Acetylacetonate complexes scandium

The acetylacetonates are stable in air and readily soluble in organic solvents. From this standpoint, they have the advantage over the alkyls and other alkoxides, which, with the exception of the iron alkoxides, are not as easily soluble. They can be readily synthesized in the laboratory. Many are used extensively as catalysts and are readily available. They are also used in CVD in the deposition of metals such as iridium, scandium and rhenium and of compounds, such as the yttrium-barium-copper oxide complexes, used as superconductors. 1 1 PI Commercially available acetyl-acetonates are shown in Table 4.2. 

Structural analysis of several octahedral Sc(III) complexes have recently been reported. The structure 44) of anhydrous scandium-tris-acetylacetonate, Sc(acac)3, consists of discrete Sc(CH3COCHCOCH3)3 entity, with slight deviation from Dz symmetry. The coordination polyhedron around Sc (III) is a distorted... 

Scandium can also be separated from rare-earth and other metals by extraction as a complex of HTTA [8,9], or salicylate [10]. Xylene [8], CHCI3 [9], and mesityl oxide [10] have also been used for extraction of Sc. Scandium has been extracted from ascorbic acid medium with Aliquat 336S [11], or with acetylacetone in the presence of 3,5-dichlorophenol [12]. Macrocyclic ethers have also been used for extraction of Sc [13]. 

The j8-diketones are excellent chelating ligands for the rare earth ions and typical examples of the types of complexes that are formed are presented in table 25.14. (The functioning of these complexes as lasers is discussed in ch. 35.) The complexes that might have been expected, R(jS-diketone)3, rarely form, except for scandium, because of the tendencies of these compounds to add one or more additional ligands, particularly water molecules. Attempts to dehydrate most of these hydrated species leads either to destruction of the complex or the formation of polymeric hydroxo species (Pope et al., 1961). If, however, the substituents on the j8-diketone are large, t-butyl groups as an example, then the anhydrous tris chelate can be prepared (eisentraut and Sievers, 1965). The anhydrous trisacetylacetonato complexes have been prepared, however, in the absence of any possible adduct formation by the reaction of acetylacetone directly with a rare earth hydride (Przystal et al., 1971). The anhydrous acetyl-... 

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