Because of these many considerations, tuning the adsorption properties and flexibility through linker functionalization or substitution is a difficult problem, and the methods of fine tuning the materials' responses through linker design are still highly sought after. Zhang et al. provided an example of tuning the gating energy barrier of a zinc-based MOF to improve molecular sieving performance. While the gate opening in the parent Zn 3 (OH) 2 (pzdc)(tz) framework (H3pzdc = 3,5pyrazoledicarboxylic acid, Htz = 1,2,4-trizole) is very easily triggered by small guest molecules, the authors demonstrated that functionalization of the Htz linker by -NH 3 (into 3-amino-1,2,4-trizole) strengthens intra-framework hydrogen bonding. This, in turn, leads to an increase in the gating energy barrier, and a shift of the pore opening pressure for C 2 and C 3 hydrocarbons, demonstrating control over flexibility and impact on molecular sieving performance.