Oxygen-bonded carbonyls

Step 1 Hydride (hydrogen + two electrons) is transferred from boron to the positively polarized carbon of the carbonyl group The carbonyl oxygen bonds to boron... 

Thermal decomposition of dihydroperoxides results in initial homolysis of an oxygen—oxygen bond foUowed by carbon—oxygen and carbon—carbon bond cleavages to yield mixtures of carbonyl compounds (ketones, aldehydes), esters, carboxyHc acids, hydrocarbons, and hydrogen peroxide. 

The zirconium—nitrogen bond is weaker than the zirconium—oxygen bond even under anhydrous conditions. When zirconium tetrachloride reacts with carbonyl-containing amides such as... 

The reduction of a ketone by a metal hydride involves the formation of two bonds the linking of the carbonyl carbon to a hydride and the formation of a metal oxygen bond (4). 

On treatment with a potassium fluoridc-orown ether complex, alkyl 1,2,2,2-tetrachloroethyl carbonates are cleaved at the carbonyl group-oxygen bond to give high yields of alkyl fluoioformates [ 15] (equation 25)... 

An example of cleavage ol the sulfur-oxygen bond in trifluoromethane-sulfonic ester has been reported Tnfluororaethyl triflate reacts with neutral or anionic nucleophiles with elimination of carbonyl difluoride and formation of trifluoromethanesulfonyl fluoride [57] (equation 32) The mechanism of this reaction involves elimination of fluoride ion, which is a chain carrier in the substitution of fluorine for the trifluoromethoxy group... 

Abstract This review is a summary of supported metal clusters with nearly molecular properties. These clusters are formed hy adsorption or sirnface-mediated synthesis of metal carbonyl clusters, some of which may he decarhonylated with the metal frame essentially intact. The decarhonylated clusters are bonded to oxide or zeolite supports by metal-oxygen bonds, typically with distances of 2.1-2.2 A they are typically not free of ligands other than the support, and on oxide surfaces they are preferentially bonded at defect sites. The catalytic activities of supported metal clusters incorporating only a few atoms are distinct from those of larger particles that may approximate bulk metals. 

Carbonyl compounds have rather large dipole moments as a result of the polarity of the carbon-oxygen bond. 

At the outset it is important to clarify the scope of this discussion by the elimination of areas which will not be considered. When one notes that the term "activation of carbon monoxide" may mean a process as little perturbative of the C-0 bond as its end-on attachment to a metal atom in carbonyls, or as strongly perturbative as its dissociation to atoms on a metal surface, the need for limits becomes obvious. In this discussion we will consider only the activation of carbon monoxide in the sense that isolable products are formed by the addition of hydrogen to the molecule without complete rupture of all carbon-oxygen bonds, oxygenates are formed. 

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