Pairing Heterocyclic Cations with closo-dodecafluoro dodecaborate(2-). Synthesis of Binary Heterocyclium(1+) Salts and a AG4(heterocycle)8(4+) Salt of B12F12(2-) (Preprint)

摘要

Eight binary salts that pair triazolium(1+), imidazolium(1+), pyrimidinium(1+), or puri-nium(1+) cations with the icosahedral closo- dodecafluorododecaborate(2-) anion (B12F122-) were synthesized using open-air benchtop metathesis reactions in water or acetonitrile. The scale of the reactions varied from just milligrams to nearly one gram of the starting material K2B12F12. Other reaction conditions, the scope of the reaction, and the solubilities for the new salts are discussed. Five of the heterocyclium (2 B12F12) salts, which were obtained in yields ranging from 84% to 99%, displayed significantly higher densities than the corresponding previously-reported analogous heterocyclium (2 B12H12 and heterocyclium CB11H12) salts. A ninth high-density salt consisted of B12F122. paired with an Ag4(triazole)84+ cation. The structures of eight of the nine new compounds were determined by single-crystal X-ray diffraction analysis. The density of five heterocyclium(2 B12F12) salts was found to increase approximately linearly as the distance between the five-membered-ring heterocyclium(1+) cation centroids decreased. This work demonstrates additional flexibility for the rational design of ionic structures with predictable properties, which will ultimately permit the tailoring of ingredient-response behavior.