Crystal Structure of Diisopropylammonium Hydrogen Maleate

Abstract

Use of salts and co-crystals of active pharmaceutical ingredients (APIs) as a method for tuning their delivery and activity is an area of growing interest. Modifying API properties such as solubility by finding new salts that employ similar hydrogen-bonding have been successful. In an effort to further study the hydrogen-bonding patterns of the maleate ion with other diisopropylammonium we report here the synthesis and diisopropylammonium maleate. The salt was isolated from reaction between diisopropylamine and maleic acid in methanol. The results of elementary analyzes (CHN) showed the presence of the nitrogen atom of diisopropylamine, carbon atoms and hydrogen. The IR spectrum of diisopropylammonium hydrogen maleate, showed the presence of two intense bands due to the vibrations of symmetricand anti-symmetric valence of the carboxylate group and a wide absorption due to the NH2 groups of the cation. Those which has been confirmed by crystallography. The asymmetric unit contains one diisopropylammonium cation, iPr2NH2+ and one hydrogen maleate anion. In the structure, anions which present an inner O-H…O hydrogen bond are linked to cations through N-H…O hydrogen bonds leading to infinite chains. Chains are connected to their neighbours through weak C-H…O hydrogen bonds affording a layer. The study of the interactions of diisopropylammonium hydrogen menaleate, by the presence of hydrogen bonds leading to supramolecular architectures has shown the possibility of its use in Active Pharmaceutical Ingredients (API).