N,N′-Bis(2-hydroxy­ethyl)-N,N′-[ethyl­ene­dioxy­bis(o-phenyl­enemethyl­ene)]­diammonium fumarate tetra­hydrate

The reaction of 1,2-bis­{2-[(2-hydroxy­ethyl)amino­methyl]­phen­oxy}ethane and fumaric acid in a mixed solution in ethanol–water (1:1 v/v) yields the title compound, C(20)H(30)N(2)O(4) (2+)·C(4)H(2)O(4) (2−)·4H(2)O. In the crystal structure, the anions, cations and water mol­ecules are connected via O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network. The fumarate anion and the N,N′-bis­(2-hydroxy­ethyl)-N,N′-[ethyl­enedioxy­bis(o-phenyl­enemethylene)]diammonium cation are located on centers of inversion, whereas the two crystallographically independent water mol­ecules occupy general positions.