Bond dissociation energy data carbonyls

The development of comprehensive models for transition metal carbonyl photochemistry requires that three types of data be obtained. First, information on the dynamics of the photochemical event is needed. Which reactant electronic states are involved What is the role of radiationless transitions Second, what are the primary photoproducts Are they stable with respect to unimolecular decay Can the unsaturated species produced by photolysis be spectroscopically characterized in the absence of solvent Finally, we require thermochemical and kinetic data i.e. metal-ligand bond dissociation energies and association rate constants. We describe below how such data is being obtained in our laboratory. 

In the dissociation of ethanal,2-diol, CH(0H)2CH=0 to C (OH)2CH=0 + H, We observe a very small, (only 75.4 kcal mol ) RC—energy in the dihydroxy C—bond. This can be explained with resonance of the carbon radical with a carbonyl group. We have calculated this energy with the G3 method to verify the data and find a similar value, 75.1 kcal mol. We have not observed this effect with species containing only one hydroxy (OH) and the carbonyl and look to study on simple dihydroxy alkanes to fiirther, understand this effect of a second OH. 

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