Date of Award

1-1-2023

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Chemistry

Content Description

1 online resource (xix, 188 pages) : illustrations (some color)

Dissertation/Thesis Chair

Jeremy I Feldblyum

Committee Members

Marina A Petrukhina, Alan A Chen, Mehmet V Yigit

Keywords

chemical education, deinterpenetration, metal–organic frameworks, post-synthetic modification, Metal-organic frameworks, Chemistry

Subject Categories

Chemistry

Abstract

Metal–organic frameworks (MOFs) have risen in popularity in recent decades due to their applications in gas storage, separations, and catalysis. The vast potential of these materials is a result of the inherent characteristics and properties afforded by the composition and combination of ligand and metal clusters used to construct MOFs. In this dissertation, we explore the properties and capabilities of these frameworks from a variety of perspectives. First, we demonstrate the characteristics of MOFs in experiments designed to be suitable for integration in an educational environment. Inorganic chemistry derives many of its concepts from multiple facets of chemistry, which makes it ideal for teaching foundational topics for introductory chemistry courses. However, inorganic chemistry and materials science are rarely explored in these introductory courses for a variety of reasons, including lack of specialized equipment, complexity of materials synthesis, and safety concerns for the reagents used. We propose MOFs as a modern class of materials suitable for the demonstration of inorganic materials synthesis for introductory chemistry laboratory classes through the “green” synthesis of the MOFs HKUST-1 and AlF. Additionally, we have designed two laboratory experiments demonstrating the porosity and adsorptive properties of these materials which can be carried out with common, inexpensive laboratory equipment. Second, we dive deeper into the properties of MOFs that dictate preferences towards certain motifs and configurations. Structural design based solely on the choice of ligand and cation has been possible for some MOFs, but synthesis outcomes are more often difficult to predict due to the subtleties of phase selection during synthesis. This work focuses on the well-known family of 2D Zn MOFs based on terephthalate and capping N-donor ligands. Four of these MOFs are synthesized, two having the expected dinuclear Zn paddlewheel cluster, and two having a less commonly observed trinuclear Zn3 cluster. Factors influencing phase selection between paddlewheel and Zn3 cluster-based MOFs are discussed. The last two chapters of this dissertation focus on post-synthetic modification of MOFs. As mentioned above, predicting desired MOF structures based on ligand and metal choice is often not reliable for many frameworks. Post-synthetic modification (PSM) is presented as a viable option for obtaining structures that are usually difficult to synthesize directly via de novo methods, offering a viable alternative means to control the structure of the final material. Both ligand and metal exchange in a nonporous 2D paddlewheel MOF is demonstrated, the first instance of such an exchange observed in nonporous 2D paddlewheel frameworks as well as the first reported instance of metal exchange in nonporous MOFs. Finally, we report the successful deinterpenetrative synthesis of IRMOF-9 to IRMOF-10 via PSM. When synthesizing MOFs possessing large pores, the risk for interpenetration, or the formation of a secondary framework within the formed voids, increases. The interpenetrating frameworks subsequently diminish the accessible porosity and available surface area of the MOF, resulting in the efforts for synthesizing frameworks with large pores to have the opposite of the intended outcome. However, using a solution of ethylammonium bromide, we propose a method to selectively etch away the interpenetrating framework in IRMOF-9 to reveal the larger pores of the deinterpenetrated framework of IRMOF-10.

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