Improved moisture resistance of a new Zn4O-based metal-organic framework by introducing hydrophobic phenyl groups

A new Zn4O-based isoreticular MOF, Zn4O(CH3PhTDC)(3) (IFMC-29, IFMC corresponds to Institute of Functional Material Chemistry) has been synthesized by using an asymmetrical rigid carboxylate ligand 3-methyl-4-phenylthieno[2,3-b]thiophene-2,5-dicarboxylic acid (H2CH3PhTDC). Powder X-ray diffraction (PXRD) experiments and contact angle measurements indicate that IFMC-29 possesses improved moisture resistance, which is attributed to the introduction of hydrophobic phenyl groups around the water-sensitive Zn4O(COO)(6) clusters. At 77 K and 1 bar, IFMC-29 displays a relatively high hydrogen storage capacity (1.75 w%) among the Zn4O-based isoreticular MOFs. This work can provide a useful strategy for designing water-stable Zn4O-based MOFs in practical application.