1D Coordination Polymers Constructed from Pyridine-2,6-Dicarboxamide Ligands Showing Selective and Recyclable Adsorption toward Methanol Vapor

Abstract

Two helical ligands (L1 and L2) containing a pyridine-2,6-dicarboxamide skeleton were synthesized, and the crystal structures indicated racemic configurations with equal amounts of P- and M-helicity. Eight one-dimensional coordination polymers (CPs), {[ZnL1Cl2]·2CH3OH}n (1), [HgL1I2]n (2), {[AgL1NO3]·CHCl3}n (3), {[Cd(L1)2Cl2]·2DMF}n (4), {[Co(L1)2Cl2]·2DMF}n (5), {[ZnL2I2]·2DMF·H2O}n (6), [HgL2Cl2]n (7), and {[Hg2(L2)2Br4]·2CH3OH}n (8), were synthesized from the reaction of the two ligands with a series of transition metal ions. The crystal structures showed that the chiral self-assembly process of these ligands resulted in homochiral complexes (CP 1, 3, and 6), heterochiral complexes (CP 2, 4, 5, and 7), or the coexistence of homochiral and heterochiral complexes (CP 8). The gas adsorption/desorption experiments were investigated at room temperature, which showed that all the CPs exhibited good selective adsorption capacities (24.6–62.5 cm3/g) toward methanol vapor over other gas. Furthermore, CP 3, 5, and 6 were selected for the recyclable methanol vapor adsorption experiments, and the results showed that all three CPs can be recycled as good adsorbents for methanol vapor.