Exploring properties of potassium 6-X-2-isonicotinoyltrifluoroborate (X=H, F, Cl, Br) salts and their anions by using ab initio calculations.

The structural, electronic, and topological properties of a series of four members of potassium 6-X-2-isonicotinoyltrifluoroborate (X=H, F, Cl, Br) salts have been explored by using ab initio calculations with the hybrid B3LYP/6-311++G** method. According to the potential energy surface only the properties for the most stable conformer of each member of the series and their anions were analyzed in function of electronegativity and atomic radius of X. The results show that when X=H, the salt and its anion have symmetry C while the symmetry change to C for the halogenated F, Cl, and Br derivatives and their anions. Both, electronegativity and atomic radius properties show higher effects on V than on μ. Similar behaviors are observed when the Mulliken charges on N and X atoms are analyzed vs electronegativites, and atomic radius of X while an important decreasing on NPA charges of X is observed when increase its electronegativity. The strong influence of electronegativity and atomic radius of X are evidenced in the low bond order value observed in the C1 atom of F salt. The strong energetic π*C2-C3 → π*C4-C5 transition observed only for the F salt confer to it a high stability. The frontier orbitals have revealed that the 6-H-IFTB salt is the less reactive species while the higher reactivity is predicted for the Br salt. Evidently, the smaller electronegativity and higher atomic radius of Br justify the high reactivity predicted for its salt. Graphical abstractExploring properties of potasium 6-X-2-isonicotinoyltrifluoroborate (X= H, F, Cl, Br).