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.     

Stabilization and Transfer of the Transient [Mes*P4]− Butterfly Anion Using BPh3

The transient bicyclo[1.1.0]tetraphosphabutane anion, generated from white phosphorus (P₄) and Mes*Li (Mes*=2,4,6‐tBu₃C₆H₂), can be trapped by BPh₃ in THF. This Lewis acid stabilized anion can be used as an [RP₄]^? transfer agent, reacting cleanly with neutral Lewis acids (B(C₆F₅)₃, BH₃, and W(CO)₅) to afford unique singly and doubly coordinated butterfly anions, and with the trityl cation to form a neutral, nonsymmetrical, all‐carbon‐substituted P₄ derivative. This reaction path enables a simple, stepwise functionalization of white phosphorus.