Synthesis, characterization, and crystal structures of two coordination polymers from 3,5-bis(pyridin-4-ylmethyl) aminobenzoic acid

Aqueous medium reactions of transition metal salts with HL under hydrothermal conditions at 90 degrees C led to two new coordination polymers, [M(L)(2)(H2O)(2)]center dot H2O [M = Co(1) and Mn(2); HL 3,5-bis(pyridin-4-ylmethyl) aminobenzoic acid]. HL contains both flexible N-donor groups [(pyridin-4-ylmethyl) amino] and carboxylate. The flexibility of (pyridin-4-ylmethyl) amino endows HL the ability to adopt varied conformations and coordination modes. Due to the presence of nitrogen and oxygen of HL and water in the reaction system, hydrogen-bonding interactions are available to assemble donor and acceptor building blocks. The two complexes are structurally similar to L doubly interconnecting M(II) to form 1-D chains. The extension of the 1-D chain through hydrogen-bonding forms fascinating 3-D supramolecular frameworks. FT-IR spectroscopy and thermal stability have been studied. The two compounds represent the first complexes containing 3,5-bis(pyridin-4-ylmethyl) amino benzoate.