Hydrogen-bonded network structures in dipyridinium, bis(2-methylpyridinium), bis(3-methylpyridinium) and bis(4-methylpyridinium) dioxidobis(oxydiacetato)uranate(VI).

Four complexes containing the [UO(2)(oda)(2)](2-) anion (oda is oxydiacetate) are reported, namely dipyridinium dioxidobis(oxydiacetato)uranate(VI), (C(5)H(6)N)(2)[U(C(4)H(4)O(5))(2)O(2)], (I), bis(2-methylpyridinium) dioxidobis(oxydiacetato)uranate(VI), (C(8)H(8)N)(2)[U(C(4)H(4)O(5))(2)O(2)], (II), bis(3-methylpyridinium) dioxidobis(oxydiacetato)uranate(VI), (C(8)H(8)N)(2)[U(C(4)H(4)O(5))(2)O(2)], (III), and bis(4-methylpyridinium) dioxidobis(oxydiacetato)uranate(VI), (C(8)H(8)N)(2)[U(C(4)H(4)O(5))(2)O(2)], (IV). The anions are achiral and are located on a mirror plane in (I) and on inversion centres in (II)-(IV). The four complexes are assembled into three-dimensional structures via N-H...O and C-H...O interactions. Compounds (III) and (IV) are isomorphous; the [UO(2)(oda)(2)](2-) anions form a porous matrix which is nearly identical in the two structures, and the cations are located in channels formed in this matrix. Compounds (I) and (II) are very different from (III) and (IV): (I) forms a layered structure, while (II) forms ribbons.