Host–guest-like thiamine–anion complexation in thiaminium bis(tetrafluoroborate)

Abstract

In the title compound, 3-[(4-amino-2-methyl-5-pyrimidin-1-io)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium(2+) bis(tetrafluoroborate), C(12)H(18)N(4)OS(2+).2BF(4)(-), the divalent thiamine cation (in the F conformation) is associated with BF(4)(-) anions via two characteristic bridging interactions between the thiazolium and pyrimidinium rings, i.e. C-H...BF(4)(-)...pyrimidinium and N-H...BF(4)(-)...thiazolium interactions. Thiamine molecules are linked by N-H...O hydrogen bonds to form a helical chain structure.