Due to the energy mismatching between the frontier orbitals of rare-earth metal and ligand atom, the rare-earth metal-phosphorus multiple bonds are very unstable. This Behind introduces our group’s struggling trip to the first rare-earth monometallic phosphinidene complex during the past 10 years.

The C–H bond functionalization has achieved many accomplishments, however among various C–H functionalization reactions, the site-selective oxidation of multiple benzylic methyl C–H bond to aryl aldehydes is an industrially important transformation and yet remains highly challenging.