Synthesis, and characterization of 1- and 2-D coordination polymers derived from the pseudopeptidic ligand oxamide-N,N′-diacetate: Insights into the supramolecular architectures constructed through H-bonds

The reaction of metal(II) nitrates with oxamide-N,N′-diacetic acid (H4L) in aqueous media under mild conditions, leads to the formation of novel coordination polymers formulated as {[M(H2L)(H2O)x]·2(H2O)}n where M = Co(II), x = 4 (1); Ni(II), x = 4 (2); Zn(II), x = 3 (3); Cd(II), x = 3 (4); Ca(II), x = 2 (5). Compounds 1–4 are 1D polymers with the ligand being doubly deprotonated and coordinated through the carboxylic edges. Compound 5 is a 2D polymer with the ligand utilizing all of the available oxygen atoms for coordination. In all cases extended hydrogen bonding leads to the formation of 3D supramolecular architectures. The structures are discussed in terms of topological description. The synthesized compounds were also characterized with spectroscopic techniques and their stability was checked with thermal studies.

Graphical abstractOxamide-N,N′-diacetic acid forms novel 1- and 2-D coordination polymers upon reaction with metal ions. 3D supramolecular architectures are formulated via H-bonding interactions between the chains or layers and lattice water molecules.Figure optionsDownload full-size imageDownload as PowerPoint slide