trans-Diaquabis[5-carboxy-4-carboxylato-2-(4-pyridinio)-1H-imidazol-1-ido-κ2N3,O4]iron(II)

Zwitterionic 4-carboxy-2-(1-methylpyridin-1-ium-4-yl)-1H-imidazole-5-carboxylate

In the title zwitterionic mol­ecule, C₁₁H₉N₃O₄, the imidazole and pyridine rings form a dihedral angle of 2.60 (2)°. An intra­molecular O—H⋯O hydrogen bond occurs. In the crystal, pairs of N—H⋯O hydrogen bonds link the mol­ecules into inversion dimers. Weak inter­molecular C—H⋯O inter­actions further consolidate the crystal packing.

trans-Diaqua-bis-[4-carboxy-5-carboxyl-ato-2-(pyridin-1-ium-4-yl)-1H-imidazol-1-ido-κN,O]cobalt(II)

In the title compound, [Co(C₁₀H₆N₃O₄)₂(H₂O)₂], the Co^II ion is coordinated by two O atoms of two water mol­ecules, two imidazole nitro­gen atoms and two carboxyl­ate O atoms of the two trans-standing chelate ligands, displaying a distorted octa­hedral coordination geometry. A three-dimensional supra­molecular framework is generated through N—H⋯O, O—H⋯N and O—H⋯O hydrogen-bonding inter­actions.

trans-Diaquabis[5-carboxy-4-carboxylato-2-(4-pyridinio)-1H-imidazol-1-ido-κ2N3,O4]zinc(II)

In the title complex, [Zn(C₁₀H₆N₃O₄)₂(H₂O)₂], the Zn^II atom is located on a twofold rotation axis and is coordinated by two trans-positioned N,O-bidentate and zwitterionic 5-carb­oxy-4-carboxyl­ato-2-(4-pyridinio)-1H-imidazol-1-ide (H₂PIDC⁻) ligands and two water mol­ecules, defining a distorted octa­hedral environment. The complete solid-state structure can be described as a three-dimensional supra­molecular framework, stabilized by extensive hydrogen-bonding inter­actions involving the coordinated water mol­ecules, uncoordin­ated imidazole N atom, protonated pyridine N and carboxyl­ate O atoms of the H₂PIDC⁻ ligands.