Per- and Poly-fluorinated Aliphatic Derivatives of the Transition Elements

Per- and Poly-fluorinated Aliphatic Derivatives of the Transition Elements 

In addition to derivatives involving direct Rf—metal bonds, this chapter includes compounds in which a fluoroaliphatic moiety Rf is attached to a transition metal via another atom e.g. P, As, or S). In general, chelate complexes of fluorinated jS-diketones are not considered, since these have been dealt with in Chapter 3 (see p. 173). Per- and poly-fluorinated aromatic derivatives of the transition metals are discussed in Chapter 6 (p. 420). 

Most of the work with these metals has involved j8-diketonate chelate complexes, particular interest being shown in the use of new jS-diketonate complexes of europium(iii) and praeseodymium(iii) [e.g. tris-(l,l,l,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionato)europium(iii) and the chiral tris(perfluoroacylcamphorato) complexes (O ] as n.m.r. shift reagents (sec Chapter 3, pp. 162 and 176). 

Addition of scandium hydroxide to aqueous trifluoroacetic acid gives Sc(0H)(02C CF3)a,2H20 in high yield at 230—330 °C the anhydrous material decomposes according to the equation  

Tetrakis(hexafluoroisopropoxides) of titanium, zirconium, and hafnium have been prepared by the reaction of sodium hexafluoroisopropoxide in an excess of hexafluoroisopropyl alcohol with the anhydrous metal chloride, and the spectroscopic properties are reported. The authors note that, in their experience, application to the Group IV transition metals of the previously published method for metal hexafluoroisopropoxide synthesis gives poor yields of material containing metal, fluorinated alkoxides, and co-ordinated ammonia. Dehydration of the hydrated metal chloride with methyl orthoformate and addition of hexafluoroisopropyl alcohol, followed by passage of dry ammonia through the solution, gives satisfactory yields for yttrium, lanthanum, neodymium, and erbium. 

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