Carbonyl oxides electronic structure

Solvent effects on relative stability and electronic and molecular structure of carbonyl oxide (Criegee) intermediates in ozonolysis have been analysed by ab initio... 

Fig. 2.3 shows the core structures of the most important 1,3-dipoles, and what they are all called. As with dienes, they can have electron-donating or withdrawing substituents attached at any of the atoms with a hydrogen atom in the core structure, and these modify the reactivity and selectivity that the dipoles show for different dipolarophiles. Some of the dipoles are stable compounds like ozone and diazomethane, or, suitably substituted, like azides, nitrones, and nitrile oxides. Others, like the ylids, imines, and carbonyl oxides, are reactive intermediates that have to be made in situ. Fig. 2.4 shows some examples of some common 1,3-dipolar cycloadditions, and Fig. 2.5 illustrates two of the many ways in which unstable dipoles can be prepared. 

The carbonyl oxide structure is usually drawn as C+—O—O, and so this structure will be most generally used in this chapter. In our opinion, however, C=0+—O-, with its smaller charge separation and carbon electron octet, is preferable. 

Asymmetric Synthesis by Homogeneous Catalysis Carbonylation Processes by Homogeneous Catalysis Coordination Organometallic Chemistry Principles Electronic Structure of Clusters Hydride Complexes of the Transition Metals Hydrides Solid State Transition Metal Complexes Organic Synthesis using Transition Metal Complexes Containing jr-Bonded Ligands Oxidation... 

Figure 7.3 Synthesis and electronic structure of bis(imino)pyridine manganese carbonyl complexes over three oxidation states.

CO has often been used as a convenient probe for investigating the electronic structures of metal oxide and zeolite supported metals. However, CO is not simply an innocent probe. For example, oxidative fragmentation occurs when CO reacts with Rh clusters on metal oxides or in zeolites. [171, 172] The breakup by CO of small clusters of metals that have some oxophilic character is consistent with the tendency of CO to fragment carbonyl clusters of these metals in solution. [31]... 

Homogeneous catalysts play an important role in industry as well as in research laboratories. Established applications include, for example, polymerization processes with zirconocene and its derivatives, rhodium- or cobalt-catalyzed hydroformylation of olefins, and enantioselective isomerization catalysts for the preparation of menthol. In contrast to heterogeneous catalysts, more experimental studies of reaction mechanisms are available and the active species can be characterized experimentally in some cases. Most catalysts are based on transition metal compounds, for which electronic structures and properties are well studied theoretically. A substantial number of elementary reactions, such as reductive elimination, oxidative addition, alkene or carbonyl migratory insertion, etc., have been experimentally Studied in detail by means of isotopic, NMR, and IR studie.s, as well as theoretically. ... 

DS/DVM calculations on compounds of element 106 have focused on the fluorides, chlorides, oxides, and oxychlorides. These calculations conclude that the dioxy-dichloride should be more stable than the oxychloride which in turn is more stable than the chloride. The same stability order has been observed for W and Mo. It wa.s also predicted that [(106)04] will be the most stable ion in aqueous solution within the Group 6 series of oxides and that the M-0 bond strengths have the following order Cr < Mo < 106 < W. DV-Xa calculations on M(CO)fi where M = Cr, W, U, and element 106 indicate that beside the increasing spin-orbit splitting of the t2g HOMO, the electronic structures of the octahedral Group 6 carbonyl complexes are very similar. The relativistic destabilization of the element 106 6d shell is responsible for this similarity. 

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