An article published in Angewantde Chemie International Edition reports the use of UV light to make tiny crystals containing cobalt, chlorine and nitrate groups jump.
Work carried out by Pance Naumov and co-workers of New York University found that single-crystal isomerisation reactions of nitropentamminecobalt(III) complexes caused a lack of homogeneity through the crystal. This led to stress being accumulated in certain areas of the crystal, which could be relieved by movement of the crystal, or even fragmentation into pieces. The various modes of movement observed upon irradiation of the crystals with UV light can be seen in the image above.
Fairly bright light led to movement on the timescale of a fraction of a second.
Pretty cool, huh?
It is thought that heat will be able to reverse the rearrangement of the atoms in the crystal, leading to the hope that phenomena such as these could use the switches of light and heat to power molecular machines or even artificial muscles.
What’s really amazing is that this macroscopic response is caused by atomic-scale rearrangements of just one motif – the nitro ligand. This work also gives a nice example of how light can be converted to mechanical energy on the macroscale.
It’s fascinating research, and could have exciting implications for future applications of this sort of process.
Check it out!