Three isomorphous threefold interpenetrated 2D supramolecular frameworks: Synthesis, structure and sorption properties

Strategically designed and synthesized three isomorphous mononuclear complex, M(bpee)2(6-me-2,3-pyrdcH)2 [M = CoII (1), NiII (2) and FeII (3)] using the mixed ligand system. Structure determination reveals that each mononuclear fragment is engaged in bidirectional H-bonding (O–H···N) interactions forming a 2D supramolecular rectangular grid. Each rectangular grid undergoes threefold interpenetration resulting a 2D interpenetrated supramolecular framework with hydrophobic small pores. CO2 sorption at 195 K in 1 shows no occlusion in the pore surface, however hysteretic sorption observed with H2O and MeOH, correlated with the H-bonding interaction of H2O and MeOH with the pendant carboxylate O-atoms, which are aligned on the 2D surface.