Synthesis and characterization of tetrapyridophenazine ligand and its novel 1-D metal-organic wave-like coordination polymer of Ni(II) ion

Abstract

Abstract A protonated tpphz ligand, H2tpphz · 2 H2O · 2 Cl, 1, and novel 1-D coordination polymer of the type [Ni2(μ2-tpphz)(μ2-tp)(H2O)6] n · (tp) · 3.65(H2O), 2 (where tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine, and H2tp = terephthalic acid) have been synthesized and characterized by single crystal X-ray diffraction analysis. The asymmetric units in both structures consist of half of their formula. In the crystal structure 1, different types of hydrogen bonds together with π—π stacking are dominant. In the structure of 2, Ni(II) ion is coordinated by two N atoms from tpphz, one oxygen atoms from terephthalic acid and three water oxygen atoms in a distorted meridional octahedral geometry. Each tp ligand bridges two Ni(II) centers through monodentate carboxylate group. In the overall structure of 2, the Ni(II) centers are connected by tp and tpphz ligands to create a 1-D wave-like chain with a period of 20.91 Å running parallel down [1, 2].