3,5-Heptanedione, 2,2,6,6-tetramethyl-, rare earth chelates

Tetramethyl-3,5-heptanedionates. Ten millimoles of each of the rare-earth chelates were prepared by the method of Eisentraut and Sievers (9). H(thd) from the Pierce Chemical Co., Rockford, 111. was used without further purification. Five mmoles of the 99.9% rare earth oxide (Michigan Chemical Corp., Saint Louis, Mich.) were dissolved in the stoichiometric amount of 6N HNO3, and appropriate amounts of H2O and 95% EtOH were added to make 50 ml. of 50% ethanol solution containing the required amount of rare-earth nitrate. The dried product was sublimed at 180°C. in vacuo, recrystallized from n-hexane in vacuo, and vacuum dried. Although no elemental analyses were made on the final product, the melting points were taken on a Fisher-Jones melting point apparatus, and the results obtained were compared with the literature values shown in Table XII. The products were stored in evacuated desiccators. 

A number of volatile rare earth chelates containing the ligands, l,l,l,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedi-one, [H(fod)], and 2,2,6,6-tetramethyl-3,5-heptanedione, [H(thd)] have been synthesized and investigated. The fod complexes are more volatile than other known compounds of the lanthanide elements. The fod complex of Sc(III) and the lanthanide thd compounds are anhydrous. The fod chelates of Y(III) and the lanthanides are isolated as hydrates but can easily be dehydrated in vacuo over P Oio. Gas chromatographic and thermo gravimetric data reveal that the volatilities of the complexes increase as the ionic radii of the metal ions become smaller. 

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See also in sourсe #XX -- [ , , , , ]

See also in sourсe #XX -- [ ]

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