Reactivity Comparison of Complexes of 4f~n5d~I and 4f~(n+1) Ln~(2+) Ions with Cydooctatetraene

摘要

Recently, complexes of the entire series of lanthanide metals have been isolated in the +2 oxidation state: [K(2.2.2-cryptand)][Cp'3Ln] (Cp' = C5H4SiMe3), 1-Ln.1,2 In this ligand field, these Ln~(2+) complexes fall into two categories, with the La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, and Lu complexes being characterized as containing 4f~n5d~1 ions (in relation to the starting 4f Ln~(3+) complex), while the Sm, Eu, Tm, and Yb complexes were characterized as traditional 4f~(n+1) Ln~(2+) ions.1"6 Previous studies have shown that complexes of the 4f~n5d~1 Ln~(2+) ions are able to reduce naphthalene, eq 1, while most traditional 4f~(n+1) ions cannot. It was desirable to find a eagent that Ln~(2+) complexes with both electron configurations could reduce to compare reaction products. 1,3,5,7-Cyclooctatetraene (C8H8) was chosen as a substrate since it was successful in differentiating the reactivity of recently isolated U~(2+) and Th~(2+) complexes.