Metal-pi Interactions Dominate in the Solid-State Structures of Molecular Heterobimetallic Alkali-Metal-Europium(II) Aryloxo Complexes

摘要

Treatment of Eu metal, 2,6-diphenylphenol (HOdpp), and MOdpp (M velence Na, K) at elevated temperature in the presence of mercury afforded heterobimetallic complexes which were structurally characterized after crystallization from toluene. The structures of [MEu(Odpp)_(3)](centre dot)nPhMe (M velence Na, n velence 1, 1; K, n(velence)2.5, 2) consist solely of bridging aryloxide ligands and feature extensive pi-Ph-metal interactions. Rather than a heterobimetallic species, treatment of Eu metal and HOdpp with LiOdpp under similar conditions afforded a number of products, including a mixed-valent europium complex, [Eu_(2)(Odpp)_(3)][Eu(Odpp)_(4)](centre dot)4 PhMe (3). The structural framework of the [Eu_(2) (Odpp)_(3)]~(+) cation of 3 is similar to that of the molecular heterobimetallics 1 and 2, including the presence of pi-Ph-Eu interactions. The reluctance of the reaction to provide a Eu/Li heterobimetallic complex was exemplified by the simultaneous crystallization of [Eu_(2) (Odpp)_(4)](centre dot)PhMe (6) and the homoleptic cubane [Li_(4)(Odpp)_(4)](centre dot)2C_(6)H_(14) (5) from toluene/hexane.