Off the wire
• Colombian Pajon defends her Olympic gold in Rio  • Lee eventually beats Lin, Marin ends Asian monopoly at Rio Olympics  • Final classification of women's football at Rio Olympics  • Result of women's football at Rio Olympics  • Authorities foil separatist march in Indian-controlled Kashmir  • Results of women's field hockey at Rio Olympics  • UNHCR refugee awareness campaign upsets Latvian Defense Ministry  • Result of women's hockey gold medal match at Rio Olympics  • Georgia's Khinchegashvili, Iranian Yazdanicharati win Olympic wrestling titles  • Brazil's state power utility company selling off distribution arms  
You are here: 　 Home

Metal-organic frameworks to reveal atomic-scale structure of samples

Xinhua, August 20, 2016 Adjust font size:

Researchers in Berkeley, northern California, have created a sort of nanoscale display case that enables new atomic-scale views of hard-to-study chemical and biological samples.

Their work, published online this week in the journal Science, could help to reveal new structural details for a range of challenging molecules, including complex chemical compounds and potentially new drugs, by stabilizing them inside sturdy structures known as metal-organic frameworks (MOFs).

The researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, introduced a series of different molecules that were chemically bound inside these porous MOFs, each measuring about 100 millionths of a meter across, and then used X-ray techniques to determine the precise molecular structure of the samples inside the MOFs.

The new method, dubbed "CAL" for covalent alignment, namely the molecules form a type of chemical bond known as a covalent bond in the MOFs, enables researchers to determine the complete structure of a molecule from a single MOF crystal that contains the sample molecules, from a simple alcohol to a complex plant hormone, in its pores. The MOFs in the study provided a sort of backbone for the sample molecules that held them still for the X-ray studies.

The researchers prepared the samples by dipping the MOFs into solutions containing different molecular mixes and then heating them until they crystallized. "We wanted to demonstrate that any of these molecules, no matter how complex, can be incorporated and their structure determined inside the MOFs," Omar Yaghi, a materials scientist at Berkeley Lab and chemistry professor at UC Berkeley who led the research, was quoted as saying by a news release from UC Berkeley.

The MOFs also possess a particular handedness known as "chirality" -- like a left-handed person vs. a right-handed person -- that selectively binds with molecular samples that also possess this handedness. The difference in a molecule's handedness is particularly important for pharmaceuticals, as it can mean the difference between a medicine and a poison.

"This is one of the holy grails: how to crystallize complex molecules, and to determine their chirality," Yaghi said. Endit