Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
The synthesis of lanthanides other than cerium in the oxidation state +IV has remained a desirable but unmet target until recently, when two examples of Tb-IV with saturated coordination spheres were isolated. Here we report the third example of an isolated molecular complex of terbium(IV), where the supporting siloxide ligands do not saturate the coordination sphere. The fully characterized six-coordinate complex [Tb-IV(OSiPh3)(4)(MeCN)(2)], 2-Tb-Ph, shows high stability and the labile MeCN ligands can be replaced by phosphinoxide ligands. Computational studies suggest that the stability is due to a strong pi(O-Tb) interaction which is stronger than in the previously reported Tb-IV complexes. Cyclic-voltammetry experiments demonstrate that non-binding counterions contribute to the stability of Tb-IV in solution by destabilizing the +III oxidation state, while alkali ions promote Tb-IV/Tb-III electron transfer.
Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Paul Varava, Wolfram Feuerstein
David Lyndon Emsley, Andrea Bertarello