Thallium III

1 Thallium(III)(CF3)3T1.2L (L = DMF,DMSO,py) have been prepared from TIX3 (X = Cl,OAc,O2CCF3) and (CF3)2Cd in aprotic, coordinating solvents, as described earlier for the gallium and indium analogues (Section 1.1). With excess (CF3)2Cd, nmr 

3 THALLIUM, T1 (A, 204-34) - THALLIUM(III) The general physical and chemical properties of thallium were discussed in Section VII.2. 

Reactions of thallium(III) ions To study these reactions use a 0 2m solution of thallium(III) chloride, T1C13. 

Sodium hydroxide or ammonia solution brown precipitate of thallium(III) hydroxide, insoluble in excess of the reagent (difference from thallium(I) salts, which give no precipitate), but readily soluble in hydrochloric acid. 

Hydrochloric acid no precipitate (difference from thallium(I) salts). 

Of special interest, though not strictly an organothallium compound, is the formally Tl(II) species, [(Me3Sn)3Si]2Tl-T1[Si(SnM63)3]. This blood red compound, prepared from 

M Wills, in Specialist Periodical Reports General and Synthetic Methods , 1994, 16, 355. 

Current Topics in the Chemistry of Boron, Specialist Publication, Royal Society of Chemistry, 1994. 

F Wiitkar, J-F Halet, Y-T Saillard, P Rosl and J Bauer, Inorg. Chem., 1994, 33, 1297. 

Y Sugihara, R Miyatake, K Takakura and S Yano, J. Chem. Soc. Chem. Commun., 1994, 1925. 

1 Thallium fill). - The electrophilic thallation of aromatic groups has led to new organothallium(III) species. 

Me2Tl(N03) reacts with KS2CPR2 to give the phosphino-dithioformates, Me2TlS2CPR2. The example with R = Ph crystallises as a weak THF adduct [Tl-0 280(3)pm], which has an octahedral trans-Me2TlS30 stereochemistry. The three sulphur 

In an investigation of the oxidation of thiols, RSH, the kinetics of reactions of 2-thiopyrimidine and 2-thiouracil with [IrCy and [IrBreJ have been measured. 

The rates are first order with respect to each reactant, with TU reacting about an order of magnitude more slowly than TP. The significant increase in rate at pH 2-5 is attributed to dissociation of the thiol. Under these conditions, two reactions occur  

There is still considerable interest in the mode of oxidation of organic substrates by this reagent. Using a scanning spectrometer, the series of rapid color changes observed in the reaction with phenothiazine have been monitored.With cerium(IV) in excess, a transient at 419 nm was observed which disappeared slowly, whereas with substrate in excess, several absorptions are identified with the formation of a dark green solution considered tentatively as a binuclear cation. The intermediates have been identified as the radical cation and the phenothiazinium cation [equation (35)]. The first reaction is too fast for 

Metal-complexed ligand radicals are formed in the oxidation of iron(II) diimine complexes with cerium(IV) in sulfate media. The reaction with /r/5-[2-pyridinal-a-methyl(methylimine)]iron(n) ([Fe(pmm)3], studied at lower acid concentrations ( 4 M H2SO4) is a complex process involving formation of Fe(II)- and Fe(III)-ligand oxidized species, a total of 10-11 mol of oxidant being required for reaction with each iron(II) complex. The [Fe(pmm)3] species undergoes intramolecular reductions to Fe(II) and a radical which may be further 

The nature of the mechanism of side-chain oxidation of alkyl aromatic compounds by one-electron reagents has been discussed.The reaction sequence  

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Thallium III) sulphate, Tl2(S04)3,7H20. Probably formed TI2O3 in cone. H2SO4. Very readily hydrolysed by water. 

Stereoselective cis-dihydroxylation of the more hindered side of cycloalkenes is achieved with silver(I) or copper(II) acetates and iodine in wet acetic acid (Woodward gly-colization J.B. Siddall, 1966 L. Mangoni, 1973 R. Criegee, 1979) or with thallium(III) acetate via organothallium intermediates (E. Glotter, 1976). In these reactions the intermediate dioxolenium cation is supposed to be opened hydrolytically, not by Sn2 reaction. 

Thallium(III) acetate reacts with alkenes to give 1,2-diol derivatives (see p. 128) while thallium(III) nitrate leads mostly to rearranged carbonyl compounds via organothallium compounds (E.C. Taylor, 1970, 1976 R.J. Ouelette, 1973 W. Rotermund, 1975 R. Criegee, 1979). Very useful reactions in complex syntheses have been those with olefins and ketones (see p. 136) containing conjugated aromatic substituents, e.g. porphyrins (G. W. Kenner, 1973 K.M. Smith, 1975). 

Ketones are rearranged oxidatively by reaction of the corresponding enols with thallium(III), e.g. to yield pyrroleacetic acids from acetyl pyrroles (G.W. Kenner, 1973 B W. Rotermund, 1975). 

Oxidation of 4H-pyran-4-thiones with thallium(III) trifluoroacetate was used in the one pot synthesis of l,6-dioxa-6n-thiapentalenes, a hypervalent heterocyclic system [57] (equation 27)... 

