Expanding the MOF Toolkit to Access New Solid-State Functionality: Porous Materials based on Phosphines, Arsines and Chalcogenides

University Of Texas At Austin, Austin TX

Investigators

Abstract

Non-Technical Summary This research program, which is supported by the Solid State and Materials Chemistry program at NSF, involves the preparation and studies of new porous materials, whose unique properties provide fundamental advances for our future energy needs. Porous materials are critical in many large-scale industrial applications, ranging from water purification to the separation of the components of air, and from the capture of toxic chemicals to the production of fuels. However, to make existing processes more efficient and environmentally-friendly, it is essential to improve the properties of materials that perform these functions. The Humphrey group at the University of Texas Austin is working to design and synthesize new porous materials that can incorporate a wide range of well-defined metal species inside their pores. At present, chemically reactive metals cannot be easily or systematically incorporated into most porous materials. Providing a general solution to this problem leads to materials that can capture certain valuable chemical species with greater selectivity and higher capacity. The research team comprised of the PI, graduate students and undergraduate researchers works together to prepare model materials, which are studied using state-of-the-art characterization tools to obtain fundamental information about their properties. Throughout this process, the research team collaborates with theoretical chemists and scientists at beamline facilities to gain a deeper understanding of how structure can affect function. This project integrates an innovative undergraduate educational program, called the Austin-International Framework (AIF). The AIF provides a fully immersive, scholarship-supported international exchange experience to UT Austin undergraduate scientists; students are given the opportunity to broaden their horizons by witnessing first-hand the global nature of science via a semester of study and research in porous materials development at one of several overseas universities of international acclaim. Technical Summary The scientific objective of this project, which is supported by the Solid State and Materials Chemistry program at NSF, is to prepare new metal-organic framework (MOF) materials based on unexplored classes of ligands, and to gain an in-depth understanding of their solid-state properties. The field of MOF research continues to expand at an increasing rate, as new potential applications of this novel class of porous materials are discovered. The potential boundaries of MOF chemical complexity remain unknown. However, advances in this regard are slow, restricted by the reliance of MOF discovery using chemically similar organic components. The Humphrey group significantly expands the MOF 'toolkit' by showing that phosphine, arsine and chalcogenide ligands can impart genuinely new solid-state functionalities. The resulting MOF micropores are decorated with structurally well-defined Lewis bases, which can be exploited as post-synthetic attachment points for low-valent, low-coordinate metal species that impart advanced solid-state functionalities (i.e., small molecule chemisorption, chemical bond activation). In essence, the target MOFs are crystalline, atomically-precise solid-state ligands. This is a challenging project, but the resulting materials provide new avenues to systematically incorporate a broad range of metal species of industrial relevance into uniquely confined micro-pore environments. From a fundamental perspective, these materials advance the frontiers of chemical reactivity in MOFs and provide ideal models on which to perform detailed characterization studies pertaining to stronger gas adsorption processes. From a technological perspective, new materials that enable selective adsorption and activation of gases are important for future applications in atmospheric remediation and the production of renewable fuels. In addition to providing research opportunities for undergraduate and graduate students at UT Austin, this project also integrates an innovative undergraduate educational program, called the Austin-International Framework (AIF). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.