Dihydrocyclam dimaleate [H2(cyclam)(maleate)2]

The asymmetric unit of the title molecular salt [systematic name: 1,4,8,11-tetraazacyclotetradecane-1,8-diium bis(3-carboxyprop-2-enoate)], C10H26N42+·2C4H3O4−, contains two half-cations (both completed by crystallographic inversion symmetry) and two maleate anions. The cyclam macrocycles adopt trans-III conformations, supported by two intramolecular N—H...O hydrogen bonds. The O-bonded H atom of each maleate ion is disordered over two positions with an occupancy ratio of 0.61 (5):0.39 (5): each one generates an intramolecular O—H...O hydrogen bond. In the crystal, the cations are linked to the anions by N—H...O hydrogen bonds, generating [001] chains