Nanocar Ready To Roll!
The latest work from the laboratory of Professor James Tour, the creator of the NanoPutian, is a nano-sized, buckyball-wheeled vehicle named nanocar.
The nanocarfs gchassish is built sturdily based on benzene rings and carbon-carbon triple bonds. The axles donft stir, but it can rotate freely to let the fullerene wheels spin (Figure 1).
The size of a nanocar is only about 1/20,000 of a human hair, but the image of it running on gold surface has been observed using scanning tunneling microscopy. The research group has also been able to pull a nanocar directly with the tip of the microscope and show that it moves perpendicular to its axles but not parallel to it. This supports the idea that it moves by rolling, not by sliding on the surface. Whatfs more, they can control the direction of the nanocarfs movement by using electric fields, so the nanocar is much more than just a car-shaped molecule and can be called a legitimate gautomobile.h
You can see that both the nanocar and the NanoPutian have the similar molecular framework based on benzene rings and carbon-carbon triple bonds. Perhaps the synthesis of the NanoPutian was a gpracticeh towards making the nanocar.
A year later, the introduction of a new and improved model of nanocar was announced. Equipped with a light-powered motor, this one can run on its own.
The motor piece was originally developed by Professor Ben Feringafs lab in the Netherlands, and the double bond in the central part of the molecule functions as a rotational axis (Figure 2). A double bond canft rotate under normal circumstances, but light breaks one of the bonds to allow free rotation. To control the direction of rotation, the Feringafs molecule uses a methyl group that works like ratchet (although the actual logic is a little more complicated than that).
Fig2 Feringa's Molecular Motor
The Tour group modified and incorporated the motor into the original nanocarfs chassis. When hit by light, the light green colored part in Figure 3 rotates and propels the machine in the direction shown by the arrow. The original nanocar used fullerene as wheels, but since it absorbs and quenches the light energy of the motor it was replaced by a structure called carborane (the yellow part in the figure).
Fig3 Nanoar with motor
Ifve always been impressed by the creative ideas and clever molecular designs
by Professor Tour, whose group has also developed nanotruck and nano-pinwheel.
Thinking about what can be added next to the nanocar by playing with a
molecular model kit must be a really fun part of their research.
How can you attach things like, for example, accelerator, brake, transmission, or cargo loading/unloading function for further evolution? Could you make gnano-deliveryh that transports a specific molecule to a specific location, or could gnano-F1h, a race among differently designed nanocars, be possible? Just by looking at the pictures in the Tour papers, fun ideas keep coming up endlessly. In my personal opinion, I think that this fun part is the privilege given to chemistry, the only genre in science that can create new gthings.h
Note: The actual nanocars have long alkyl chains to increase solubility in organic solvent, but they arenft shown for clarity purpose.