Using rosarins, a class of expanded porphyrinoids, researchers have synthesised1 a new organic compound that shows an interesting electronic structure and intriguing properties when treated with acids and bases. This new compound could help design new scaffolds to make smart electronic devices.

The key to the fascinating electronic properties of porphyrinoids lies in their ability to participate in proton-coupled electron transfer (PCET) reactions.

PCET processes are not yet well understood in discrete organic molecules like expanded porphyrinoids. To shed new light on PCET reactions in a new porphyrinoid molecule, the researcher prepared a new rosarin derivative, then performed experiments reducing the rosarin-derived new compound with acids. They also analyzed how change in electronic structure changed electronic properties, which then gave off absorption signals in spectroscopic studies.

The new rosarin-derived compound exhibited excited-state absorption signals that lasted for less than a picosecond and for a few picoseconds. However, the acid-reduced derivative showed absorption signals that lasted longer than signals from the original compound.

The study found that addition of hydrogen chloride in methylene chloride to solutions of the new rosarin-derived compound in methylene chloride gave rise to dramatic changes in the optical spectrum. The new compound could exist in well-defined oxidation states and readily convert between them via the application of external acids at ambient conditions.

The researchers say that the new rosarin-derived compound could act as scaffolding, finding applications in the creation of smart electronic materials.

The authors of this work are from: Yonsei University, Seoul, Kangwon National University, Chun-chon, and Ewha Womans University, Seoul, Korea; The University of Texas, Texas, USA; Graduate School of Engineering, Osaka University, ALCA, Science and Technology Agency, Suita, Osaka, Japan; and University of Hyderabad, Hyderabad, India.