New structural features in heavy alkaline earth-metal chemistry--molecular heterobimetallic group 1, Ba complexes

The preparation of heterobimetallic complexes consisting of alkali and heavy alkaline earth metals remains a challenge due to limited available synthetic strategies. Here we present a new class of group 1, Ba compounds of the type M(n){Ba(Odpp)(2+n)}] (M=Na(n=1) (1), K(n=1) (2), Cs(n=1) (3), Li(n=2) (4); HOdpp=2,6-diphenylphenol) and the Lewis base adducts Li(2)(thf)(2){Ba(Odpp)(4)}]PhMe (5) and K{Ba(Odpp)(3)(diglyme)}] (6) (diglyme=bis(2-methoxy)ethyl ether]) as the first representatives of heterobimetallic group 1, Ba species of low nuclearity. The compounds display a significant degree of metal-arene interaction, believed to be a key factor in stabilizing these highly reactive species. Obtained by solid-state direct metalation, the target compounds are available without further work-up.