ISSN:
0947-6539
Schlagwort(e):
actinides
;
C-H activation
;
lanthanides
;
mass spectrometry
;
metal oxides
;
oxygen transfer
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The effects of oxo ligands on lanthanide and actinide cations have been examined for the mono- and dioxocations MO+ and MO+2 of cerium, neodymium, thorium, and uranium by probing C-H and C-C bond activation of hydrocarbons in an FT-ICR mass spectrometer. The metal monoxide cations are readily available by reaction of the “bare” metal cations with O2, CO2, N2O, or H2O. In the ensuing oxidation of MO+, UO+2 is obtained by each of these oxidants, while CeO+ could only be oxidized by N2O. NO2 was necessary for the generation of ThO+2, and NdO+2 could not be prepared at all. The monoxides are rather unreactive and only dehydrogenate reactive substrates such as 1-butene and 1,4-cyclohexadiene to generate the corresponding butadiene or benzene complexes. In contrast, CeO+2 and ThO+2 react efficiently with different substrates by abstraction of a hydrogen atom and formation of the closed-shell species OMOH+, or by oxygen atom transfer to unsaturated hydrocarbons. In marked contrast, UO+2 only undergoes very slow adduct formation with unsaturated hydrocarbons. The results are compared with the reactions of the “bare” metals with respect to the influence of the oxo ligand as well as to the underlying electronic features of the investigated complexes.
Zusätzliches Material:
4 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/chem.19970030716
