From PNNL: “A Duet of Firsts: Imaging Chemical Building Blocks”


July 2017

The new metallic-organic framework, NU-1301, is made up of uranium oxide nodes and tricarboxylate organic linkers. Image courtesy of Northwestern University.

Two firsts in science came about because of a near-dare. According to Nigel Browning at Pacific Northwest National Laboratory, “Omar Farha was giving a presentation on MOFs [metal-organic frameworks] and someone said ‘I bet you couldn’t make one out of uranium.’” Farha took the challenge and proved them wrong. In designing the uranium-laden frameworks, PNNL scientists Dr. Nigel Browning and Dr. Layla Mehdi helped Farha and his colleagues at Northwestern University overcome a troubling bottleneck in imaging the material. Before this study, scientists used x-ray analysis and modeling to map out MOF structures. The approaches come with sharp drawbacks. Browning and Mehdi showed that low-dose imaging is a viable option for MOF imaging, allowing for the structure to be resolved at the near-atomic level.

This collaborative effort produced two notable milestones; it was first MOF made out of uranium, and the first time low-dose electron microscopy was used to map the MOF structure.

Reference: Li P, NA Vermeulen, CD Malliakas, DA Gómez-Gualdrón, AJ Howarth, BL Mehdi, A Dohnalkova, ND Browning, M O’Keeffe, and OK Farha. 2017. Bottom-up construction of a superstructure in a porous uranium-organic crystal. Science 356(6338):624-627. DOI: 10.1126/science.aam7851

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

Pacific Northwest National Laboratory (PNNL) is one of the United States Department of Energy National Laboratories, managed by the Department of Energy’s Office of Science. The main campus of the laboratory is in Richland, Washington.

PNNL scientists conduct basic and applied research and development to strengthen U.S. scientific foundations for fundamental research and innovation; prevent and counter acts of terrorism through applied research in information analysis, cyber security, and the nonproliferation of weapons of mass destruction; increase the U.S. energy capacity and reduce dependence on imported oil; and reduce the effects of human activity on the environment. PNNL has been operated by Battelle Memorial Institute since 1965.