The influence of β-diketones on the induction times for hydrolysis of zirconium(IV) alkoxides

Autor:	Bruce O. West, John R. Bartlett, Leone Spiccia, M J Percy, J.L. Woolfrey
Rok vydání:	1999
Předmět:	Steric effects Dibenzoylmethane Chemistry Ligand Induction period Acetylacetone Hexafluoroacetylacetone Inorganic chemistry General Chemistry Medicinal chemistry chemistry.chemical_compound Hydrolysis Alkoxide Materials Chemistry
Zdroj:	Journal of Materials Chemistry. 9:499-505
ISSN:	1364-5501 0959-9428
DOI:	10.1039/a806782a
Popis:	The influence of low ligand/Zr mole ratios (ρ=0-0.1) of acetylacetone on the hydrolysis of Zr(OPr n ) 4 has been examined by investigating its effect on the induction time (t i ) before precipitation commences in the system. A remarkable feature of the data is the large increase in the induction time (reduction in hydrolysis/condensation rate) caused by addition of acetylacetone. This occurs even though only a maximum of one in eighty Zr-OR bonds have reacted with ligand and are no longer available for hydrolysis or further condensation. The effects on t i of five other β-diketones having varying steric properties (trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone, dibenzoylmethane and dipivaloylmethane) are compared with that of acetylacetone, under similar concentration conditions, with ρ=0.1. Each shows a greater effect than acetylacetone, the largest change being caused by dibenzoylmethane which, under the conditions used, increases the induction time by a factor of 26 relative to acetylacetone. A mechanism rationalising the origin of the effect is discussed.
Databáze:	OpenAIRE
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