Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Molecular Mixers

Scientists engineer light-driven molecular motors to create a stir

by Matt Davenport
October 6, 2014 | A version of this story appeared in Volume 92, Issue 40

Laboratory stir bars may soon come in a new size: nanoscopic. Researchers at the University of Groningen, in the Netherlands, have synthesized rodlike molecular rotors of differing lengths that could one day help control chemical reactions and drug delivery (J. Am. Chem. Soc. 2014, DOI: 10.1021/ja507711h). Group leader Ben L. Feringa had previously helped develop a molecular motor that spins when illuminated with ultraviolet light. But the compact compound couldn’t agitate solvents. So the current team grafted arms in the form of flexible hexadecyl chains or rigid phenylene-ethynylene oligomers onto the rotating molecule, extending its reach by up to 32 Å. The researchers characterized the resulting rotation about the molecule’s axle using NMR and UV-Vis spectroscopy. They found that the rotor stir rate dropped in increasingly viscous solvents and that the slowing was more pronounced for the longer, more rigid molecules. However, the larger stirrers moved more solvent. Feringa says arm length and rigidity could thus become variables for researchers to tweak when designing future nanomixers.

Illustration and structure show nanosized stir bars with molecular arms (blue) attached to a core rotor (orange).
Credit: J. Am. Chem. Soc.
By adding molecular arms (blue) to a core rotor (orange), researchers designed nanosized stir bars (structure shown).

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.