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Dr. Wonyoung Choe, Assistant Professor
Chemistry
University of Nebraska - Lincoln
647 Hamilton Hall
Lincoln, Nebraska 68588-0304
office: (402) 472-0751
lab: (402) 472-5074
email: wchoe2@unl.edu
Choe's web page
Current Research
- Solid state chemistry
- Materials chemistry
- Hydrogen storage
- Inorganic-organic hybrids
- Chemical sensors
- Magnetic refrigeration
One of the fastest growing areas in materials chemistry is metal-organic frameworks, emerging as a new class of inorganic-organic hybrid materials. These materials are potentially useful in many applications ranging from gas storage to catalysis. The research group led by Prof. Wonyoung Choe focuses on porphyrin-based metal-organic frameworks with nanopores.
A daunting challenge in metal-organic frameworks has been how to 'decorate' pore surfaces with redox-active metal centers for the energy-related applications mentioned above. To address this urgent issue, porphyrins are chosen as molecular building blocks to build nanoporous materials. Porphyrins are important biomolecules, as exemplified by the iron porphyrin in hemoglobin (which is responsible for the oxygen transport in human body), and have been extensively studied over the past several decades. However, the use of porphyrins in nanochemistry is still in its infancy. Considering the fact that many interesting physical properties of porphyrins are closely related to the metal centers incorporated inside the porphyrins, the research outcome from such biomimetic framework solids may shed new light on multifunctional nanomaterials.
The Choe group members have successfully demonstrated a series of crystalline 2D/3D metal-organic frameworks with fascinating topologies, built from porphyrins and paddlewheel clusters (see an example in the figure above). These solids are referred as porphyrin paddlewheel frameworks (PPFs). Interestingly, these PPFs have large void spaces with channel sizes up to ca. 2nm. The topologies of PPFs can be systematically controlled by the coordination chemistry of the metal centers inside porphyrins. Currently, the group is working on physical characterization of these PPFs, and the topological design of new ones. These porphyrin-based materials may provide important chemical understanding in areas such as gas storage, heterogeneous catalysis, and chemical sensors. A new collaborative activity includes 2D porphyrin surface structures with Drs. Enders (physics) and Zheng (Chemistry) at UNL. Utilizing hydrogen- or coordination-bond, self-assembled porphyrins form interesting 2D surface patterns, which can be used as a basis for building surface-supported 3D hybrid structures.
Dr. Wonyoung Choe was born in Seoul, Korea. After finishing his B.S and M.S degrees at Seoul National University, Korea, he studied rare earth/transition metal chalcogenides and received his Ph.D at University of Michigan, Ann Arbor. Before joining UNL as a faculty, he finished his postdoctoral training at Iowa State University and Lawrence Livermore National Laboratory, where his research areas were magnetocaloric intermetallic alloys and magnetic nanoparticles.
Recent Publications
Testing the flexibility in a crystalline metal-organic framework: A case study of CdSO4-type porphyrin framework that exhibit concerted rotation in the solid. Hurley, E. P.; DeVries, L. D.; Hu, C.; Choi, E. - Y.; Choe, W. in preparation.
Isoreticular pillared porphyrin frameworks: Testing the limit of the pillar length and framework catenation. Chung H.; Barron, P. M.; Hu, Chunhua, H.; Choe, W. in preparation.
Construction of heterobimetallic porphyrin frameworks with 1D zig-zag porphyrin rods. Hurley, E. P.; Wray, C. A.; Choi, E. - Y.; DeVries, L. D.; Hu, C.; Choe, W. in preparation.
An interdigitated metalloporphyrin framework: 2D tessellation and framework flexibility. Choi, E. - Y.; DeVries, L. D.; Novotny, R. W.; Hu, C.; Choe, W. in preparation.
A metal-organic framework assembled from T-shaped and octahedral nodes: A mixed-linker strategy to create a rare anatase TiO2 topology. McDonald, J.; Chung, H.; Hu, C.; Choe, W. in preparation.
Bioinspired assembly of metal-organic frameworks: Selective metal site recognition and decoration of channel surfaces with transition metal centers. Wray, C. A.; Barron, P. M.; Hu, C.; Choi, E. - Y.; Choe, W. in preparation.
Structural variation in porphyrin pillared homologous series: Influence of distinct coordination centers for pillars on framework topology. Chung, H.; Barron, P. M.; Novotny, R. W.; Son, H.-T.; Hu, C.; Choe, W. Cryst. Growth Des. 2009. DOI: 10.1021/cg900220g
Highly tunable heterometallic frameworks constructed from paddle-wheel units and metalloporphyrins. Barron, P. M; Son, H. - T. Cryst. Growth Des. 2009, 9, 1960. DOI: 10.1021/cg801267m
Pillared porphyrin Homologous Series: Intergrowth in Metal-Organic Frameworks. Choi, E.-Y. Barron, P. M.; Novotny, R. W. Son, H. - T.; Hu, C.; Choe, W. Inorg. Chem. 2009, 48, 426. DOI: 10.1021/ic801677y.
Highly tunable metal-organic frameworks with open metal centers. Choi, E.-Y.; Wray, C. A.; Hu, C.; Choe, W. CrystEngComm, 2009, 11, 553. DOI: 10.1039/b819707p.
Classification of structural motifs in porphyrinic coordination polymers assembled from 5,10,15,20-tetrapyridylporphyrin and its derivatives. DeVries, L. D; Choe, W. J. Chem. Crystallogr. 2009, 39, 229. DOI : 10.1007/s10870-008-9474-z
A mixed-linker porphyrin framework with CdI2 topology. Choi, E. - Y.; Barron, P. M.; Novotny, R. W.; Hu, C.; Kwon, Y.-K.; Choe, W. CrystEngComm. 2008, 10, 824.
DOI: 10.1039/b720035h