Hydrogen-bonded supramolecular motif in trimethoprim-terephthalate-terephthalic acid (2/1/1)

Studies on hydrogen-bonding patterns playing a key role in molecular recognition and crystal engineering. In the title compound [2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium terephthalate terephthalic acid], the trimethoprim molecule is protonated at one of the pyrimidine N atoms. The carboxylate groups of the terephthalate anion form double hydrogen bonds of type N-HO, resulting in a fork-like interaction with the protonated diaminopyrimidine rings.