Systematic Expansion of Porous Crystals to Include Large Molecules

February 2013 SSRL Science Summary by Lori Ann White, SLAC Office of Communications

Recently, scientists at the University of California, Berkeley and Lawrence Berkeley National Laboratory and their collaborators synthesized a series of metal-organic frameworks (MOFs) with pores up to 98 Å in diameter-large enough to house protein molecules. For the first time the researchers were able to design strategies to overcome three major obstacles to increasing pore capacity: (a) limited solubility of large organic links; (b) structure interpenetration; and (c) collapse of pores after guest molecule removal. They targeted MOF-74, a well-studied MOF with a honeycomb-like pore structure built from linkers with one phenylene ring. Expanding the linkers generated a series of structures with sequentially larger pores that maintained the topology of MOF-74.

The researchers determined the crystal structures of these new MOFs by comparing their powder X-ray diffraction (PXRD) patterns with predicted structures generated by computer simulation. The predicted structures were validated with Rietveld refinements on PXRD patterns collected at SSRL Beam Line 2-1. The new MOF crystals demonstrate remarkable stability, ultrahigh porosity and extremely large pore apertures. Several members of this series have pores large enough to accommodate biomolecules such as myoglobin and green fluorescent proteins (GFPs) and show potential for use in molecular recognition and drug delivery.

The synthesis and characterization of the new MOFs and their properties are publically available and can be found in: http://www.sciencemag.org/content/336/6084/1018.full

 

Primary Citation

H. Deng, S. Grunder, K. Cordova, C. Valente, H. Furukawa, M. Hmadeh, F. Gándara, A. C. Walley, Z. Liu, S. Asahina, H. Kazumori, M. O'Keeffe, O. Terasaki, J. F. Stoddart, and O. M. Yaghi, "Large pore apertures in a series of metal-organic frameworks", Science, 336, 1018-1023 (2012) [DOI:10.1126/science.122013]

Related Links

• Science Highlight – HTML /  PDF

Contacts

Hexiang Deng, UC Berkeley
Omar M. Yaghi, UC Berkeley