Propane-1,2-diaminium bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O)cadmate dihydrate.

The reaction of cadmium nitrate dihydrate, propane-1,2-diamine and pyridine-2,6-dicarb-oxy-lic acid in a 1:1:2 molar ratio in an aqueous solution resulted in the formation of the title compound, (C(3)H(12)N(2))[Cd(C(7)H(3)NO(4))(2)]·2H(2)O or (p-1,2-daH(2))-[Cd(pydc)(2)]·2H(2)O (where p-1,2-da is propane-1,2-diamine and pydcH(2) is pyridine-2,6-dicarb-oxy-lic acid). The Cd(II) ion is coordinated by four O and two N atoms of two pydc ligands in a distorted octa-hedral environment. The structure also contains two uncoordinated water mol-ecules. In the crystal, there are several inter-molecular N-H⋯O, O-H⋯O and weak C-H⋯O hydrogen bonds. There are also π-π stacking inter-actions between the pyridine rings of pydc units, with centroid-centroid distances of 3.4708 (16) Å.

Propane-1,2-diaminium bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O)mercurate(II) dihydrate.

In the title compound, (C(3)H(12)N(2))[Hg(C(7)H(3)NO(4))(2)]·2H(2)O, the Hg(II) ion is coordinated by four O and two N atoms of two pyridine-2,6-dicarboxyl-ate (pydc) ligands in a distorted octa-hedral environment. The structure contains two uncoordinated water mol-ecules. In the crystal, N-H⋯O, O-H⋯O and weak C-H⋯O hydrogen bonds and π-π stacking inter-actions between the pyridine rings of the pydc ligands, with a centroid-centroid distance of 3.4582 (18) Å, stabilize the structure.

Propane-1,2-diaminium bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O)cuprate(II) tetra-hydrate.

In the title compound, (C(3)H(12)N(2))[Cu(C(7)H(3)NO(4))(2)]·4H(2)O, the Cu(II) atom is six-coordinated in a distorted octa-hedral geometry by two tridentate pyridine-2,6-dicarboxyl-ate (pydc) ligands. In the crystal, inter-molecular O-H⋯O, N-H⋯O and weak C-H⋯O hydrogen bonds, as well as π-π stacking inter-actions between the pyridine rings of the pydc ligands [centroid-centroid distance = 3.4714 (14) Å] are present. C=O⋯π inter-actions between the carbonyl groups and pyridine rings [O⋯centroid distances = 3.150 (2) and 3.2233 (19) Å] are also observed.

Bis(2,3-diamino-pyridinium) bis-(µ-pyridine-2,6-dicarboxyl-ato)-κO,N,O:O;κO:O,N,O-bis-[aqua-(pyridine-2,6-dicarboxyl-ato-κO,N,O)bis-muthate(III)] tetra-hydrate.

In the centrosymmetric dinuclear complex anion of the title compound, (C(5)H(8)N(3))(2)[Bi(2)(C(7)H(3)NO(4))(4)(H(2)O)(2)]·4H(2)O, the Bi(III) atom is eight-coordinated in an N(2)O(6) environment and has a distorted bicapped trigonal-prismatic coordination environment. Extensive inter-molecular O-H⋯O, N-H⋯O and weak C-H⋯O hydrogen bonds lead to the stability of the crystal structure. Inter-actions between one C-H group of the 2,3-diamino-pyridinium [(2,3-dapyH)(+)] cation and the aromatic ring of the pyridine-2,6-dicarboxyl-ate (pydc) ligand (C-H⋯centroid distance = 2.78 Å) and π-π inter-actions between the (2,3-dapyH)(+) cations and between the (2,3-dapyH)(+) cation and the pydc ligand [centroid-centroid distances = 3.489 (5) and 3.694 (5) Å] are observed.