2019

New Synthesis Approach for Creating a Novel Hierarchical Self-Assembled Supramolecular Porous Material

Presenter: Javier Fonseca

Research Category: Engineering and Technology
PI: Javier Fonseca

Hierarchically porous materials with high stability and tailorable pore characters have the potential for mass transfer applications, including bulky molecule capture and separation, heterogeneous catalysis and drug delivery. Prospectively, the scope of functionalities would be notably broadened by employing tunable thickness metal-organic framework sheets as giant molecular building blocks for self-assembly into hierarchical supramolecular porous coordination materials. However, synthesizing metal-organic framework sheets with controllable bulkiness has proved challenging. We present a rational and unprecedented bottom-up strategy to prepare a novel two-dimensional metal organic framework sheet [Zn(BPDI)] (BPDI = N,N’-bis(glycinyl)pyromellitic diimide) with unusual and highly desired tunable thickness. Our synthesis approach relies on three intercorrelated steps: (1) promoting electron transfer from the metal source to the open-shell ligand, (2) controlling basicity and acidity to create a propitious medium for MOF synthesis, and (3) regulating the MOF growth kinetics via modulation of reagents. Zn(BPDI) sheets self-organize into a unique three-dimensional supramolecular coordination material (NEU-1) with tailorable porosity.  Therefore, our approach opens the door to non-straightforward MOF nanosheets and beyond, to a hierarchical supramolecular metal-organic framework with tunable pore system.