MECHANISM OF INTRAMOLECULAR REARRANGEMENTS OF (ACETYLACETONATO)BIS(4,4,4-TRIFLUORO-1-PHENYL-1,3-BUTANEDIONATO)RUTHENIUM(III)

Time variations of mole fractions of the three isomers of [Ru(acac)(tfpb)2] (acac− = acetylacetonate ion, tfpb− = 4,4,4-trifluoro-l-phenyl-1,3-butanedionate ion) were measured in N,N-dimethylformamide at 90, 110, and 130 °C. They were analyzed by a numerical method for the reversible, first-order, triangular network reactions previously developed. The results show that the direct conversion between the fc,de-(tfpb)2 isomer and the cf,ed-(tfpb)2 isomer was forbidden, which indicates that the bond-rupture mechanism through trigonal-bipyramidal intermediates with a single rearrangement is more plausible than the twist mechanism. Analysis of the rate constants according to the former mechanism suggests that the rate of rupture of a particular Ru-O bond is mainly, but not completely, determined by the kind of the nearest β-substituents. © 1990, American Chemical Society. All rights reserved.