Synthesis, structures, and properties of alkali and alkaline earth coordination polymers based on V-shaped ligand

A series of metal coordination polymers, [Li₂(OBA)] (1), [Na₂(OBA)(H₂O)] (2), [K(HOBA)] (3), [Rb(HOBA)] (4), [Cs(HOBA)] (5), [Mg(OBA)(H₂O)₂] (6), [Ca(OBA)(H ₂O)] (7), and [Sr(OBA)(H₂O)] (8) (H₂OBA = 4,4′-oxybisbenzoic acid), was synthesized from alkali and alkaline-earth metal salts and 4,4′-oxybisbenzoic acid by solvothermal reactions. Single crystal X-ray structure analysis revealed that compounds 1-5 and 7-8 are three-dimensional while complex 6 has a layered structure. The inorganic motifs, ranging from discrete octahedra (6), edge-sharing octahedral dimers (7), and straight one-dimensional inorganic chains (1 and 8) to two-dimensional inorganic layers (2-5), are connected through organic linkers and thus form neutral networks. High thermal stabilities were observed for compounds 1, 2, 6, 7, and 8 up to approximately 500 °C. Electrochemical measurements of 1 revealed a stabilized reversible capacity of approximately 100 mAh g^-1 after more than 30 charge/discharge cycles.