Hydrogen bonding networks in ammonium carboxylate salts : the crystal structures of phenylethylammonium fumarate-fumaric acid, phenylethylammonium succinate-succinic acid and anilinium fumarate-fumaric acid

Abstract

Three novel carboxylate salts, phenylethylammonium fumarate-fumaric acid, phenylethylammonium succinate-succinic acid and anilinium fumarate-fumaric acid, have been prepared and structurally characterized. Their crystal structures, which all contain unionized acid molecules in addition to the carboxylate di-anion, are closely related to one another. The solid-state structures of these salts are described, and discussed in the context of the structures of related salts. Recurrent hydrogen bonding motifs in fumarate and succinate salts containing unionized acid are identified. It is shown that the syn-syn hydrogen bonding motif seen in these salts is unusual in fumarate and succinate salts in general.