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The design of homogeneous catalysts based on Ir and other late transition metal complexes using O-donor ligands like acetylacetonate (aca), tropolone, aryloxides, catechols, hydroxyaetophenone to stabilize the complexes to the reaction conditions needed for generating functionalized products is discussed. The outcome of the studies helps to utilize, design new, more effective, thermally protic-and oxidant-stable O-donor catalysts for hydrocarbon conversion.

Two organometallic systems([Ir(Mu-acac-O)(acac-C(super 3)](sub 2) and (Tp)Ru(CO)(Ph)-(NCCH3) is discovered that catalyze hydroarylation of unactivated olefins. Hybridization is dependent on the amount of back-bonding to the olefin, these relationships translate into correlations between the amount of back-bonding and activation energy/thermodynamics.

This review summarizes the deliberations of a workshop colloquium on the 'opportunities for catalysis research in carbon management'. Research progress within the context of greenhouse gas/carbon issues in the areas of hydrogen generation and utilization, carbon dioxide activation, catalysis research to further our search for new and more efficient catalytic processes.

The ability of (IPI)Ru(II)[(OH).sub.n][([H.sub.2]O).sub.m] where IPI is the NNN-pincer ligand, 2,6-diimidizoylpyridine to catalyze H/D exchange between hydrocarbons and strongly basic solvents at higher rates than in the case of the solvent alone is described. The evidence indicated that the reaction proceeding by base modulated nucleophilic CH activation could be increased by solvent basicity.

The Catalytica catalyst is successful because the methanol is protected as methyl bisulfate, which is less reactive than methanol toward the catalyst. The analysis has shown a limiting performance for systems that is operated by this type of protection that is well above the Catalytica system.

Several studies are conducted to analyze the localized molecular orbital energy decomposition of the various C-H activation transition states (TSs). The results prove that these discussed metal centers exhibit an electrophilic, ambiphilic and nucleophilic charge transfer in the bond activation.

Se[O.sub.2] has catalyzed the facile oxy-functionalization of [(CO).sub.5]Re(I)-[Me.sup.5-] with I[O.sub.4.sup.-] to generate methanol. Density functional theory calculations have shown that catalysis has involved methyl group transfer from Re to the electrophilic Se center followed by oxidation and subsequent reductive functionalization of the resulting C[H.sub.3]Se(VI) species.

The density functional theory (DFT) is used for studying the mechanisms for the interactions between methylrhenium trioxide (MTO) and [H.sub.2][O.sub.2]/NaOH in THF. The studies have shown that methanol is formed through Baeyer-Villiger type mechanism and another oxygen insertion transition state with a low relative barrier is isolated.

The combined experimental and theoretical evidence is presented for a facile Re-R to Re-OR bond conversion with non-peroxo YOs that proceeds through a low-energy, Baeyer-Villiger (BV)-type, electrophilic O-atom insertion. The results might point to a facile pathway for heteroatom functionalization of M-R intermediates of more electron-rich metals via a BV-type pathway with electrophilic, heteroatom-atom donors, such as YO.

The mechanism of hydroarylation of olefins by a homogeneous Ph-Ir(acac)2(L) catalyst is elucidated by first principles quantum mechanical methods (DFT), with particular emphasis on activation of the catalyst is discussed. Electron-withdrawing substituents on the acac ligands are good modifications for catalysts with higher activity.

SbVF5 is generally assumed to oxidize methane through a methanium-to-methyl cation mechanism. However, experimentally no H2 is observed, and the mechanism of methane oxidation has remained unsolved for several decades. To solve this problem, density functional theory calculations with multiple chemical models (mononuclear and dinuclear) were used to examine methane oxidation by SbVF5 in the presence of CO leading to the methyl acylium cation ([CH3CO]+). While there is a low barrier for methane protonation by [SbVF6]-[H]+ (the combination of SbVF5 and HF) to give the [SbVF5]-[CH5]+ ion pair, H2 dissociation is a relatively high energy process, even with CO assistance, and so this protonation pathway is reversible. While Sb-mediated hydride transfer has a reasonable barrier, the C--H activation/σ-bond metathesis mechanism with the formation of an SbV--Me intermediate is lower in energy. This pathway leads to the acylium cation by functionalization of the SbV--Me intermediate with CO and is consistent with no observation of H2. Because this C--H activation/metal-alkyl functionalization pathway is higher in energy than methane protonation, it is also consistent with the experimentally observed methane hydrogen-todeuterium exchange. This is the first time that evidence is presented demonstrating that SbVF5 acts beyond a Bronsted superacid and involves C--H activation with an organometallic intermediate. In contrast to methane, due to the much lower carbocation hydride affinity, isobutane significantly favors hydride transfer to give the tert-butyl carbocation with concomitant SbV to SbIII reduction. In this mechanism, the resulting highly acidic SbV--H intermediate provides a route to H2 through protonation of isobutane, which is consistent with experiments and resolves the longstanding enigma of different experimental results for methane versus isobutane. [ABSTRACT FROM AUTHOR]