A new supramolecular cobalt(II) complex based on 1,10-phenanthroline and 4-nitrophthalate ligands
Abstract
The title compound, bis(μ-2-carboxy-4-nitrobenzoato-κ 2 O 1 : O 1′ )bis[bis(1,10-phenanthroline-κ 2 N , N ′)cobalt(II)] bis(2-carboxy-4-nitrobenzoate) tetrahydrate, [Co 2 (C 8 H 4 NO 6 ) 2 (C 12 H 8 N 2 ) 4 ](C 8 H 4 NO 6 ) 2 ·4H 2 O, comprises a centrosymmetric dinuclear cobalt(II) complex dication, two hydrogen 4-nitrophthalate anions and four water molecules of crystallization. The two Co II atoms are linked by two μ-hydrogen 4-nitrophthalato ligands, generating a centrosymmetric dinuclear unit. Each cobalt(II) centre adopts a distorted octahedral coordination geometry defined by four N atoms from two chelating 1,10-phenanthroline ligands and two O atoms from two symmetry-related bridging hydrogen 4-nitrophthalate ligands. In the crystal, O—H...O and C—H...O hydrogen bonds link the ionic components into a three-dimensional supramolecular framework, which is further reinforced by aromatic π–π stacking interactions between neighbouring phenanthroline and hydrogen 4-nitrophthalate rings, with centroid-to-centroid separations ranging from 3.501 (5) to 3.687 (4) Å. Hirshfeld surface analysis shows that O...H/H...O contacts make the largest contribution (38.1%) to the crystal packing, confirming the dominant role of hydrogen bonding in consolidating the crystal structure.