Thallium chloride complexes

Thallium lII) chloride, TlCl3,4H20. Formed by passing CI2 through a suspension of TlCl in water. Hygroscopic, loses CI2 at lOO C. The [TlCl2l ion is stable chloro complexes up to [TlClfi] are formed. 

The mixture is stirred for 45 min at room temperature, and subsequently for 2 h at 80 °C. The precipitated thallium(I) chloride is filtered and the filtrate is evaporated to dryness. The white residue is extracted with 30 mL of diethyl ether, concentrated to 8 mL and addition of 30 mL of hexane causes precipitation of the white title complex. Yield 1.29 g (82%). 

Alkali metal 1-methyl- and 1-phenyl-borinates are also available from bis(borinato)cobalt complexes (see below) on treatment with sodium or potassium cyanide in an aprotic solvent like acetonitrile. Cobalt cyanide precipitates and the alkali borinate remains in solution. After addition of thallium(I) chloride to some complexes, thallium 1-methyl- or 1-phenyl-borinate could be isolated as pale yellow solids, the only main group borinates isolated hitherto. They are insoluble in most organic solvents but readily soluble in pyridine and DMSO. The solids are stable on treatment with water and aqueous potassium hydride, but are decomposed by acids <78JOM(153)265). 

Addition of CI2 to organogold(I) complexes has also been achieved by reaction with thallium(III) chloride [Eq. (47)] (13, 36, 180-182), the cis isomers being produced by this method. Reactions with X2 gave the trans isomers (179). 

Borabenzene anions can serve as n ligands to a thallium(I) center, as demonstrated by the work of Herberich et al. (183). Reaction of alkali metal borinates with thallium(I) chloride yields the pale yellow, sublimable complexes LVIa,b [Eq. (16)] (see Fig. 11), which are only sparingly soluble in nonpolar aprotic solvents but easily soluble in pyridine and dimethylsulfoxide (183). 

Thallium(III) chloride reacts with 1,4,7-triazacyclononane and l,4,7-trimethyl-l,4,7-triazacyclo-nonane to produce 1 1 complexes. It is also possible to prepare the InBr3 adduct of 1,4,7-triazacyclononane. As noted earlier, the hydrolysis of this compound leads to the first well-authenticated In(III) /.t-hydroxo complex. 

Thallium(I) chloride, bromide and iodide are made by precipitation from a thallium(I) sulphate solution. TlCl resembles AgCl in solubility, structure and sensitivity to light but is insoluble in ammonia the T1+ ion is evidently too large to form ammonia complexes. TIF is yellow and resembles AgF in colour, structure and solubility. 

Calculated and Experimental Stability Constants for Thallium(III) Chloride Complexes in Aqueous Solution at 25°C (in Molar Units)"... 

Far more surprising was the fact that the anation reactions constituted only a minor part of the chloride exchange in this chemical system. Instead, up to the Cl/Tl ratio 3, the dynamics is dominated by a direct ligand exchange between two thallium complexes. 

For the direct exchange between the thallium complexes, Eq. (9), the dissociatively activated reaction mechanism previously proposed for the thallium chloride system (169) could now be confirmed and... 

Relatively little work has been done on the redox reaction between thallium and halide/pseudohalide ions (75, 93, 97,110, 328-330). Let us consider the qualitative order of stability of thallium(III) in the form of TlXp " complexes, where X = Cl, Br, I, SCN, CN, Thallium(III) forms strong complexes with all these ligands on the other hand, it can oxidize the X ions to X2. It is well known that the thallium(III) chloride complexes are perfectly stable for an indefinite period of time. The corresponding bromide complexes are usually stable, but at low Br/Tl ratios Tl(III) can be reduced by Br the reduction is easily prevented by adding excess of bromine. The iodo and thiocyanato complexes are approximately equally unstable toward redox reaction Tl(III) is rapidly reduced by the anion.Finally, the cyano complexes... 

Blewitt JP (1946) Radiation losses in the induction electron accelerator. Phys Rev 69, 87-95 Blixt J, Glaser J, Mink J, Persson I, Persson P, Sandstroem M (1995) Structure of thallium(III) chloride, bromide, and cyanide complexes in aqueous solution. J Am Chem Soc 117 5089-5104 Blonski S, Garofalini SH (1993) Molecular dynamics simulation of -alumina and y-alumina surfaces. Surf Sci 295 263-274... 

An excess of ethylenedlamlnetetraacetlc acid (EDTA). causes lead to be soluble In chloride solutions (Cl) due to formation of the very stable EDTA-lead complex. Silver (l) and thallium (l) chlorides remain Insoluble and can be separated from lead. Mercury (I) also forms a soluble EDTA complex imder these conditions. The presence of citrate also keeps lead from precipitating from dilute chloride solutions. Mukherjl and Dey have used this to separate lead from silver (m4). In their procedure an excess of sodium citrate Is added to the mixture containing silver and lead nitrate. The Insoluble citrates of lead and silver which are at first precipitated redlssolve upon gentle heating as complex citrates. Upon addition of dilute hydrochloric acid silver chloride precipitates. Lead may be removed from the filtrate as lead chromate. 

In this communication we will describe a reaction calorimeter developed by GERDING et al (1) and also give an example of its use for the study of the composition of the thallium(III)chloride and bromide complexes. 

Thallium(III) exhibits coordination numbers higher than 4 in complex chlorides, prepared by addition of chloride salts to TICI3. In [H3N(CH2)5NH3][T1C15], a square-based pyramidal structure for the anion has been confirmed (Fig. 13.17a). In K3[TlCl6], the anion has the expected octahedral structure, and in CS3 [TI2CI9], the T1(III) centres in the anion are also octahedral (Fig. 13.17b). 

The structures and Raman spectra of thallium(III) chloride, bromide, and cyanide in aqueous solution were studied by Persson and co-workers [96]. Up to 14 different complexes were analyzed. These include the series [T1(H20) L ] " (L = ligand. Cl, Br, or CN) with X = 1-4 and n = 5, 4, or 2 and two chloro-complexes with x > 4, namely [TlCl5(H20)] and [TlCle]. Table 3 gives the stoichiometry and the point group (obviating the hydrogen bonds) of the different complexes as well as the Raman shift corresponding to the symmetric v(T —L) vibration. 

Thallium(I) chloride cm 4.54299 2 Benzene-krypton complex CjHj.Kr 0.136 0.002 58... 

Thallium(l) chloride and bromide do not form stable complexes with typical anions and do not undergo disproportionation thus electrodes using these salts are characterized by good performance and low temperature hysteresis [153, 154]. Upon galvanostatic polarization they exhibit slight hysteresis, however, lower than for calomel electrode. Electrode potentials are reversible with respect to temperature changes and the dependence of potential on temperature is described by third-degree polynomial functions [153, 154] ... 

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