Zinc coordination polymers containing substituted isophthalate ligands and fragments from in situ hydrolysis of 4-pyridylisonicotinamide

Hydrothermal treatment of zinc nitrate, a 5-substituted isophthalic acid and 4-pyridylisonicotinamide (4-pina) resulted in luminescent 2-D or 3-D coordination polymers that incorporated different fragments formed by in situ hydrolysis of the 4-pina precursor. [Zn7(isonicotinate)4(OH)6(5-nitroisophthalate)2]n manifests [Zn7(OH)6]n cationic chains linked into a 3-D pcu topology. [Display omitted] •Luminescent zinc coordination polymers with substituted isophthalate ligands.•4-Pyridylisonicotinamide in situ reaction yields 4-aminopyridine, isonicotinate.•2-D anionic grid for 5-hydroxyisophthalate, with 4-aminopyridinium cations.•3-D pcu net based on [Zn7(OH)6]n cationic chains for 5-nitroisophthalate. Hydrothermal treatment of zinc nitrate, a 5-substituted isophthalic acid, and 4-pyridylisonicotinamide (4-pina) resulted in crystalline coordination polymers that incorporated different fragments formed by in situ hydrolysis of the 4-pina precursor. These materials were characterized by single crystal X-ray diffraction. In the case of {[4-ampyrH]2[Zn(hip)2]·H2O}n (1, 4-ampyrH=4-aminopyridinium, hip=5-hydroxyisophthalate), anionic [Zn(hip)2]n2n− (4,4) grid layers co-crystallize with protonated 4-ampyr cations. Using 5-nitroisophthalic acid (H2nip), [Zn7(isonic)4(OH)6(nip)2]n (2, isonic=isonicotinate) was formed. This material manifests [Zn7(OH)6]n cationic inorganic chain motifs linked by isonic and nip ligands into a non-interpenetrated 3-D coordination polymer network with pcu topology. Luminescent behavior is attributed to intra-ligand molecular orbital transitions.