Dinuclear Zn(II) and Hg(II) complexes of an angular dipyridyl ligand: syntheses, crystal structures, and properties

The purine-carboxylate-containing coordination polymer poly[[μ4-1-(2-carboxylatoethyl)-6-oxo-6,9-dihydro-1H-purin-9-ido]zinc(II)]

The title compound, [Zn(C8H6N4O3)]n or [Zn(L)]n [H2L is 3-(6-oxo-6,9-dihydro-1H-purin-1-yl)propionic acid], crystallized as a nonmerohedral twin. The Zn(II) cation is four-coordinated, ligated by two carboxylate O atoms from two L ligands and two N atoms from another two ligands. Each ligand bridges four Zn(II) centres, extending the structure into a three-dimensional polymer with a 4-connected (6(5),4(1)) topological structure containing two-dimensional homochiral layers constructed from one-dimensional metal-organic helices. Investigation of the thermal stability of the compound shows that the network has very high thermostability and is stable up to 720 K.