Scandium preparation

The first allyl derivative of a rare earth was the complex dicyclopentadienyl allyl scandium, prepared by Coutts and Wailes (1970) from dicyclopentadienyl scandium chloride and allyl magnesium chloride in benzene-tetrahydrofuran. The orange compound shows an NMR spectrum with a singlet for the cyclopentadienyl protons at 5.90 ppm, and a quintet at 7.29 and a doublet at 3.05 ppm for the fluxional allyl group. The fluxional allyl group is also implicated by the IR band at 1475 cm for a delocalized C—C stretching vibration. 

The element was discovered by Nilson in 1878 in the minerals euxenite and gadolinite, which had not yet been found anywhere except in Scandinavia. By processing 10 kg of euxenite and other residues of rare-earth minerals, Nilson was able to prepare about 2g of highly pure scandium oxide. Later scientists pointed out that Nilson s scandium was idenhcal with Mendeleev s ekaboron. 

Calcium metal is an excellent reducing agent for production of the less common metals because of the large free energy of formation of its oxides and hahdes. The following metals have been prepared by the reduction of their oxides or fluorides with calcium hafnium (22), plutonium (23), scandium (24), thorium (25), tungsten (26), uranium (27,28), vanadium (29), yttrium (30), zirconium (22,31), and most of the rare-earth metals (32). 

Scandium phthalocyanine (PcScCl) can be prepared by refluxing scandium(III) chloride and phthalonitrile in 1-chloronaphthalene. It was recrystallized from quinoline.143... 

Lanthanide, yttrium and scandium trihalides preparation of anhydrous materials and solution thermochemistry. J. Burgess and J. Kijowski, Adv. Inorg. Chem. Radiochem., 1981, 24, 57-114, (320). 

DAS has rivb° 1.6156 and d25° 1.3992 the nuclear magnetic resonance spectrum has a singlet at 8.83 r and an A2B2 pattern at 2.62 r. Although DAS is very oxygen-sensitive, it is readily stored in sample bottles with serum caps. Complexes of many metals have been prepared exceptions include scandium, yttrium, lanthanum, and zinc. 

The Skraup cyclization is another reaction principle that provides rapid access to the quinoline moiety. Theoclitou and Robinson have published the preparation of a 44-member library based on the 2,2,4-trisubstituted 1,2-dihydroquinoline scaffold by the Lewis acid-catalyzed cyclization of substituted anilines or aminoheterocyc-les with appropriate ketones (Scheme 6.237) [420], The best results were obtained using 10 mol% of scandium(III) triflate as a catalyst in acetonitrile as solvent at... 

LANTHANIDE, YTTRIUM, AND SCANDIUM TRIHALIDES PREPARATION OF ANHYDROUS MATERIALS AND SOLUTION THERMOCHEMISTRY... 

The preparations of rare-earth trihalides can be found in various books (2-8) and in Taylor s review (2 ). This review, however, did not include the preparation of scandium and yttrium trihalides, and only covered the preparation of the trifluorides very briefly. We have reviewed the preparation of all the trihalides (including scandium and yttrium) from Taylor s review up to June 1979 and have also included some methods and references missed by Taylor. Although we have mentioned all the methods available for the preparation of the trihalides, emphasis has been placed on the methods used since Taylor s review, and these have been referenced fully, whereas for the other methods, Taylor s review is recommended as a source of references. 

Undoubtedly, the best method for the production of pure anhydrous lanthanide trihalides involves direct reaction of the elements. However, suitable reaction vessels, of molybdenum, tungsten, or tantalum, have to be employed silica containers result in oxohalides (27). Trichlorides have been produced by reacting metal with chlorine (28), methyl chloride (28), or hydrogen chloride (28-31). Of the tribromides, only that of scandium has been prepared by direct reaction with bromine (32). The triiodides have been prepared by reacting the metal with iodine (27, 29, 31, 33-41) or with ammonium iodide (42). 

Purification of Scandium and Preparation of MCa. U.S. Atomic Energy Commiss. Rep., AECD. 2616 (July 29th, 1947). 

Scandium oxide TSc " + 30 —> Sc O. Scandium oxide is used to prepare scan-... 

The thenoyltrifluoroacetate (tta) complex, [Sc tta)3 OP(OBu)3)], has been prepared. Scandium also afforded, with l,2-dihydroxybenzene-3,5-disodium sulphonate (Tiron), a monoprotonated chelate below pH 2.5, but above pH 6.0 hydrolysis afforded a monohydroxo-Sc-Tiron complex. Ligand-exchange equilibria for the piperidium salts of [Y(ffac)4] and [Y(tfac)4] have been studied by n.m.r. spectroscopy. The fully fluorinated ligands appear to exchange faster than the partially fluorinated species, and the mixed compounds, [Y(Hffac) (tfac)4 ] , n = 0 — 4, were obtained. 

Recently, rare-earth metal complexes have attracted considerable attention as initiators for the preparation of PLA via ROP of lactides, and promising results were reported in most cases [94—100]. Group 3 members (e.g. scandium, yttrium) and lanthanides such as lutetium, ytterbium, and samarium have been frequently used to develop catalysts for the ROP of lactide. The principal objectives of applying rare-earth complexes as initiators for the preparation of PLAs were to investigate (1) how the spectator ligands would affect the polymerization dynamics (i.e., reaction kinetics, polymer composition, etc.), and (2) the relative catalytic efficiency of lanthanide(II) and (III) towards ROPs. 

Scandium also may be produced by electrolysis of scadium chloride in a molten salt bath. The first preparation of the metal was carried out by this... 

Lars Fredrik Nilson, 1840-1899. Professor of analytical chemistry at the University of Upsala and at the Agricultural Academy at Stockholm. Discoverer of scandium His researches on soils and fertilizers transformed the barren plains of his native island into an agricultural region With Otto Pettersson he investigated the rare earths and prepared metallic titanium. 

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