A unique type of a dicobalt cage templated by a weakly coordinated hexafluorophosphate anion: design, structure and solid-state NMR investigations.

A dinuclear cobalt capsule [PF(6) subset(CH(3)CN)(2)(Co(2)L(4))][PF(6)](3) (2), (L = bis-benzimidazole-1,3-phenylene) has been prepared using a self-assembly approach. This unique class of cage is perfectly designed to encapsulate weakly coordinated anions, i.e. BF(4)(-) and PF(6)(-)via an Manion weak interaction as illustrated by X-ray and solid-state NMR investigations. Selective anion binding for BF(4)(-) over PF(6)(-) is also observed.