A robust viologen and Mn-based porous coordination polymer with two types of Lewis acid sites providing high affinity for H2O, CO2 and NH3

Abstract

A novel porous coordination polymer [Mn(pc3)(H₂O)₂]·xH₂O (3 < x < 4) is synthesized in water at pH = 7 using the anionic viologen-carboxylate ligand 4,4′-bipyridinium,1,1′-bis-(2,4-dicarboxyphenyl) (pc3²⁻). Dehydration of the material results in the formation of open pores containing two types of accessible Lewis acid sites: exposed Mn²⁺ cations and N⁺ atoms of viologen units. Due to this property the PCP shows high affinity and capacity in the adsorption of H₂O, CO₂ and NH₃. Despite the presence of strong adsorption sites this material is stable in liquid water and in gaseous NH₃.