Scientists Create Worlds Smallest Molecular Machine Successfully

Researchers at Chiba University in Japan have created the world’s smallest molecular machine, a ferrocene-based device that can perform reversible sliding motion when controlled by an electrical voltage. Led by Associate Professor Toyo Kazu Yamada, the team overcame the challenge of stabilizing ferrocene molecules on a flat substrate by linking them with ammonium salts and trapping them in a molecular film made up of cyclic crown ether molecules.

This breakthrough was achieved in collaboration with Professor Peter Krüger, Professor Satoshi Kera, and Professor Masaki Horie from various institutions. The discovery has significant implications for developing artificial molecular machines that can transform fields such as catalysts, molecular electronics, medicines, and quantum materials. Yamada’s team used scanning tunneling microscopy to demonstrate the controlled motion of the molecule, which could lead to revolutionary innovations in precision medicine, smart materials, and advanced manufacturing.

The team modified the ferrocene molecules by adding ammonium salts, forming ferrocene ammonium salts (Fc-amm), which improved their durability and enabled them to be securely fixed to the surface of the substrate. They then anchored these new molecules onto a monolayer film made up of crown ether cyclic molecules on a flat copper substrate.

Using scanning tunneling microscopy (STM), the team applied an electrical voltage to the Fc-amm molecule, causing a lateral sliding motion of the molecules. The voltage triggered a rotation of the carbon rings accompanied by a lateral sliding motion of the molecule, which was reversible and could be precisely controlled using electrical signals.

This breakthrough has significant implications for the development of ferrocene-based molecular machinery, which could lead to innovations in precision medicine, smart materials, and advanced manufacturing. The study demonstrates the potential for molecular machines to perform specialized tasks at the molecular level, opening up new possibilities for scientific and industrial applications.

Key findings:

• Ferrocene molecules were stabilized and adsorbed onto a noble metal surface using a two-dimensional crown ether molecular film.
• The team created ferrocene ammonium salts (Fc-amm) by modifying ferrocene molecules with ammonium salts, improving their durability and enabling them to be securely fixed to the surface of the substrate.
• The Fc-amm molecules were anchored onto a monolayer film made up of crown ether cyclic molecules on a flat copper substrate.
• Scanning tunneling microscopy (STM) was used to apply an electrical voltage to the Fc-amm molecule, causing a lateral sliding motion of the molecules.
• The motion was reversible and could be precisely controlled using electrical signals.

Potential applications:

• Precision medicine
• Smart materials
• Advanced manufacturing