Thallium , reaction with iron complexes

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... 

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... 

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. 

Several other useful reviews of reactions involving metal ions have also been published. Redox reactions of chromium(m)-amine species have been described and a survey has been made of the solution chemistry together with reaction paths involved in the redox reactions of various plutonium species. Oxidation reactions of thallium(m) have also been described. Developments in the redox chemistry of peroxides have been reviewed, the nature of the reactions which involve iron(iii) in various complexed forms providing a fascinating example of the manner in which geometry and co-ordination to the metal centre greatly affect the reactivity of the system. Redox properties of cobalt chelates, with delocalized... 

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