High-fidelity Recognition of Organotrifluoroborate Anions (R-BF ) as Designer Guest Molecules.

The recognition of boron compounds is well developed as boronic acids but untapped as organotrifluoroborate anions (R-BF ). We are exploring the development of these and other designer anions as anion-recognition motifs by considering them as substituted versions of the parent inorganic ion. To this end, we demonstrate strong and reliable binding of organic trifluoroborates, R-BF , by cyanostar macrocycles that are size-complementary to the inorganic BF progenitors. We find that recognition is modulated by the substituent's sterics and that the affinities are retained using the common K salts of R-BF anions.