Nuclear magnetic resonance studies of ligand-exchange processes. II. Kinetics of configurational rearrangement for some mixed β-diketonate complexes of gallium(III)

Thomas J. PinnaVaia, John M. Sebeson, David A. Case

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Abstract

Nmr studies of Ga(acac)2(hfac) in dichloromethane and of Ga(acac)2(bzbz) in benzene, where acac = acetylacetonate, hfac = hexafluoroacetylacetonate, and bzbz = dibenzoylmethanate, have shown that the molecules undergo intramolecular configurational rearrangement processes which result in exchange of nonequivalent terminal methyl groups on the acac ligands. First-order rate constants for the rearrangement processes have been determined by line-broadening techniques. The rate of methyl group exchange at 25° for Ga(acac)2(hfac) is ca. 104 times larger than the rate for Ga(acac)2(bzbz). Activation energies and activation entropies were found to be, respectively: 14.5 ± 1.1 kcal/mol and 1.7 ± 4.4 eu for Ga(acac)2(hfac); 20.6 ± 2.7 kcal/mol and 3.5 ± 8.0 eu for Ga(acac)2(bzbz). The activation energies are discussed briefly and are compared with available parameters for terminal group exchange in other group IIIb metal γ-diketonates.

Original languageEnglish (US)
Pages (from-to)644-648
Number of pages5
JournalInorganic Chemistry
Volume8
Issue number3
DOIs
Publication statusPublished - Mar 1 1969
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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