Uranium bond dissociation energies

Table 14.1 Fluorine-uranium bond dissociation energy for the reaction UF(, —> UFs + F. The table Illustrates the critical effect of including the closed shells 5d, 5p, and 5s in the valence space of the DFT calculation. Reprinted with permission from Batista et al. [39] Copyright 2004, American Institute of Physics.

Table II. Mean Bond Dissociation Energy Data for Some Early Transition Metal Complexesa and Estimated 5 Values for Thorium and Uranium.

It is reasonable to postulate that the main driving force for the reaction of (MeC5H4)3U(t-Bu) with hexafluorobenzene is thermodynamic. A weak uranium-carbon bond and a carbon-fluorine bond have to be broken. This is offset by the formation of a strong uranium-fluorine bond and either a carbon-carbon or a carbon-hydrogen bond. As illustrated in equation 8, the uranium-fluorine bond energy can be estimated to be on the order of 150 kcal/mol based on known thermochemical data for uranium fluorides (21), The carbon-fluorine bond dissociation energy for hexafluorobenzene is reported to be 154 kcal/mol (17), The... 

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