Salts of barbituric and 2-thiobarbituric acids with imidazole: polymorphism, supramolecular structure, thermal stability and water solubility

Imidazolium barbiturate (two polymorphs, 1 and 2) and imidazolium 2-thiobarbiturate (3) with an unusual geometry of HB motifs were synthesized. Interestingly, 2 was more soluble in water than 3, while initial barbituric acids showed inverse tendency.