Oxidation C-H bond activation

From the reaction of [Ir(Tp)(C2H4)2] with dppe, complete displacement of Tp from the Ir coordination sphere and [Ir(dppe)2](Tp) formation is observed, whereas the reaction of [Ir(Tp)(C2H4)2] with dppm shows an intramolecular proton transfer from the methylene bridge to the iridium center yielding an iridium hydride species by oxidative C-H bond activation (Fig. 2.102). Finally, reaction... 

A handful of diplatinum(lll) aryl compounds with Pt(lll) - Pt(lll) bonds were made from oxidative C-H bond activation mediated by Pt(ll) precursors (203-205, Figure 10.22) [143], These compounds were studied as platinum models of Pd-catalyzed C-H bond functionalization (203) [143a], for their unique physical properties, for example, as a liquid crystal material (204) [143b] or a chi-roptical material (205) [143c],... 

Figure 10.22 Diplatinum(lll) compounds 203-205, which are made from oxidative C-H bond activation mediated by Pt(ll) precursors [143].

Pd(OAc)2 catalyzed intramolecular aromatic annulation with oxidative C-H bond activation was reported. Cu(OAc)2 was used as the reoxidant for the Pd catalyst (eq 27). 

Cho, S. H. Kim, J. Y Kwak, J. Chang, S. Recent advances in the transition metal-catalyzed twofold oxidative C-H bond activation strategy for C-C and C-N bond formation. Chem. Soc. Rev. 2011,40, 5068-5083. 

Note that the main difference between zirconium hydride and tantalum hydride is that tantalum hydride is formally a d 8-electron Ta complex. On the one hand, a direct oxidative addition of the carbon-carbon bond of ethane or other alkanes could explain the products such a type of elementary step is rare and is usually a high energy process. On the other hand, formation of tantalum alkyl intermediates via C - H bond activation, a process already ob-... 

A free carbene B base-containing complex C transmetallation D oxidative addition E C=C activation F C-H bond activation... 

The elementary reaction energies and thermodynamics for methanol dehydrogenation have been shown to be significantly influenced by electrode potential. The oxidation pathways become much more favorable at higher potentials. The relative barriers of O—H to C—H bond activation decrease with increasing potential, which decreases the overall selectivity to CO and CO2 and increases the yield of formaldehyde. This is consistent with experimental studies. The oxidation of CO intermediates appears to occur via adsorbed hydroxyl intermediates. The hydroxyl intermediates are more weakly held to the surface than atomic oxygen, and thus have significantly lower barriers for the oxidation of CO. 

Murahashi S-I, Nakae T, Terai H, Komiya N (2008) Ruthenium-catalyzed oxidative cyana-tion of tertiary amines with molecular oxygen or hydrogen peroxide and sodium cyanide sp3 C-H bond activation and carbon-carbon bond formation. J Am Chem Soc 130 11005-11012... 

Synthetic Reactions via C-H Bond Activation Oxidation of C-H Bonds... 

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