#charge transfer

Charge transfer, or the movement of electrons, can occur either within a molecule or between two molecules. Combining the two types of charge transfer is challenging. Now, scientists from Shibaura Institute of Technology, Japan, have developed a hybrid charge transfer crystal using a novel pyrazinacene molecule. This crystal is capable of reacting with naphthalene to produce a reversible color shift, from greenish-blue to red-violet. Such color-changing crystals can have various potential applications in materials science. Transfer of charge is a process in which electrons move within a molecule or between two molecules. It is a crucial chemical process that can be applied to a wide range of technologies. Intramolecular charge transfer (ICT) occurs when electrons are exchanged between donor and acceptor groups within a molecule via a series of overlapping electron orbits. This exchange creates a shift in light wavelength towards the red end of the light spectrum (redshift). This observable color shift due to ICT has applications in dye manufacturing and organic LEDs (OLEDs).

A catalyst's utility is influenced by its surface charge and how that charge is transferred. Until recently, studying charge transfer has relied on complex imaging techniques that are both expensive and time-consuming. Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) report an approach for studying charge transfer that does not rely on complicated equipment -- simplifying the real-time observation of catalysis.

The team describes an experimental setup using a tiny ruthenium catalyst, a nanocluster, that reacts with oxygen in the air when heated to high temperatures. This oxidation reaction is detected by a support structure attached to the catalyst that provides a live readout to a computer. Ruthenium can be used to detect breath acetone, which is a biomarker for various disease states, but this setup also has wider value in demonstrating exactly how catalysts facilitate a reaction.

"Essentially, the attached support structure detects a change in current, corresponding to a change in the catalyst nanocluster," explains Dr. Alexander Porkovich, first author of the study, published in ACS Nano. "In this case, that change is a shift in oxidation state as the ruthenium reacts with oxygen."

"When studying charge transfer phenomena, we are interested in the interface between the catalyst and the support -- and this experimental setup is ideal. With such a clean interface, we can be confident that our data accurately captures the unfolding oxidation reaction."