Cerium , direct bonding

The electron density p(r) which emphasizes the frontier levels (b) clearly shows that the states just below p are centered along the directions of the Ce " -Ce + interactions, and the remaining electron on cerium is localized in a cerium-cerium (partial) bond instead of being localized on the ion it-... 

The hydrolysis of phosphonic acid esters in Brij-35 micelles by cerium(IV) was investigated by Moss and Ragunathan (1999). The phosphonic esters differ from the phosphodiesters by the presence of only one ester bond and by a direct bond between phosphorus and the carbon atom of an alkyl or aryl group. Cerium(IV) ions also accelerate the hydrolysis of these diesters (Moss and Morales-Rojas, 2001 Moss et al., 2004). The phosphonoformate diesters show structural similarities with the phosphodiesters. Whereas zirconium(IV) and hafnium(IV) hydrolyze mainly the P-OR bond, cerium(IV) and thorium(IV) hydrolyze principally the C-OR bond in the phosphonoformate diesters. This chemoselective ester hydrolysis was not observed for the phosphodiester compounds. 

Ceric ions react rapidly with 1,2-diols. There is evidence for chelation of cerium and these complexes are likely intermediates in radical generation10 106 The overall chemistry may be understood in terms of an intermediate alkoxy radical which undergoes p-scission to give a carbonyl compound and a hydroxyalkyl radical (Scheme 3.59). However, it is also possible that there is concerted electron transfer and bond-cleavage. There is little direct data on the chemical nature of the radical in termediates. 

Cationic polymerization of alkenes and alkene derivatives has been carried out frequently in aqueous media.107 On the other hand, the reaction of simple olefins with aldehydes in the presence of an acid catalyst is referred to as the Prins reaction.108 The reaction can be carried out by using an aqueous solution of the aldehyde, often resulting in a mixture of carbon-carbon bond formation products.109 Recently, Li and co-workers reported a direct formation of tetrahydropyranol derivatives in water using a cerium-salt catalyzed cyclization in aqueous ionic liquids (Eq. 3.24).110... 

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