Molecular switch for controlling color and fluorescence

Molecular switch for controlling color and fluorescence
An efficient chemical synthesis method for picene-13, 14-dione. Credit: Dr. Hayato Ishikawa

Scientists from various universities of Japan cultivates a new method to control color and fluorescence of any compound. They have developed a molecular switch that completely changes color and fluorescence of compound by using oxygen and hydrogen. This latest research has been done in collaboration with researchers from Kumamoto, Yamaguchi, and Osaka Universities in Japan.

This molecular switch uses energy from gases. Thus, it may become as style in future for switching color and fluorescence properties of any compound. Like detection sensor for gases, it also has applications in switching organic semiconductor properties and organic OLEDs properties.

Discovery of molecular switch:

This new research’s intention was using energy from gases to generate molecular switch in Polyaromatic compounds (PACs). Through redox reaction, the researcher tried to discover a most appealing compound that dramatically changes properties of PAC. They then exposed orthoquinone moiety to PAC. Under a redox reaction with hydrogen and oxygen gases, it maintains perfect switching properties. In results, molecules apparently showed changes in fluorescence emission and color. The color region changes into the colorless state. At last scientists have found Picene-13, 14-dione as most promising compounds.

After that, scientists developed an original protocol for effectively combing the compound from easily available petroleum raw materials. The metal-catalyzed coupling reaction and the ring construction reaction was important steps for a combination of compounds.

A palladium nanoparticle catalyst was added to the combined picene-13, 14-dione. Then hydrogen gas was boiled into the solution. A dramatic change in color and fluorescence of the solution was observed. Its yellow color changes to colorless state and from non-fluorescent changed into blue fluorescent respectively. When Hydrogen gas was exchanged for Oxygen gas, and the solution goes back to its original state, the important reverse oxidation flows smoothly.

Associate Professor Ishikawa, said that “While performing a detailed analysis, they observed changes in color and fluorescence caused by two different molecular states. Computational analysis and the experimental results support them in the declaration of these states, and their ideas about this phenomenon.”

“The molecular switching technology of any compound is a new insight that appears to have been reported first by our research team,” he then said.

Advantage of this molecular switch:

  • It is environmentally friendly.
  • It has excellent reusability. The synthetic PACs don’t experience very much damage after each reaction.

The applications for this molecular switch technology are numerous:

  • This molecular sheet can put into a food package filled with an inert gas to check whether oxygen. Oxygen may lead to the spoilage of food, once it entered into the package.
  • Switching in organic semiconductor properties and organic OLEDs properties.
  • The detection sensor for gases.