Solvothermal syntheses, structures and properties of two new metal coordination polymers based on rigid 1,3-adamantanedicarboxylic acid ligand

Two new metal coordination polymers (CPs) based on rigid 1,3-adamantanedicarboxylic acid (1,3-H2adc) ligand have been successfully prepared under different solvothermal conditions. In these two compounds, Ni2Cl2(2,2′-bipy)2(1,3-adc) (1) (2,2′-bipy = 2,2′-bipyridine) and Pb(H2O)(1,3-adc) (2), 1,3-adc2− ligand displays two different coordination modes, constructing disparate architectures by bridging the different building units. Compound 1 features a chiral 1D zigzag chain containing the dimeric [Ni2Cl2(2,2′-bipy)2]2+ units and 1,3-adc2− bridging ligands. The zigzag chain and its enantiomer alternately stack along the a axis through the π–π stacking interactions of bipy ligands. Compound 2 shows a 2D layer with the rhombic windows built from the infinite bent Pb–O chains and 1,3-adc2− bridging ligands. Moreover, compound 1 shows a high thermal stability limit of 425 °C and displays ferromagnetic interactions in the range of 4–300 K.