Crystal structure of a binuclear nickel(II) complex constructed of 1H-imidazo[4,5-f][1,10]phenanthroline and doubly deprotonated benzene-1,3,5-tri­carb­oxy­lic acid

The title complex, [Ni(2)(C(9)H(4)O(6))(2)(C(13)H(8)N(4))(2)(H(2)O)(4)]·2H(2)O, bis­(μ-5-carb­oxy­benzene-1,3-di­carboxyl­ato-κ(2) O (1):O (1′))bis­[di­aqua(1H-imidazo[4,5-f][1,10]phenanthroline-κ(2) N (7),N (8))nickel(II)] di­hydrate, was obtained under solvothermal conditions by the reaction of benzene-1,3,5-tricarboxylic acid (H(3)BTC) with Ni(NO(3))(2) in the presence of 1H-imidazo[4,5-f][1,10]phenanthroline (IP). The crystal has triclinic (P-1) symmetry with a centrosymmetric binuclear nickel(II) cluster. The Ni(II) atom is coordinated by two N atoms from a chelating 1H-imidazo[4,5-f][1,10]phenanthroline ligand, two carboxyl­ate O atoms from two 5-carb­oxy­benzene-1,3-di­carboxyl­ate ligands and two water mol­ecules in a slightly distorted octa­hedral geometry. Two carboxyl­ate groups bridge two Ni(II) cations, forming the binuclear complex. Extensive N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonding is present in the crystal structure, forming a three-dimensional supermolecular framework. Weak π–π stacking is observed between parallel HBTC(2−) and IP ring systems, the face-to-face separation being 3.695 (2) Å.