Coordinate Bond Energies and Inner Orbital Splitting in Some Tervalent Transition Metal Acetylacetonates

Abstract

The heats of combustion of the tris acetylacetonate complexes of the transition metal ions from scandium(III) through cobalt(III) have been measured in an oxygen bomb calorimeter. The heats of sublimation of these complexes were determined using a static vapor pressure method. Using these data in a suitable thermochemical cycle, the bond energies for the heterolytic cleavage of the metal to ligand bonds were calculated. These heterolytic bond energies vary with the atomic number of the central metal ion in the fashion predicted by crystal field theory. From a knowledge of the spin states of the central ions it is possible to estimate 10Dq for some of these complexes from thermochemical data alone. These thermochemical 10Dq values are in fair agreement with those obtained by spectroscopic methods. © 1964, American Chemical Society. All rights reserved.