Liquid-liquid interface synthesis method of unprecedented metal-organic frameworks : fundamental theory, new materials and applications

Abstract

Hierarchically porous materials with high stability have potential for mass transfer applications, including bulky molecule capture and separation, heterogeneous catalysis, and drug delivery. The scope of functionalities can be notably broadened by employing metal-organic framework (MOF) sheets as giant molecular building blocks for self-assembly into hierarchical supramolecular porous coordination materials. A rational yet unprecedented bottom-up strategy (liquid-liquid interface synthesis method) to prepare novel two-dimensional MOF sheets is developed in the first part of this Dissertation. This approach opens the door to both new MOF sheets and unique hierarchical supramolecular MOFs. In the second part of this Dissertation, two novel MOFs (crystalline NEU-1c = Zn(BPDI)(Py)2 and amorphous NEU-2 = Fe(BPDI)(Py)2) with multi-channel pore systems are synthesized (via liquid-liquid interface synthesis method), and subsequently tested as class 1 sorbents by evaluating their CO2 capture capacity. This research demonstrates that the ordered crystalline state of MOFs is not a requirement for gas uptake, establishing amorphous MOFs with hierarchical porosity as promising materials for CO2 capture applications. It is evidenced that amorphous MOFs may facilitate a variety of chemical separations due to its framework flexibility and, ultimately, its guest-responsive capability. In the third and last part of this Dissertation, two new porous, dynamic and amorphous MOFs, NEU-3 = Zn(PMDA)(Py)2 and NEU-4 = Fe(PMDA)(Py)2, are designed and synthesized (via liquid-liquid interface synthesis method). These MOFs along with NEU-1c and NEU-2 are unique smart guest-responsive materials owing to their π Lewis acidic pore surface and framework flexibility. It is achieved a variety of effective adsorptions and adsorptive separations by using beds of NEU-1c, NEU-2, NEU-3 and NEU-4. Promising for further investigations into the petrochemical industry, NEU-4 shows ultrahigh benzene adsorption, recognition capability, selectivity for benzene over its analogues, and high stability and regenerability.--Author's abstract