Thallium m Compounds

Thallium(m) Compounds.—The kinetics of the isotope exchange by electron transfer between Tl and as [Tl(bipy)2] + or [Tl(phen)3] + have been studied using labelled 204xi+. 8o 

The electrode potentials of thallium couples have been measured in fused LiCl-KCl eutectic at 450 °C. The standard molar electrode potential Tiiii I Tl is +0.155 V (with respect to the standard Pt reference electrode), while the Tl Tl° couple was calculated to have a standard potential of -0.385 V. 8i 

Least-squares analysis of the homogeneous pyrolysis of TIM, via the step  

Tris-(cyclopentadienyl)- and -(mdenyl)-thallium(iii) may be prepared thus  

The rate of the reaction between Tl and Sb in aqueous perchloric acid is measurable by conventional methods at 60 °C. Two transition states were suggested, [T10H,HSb02] + and [TlHSb02] +, reaction occurring mainly (85%) via the former. The rate law is tentatively  

Thallium(m) Compounds.—Potentiometric methods have been used to investigate the hydrolysis of Tl ions in H2O-DMSO and H20-acetone solutions. The ° T1 n.m.r. frequency in (substituted aryl)thallium(iii) bis(trifluoroacetate) compounds is very sensitive to the nature of the aryl substituent. A correlation exists between the frequency and the Hammett r-parameter for the substituent, and also the T1- H coupling constants.  

The dimethylthallium(iii) compounds Mc2TlX, where X = OCOMe , and (Me2Tl)2X, where X = malonate, succinate, maleate, fumarate, CO, or 8203 , may be prepared in high yields (greater than 80%) and in one step by anion exchange between Me2TlBr and the appropriate Tl compound.  

Me2TlNMe2 and Me2T10Et undergo insertion reactions into the Tl—N or Tl—O bond on reaction with RNCS, PhNCO, CS2, COS, CO2, SO2, or SO3. The 

Calculated and thermodynamic values of the cohesive energies of a- and j3-TlF are in good agreement, and consistent with their having ionic structures.  

and Raman spectra have been obtained for monomeric and dimeric Tl halides in Ar matrices TIF, T12F2, TlCl, and Tl2Cl2- Dimers have planar rhombic structures, not the linear configurations previously assigned. The present results agree with an electron-diffraction study on TI2F2, however.  

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Thallium(m) Compounds.—The electron-transfer reaction between Tl1 and Tlm in the presence of CeIV proceeds via Tl11 as an intermediate.577 In the absence of such one-electron oxidants, two electrons are transferred from the Tl1 to the Tl111 in a single step. 

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