Ligand Cross-Links as a Design Element in Oligo- and PolyMOFs

Abstract

Metal-Organic Frameworks (MOFs) constructed using cross-linked oligomeric or polymeric ligands (OligoMOFs and PolyMOFs respectively) have so far relied on a handful of canonical structural blueprints, in which the cross-links have not played a significant role in determining structure. In this study, we show that cross-links between terephthalate ligands in dabco-based Zn-MOFs (DMOFs) can exert control over the overall phase landscape of resulting oligo- and polyMOFs. We find that cross-links can direct the overall topology of the resulting MOF (pcu vs. kag) based on their length or rigidity, and can influence the phase transformation behavior of the pcu network. We also show the first example of tethered ligand dimers adopting a different MOF structure to the analogous trimer and polymer. Understanding the influence of cross-links on the formation of these MOFs will help guide the design of future MOF-Polymer hybrid materials.