Precise C₂H₂ Adsorption Affinity Modulation by Nitrogen Functionalization in Isostructural Coordination Networks

Meticulous regulation of pore chemistry is essential for elucidating the intricate mechanism of the adsorption efficacy of porous materials. However, it is a great challenge to address the functionalization of pore chemistry while preserving pore size and geometry. In this study, the robust NPU-1 series network is selected as a platform to address this challenge. By regulating the nitrogen distribution in bilayer-pyridine ligands, a series of coordination networks (NPU-1-TPB/TPP/TPT) with the same pore size and geometry but different pore polarity is obtained, affording an increase in C₂H₂ enthalpies from -28.3 to -33.1 kJ mol^-1. In situ, infrared spectroscopy uncovers the enhanced C₂H₂ interaction with the central phenyl ring of bilayer-pyridine ligands with the extent of nitrogen functionalization.