A combined experimental and theoretical study of anion-pi interactions in bis(pyrimidine) salts

Abstract

[eng] We report the synthesis and X‐ray characterization of an N,N′‐tetramethylenebis(2‐aminopyrimidinium) tetrafluoroborate salt that exhibits anion-π interactions that are responsible for the crystal packing. The anion forms a sandwich complex with two pyrimidine rings. When the anion is nitrate, the crystal packing is governed by anion-π interactions and hydrogen bonds, and the sandwich complex is not formed. Finally, a theoretical study of the anion-π interactions in charged pyrimidine rings is in good agreement with the experimental findings. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)