Developments in heterobimetallic s-block systems: Synthesis and structural survey of molecular M/Ae (M = Li, Na, K, Cs; Ae = Ca, Sr) aryloxo complexes

A series of novel heterobimetallic group 1/strontium and group 1/calcium aryloxo complexes having the composition [MAe(OdPP)(3)] [Ae = Sr and M = Na (1), K (2, 3), Cs (4); Ae = Ca and M = Na (5), K (6), Cs (7)] or [M(2)Ae(OdPP)(4)] [M = Li and Ae = Sr (9), Ca (10)] have been prepared using 2,6-diphenylphenol (HOdpp) as the ligand. Through the use of solid-state direct metalation, these compounds were obtained either directly from the reaction vessel or after workup in toluene. The Lewis base adduct [KCa(OdPP)(3)(thf)] (8) was obtained by treatment of [KCa(OdPP)3] (6) with tetrahydrofuran (thf). All of the compounds displayed extensive metal-pi-arene interactions, which provide significant stabilization in these reactive species. The thermal stabilities and volatilities of representative heterobimetallic strontium and calcium complexes were investigated using thermogravimetric analysis.