Palladium hydride, enthalpies

Standard Free Energies, Enthalpies, and Entropies of Formation of Palladium and Nickel Hydrides ... 

Various mechanisms for the aerobic oxidation of alcohols catalysed by (NHC)Pd (carboxylate)2(H20) complexes [NHC = l,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] were investigated using DFT combined with a solvent model. Of these, reductive j3-hydride elimination, in which the -hydrogen of a palladium-bound alkoxide is transferred directly to the free oxygen of the bound carboxylate, provided the lowest-energy route and explained the published kinetic isotope effect, activation enthalpy, reaction orders, and dependence of rate on carboxylate pKa.26S... 

Figure 2.17. Several elements arranged according to their parameter values in the Miedema model. The sign of the reaction enthalpy is indicated in the quadrant bounded by the P/Q lines of the group of metals. The stable binary (metallic) compounds can be identified at a glance. The metallic form of hydrogen is also placed with the metals. Hydrogen has a negative charge in lithium hydride and a positive charge in the stable compound with palladium.

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