Isomorphous and Isostructural Coordination Polymers Besides Metal‐Organic Frameworks (MOFs) of bis(4‐Nitrophenyl)‐phosphoric Acid in Conjunction with Some N‐donor Compounds

Abstract

Various coordination complexes, in the form of infinite coordination polymers and metal‐organic frameworks (MOFs) of an organophosphorous acid, bis(4‐nitrophenyl)phosphoric acid (BNPP), in the presence of some N‐donor compounds like 4,4′‐bipyridine (bpy), 1,2‐bis(4‐pyridyl)ethene (bpyee), 1,2‐bis(4‐pyridyl)ethane (bpyea) and 1,3‐bis(4‐pyridyl)propane (bpypa) along with metal ions, Co+2, Cd+2, Cu+2, and Ni+2, have been reported. Using the single crystal X‐ray diffraction method, the obtained structures are classified into isomorphous, isostructural coordination polymers, and metal‐organic framework structures. Except for the structures, formed by bpy with Ni(II) and Cu(II), bpypa with Cu(II) and bpyee with Co(II) and Ni(II), all of the complexes crystallize with both BNPP and N‐donor ligands forming coordinate bonds with the metal ions, yielding dumbbell‐shaped moieties in the lattices. A noteworthy feature in the structures obtained with bpyee, is that BNPP molecules do not form coordination bonds with metal ions Co(II) and Ni(II), while N‐donor ligands (bpyee) are only connected to the metal ions. Furthermore, in these complexes, the BNPP molecules occupy the same positions in the crystal lattice as those of coordinated BNPP moieties, but by hydrogen bonds, thus, establishing a high correlation of isostructurality in three‐dimensional packing between structures having coordinated and uncoordinated BNPP molecules, and highlighting the significance of hydrogen bonds in comparison with coordinated bonds. All of the complexes described, herein, are stabilized by different types of intermolecular interactions, specifically through a large number of C−H⋅⋅⋅O hydrogen bonds. Hirshfeld analysis further demonstrates surface properties and establishes accountability of various intermolecular interactions towards the stabilization of the complexes, emphasising, in particular, the importance of the C−H⋅⋅⋅O hydrogen bonds