Unraveling the Energetics and Dynamics of Ibuprofen in Mesoporous Metal-Organic Frameworks

A computational study is reported to investigate the microscopic behavior of ibuprofen (IBU) in two mesoporous metal-organic frameworks (MOFs), MIL-101 and UMCM-1. Both host structures posses remarkably large pore volumes and surface areas. The predicted maximum loading of IBU is in good agreement with experimental measurement and approximately four times greater than that in silica MCM-41. The lowest-energy conformation of IBU in MIL-101 is preferentially located near the metal-oxide. From the highest-occupied molecular orbitals (HOMOs) and hand gap, a coordination bond is found to form between the carboxylic, group of IBU and the exposed metal site of MIL-101. IBU exhibits a stronger binding energy and a smaller mobility in MIL-101 than in UMCM-1. These factors are crucial for the delayed release of IBU from MIL-101, which was observed experimentally, This work unravels the energetics and dynamics of IBV in MOFs at the molecular level and provides useful insight into the interactions of drug with host MOFs.