Structural diversity and properties of six coordination polymers derived from 1,2/1,3-phenylenedioxydiacetic acids and varied N-donor co-ligands

• Six new coordination polymers based on o/m-phenylenedioxydiacetate.
• The syntheses, crystal structures, topological analyses, solid-state properties of 1–6.
• The diverse coordination modes of o/m-phenylenedioxydiacetate.

Based on two positional isomers of phenylenedioxydiacetate ligands and different N-containing co-ligands, six novel coordination polymers, formulated as {[Zn(o-PDOA)(bpp)]·2H2O}n (1), {[Cd(o-PDOA)(bix)]·3H2O}n (2), [Cd(m-PDOA)(bix)]n (3), [Cd(m-PDOA)(bib)]n (4), [Zn(m-PDOA)(bix)]n (5), {[Zn(m-PDOA)(bib)]·2H2O}n (6), (o/m-H2PDOA = 1,2/1,3-phenylenedioxydiacetic acid; bix = 1,4-bis(imidazol-ylmethyl)benzene; bib = 1,4-bis(1H-imidazol-1-yl)-butane; bpp = 1,3-bis(4-pyridyl)propane), have been synthesized under hydrothermal conditions. Compound 1 features a three-dimensional (3D) 2-fold interpenetrating cds topology. In 2, the (H2O)6 clusters interlink the 1D double [Cd2(o-PDOA)2(bix)2]n chains into a 3D supramolecular network. Compound 3 is a (3,5)-connected 2D layer with (42.6)(42.67.8) topology. Compound 4 exhibits a 3-fold interpenetrating pcu topological network, while, 5 is a 2D puckered meso-helical 44-sql layer built by alternately arranged right-handed and left-handed helical chains. In contrast to 1–5, compound 6 possesses a 1D loop-like chain and, interestingly, rare D4 tetrameric (H2O)4 cluster extends the chains into a 3D supramolecular framework. Moreover, the thermal stabilities and luminescent properties of compounds 1–6 have also been investigated.

Under hydrothermal conditions, six new coordination polymers have been produced by the reaction of two positional isomers of phenylenedioxydiacetate ligands with ZnII/CdII salts in the presence of different N-containing co-ligands. The syntheses, crystal structures, topological analyses, photoluminescent properties, and thermal properties of 1–6 are studied in detail.Figure optionsDownload as PowerPoint slide