Halo 2,4-pentanedionato zirconium IV Complexes

Submitted by THOMAS J. PINNA VAIA t and ROBERT C. FAY Checked by JAMES MOYERf and EDWIN M. LARSENt 

Iodotris(2,4-pentanedionato) zirconium (IV) has been prepared by reaction of zirconium (IV) iodide with 2,4-pentanedione in isopropyl ether and by the ligand-exchange reaction between zirconium (IV) iodide and tetrakis(2,4-pentane-dionato)zirconium(IV) in tetrahydrofuran.7 The latter approach, which yields a higher-purity product, is described here. 

The anhydrous zirconium (IV) halidesf are freshly sublimed in vacuo at 250-300°C. 2,4-pentanedione (Matheson Coleman and Bell b.p. 136-140°C.) is freshly distilled through a small fractionating column before use. The anhydrous tetrahalides and the products are readily hydrolyzed and must be handled in a dry-box or in a plastic bag filled with dry nitrogen. J All glassware is dried at 180°C. and is cooled, whenever possible, 

During all manipulations, it is important that nitrogen pressure be continuously applied to the filter stick except for the brief moments when it is necessary to reverse the direction of nitrogen flow. 

Recrystallizations are performed in a glass-stoppered Erlen-meyer flask fitted with a sidearm and stopcock (similar to B in Fig. 5). During recrystallizations, solutions are kept out of contact with moist air, while being heated, by passing dry nitrogen into the sidearm and over the surface of the solution. The recrystallized product is filtered, washed, and collected as described above except that the recrystallizing flask is substituted for the reaction flask in the filtration step. 

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Fig. S. Apparatus for the synthesis and purification of halo(2,4-pentanedionato)zirconium(IV) complexes.

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