Hydride Transfer Reactions of Metal Hydrides

DuBois and coworkers carried out extensive studies of the thermodynamic hydric-ity of metal hydrides (3.2) in many cases the metal product resulting following hydride transfer will bind a CH3CN ligand (not shown in 3.2), so comparisons of hydricity wiU be solvent-dependent. 

The data in Table 3.3 show an extraordinary range of hydride donating ability of metal hydrides, spanning over 40 kcalmoT Note that the smaller numbers are 

Thermochemical studies of acidity and hydricity are extremely valuable, since they can help determine the energies of potential intermediates in catalytic cycles, and can thus guide the choice of complexes proposed as catalysts. But, since catalysis is a kinetic phenomenon, the kinetics of delivery of a proton or hydride are also important. The kinetics of proton transfer from metal hydrides to amines [21] or metal alkynyl complexes [22], as well as degenerate proton transfers between metal hydrides and metal anions [21] led to the conclusion that proton transfers from metal hydrides have a high intrinsic barrier. 

The kinetics of hydride transfer from metal carbonyl hydrides to trityl cation were studied using stopped-flow methods (3.3) [23, 24]. 

Stoichiometric Hydride Transfer Reactivity of Anionic Metai Hydride Complexes 

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The proposed mechanism shown in Scheme 7.11 is supported by stoichiometric proton- and hydride-transfer reactions of metal hydrides that were dis-... 

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