Evaluation and X-Ray Induced Modification of the Cerium Oxidation State in Cerium Calixarene Complexes
The cerium oxidation state in novel calixarene-supported cerium(IV) β-diketonate complexes [p-tBu-calix(OMe)2(O)2]Ce(acac)2 (1) and [p-tBu-calix(OMe)2(O)2]Ce(hfac)2 (2), which are a new class of potential precursors for homogeneous oxidative transformations, has been determined using X-ray photoelectron spectroscopy (XPS). Cerium oxidation states between 3.6 and 3.65 were detected, distinctly different from their nominal value of +4. An X-ray induced photoreduction of these compounds was detected. Because of the observed stability of the X-ray modified oxidation state under ambient conditions this effect might be used for a long-standing fine tuning of the Ce oxidation state in cerium calixarenes.
Witold Łojkowski and John R. Blizzard, Urszula Narkiewicz and Janusz D. Fidelus
Y. Suchorski et al., "Evaluation and X-Ray Induced Modification of the Cerium Oxidation State in Cerium Calixarene Complexes", Solid State Phenomena, Vol. 128, pp. 115-120, 2007