Syntheses, structures, and properties of multidimensional lithium coordination polymers based on aliphatic carboxylic acids

Three lithium coordination polymers, [Li₄(H₂O) ₂(EDTA)] (1), [Li₄(H₂O)₄(BTCA)] (2), and (H₂NMe₂)₂[Li₂(H ₂O)₂(BTCA)] (3) (H₄EDTA = ethylenediaminetetraacetic acid, H₄BTCA = 1,2,3,4-butane tetracarboxylic acid, H₂NMe₂ = dimethyl amine), have been synthesized by reacting lithium salts with aliphatic carboxylic acids using a solvothermal method. The structures of all the three complexes have been determined by single crystal X-ray diffraction studies. The single crystal structure analysis revealed that complex 1 has a three-dimensional framework, whereas complex 2 has 2D sheets and complex 3 has 1D chains. In addition, these lithium complexes contain various inorganic motifs with a tetramer in 1 and 2, and discrete tetrahedra in 3 and have further been connected through organic ligands to construct multidimensional structures. Further, the electrochemical properties of complexes 1-3 have been studied to evaluate these compounds as electrode materials for lithium ion batteries with discharge capacities of around 100 mA h g^-1 in the first thirty cycles.