Anion Recognition by Highly Sterically Encumbered 1,2-Diborylferrocenes

The syntheses and structural characterization of sterically encumbered 1,2-diborylferrocenes are reported, together with an investigation of their anion recognition capabilities with respect to fluoride and cyanide. Surprisingly, 1,2-fc(BMes(2))(2) is found to be highly selective for CN-, with the uptake of F- being shown to be not only thermodynamically less favorable but also kinetically much slower.