earth metals with the exception of beryllium, the rare earth metals with the exception of cerium, and especially the elements scandium, yttrium, lanfiianiun, copper, silver, gold, zinc, cadmium, mercury, indium, thallium, tin, lead, antimony, bismuth, and polonium. 

A similar electrophilic activation of the vinylallene to 2-cyclopentenone cyclization is possible using either mercury(II) acetate or thallium acetate. Solvometallation of allenes is a well studied pro-cess following expected Markovnikov attack at the central carbon by the metal salt. The yield of cyclopentenones was generally higher with acetoxymercuration (49-79%) compared to acetoxythallation (25-68%). Compounds of similar substitution pattern as were investigated with epoxidation (Scheme 31) were prepared. Mechanistically the reaction is remarkable for the facility of solvodemercuration (Scheme 33). Intermediates such as (69) or (70) lose elemental mercury spontaneously in the acetic acid medium to give the 2-cyclopentenones. 

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