Superfast Light Driven Molecular Motor Designed By Scientists

Geometrical schematic of the light-driven motor attached with one end to a surface. One pair of the substituents on either end of the molecule are chromophores illustrated by their transition dipoles (shown as blue arrows). The other substituents (red and green) are chosen in a manner that makes the molecule chiral.
Credit: Thomas Jansen

Light-driven molecular motors are around for over 20 years. These motors typically take microseconds to nanoseconds for one revolution. Thomas Jansen, professor of physics at the University of Groningen, and Master’s student Atreya Majumdar have now designed a even a good faster molecular motor. The new design is driven by light only and may make a full turn in picoseconds using power of one photon. Jansen says, “We have developed a latest and new out-of-the-box design for a motor molecule that’s much faster.” The design was published in Journal of Physical chemistry Letters.

The new motor molecule design started with a project in-which Jansen wanted to know the energy landscape of excited chromophores. “These chromophores can attract or repel one another . I wondered if we could use this to form them do something,” explains Jansen. He gave the project to Atreya Majumdar, then a first-year student within the Top academic degree program in Nanoscience in Groningen. Majumdar simulated the interaction between two chromophores that were connected to make one molecule.

Light

Majumdar, who is now a Ph.D. student in nanoscience at the Université Paris-Saclay in France, says, “A single photon will excite both chromophores simultaneously, creating dipoles that make them repel one another .” But as they’re stuck together, connected by a triple bond axis, the 2 halves push one another away round the axis. “During this movement, they begin to attract in one another .” Together, this leads to a full rotation, generated by light-energy and therefore the electrostatic communication between the 2 chromophores.

The original light-driven molecular motor was developed by Jansen’s colleague Ben Feringa, professor of chemistry at the University of Groningen and recipient of the 2016 Nobel prize for Chemistry. This motor makes one revolution in four steps. Two steps are driven by light and two are driven by heat. “The heat steps are rate-limiting,” explains Jansen. “The molecule has got to await a fluctuation in heat to drive it to subsequent step.”

Bottlenecks

By contrast, within the new design, a rotation is fully downhill from an excited state. thanks to the laws of quantum dynamics, one photon excites both chromophores simultaneously, so there are not any major bottlenecks to limit the speed of rotation, which is therefore 2-3 orders of magnitude greater than that of the classic Feringa motors.

All of this is often still theoretical, depend on calculations & simulations. “Building one among these motors isn’t trivial,” says Jansen. The chromophores are widely used but slightly fragile. Creating a triple bond axis is also tough . Jansen expects that somebody will attempt to build this organic molecule now that its properties are described. And it’s not one specific molecule that has these properties, adds Majumdar: “We have created a general guide for design of this sort of molecular motor.”

Blueprint

Jansen says there are a couple of potential applications: they could be wont to power drug delivery or move nanoscale objects on a surface, or they could be utilized in other nanotech applications. and therefore the rotational speed is well above that of the typical biophysical process, so it’s going to be wont to control biological processes. within the simulations, the motors were attached to a surface but they’re going to also rotate in solution. Jansen says, “It would require much of engineering and tweaking to understand these motors but our blueprint will deliver a brand-new sort of molecular motor.”

The findings were published on Journal of Physical Chemistry Letters.