A Magnetically Bistable Rigid Carbene─2,3-Benzofluorenylidene

This work reveals how an unusually rigid carbene can be trapped at ultralow temperature in two distinct electronic states, known as singlet and triplet, which differ in both their magnetic properties and chemical behaviour. By combining low-temperature ultraviolet-visible, infrared and electron paramagnetic resonance (EPR, a magnetic spectroscopy technique) measurements with advanced multiscale calculations, we showed that the surrounding environment plays a decisive role in determining which state forms. Remarkably, once generated, the two states become effectively locked in place and do not readily switch between one another. This offers a rare opportunity to compare their photophysics and reactivity directly. Beyond its importance for fundamental carbene chemistry, the study highlights a promising route towards controlling molecular switching and long-lived spin states for future quantum and information-storage technologies.

Authors: Kseniya Gorbatenko, Enrique Mendez-Vega, María Eugenia Sandoval-Salinas, Federico J. Hernández, Rachel Crespo-Otero, Wolfram Sander

DOI: A Magnetically Bistable Rigid Carbene─2,3-Benzofluorenylidene