Two new 2D coordination polymers constructed from 2, 6-dimethylpyridine-3, 5-dicarboxylic acid ligands and alkaline earth metals (Sr and Ba)

•Two compounds constructed from H2MPDC ligand and alkaline earth metals.•Both the two compounds are linked by 1D chains to form a 2D layer.•In compound 2, it contains interesting chiral helical chains.•Both compound 1 and 2 exhibit strong blue photoluminescence properties.

Two new alkaline earth metals coordination polymers, namely, [Sr(C9NO4H7)(H2O)2] 1 and [Ba(C9NO4H7)(H2O)2] 2 have been constructed under solvothermal conditions, employing 2, 6-dimethylpyridine-3, 5-dicarboxylic acid (H2MPDC) as organic ligand. Both the two compounds have been characterized by thermogravimetric analysis, IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analyses. The results of crystal structural analysis indicate that compound 1 shows infinite chains which extend into two-dimensional (2D) sheets by μ4-MPDC2 −. Compound 2 is also a 2D layer structure and in the intralayer regions parallel left- and right-handed helical chains exist. In addition, compounds 1 and 2 exhibit strong phosphorescent emissions in the solid state at room temperature.

Graphical abstractStructural view of the coordination polymer [Ba(C9NO4H7)(H2O)2] (2). For compound 2, the [BaO8] units are connected with μ5-MPDC2 − ligands to form an interesting chiral helical chain, and the adjacent chiral helical chains are further connected by the μ5-MPDC2 − bridges to form a 2-D layer.Figure optionsDownload full-size imageDownload as PowerPoint slide