Synthesis, characterization, and catalytic properties of γ-Al2O3-supported zirconium hydrides through a combined use of surface organometallic chemistry and periodic calculations

The treatment of the alumina-supported [Zr(CH(2)tBu)(4)], [(AlsO)(2)Zr(CH(2)tBu)(+)(tBuCH(2))Al-s(-)], where Al-s stands for surface aluminum atoms, by H-2 yields a mixture of alumina-supported zirconium hydride species, [(AlsO)(2)Zr(H)(mu-H)Al-VI] and [(AlsO)(2)Zr(H)(mu-R)Al-VI], along with cationic [(AlsO)(2)Zr(H)](+) in the vicinity of anionic tetrahedral aluminum hydrides [Al-IV-H-] according to mass balance analysis, reactivity studies, IR spectroscopy, and periodic calculations. Initial and final selectivities in the hydrogenolysis of alkanes as well as DFT calculations show that beta-alkyl transfer is the key carbon-carbon cleavage step.