If engineers ever hope to build structures at the nanoscale, they’re going to need very, very tiny fingers. Or at least very tiny tools. By building a wrench that’s just 1.7 nanometers across, researchers from the University of Vermont have taken a critical step in that direction.
This technique leverages an attribute of molecules known as chirality. A molecule is considered chiral if comes in two identical, but mirrored, forms. Like our hands, molecules can either be right- or left-handed. University of Vermont chemist Severin Schneebeli assembled C-shaped strips of anthracene molecules (a hydrocarbon derived from distilled crude oil) that, owing to their chirality, are able to connect to each other, but in only one direction.
“They’re like Legos,” explained Schneebeli in a release.
Like a wrench hunting for a bolt: This simulation shows a pillarene ring getting found and embraced by a larger chemical structure. (Caption and video credit: Jianing Li, UVM/Xiaoxi Liu et al., 2015)
These strips can form a rigid structure capable of holding rings of other chemicals, similar to how a five-sided bolt fits snugly into a pentagonal wrench. “It’s like a real wrench,” says Schneebeli — but with an opening a hundred-thousand-times smaller than the width of human hair. The structure is able to retain its shape, even when dipped in various solvents and when exposed to different temperatures.
A blue wrench (of molecules) to adjust a green bolt (a pillarene ring) that binds a yellow chemical “guest.” It’s a new tool — just 1.7 nanometers wide — that could help scientists catalyze and create a host of useful new materials. (Caption and image credit: Severin Schneebeli)·
The technique could eventually be used as a highly accurate and rapid method of creating customized molecules. Called “chirality-assisted synthesis,” the nano-wrench could help to build the next generation of complex synthetic materials, including polymers and medicines.
“Fully shape-persistent structures can thus be created, even in the form of linear chains,” write the researchers. “With CAS, selective recognition between large host and guest molecules can reliably be designed [from scratch].”
Read the entire study at Angewandte Chemie: “Regulating Molecular Recognition with C-Shaped Strips Attained by Chirality-Assisted Synthesis”.
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