The smell of cyclopentadiene or more accurately, dicyclopentadiene can turn some stomachs. I actually happen to like the smell of diCp. And the Cp ligand is one of the most iconic ligands in organometallic chemistry.

Back in the olden days, you had to crack the cyclopentadiene, CpH, first before deprotonating to form the Cp anion. Then Roesky changed the game with this paper.

This prep has everything in it. Molten sodium metal, dicp and CpH. What more could you ask for? I remember making NaCp.DME back in graduate school. What a pain that was. This is so much easier. Just a 1 gram scale of Na metal.