High-fidelity Recognition of Organotrifluoroborate Anions (R-BF3-) as Designer Guest Molecules

Abstract The recognition of boron compounds is well developed as boronic acids but untapped as organotrifluoroborate anions (R−BF 3 − ). 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 3 − , by cyanostar macrocycles that are size‐complementary to the inorganic BF 4 − 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 3 − anions.