Crystal structures of the hydrated disodium and paraquat salts of 1,8-disulfonato-3,4,5,6-acridinetetracarboxylic acid

Two hydrated salts of 1,8-disulfonato-3,4,5,6-acridinetetracarboxylic acid, H₂L, have been characterized by single-crystal X-ray analysis. Compound 1, Na₂L·9H₂O, crystallizes in the monoclinic space group C2/c with a = 42.005(1), b = 6.838(1), c = 23.807 (1) Å, = 122.71 (1)°, and Z = 8. Compound 2, (paraquat)L·2H₂O, belongs to the triclinic space group with a = 9.940(1), b = 11.543(1), c = 14.033(1) Å, = 105.45(1), = 95.82(1), = 100.14(1)° and and Z = 2. All four carboxyl groups in the 3,4,5,6-tetracarboxyacridine-1,8-disulfonate dianion L^2– are un-ionized. In 1 the distorted octahedrally coordinated sodium cations, the anions, and the lattice water molecules are joined together by hydrogen bonds to generate a three-dimensional network. In the crystal structure of 2, a host framework composed of L^2– ions and water molecules accommodate the paraquat dications within two channel systems running parallel to the a and b axes.