Fluoride Anion Complexation by a Triptycene-Based Distiborane: Taking Advantage of a Weak but Observable C-H⋠⋠⋠F Interaction.

Fluoride anion complexation impacts a number of areas ranging from sensing to nucleophilic fluorination chemistry. Described here is a new bidentate Lewis acid consisting of two stiborane units connected by a 1,8-triptycenediyl backbone. This neutral derivative captures fluoride with an unprecedented affinity for a neutral, water-compatible Lewis acid. Structural, spectroscopic and computational studies demonstrate that fluoride anion binding is assisted by the formation of a C-H⋅⋅⋅F hydrogen bond which involves a methine group of the 1,8-triptycenediyl backbone.