Mother-Solvent-Driven Reconstruction of Hydrolytically Transformed Metal–Organic Frameworks Tracked by Metal–Linker Vibrations

Abstract

Metal–organic frameworks (MOFs) with open metal sites derive their functions from dynamic metal–linker coordination, yet the same coordination lability often makes them vulnerable to water-induced structural transformation. Here, we show that hydrolytically transformed Cu-based MOFs can be reconstructed by re-exposure to their original mother-solvent environment without supplying external metal or linker sources. Using Cu3(BTC)2 and MOF-14 as representative Cu–carboxylate frameworks, we identify mother-solvent-driven reconstruction as a coordination-equilibrium-controlled process that restores long-range crystallinity, permanent porosity, local metal–linker bonding, and CO2 adsorption function. Powder X-ray diffraction and N2 sorption isotherms reveal framework-level recovery, while Fourier-transform infrared spectroscopy, Raman spectroscopy, and DFT-assisted vibrational assignments track the reorganization of carboxylate coordination, linker protonation states, and Cu paddlewheel node environments. The reconstructed Cu3(BTC)2 and MOF-14 recover CO2 uptakes of 5.08 and 2.47 mmol g–1, respectively, approaching their pristine values of 5.29 and 2.58 mmol g–1. These findings establish mother-solvent treatment as a mild route for recovering hydrolytically transformed MOFs and show that water-induced framework transformation can be reversed through solvent-defined coordination reorganization.