In particular, the H1 … Ofw RDF (Figure ), averaged over all four trajectories, exhibits only a shoulder in the distance range between 2 and 2.5 Å, not a pronounced maximum. This indicates that hydrogen bonds to oxygen atoms of the all-silica framework are relatively weak and transient, as observed previously for triclosan in all-silica FAU and MOR. In the lowest-energy configuration obtained for 5-FU@H-FAU_1H, the framework is deprotonated by the adsorbed molecule, with the proton now being bonded to the O4 atom of 5-FU. As is visible in Figure , the protonated 5-FU species is stabilised by two short hydrogen bonds from the H@O4 and H3 atoms to two Ofw atoms neighbouring the framework Al site.