Coordination polymers with the chiral ligand N-p-tolylsulfonyl-l-glutamic acid: Influence of metal ions and different bipyridine ligands on structural chirality

Four new polymers, namely [Ni(-tsgluO)(2,4′-bipy)2(H2O)2]n·5nH2O (1), [Co(-tsgluO)(2,4′-bipy)2(H2O)2]n·5nH2O (2), [Ni(-tsgluO)(4,4′-bipy)]n·0.5nH2O (3), and [Co(-tsgluO)(4,4′-bipy)]n·0.5nH2O (4), where tsgluO2−=(+)-N-p-tolylsulfonyl-l-glutamate dianion, 2,4′-bipy=2,4′-bipyridine, and 4,4′-bipy=4,4'-bipyridine, have been prepared and structurally characterized. Compounds 1 and 2 are isostructural and mononuclear, and crystallize in the acentric monoclinic space group Cc, forming 1D chain structures. Compound 3 is also mononuclear, but crystallizes in the chiral space group P21, forming a homochiral 2D architecture. In contrast to the other complexes, compound 4 crystallizes in the space group P−1 and is composed of binuclear [Co2O6N2]n4− units, which give rise to a 2D bilayer framework. Moreover, compounds 1, 2, and 4 self-assemble to form 3D supramolecular structures through π–π stacking and hydrogen-bonding interactions, while compound 3 is further hydrogen-bonded to form 3D frameworks. We have demonstrated the influence of the central metal and bipyridine ligands on the framework chirality of the coordination complexes.

Graphical abstractFour novel polymers based on a chiral ligand were prepared and structurally characterized; it represents the first series of investigations about the effect of central metals and bipyridine ligands on framework chirality.Figure optionsDownload full-size imageDownload as PowerPoint slide