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Stable and Functional Metal-Organic Frameworks: from Synthesis to Application

2016-07-08

 

TOPIC:Stable and Functional Metal-Organic Frameworks: from Synthesis to Application
SPEAKER:Prof. Dr. Hong-Cai Zhou, Associate Editor of Inorganic Chemistry, Texas A&M University, USA
TIME:July 8 (Friday) PM15:00 
LOCATION:Room 518, Chemistry Building A 
INVITER:Prof. Yong Cui 
 

 

Abstract: As an emerging class of highly ordered porous materials, metal–organic frameworks (MOFs) have attracted a great deal of attention in the last two decades. The modular nature empowers MOFs with extraordinary flexibility such as designable topology, adjustable porosity, tunable surface properties, and variable surface functionalities within a single material, which enables potential MOF applications in many areas including gas storage, separation, catalysis, and biomedical applications. Two prerequisites for these applications are functionality and stability. Thus, functionalization of exceptionally stable MOFs that have the most upsides in applications becomes a sought-after goal. MOF synthetic work has relied almost exclusively on the “one-pot” approach initially. In the last few years, attentions have been focused on the labile nature of the metalcarboxylate bonds. Recent work in stepwise MOF synthesis has led to a new synthetic toolbox. Using existing coordination assemblies, including preformed clusters, metal-organic polyhedron (MOPs) and MOFs, as starting materials, through bridging ligand exchange or metal metathesis, new MOPs and MOFs that are otherwise difficult or unforeseeable to obtain are now readily accessible. The key is to systematically analyze the kinetics and thermodynamics (K&T) of ligand exchange and metathesis reactions and apply K&T control. For instance, for high-valent MOFs, the inertness of the metal-carboxylate bonds is a double-edged sword: The MOFs are difficult to make but they are generally exceptionally stable. This has posed a synthetic challenge for the preparation of high-valent MOFs, which may have the most application potential. By judicious K&T control, we have developed the following synthetic methods: (1) Kinetically tuned dimensional augmentation, in which a robust cluster with terminal carboxylate groups has been extended to 3D frameworks by systematically tuning the kinetics of the synthetic procedure; (2) post-synthetic metathesis and oxidation, where redox chemistry has been applied to tune the kinetics of bridging ligand exchange; and (3) sequential linker installation, through which up to three different linkers can be installed sequentially to obtained mixed linker MOFs with crystallographically ordered structure.

 

Biographical Sketch: Hong-Cai “Joe” Zhou obtained his Ph.D. in 2000 from Texas A&M University under the supervision of F. A. Cotton. After a postdoctoral stint at Harvard University with R. H. Holm, he joined the faculty of Miami University, Oxford in 2002. He moved back to Texas A&M University and became a full professor in 2008. He was promoted to a Davidson Professor of Science in 2014 and a Robert A. Welch Chair in Chemistry in 2015. He was recognized as a Thomson Reuters “Highly Cited Researcher” in both 2014 and 2015 and was selected as a Fellow of the American Chemical Society in 2016. His research focuses on the discovery of synthetic methods to obtain robust framework materials with unique catalytic activities or desirable properties for clean-energy-related applications.