Thalh-. thallic. thallium(III). -chlorat, n. tballic chlorate. thalliuin(III) chlorate, chlo-rid, n. thallic chloride. thallium(III) chloride, -ion, n thallic ion. thallium(III) ion. -oxyd,... 

The Teijin oxychlorination, on the other hand, is considered a modern version of the obsolete chlorohydrin process for the production of ethylene oxide. In this process, ethylene chlorohydrin is obtained by the catalytic reaction of ethylene with hydrochloric acid in presence of thallium(III) chloride catalyst ... 

Determination of thallium as chromate Discussion. The thallium must be present in the thallium(I) state. If present as a thallium(III) salt, reduction must be effected (before precipitation) with sulphur dioxide the excess of sulphur dioxide is boiled off. 

Trithiadiazepine 4 is readily thalliated by thallium(III) trifluoroacetate the product 19 reacts in situ with potassium iodide, copper(I) cyanide, and methanol/carbon monoxide300 to give 20a-c, respectively.33 ... 

Thallium phthalocyanine (PcT12) can be obtained by heating phthalonitrile with an inter-metallic alloy of indium and thallium in an evacuated glass ampule.145 The structure of this compound is unique among metal phthalocyanines as the two thallium cations occupy two opposite corners of an octahedron, which is formed by the thallium cations and the four iso-indolinc nitrogen atoms facing the center of the macrocycle.147 Another unusual type of phthalocyanine can be prepared by heating phthalonitrile with thallium metal.148 It was identified as a bicyclic thallium(III) phthalocyanine (Pc3/2T1).14S... 

Both the submitters and the checkers used thallium(III) tri-fluoroacetate prepared from thallium(III) oxide and trifluoroacetic acid.3 Although this material may be purchased from Aldrich Chemical Company, Inc. and Eastman Organic Chemicals, the submitters recommend that the reagent be freshly prepared prior to use. 

The reaction mixture first turns muddy brown, due to the hydrolysis of thallium(III) nitrate to thallium(III) hydroxide and thallium(III) oxide, and then yellow with the separation of colorless thallium(I) nitrate. 

The reduction of thallium(III) to thallium(I) may be followed with potassium iodide-starch paper. A drop of solution is placed on the... 

The exhibition of variable valency is indeed a characteristic of transition metals. Main group metal ions such as those of groups 1 or 2 exhibit a single valence state. Other main group metals may show a number of valencies (usually two) which are related by a change in oxidation state of two units. This is typified by the occurrence of lead(iv) and lead(ii) or thallium(iii) and thallium(i). However, all the transition metals exhibit a range of valencies that is generally not limited in this manner. 

Mercuration of aromatic compounds can be accomplished with mercuric salts, most often Hg(OAc)2 ° to give ArHgOAc. This is ordinary electrophilic aromatic substitution and takes place by the arenium ion mechanism (p. 675). ° Aromatic compounds can also be converted to arylthallium bis(trifluoroacetates), ArTl(OOCCF3)2, by treatment with thallium(III) trifluoroacetate in trifluoroace-tic acid. ° These arylthallium compounds can be converted to phenols, aryl iodides or fluorides (12-28), aryl cyanides (12-31), aryl nitro compounds, or aryl esters (12-30). The mechanism of thallation appears to be complex, with electrophilic and electron-transfer mechanisms both taking place. 

Alkenes can also be oxidized with metallic acetates such as lead tetraacetate or thallium(III) acetate " to give bis-acetates of glycols. Oxidizing agents such as benzoquinone, Mn02, or 02, along with palladium acetate, have been used to convert conjugated dienes to l,4-diacetoxy-2-alkenes (1,4 addition). ... 

Primary (R = H) and secondary aromatic amines react with alkenes in the presence of thallium(III) acetate to give vie- diamines in good yields. " The reaction is not successful for primary aliphatic amines. In another procedure, alkenes can be diaminated by treatment with the osmium compounds R2NOSO2 and R3NOSO (R = t-Bu)," analogous to the osmium compound mentioned at 15-51. The palladium-promoted method of 15-51 has also been extended to diamination. " Alkenes can also be diaminated indirectly by treatment of the aminomercurial compound mentioned in 15-51 with a primary or secondary aromatic amine. 

The mechanism of oxidation probably involves in most cases the initial formation of a glycol (15-35) or cyclic ester,and then further oxidation as in 19-7. In line with the electrophilic attack on the alkene, triple-bonds are more resistant to oxidation than double bonds. Terminal triple-bond compounds can be cleaved to carboxylic acids (RC=CHRCOOH) with thallium(III) nitrate or with [bis(trifluoroacetoxy)iodo]pentafluorobenzene, that is, C6F5l(OCOCF3)2, among other reagents. 

In a modified version of a previously published procedure <83JOC3214>, the thallium induced transposition of 3-acetyl-1-tosylpyrrole to the corresponding 2-(3-pyrrolyl)acetic acid has been reported employing thallium(III) nitrate supported on acidic montmorillonite K-10 <96SC1289>. In this sequence, Af-tosylpyrrole (39) undergoes regioselective C-3 acylation to afford 40 which is rearranged with T1(III)/K-10 in methanol to yield the ester 41. 

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