Hygroscopic metal-organic framework MIL-160(Al) In-situ time-dependent ATR-FTIR and gravimetric study of mechanism and kinetics of water vapor sorption.
Metal-organic frameworks (MOFs) are advanced highly porous coordination polymers of high interest to separations, environmental remediation, catalysis, and biomedicine. While many MOFs are unstable in water and aqueous solutions, aluminum MOFs (Al-MOFs) offer an unprecedented stability. First, we synthesize unusual highly hygroscopic Al-MOF MIL-160(Al), purify it and assign FTIR peaks to specific groups as potential water binding sites. Further, we introduce a novel method of in-situ time-dependent ATR-FTIR spectroscopy to detect specific binding sites in MIL-160(Al) and investigate the progress of reaction. Specifically, we combine in-situ time-dependent ATR-FTIR spectroscopy with using water as spectroscopic probe to determine binding sites in MIL-160(Al) and their evolution during the reaction. The in-situ time-dependent ATR-FTIR spectra provide evidence of water bonding to the μ-OH group, the carboxylate anion COO