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

Abstract

Aqueous medium reactions of transition metal salts with HL under hydrothermal conditions at 90°C led to two new coordination polymers, [M(L)₂(H₂O)₂] · 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.

Keywords:

• Cobalt
• Manganese
• Flexibility
• Metal-organic frameworks

Acknowledgments

The authors gratefully acknowledge the Natural Science Foundation of Jiangsu Province of China (BK2008195) and the Science Research Foundation of Huaiyin Institute of Technology (HGQ0649) for financial support of this work.