Cyclopentadienyl (Cp) is a classic ancillary ligand and usually remains chemically “innocent” during reactions when coordinated to transition metals. However, Cp can actually be used as a docking site for H+, H–, or H• in proton-coupled electron transfer (PCET) chemistry and catalysis. Demyan and Andy recently wrote a review in Nature Reviews Chemistry that chronicles this fascinating mode of reactivity. Congrats Andy!
