Thallium iii Compounds

Thallium(iii) Compounds.—Kurosawa and Okawara have reviewed the literature on organothallium derivatives for 1973.  

Thallium(ir) ions are generated by flash photolysis of thalliumaii) solutions, and rate constants were measured for reactions (53—(55). 

Chao and R. D. Rieke, Synth. React. Inorg. Metal-Org. Chem., 1974, 4, 373. 

outer-sphere, one-electron reactions appear to have activation energies of ca. 25 kJ mol less than those for related two-electron processes. 

A photochemical reaction between Tl and Ru(bipy)3 has been studied. ions are produced as intermediates, and these can oxidize Rufbipy) and reduce Ru(bipy) .  

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The effect of structure of the alkyl group on the stability of monoalkyl-thallium(III) compounds can best be understood by reference to the different mechanisms by which these compounds undergo decomposition. A number of authors have attributed the instability of monoalkylthallium(III) compounds to facile C—T1 bond heterolysis and formation of carbonium ions [Eq. (25)] (52, 66, 79). This explanation is, however, somewhat suspect in cases where primary carbonium ions would be involved and either the two-step sequence shown in Eqs. (26), (27), or the fully synchronous 8 2 displacement shown in Eq. (28), is more compatible with the known facts. Examination of the oxythallation reactions that have been described reveals that Eq. (27) [or, for concerted reactions, Eq. (28)] can be elaborated, and that five major types of decomposition can be recognized for RTlXj compounds. These are outlined in Scheme 8, where Y, the nucleophile... 

Thallium(I) acetate, 24 630-632 Thallium compounds, in organic reactions, 24 635 Thallium formate, 24 630 Thallium halides, 24 632 Thallium ion, 24 629 Thallium nitrate, uses for, 24 636 Thallium salts, 24 630, 632 Thallium sulfate, uses for, 24 636 Thallium (III) compounds, in organic reactions, 24 635-636 Thallium(III) fluoride, 24 632 Thallium(III) ion, 24 630 Thallium(III) salts, 24 632 Thallium(III) trifluoroacetate, 24 635 Thallium (Tl), 24 627-641... 

Thallium (III) Compounds. Thallium (ITT) derivatives have been used extensively as oxidants in oiganic synthesis. In particular, thallic acetate and trifluoroacetate are extremely effective as electrophiles in oxythallation and thallation reactions. For example, ketones can be prepared from terminal acetylenes by means of Tl(OOCCH3)3 in acetic acid (oxythallation) (30) ... 

Thallium(III) compounds usually react to cause oxidation of gold(I), but in certain cases arylgold(I) species have been isolated [Eqs. (11) and (12)] (38, 39). Oxidative addition was prevented in the former due to the inability of X to form the necessary bridges in the intermediate species (J[Pg.45]

Mixed triarylgold(III) complexes have been obtained by oxidation (187) of [Au(CeF5)(tht)] with thallium(III) compounds [Eq. (78)], whereas the... 

In contrast to the behavior of comparable aluminum, gallium, and indium compounds, the hitherto known alkynyl thallium(III) compounds (170) of the type R2T1C=CR show no tendency to dimerize via n complexation. Molecular weight determinations performed in aniline show the monomeric character of these species, which behave as weak electrolytes due to partial dissociation into R2T1+ and C=CR" (170). 

Thallium(III) compounds dominate the known organo-metallic chemistry of thallium. The structural chemistry organothallium(III) compounds has been reviewed. ... 

The starting solution for studies of aqueous thallium(III) compounds can be prepared by dissolving commercial TI2O3 in a mineral acid. However, because of the insolubility of the oxide, this procedure may be tedious and normally works only for the preparation of dilute Tl(III)... 

One more class of thallium(III) compounds has been subjected to structural investigations, namely the compounds of the type TKpoly-dentate ligandlX, where the polydentate ligands were EDTA (ethylene-diaminetetraacetate), DTPA (diethylenetriaminepentaacetate), TPEN (tetrakis-(2-pyridylmethyl)-ethylenediamine), NTA (nitrilotriacetate), bipy (bipyridine), terpy (2,2" 6, 2 terpyridine), pent-en (N,N,N, N -tet-rakis-(2-aminoethyl)-ethylenediamine), andX = OH, H2O, CN", N03 (106, 109, 94). In these compounds, thallium(III) is usually hepta- or even octa-coordinated, in contrast to monodentate ligands, where the... 

There is also a lot of structural information for other thallium(III) compounds (e.g., organothallium compounds), which has been obtained from the spin-spin coupling pattern of their NMR spectra. However, no interatomic distances have been obtained in this way. 

Table 2 Triorgano thallium (III) compounds characterized by X-ray diffraction...

There appear to be no thallium(III) compounds with such ligands. 

The thermal decomposition of a series of polyfluorobenzoato-bis(polyfluoro-phenyl)thallium(iii) compounds in pyridine gave tris(polyfluorophenyl)thallium-(iii) compounds by elimination of CO2, reaction (35), (R = CgFs, p-MeOC F4, p-HC6F4, or W-HC8F4). The ease of decarboxylation followed the sequence... 

Although in this chapter we shall be restricting coverage to reactions of transition-metal complexes, the phenomenon of oxidative addition is not confined to this type of compound. Such reactions are also well established for non-transition metals—a recently reported example concerns the oxidative addition of methyl bromide to indium(i) bromide to give InBr2Me— and for non-metals, as in the reaction of phosphorus trichloride with chlorine, to cite a very familiar example. Likewise, reductive eliminations are known and studied outside the area of transition-metal complexes. One example has been mentioned in Chapter 1 of Part II of this volume, namely the elimination of alkyl halides from the thallium(iii) compounds TlRXa. ... 

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