Thallium-iron complexes

When FeCl2(TlTF)i 5 reacts with the sterically hindered thallium salt of ( BuTp,Bu), the complex tra s-FeCl2(Hpz/Bu)4 is formed, the only isolable product appearing to be the first example of a trans-dichloro pseudo-octahedral iron (II) complex bearing four neutral pyrazole ligands.189... 

Most recently, Cramer and Jenkins have developed a novel tetracarbene iron(ll) complex 8, which was readily prepared by the reaction of the macrocyclic tetraimidazolium 7 with iron(ll) iodide using lithium diisopropylamide followed by the addition of thallium hexafluorophosphate (Scheme 2.12) [18]. Employing this catalyst system, aziridination reactions of various types of substituted aliphatic alkenes including trisubstituted and tetrasubstituted ones with both electron-donating and electron-withdrawing aryl azides were achieved. One advantage of this methodology is... 

Tri-n-butyl phosphate, ( -C4H9)3P04. This solvent is useful for the extraction of metal thiocyanate complexes, of nitrates from nitric acid solution (e.g. cerium, thallium, and uranium), of chloride complexes, and of acetic acid from aqueous solution. In the analysis of steel, iron(III) may be removed as the soluble iron(III) thiocyanate . The solvent is non-volatile, non-flammable, and rapid in its action. 

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. 

In a similar way to the corresponding thallium salts 153, cobalt(n) complexes [PhB(CH2PPh2)3]CoI 156 <2001CC2152>, [PhBtCfTPTr lCoCl 157, and [PhB(CH2PiPr2)3]CoI 158 <2003IC5074> iron(n)... 

Alternatively, a-(dialkylsulfonium)alkyl iron complexes can be prepared from a-haloalkyl iron complexes by silver- or thallium-promoted nucleophilic substitution with thioethers [474],... 

The values of AH for the thallium (III) halide systems becomes less exothermic as complex formation proceeds. There are no steps with about the same value of AH , in marked contrast to e.g. Hg2+ and Pd2+. The trend of AH is in fact opposite to that found for several t)q)ical hard-hard interactions, e.g. iron (III) fluoride, lanthanum sulphate and yttrium acetate (Table 1). An even more striking feature of the thallium (III) halides is that AS°n is approximately constant for all steps. This is indeed different not only from ions such as In +, Cd2+ and Zn +, where reversals of the decreasing trend of AS°n occur for certain steps, but also from Hg2+ and Pd + where the higher steps have a much lower value of ASn than the earlier ones. 

Many 1,2,4-triazines form complexes with metal ions and can be used for their determination. Thus, 3- and/or 5-(2-pyridyl)-substituted 1,2,4-triazines (e.g. 820) can be used for the determination of iron (II), cobalt(II), nickel(II), zinc(II) and copper(I) ions, thallium and palladium ions can be analyzed by 6-phenyl- (821a) and 5,6-diphenyl-l,2,4-triazine-3-thione (821b), while osmium can be determined by 3-thioxo-l,2,4-triazin-5-one (822), 3-thioxo-dihydro-l,2,4-triazin-5-one (823), 6-mercapto-l,2,4-triazine-3,5-dione (824a), 6-mercapto-5-thioxo-l,2,4-triazin-3-one (824b) and 3,5-dithioxo-l,2,4-triazine-6-carboxyl-ates (825) <78HC(33)189, p. 1004). 

Silver, lead, copper(l). and thallium(I) thiocyanates are insoluble and mercuiy(II), bismuth, and tm(II) thiocyanates slightly soluble. All of these, are soluble in excess of soluble (e.g., ammonium) thiocyanate, forming complexes. Iron(III) thiocyanate gives a blood-red solution, used in detecting either Fe(lll) or thiocyanate in solution, and is extracted from water by amyl alcohol. It is not formed in the presence of fluoride, phosphate and other strongly complexing ions,... 

The most extensive series of compounds that fall within this section are the anionic iron carbonyl-thallium clusters recently described by Whitmire (30-30h). These are generally made by reactions between iron carbonylate anions and either T1(I) or Tl(III) salts. Thus treatment of K[HFe(CO)4] with a variety of thallium salts followed by addition of [Et4N]Cl or Br affords the hexanuclear complex [Et4N]2[ Fe(CO)4 2 //-TlFe(CO)4 2], 17... 

State. When both iron environments contain only iron(II), the resulting salt is not colored (Prussian White). The oxidation state localization in PB has been studied extensively. Structures, electrochemical behavior (electrodes batteries), and uses in medicine (treatment of Cs and of thallium poisoning) of Prussian Blue are mentioned in a review of cyanide complexes. In cobalt-iron Prussian Blue analogues, NaxCo3,Fe(CN)6-zH20 electronic and spin states are controlled by temperature and the ligand field strength around the Co + ions, which in turn is determined by the Co Fe ratio. ... 

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